1
|
Mondal S, Riyaz M, Bagchi D, Dutta N, Singh AK, Vinod CP, Peter SC. Distortion-Induced Interfacial Charge Transfer at Single Cobalt Atom Secured on Ordered Intermetallic Surface Enhances Pure Oxygen Production. ACS Nano 2023; 17:23169-23180. [PMID: 37955244 DOI: 10.1021/acsnano.3c09680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
In this work, atomic cobalt (Co) incorporation into the Pd2Ge intermetallic lattice facilitates operando generation of a thin layer of CoO over Co-substituted Pd2Ge, with Co in the CoO surface layer functioning as single metal sites. Hence the catalyst has been titled Co1-CoO-Pd2Ge. High-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy confirm the existence of CoO, with some of the Co bonded to Ge by substitution of Pd sites in the Pd2Ge lattice. The role of the CoO layer in the oxygen evolution reaction (OER) has been verified by its selective removal using argon sputtering and conducting the OER on the etched catalyst. In situ X-ray absorption near-edge structure and extended X-ray absorption fine structure spectroscopy demonstrate that CoO gets transformed to CoOOH (Co3+) in operando condition with faster charge transfer through Pd atoms in the core Pd2Ge lattice. In situ Raman spectroscopy depicts the emergence of a CoOOH phase on applying potential and shows that the phase is stable with increasing potential and time without getting converted to CoO2. Density functional theory calculations indicate that the Pd2Ge lattice induces distortion in the CoO phase and generates unpaired spins in a nonmagnetic CoOOH system resulting in an increase in the OER activity and durability. The existence of spin density even after electrocatalysis is verified from electron paramagnetic resonance spectroscopy. We have thus successfully synthesized intermetallic supported CoO during synthesis and rigorously verified the role played by an intermetallic Pd2Ge core in enhancing charge transfer, generating spin density, improving electrochemical durability, and imparting mechanical stability to a thin CoOOH overlayer. Differential electrochemical mass spectrometry has been explored to visualize the instantaneous generation of oxygen gas during the onset of the reaction.
Collapse
Affiliation(s)
- Soumi Mondal
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
| | - Mohd Riyaz
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
| | - Debabrata Bagchi
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
| | - Nilutpal Dutta
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
| | - Ashutosh Kumar Singh
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
| | - Chathakudath P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, Maharashtra 410008, India
| | - Sebastian C Peter
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
| |
Collapse
|
2
|
Barik S, Kharabe GP, Illathvalappil R, Singh CP, Kanheerampockil F, Walko PS, Bhat SK, Devi RN, Vinod CP, Krishnamurty S, Kurungot S. Active Site Engineering and Theoretical Aspects of "Superhydrophilic" Nanostructure Array Enabling Efficient Overall Water Electrolysis. Small 2023:e2304143. [PMID: 37612811 DOI: 10.1002/smll.202304143] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/21/2023] [Indexed: 08/25/2023]
Abstract
The rational design of noble metal-free electrocatalysts holds great promise for cost-effective green hydrogen generation through water electrolysis. In this context, here, the development of a superhydrophilic bifunctional electrocatalyst that facilitates both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline conditions is demonstrated. This is achieved through the in situ growth of hierarchical NiMoO4 @CoMoO4 ·xH2 O nanostructure on nickel foam (NF) via a two-step hydrothermal synthesis method. NiMoO4 @CoMoO4 ·xH2 O/NF facilitates OER and HER at the overpotentials of 180 and 220 mV, respectively, at the current density of 10 mA cm-2 . The NiMoO4 @CoMoO4 ·xH2 O/NF ǁ NiMoO4 @CoMoO4 ·xH2 O/NF cell can be operated at a potential of 1.60 V compared to 1.63 V displayed by the system based on the Pt/C@NFǁRuO2 @NF standard electrode pair configuration at 10 mA cm-2 for overall water splitting. The density functional theory calculations for the OER process elucidate that the lowest ΔG of NiMoO4 @CoMoO4 compared to both Ni and NiMoO4 is due to the presence of Co in the OER catalytic site and its synergistic interaction with NiMoO4 . The preparative strategy and mechanistic understanding make the windows open for the large-scale production of the robust and less expensive electrode material for the overall water electrolysis.
Collapse
Affiliation(s)
- Sidharth Barik
- Physical & Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, Maharashtra, 411008, India
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, 201002, India
| | - Geeta Pandurang Kharabe
- Physical & Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, Maharashtra, 411008, India
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, 201002, India
| | - Rajith Illathvalappil
- Physical & Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, Maharashtra, 411008, India
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, 201002, India
| | - Chandrodai Pratap Singh
- Physical & Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, Maharashtra, 411008, India
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, 201002, India
| | - Fayis Kanheerampockil
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, 201002, India
- Polymer Science and Engineering Division, CSIR-National Chemical Laboratory, Pune, Maharashtra, 411008, India
| | - Priyanka S Walko
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, 201002, India
- Catalysis and Inorganic Chemistry Division CSIR-National Chemical Laboratory, Pune, Maharashtra, 411008, India
| | - Suresh K Bhat
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, 201002, India
- Polymer Science and Engineering Division, CSIR-National Chemical Laboratory, Pune, Maharashtra, 411008, India
| | - R Nandini Devi
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, 201002, India
- Catalysis and Inorganic Chemistry Division CSIR-National Chemical Laboratory, Pune, Maharashtra, 411008, India
| | - C P Vinod
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, 201002, India
- Catalysis and Inorganic Chemistry Division CSIR-National Chemical Laboratory, Pune, Maharashtra, 411008, India
| | - Sailaja Krishnamurty
- Physical & Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, Maharashtra, 411008, India
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, 201002, India
| | - Sreekumar Kurungot
- Physical & Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, Maharashtra, 411008, India
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, 201002, India
| |
Collapse
|
3
|
Chakraborty S, Das R, Riyaz M, Das K, Singh AK, Bagchi D, Vinod CP, Peter SC. Wurtzite CuGaS 2 with an In-Situ-Formed CuO Layer Photocatalyzes CO 2 Conversion to Ethylene with High Selectivity. Angew Chem Int Ed Engl 2023; 62:e202216613. [PMID: 36537874 DOI: 10.1002/anie.202216613] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/18/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022]
Abstract
We present surface reconstruction-induced C-C coupling whereby CO2 is converted into ethylene. The wurtzite phase of CuGaS2. undergoes in situ surface reconstruction, leading to the formation of a thin CuO layer over the pristine catalyst, which facilitates selective conversion of CO2 to ethylene (C2 H4 ). Upon illumination, the catalyst efficiently converts CO2 to C2 H4 with 75.1 % selectivity (92.7 % selectivity in terms of Relectron ) and a 20.6 μmol g-1 h-1 evolution rate. Subsequent spectroscopic and microscopic studies supported by theoretical analysis revealed operando-generated Cu2+ , with the assistance of existing Cu+ , functioning as an anchor for the generated *CO and thereby facilitating C-C coupling. This study demonstrates strain-induced in situ surface reconstruction leading to heterojunction formation, which finetunes the oxidation state of Cu and modulates the CO2 reduction reaction pathway to selective formation of ethylene.
Collapse
Affiliation(s)
- Subhajit Chakraborty
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India.,School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India
| | - Risov Das
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India.,School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India
| | - Mohd Riyaz
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India.,School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India
| | - Kousik Das
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India.,School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India
| | - Ashutosh Kumar Singh
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India.,Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India
| | - Debabrata Bagchi
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India.,School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India
| | - Chathakudath P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 410008, India
| | - Sebastian C Peter
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India.,School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore, 560064, India
| |
Collapse
|
4
|
Das K, Das R, Riyaz M, Parui A, Bagchi D, Singh AK, Singh AK, Vinod CP, Peter SC. Intrinsic Charge Polarization in Bi 19 S 27 Cl 3 Nanorods Promotes Selective CC Coupling Reaction during Photoreduction of CO 2 to Ethanol. Adv Mater 2023; 35:e2205994. [PMID: 36469557 DOI: 10.1002/adma.202205994] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/30/2022] [Indexed: 06/17/2023]
Abstract
Obtaining multi-carbon products via CO2 photoreduction is a major catalytic challenge involving multielectron-mediated CC bond formation. Complex design of multicomponent interfaces that are exploited to achieve this chemical transformation, often leads to untraceable deleterious changes in the interfacial chemical environment affecting CO2 conversion efficiency and product selectivity. Alternatively, robust metal centers having asymmetric charge distribution can effectuate CC coupling reaction through the stabilization of intermediates, for desired product selectivity. However, generating inherent charge distribution in a single component catalyst is a difficult material design challenge. Here, a novel photocatalyst, Bi19 S27 Cl3 , is presented which selectively converts CO2 to a C2 product, ethanol, in high yield under visible light irradiation. Structural analysis through transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy reveals the presence of charge polarized bismuth centers in Bi19 S27 Cl3 . The intrinsic electric field induced by charge polarized bismuth centers renders better separation efficiency of photogenerated electron-hole pair. Furthermore, charge polarized centers yield better adsorption of CO* intermediate and accelerate the rate determining CC coupling step through the formation of OCCOH intermediate. Formation of these intermediates is experimentally mapped by in situ Fourier-transform infrared spectroscopy and further confirmed by theoretical calculation.
Collapse
Affiliation(s)
- Kousik Das
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Risov Das
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Mohd Riyaz
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Arko Parui
- Materials Research Centre, Indian Institute of Science, Bangalore, 560012, India
| | - Debabrata Bagchi
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Ashutosh Kumar Singh
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Abhishek Kumar Singh
- Materials Research Centre, Indian Institute of Science, Bangalore, 560012, India
| | - Chathakudath P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 410008, India
| | - Sebastian C Peter
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| |
Collapse
|
5
|
Chakraborty S, Das R, Riyaz M, Das K, Singh AK, Bgachi D, Vinod CP, Peter SC. Wurtzite CuGaS2 with an In‐Situ‐Formed CuO Layer Photocatalyzes CO2 Conversion to Ethylene with High Selectivity. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202216613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Subhajit Chakraborty
- JNCASR: Jawaharlal Nehru Centre for Advanced Scientific Research New Chemistry Unit INDIA
| | - Risov Das
- JNCASR: Jawaharlal Nehru Centre for Advanced Scientific Research New Chemistry Unit INDIA
| | - Mohd Riyaz
- JNCASR: Jawaharlal Nehru Centre for Advanced Scientific Research New Chemistry Unit INDIA
| | - Kousik Das
- JNCASR: Jawaharlal Nehru Centre for Advanced Scientific Research New Chemistry Unit INDIA
| | - Ashutosh Kumar Singh
- JNCASR: Jawaharlal Nehru Centre for Advanced Scientific Research Chemistry and Physics of Materials Unit INDIA
| | - Debabrata Bgachi
- JNCASR: Jawaharlal Nehru Centre for Advanced Scientific Research New Chemistry Unit INDIA
| | - Chathakudath P Vinod
- NCL: National Chemical Laboratory CSIR Catalysis and Inorganic Chemistry Division INDIA
| | - Sebastian C Peter
- Jawaharlal Nehru Centre for Advanced Scientific Research New Chemistry Unit Jakkur 560064 Bangalore INDIA
| |
Collapse
|
6
|
Kashyap V, Pandikassala A, Singla G, Khan TS, Ali Haider M, Vinod CP, Kurungot S. Unravelling faradaic electrochemical efficiencies over Fe/Co spinel metal oxides using surface spectroscopy and microscopy techniques. Nanoscale 2022; 14:15928-15941. [PMID: 36268905 DOI: 10.1039/d2nr04170g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Cobalt and iron metal-based oxide catalysts play a significant role in energy devices. To unravel some interesting parameters, we have synthesized metal oxides of cobalt and iron (i.e. Fe2O3, Co3O4, Co2FeO4 and CoFe2O4), and measured the effect of the valence band structure, morphology, size and defects in the nanoparticles towards the electrocatalytic hydrogen evolution reaction (HER), the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). The compositional variations in the cobalt and iron precursors significantly alter the particle size from 60 to <10 nm and simultaneously the shape of the particles (cubic and spherical). The Tauc plot obtained from the solution phase ultraviolet (UV) spectra of the nanoparticles showed band gaps of 2.2, 2.3, 2.5 and 2.8 eV for Fe2O3, Co3O4, Co2FeO4 and CoFe2O4, respectively. Further, the valence band structure and work function analysis using ultraviolet photoelectron spectroscopy (UPS) and core level X-ray photoelectron spectroscopy (XPS) analyses provided better structural insight into metal oxide catalysts. In the Co3O4 system, the valence band structure favors the HER and Fe2O3 favors the OER. The composites Co2FeO4 and CoFe2O4 show a significant change in their core level (O 1s, Co 2p and Fe 2p spectra) and valence band structure. Co3O4 shows an overpotential of 370 mV against 416 mV for Fe2O3 at a current density of 2 mA cm-2 for the HER. Similarly, Fe2O3 shows an overpotential of 410 mV against the 435 mV for Co3O4 at a current density of 10 mA cm-2 for the OER. However, for the ORR, Co3O4 shows 70 mV improvement in the half-wave potential against Fe2O3. The composites (Co2FeO4 and CoFe2O4) display better performance compared to their respective parent oxide systems (i.e., Co3O4 and Fe2O3, respectively) in terms of the ORR half-wave potential, which can be attributed to the presence of the oxygen vacancies over the surface in these systems. This was further corroborated in density functional theory (DFT) simulations, wherein the oxygen vacancy formation on the surface of CoFe2O4(001) was calculated to be significantly lower (∼50 kJ mol-1) compared to Co3O4 (001). The band diagram of the nanoparticles constructed from the various spectroscopic measurements with work function and band gap provides in-depth understanding of the electrocatalytic process.
Collapse
Affiliation(s)
- Varchaswal Kashyap
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune 41108, India.
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh-201002, India
| | - Ajmal Pandikassala
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune 41108, India.
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh-201002, India
| | - Gourav Singla
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune 41108, India.
| | - Tuhin Suvra Khan
- Nanocatalysis Area, Light Stock Processing Division, CSIR-Indian Institute of Petroleum, Dehradun 248005, Uttarakhand, India.
| | - M Ali Haider
- Renewable Energy and Chemicals Laboratory, Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, Delhi 110016, India
| | - C P Vinod
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh-201002, India
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune 41108, India.
| | - Sreekumar Kurungot
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune 41108, India.
- Academy of Scientific and Innovative Research, Postal Staff College Area, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh-201002, India
| |
Collapse
|
7
|
Kumar P, Vijay Jagtap A, Gupta S, Vinod CP. La-Cu based heterogeneous perovskite catalyst for highly selective benzene hydroxylation under mild conditions. Chem Asian J 2022; 17:e202200788. [PMID: 36216572 DOI: 10.1002/asia.202200788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/19/2022] [Indexed: 11/09/2022]
Abstract
Direct hydroxylation of benzene towards phenol with high conversion and selectivity remains a great challenge. We report herein an efficient La2 CuO4 perovskite catalyst for one-step oxidation of benzene using hydrogen peroxide under mild conditions. The catalyst was characterized using XRD, TEM, XPS, TG-DTA, and other advanced techniques. The one-pot hydroxylation reaction carried out at 60 °C under optimum reaction conditions in the presence of catalytic material shows benzene to phenol transformation with 51% conversion with >99% selectivity with 65 percent peroxide efficiency, respectively. The influence of reaction conditions such as temperature, amount of oxidant, reaction time and mode of addition of the oxidant was crucial in selectivity optimization.
Collapse
Affiliation(s)
- Pawan Kumar
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, 411008, Pune, Maharashtra, India.,Academy of Scientific and Innovative Research (AcSIR), 201002, Ghaziabad, India
| | - Anuradha Vijay Jagtap
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, 411008, Pune, Maharashtra, India.,Academy of Scientific and Innovative Research (AcSIR), 201002, Ghaziabad, India
| | - Sharad Gupta
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, 411008, Pune, Maharashtra, India
| | - Chathakudath P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, 411008, Pune, Maharashtra, India.,Academy of Scientific and Innovative Research (AcSIR), 201002, Ghaziabad, India
| |
Collapse
|
8
|
Chakraborty S, Marappa S, Agarwal S, Bagchi D, Rao A, Vinod CP, Peter SC, Singh A, Eswaramoorthy M. Improvement in Oxygen Evolution Performance of NiFe Layered Double Hydroxide Grown in the Presence of 1T-Rich MoS 2. ACS Appl Mater Interfaces 2022; 14:31951-31961. [PMID: 35796762 DOI: 10.1021/acsami.2c06210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
NiFe layered double hydroxide (NiFe LDH) grown in the presence of MoS2 (rich in 1T phase) shows exceptional performance metrics for alkaline oxygen evolution reaction (OER) in this class of composites. The as-prepared NiFe LDH/MoS2 composite (abbreviated as MNF) exhibits a low overpotential (η10) of 190 mV; a low Tafel slope of 31 mV dec-1; and more importantly, a high stability in its performance manifested by the delivery of current output for 45 h. It is important to note that this could be achieved with an exceedingly low loading of 0.14 mg cm-2. The mass activity of this composite (97 A g-1) is about 14 times greater than that of the conventional RuO2 (7 A g-1) at η = 200 mV. When normalized with respect to the total metal content, a mass activity of 1000 A g-1 (η = 300 mV) was achieved. Impedance analysis further reveals that the significant reduction in charge-transfer resistance and hence high current density (5 times greater as compared to NiFe LDH at η = 300 mV) observed for MNF is associated with interfacial adsorption kinetics of intermediates (R1). Significant enhancement in the intrinsic activity of MNF over LDH has been observed through normalization of current with the electrochemically active surface area. Computational studies suggest that the Ni centers in the composite act as the active sites for OER, which is well-corroborated with the observed postreaction appearance of Ni3+ species.
Collapse
Affiliation(s)
- Soumita Chakraborty
- Chemistry and Physics of Materials Unit, School of Advanced Materials (SAMat), JNCASR, Bengaluru 560064, India
| | - Shivanna Marappa
- Chemistry and Physics of Materials Unit, School of Advanced Materials (SAMat), JNCASR, Bengaluru 560064, India
| | - Sakshi Agarwal
- Materials Research Centre, IISc, Bengaluru, Karnataka 560012, India
| | - Debabrata Bagchi
- New Chemistry Unit, School of Advanced Materials (SAMat), JNCASR, Bengaluru 560064, India
| | - Ankit Rao
- Centre for Nano Science and Engineering, IISc, Bengaluru, Karnataka 560012, India
| | | | - Sebastian C Peter
- New Chemistry Unit, School of Advanced Materials (SAMat), JNCASR, Bengaluru 560064, India
| | - Abhishek Singh
- Materials Research Centre, IISc, Bengaluru, Karnataka 560012, India
| | - Muthusamy Eswaramoorthy
- Chemistry and Physics of Materials Unit, School of Advanced Materials (SAMat), JNCASR, Bengaluru 560064, India
| |
Collapse
|
9
|
Mondal S, Sarkar S, Bagchi D, Das T, Das R, Singh AK, Prasanna PK, Vinod CP, Chakraborty S, Peter SC. Morphology-Tuned Pt 3 Ge Accelerates Water Dissociation to Industrial-Standard Hydrogen Production over a wide pH Range. Adv Mater 2022; 34:e2202294. [PMID: 35609013 DOI: 10.1002/adma.202202294] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/14/2022] [Indexed: 06/15/2023]
Abstract
The discovery of novel materials for industrial-standard hydrogen production is the present need considering the global energy infrastructure. A novel electrocatalyst, Pt3 Ge, which is engineered with a desired crystallographic facet (202), accelerates hydrogen production by water electrolysis, and records industrially desired operational stability compared to the commercial catalyst platinum is introduced. Pt3 Ge-(202) exhibits low overpotential of 21.7 mV (24.6 mV for Pt/C) and 92 mV for 10 and 200 mA cm-2 current density, respectively in 0.5 m H2 SO4 . It also exhibits remarkable stability of 15 000 accelerated degradation tests cycles (5000 for Pt/C) and exceptional durability of 500 h (@10 mA cm-2 ) in acidic media. Pt3 Ge-(202) also displays low overpotential of 96 mV for 10 mA cm-2 current density in the alkaline medium, rationalizing its hydrogen production ability over a wide pH range required commercial operations. Long-term durability (>75 h in alkaline media) with the industrial level current density (>500 mA cm-2 ) has been demonstrated by utilizing the electrochemical flow reactor. The driving force behind this stupendous performance of Pt3 Ge-(202) has been envisaged by mapping the reaction mechanism, active sites, and charge-transfer kinetics via controlled electrochemical experiments, ex situ X-ray photoelectron spectroscopy, in situ infrared spectroscopy, and in situ X-ray absorption spectroscopy further corroborated by first principles calculations.
Collapse
Affiliation(s)
- Soumi Mondal
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Shreya Sarkar
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Debabrata Bagchi
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Tisita Das
- Materials Theory for Energy Scavenging (MATES) Lab, Harish-Chandra Research Institute (HRI) Allahabad, HBNI, Chhatnag Road, Jhunsi, Prayagraj (Allahabad), 211019, India
| | - Risov Das
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Ashutosh Kumar Singh
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Ponnappa Kechanda Prasanna
- Materials Theory for Energy Scavenging (MATES) Lab, Harish-Chandra Research Institute (HRI) Allahabad, HBNI, Chhatnag Road, Jhunsi, Prayagraj (Allahabad), 211019, India
| | - C P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 410008, India
| | - Sudip Chakraborty
- Materials Theory for Energy Scavenging (MATES) Lab, Harish-Chandra Research Institute (HRI) Allahabad, HBNI, Chhatnag Road, Jhunsi, Prayagraj (Allahabad), 211019, India
| | - Sebastian C Peter
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| |
Collapse
|
10
|
Mondal S, Bagchi D, Riyaz M, Sarkar S, Singh AK, Vinod CP, Peter SC. In Situ Mechanistic Insights for the Oxygen Reduction Reaction in Chemically Modulated Ordered Intermetallic Catalyst Promoting Complete Electron Transfer. J Am Chem Soc 2022; 144:11859-11869. [PMID: 35749229 DOI: 10.1021/jacs.2c04541] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The well-known limitation of alkaline fuel cells is the slack kinetics of the cathodic half-cell reaction, the oxygen reduction reaction (ORR). Platinum, being the most active ORR catalyst, is still facing challenges due to its corrosive nature and sluggish kinetics. Many novel approaches for substituting Pt have been reported, which suffer from stability issues even after mighty modifications. Designing an extremely stable, but unexplored ordered intermetallic structure, Pd2Ge, and tuning the electronic environment of the active sites by site-selective Pt substitution to overcome the hurdle of alkaline ORR is the main motive of this paper. The substitution of platinum atoms at a specific Pd position leads to Pt0.2Pd1.8Ge demonstrating a half-wave potential (E1/2) of 0.95 V vs RHE, which outperforms the state-of-the-art catalyst 20% Pt/C. The mass activity (MA) of Pt0.2Pd1.8Ge is 320 mA/mgPt, which is almost 3.2 times better than that of Pt/C. E1/2 and MA remained unaltered even after 50,000 accelerated degradation test (ADT) cycles, which makes it a promising stable catalyst with its activity better than that of the state-of-the-art Pt/C. The undesired 2e- transfer ORR forming hydrogen peroxide (H2O2) is diminished in Pt0.2Pd1.8Ge as visible from the rotating ring-disk electrode (RRDE) experiment, spectroscopically visualized by in situ Fourier transform infrared (FTIR) spectroscopy and supported by computational studies. The effect of Pt substitution on Pd has been properly manifested by X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS). The swinging of the oxidation state of atomic sites of Pt0.2Pd1.8Ge during the reaction is probed by in situ XAS, which efficiently enhances 4e- transfer, producing an extremely low percentage of H2O2.
Collapse
Affiliation(s)
- Soumi Mondal
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.,School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Debabrata Bagchi
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.,School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Mohd Riyaz
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.,School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Shreya Sarkar
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.,School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Ashutosh Kumar Singh
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.,Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore560064, India
| | - C P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 410008, India
| | - Sebastian C Peter
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.,School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| |
Collapse
|
11
|
Bagchi D, Raj J, Singh AK, Cherevotan A, Roy S, Manoj KS, Vinod CP, Peter SC. Structure-Tailored Surface Oxide on Cu-Ga Intermetallics Enhances CO 2 Reduction Selectivity to Methanol at Ultralow Potential. Adv Mater 2022; 34:e2109426. [PMID: 35278256 DOI: 10.1002/adma.202109426] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 03/10/2022] [Indexed: 06/14/2023]
Abstract
Electrochemical CO2 reduction reaction (eCO2 RR) is performed on two intermetallic compounds formed by copper and gallium metals (CuGa2 and Cu9 Ga4 ). Among them, CuGa2 selectively converts CO2 to methanol with remarkable Faradaic efficiency of 77.26% at an extremely low potential of -0.3 V vs RHE. The high performance of CuGa2 compared to Cu9 Ga4 is driven by its unique 2D structure, which retains surface and subsurface oxide species (Ga2 O3 ) even in the reduction atmosphere. The Ga2 O3 species is mapped by X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) techniques and electrochemical measurements. The eCO2 RR selectivity to methanol are decreased at higher potential due to the lattice expansion caused by the reduction of the Ga2 O3 , which is probed by in situ XAFS, quasi in situ powder X-ray diffraction, and ex situ XPS measurements. The mechanism of the formation of methanol is visualized by in situ infrared (IR) spectroscopy and the source of the carbon of methanol at the molecular level is confirmed from the isotope-labeling experiments in presence of 13 CO2 . Finally, to minimize the mass transport limitations and improve the overall eCO2 RR performance, a poly(tetrafluoroethylene)-based gas diffusion electrode is used in the flow cell configuration.
Collapse
Affiliation(s)
- Debabrata Bagchi
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Jithu Raj
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Ashutosh Kumar Singh
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Arjun Cherevotan
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Soumyabrata Roy
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Kaja Sai Manoj
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - C P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Sebastian C Peter
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| |
Collapse
|
12
|
Bagchi D, Sarkar S, Singh AK, Vinod CP, Peter SC. Potential- and Time-Dependent Dynamic Nature of an Oxide-Derived PdIn Nanocatalyst during Electrochemical CO 2 Reduction. ACS Nano 2022; 16:6185-6196. [PMID: 35377140 DOI: 10.1021/acsnano.1c11664] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Electrochemical reduction of CO2 into valuable fuels and chemicals is a promising route of replacing fossil fuels by reducing CO2 emissions and minimizing its adverse effects on the climate. Tremendous efforts have been carried out for designing efficient catalyst materials to selectively produce the desired product in high yield from CO2 by the electrochemical process. In this work, a strategy is reported to enhance the electrochemical CO2 reduction reaction (ECO2RR) by constructing an interface between a metal-based alloy (PdIn) nanoparticle and an oxide (In2O3), which was synthesized by a facile solution method. The oxide-derived PdIn surface has shown excellent eCO2RR activity and enhanced CO selectivity with a Faradaic efficiency (FE) of 92.13% at -0.9 V (vs RHE). On the other hand, surface PdO formation due to charge transfer on the bare PdIn alloy reduces the CO2RR activity. With the support of in situ (EXAFS and IR) and ex situ (XPS, Raman) spectroscopic techniques, the optimum presence of the Pd-In-O interface has been identified as a crucial parameter for enhancing eCO2RR toward CO in a reducing atmosphere. The influence of eCO2RR duration is reported to affect the overall performance by switching the product selectivity from H2 (from water reduction) to CO (from eCO2RR) on the oxide-derived alloy surface. This work also succeeded in the multifold enhancement of the current density by employing the gas diffusion electrode (GDE) and optimizing its process parameters in a flow cell configuration.
Collapse
Affiliation(s)
- Debabrata Bagchi
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
| | - Shreya Sarkar
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
| | - Ashutosh Kumar Singh
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
| | - Chathakudath P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune-411008, India
| | - Sebastian C Peter
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
| |
Collapse
|
13
|
Sahoo L, Garg R, Kaur K, Vinod CP, Gautam UK. Ultrathin Twisty PdNi Alloy Nanowires as Highly Active ORR Electrocatalysts Exhibiting Morphology-Induced Durability over 200 K Cycles. Nano Lett 2022; 22:246-254. [PMID: 34978836 DOI: 10.1021/acs.nanolett.1c03704] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Even though the anion exchange membrane fuel cells have many advantages, the stability of their electrocatalysts for oxygen reduction reaction (ORR) has remained remarkably poor. We report here on the ultrathin twisty PdNi-alloy nanowires (NWs) exhibiting a very low reaction overpotential with an E1/2 ∼ 0.95 V versus RHE in alkaline media maintained over 200 K cycles, the highest ever recorded for an electrocatalyst. The mass activity of the used NWs is >10 times higher than fresh commercial Pt/C. Therein, Ni improves the Pd d-band center for a more efficient ORR, and its leaching continuously regenerates the surface active sites. The twisty nanowire morphology imparts multiple anchor points on the electrode surface to arrest their detachment or coalescence and extra stability from self-entanglement. The significance of the NW morphology was further confirmed from the high-temperature durability studies. The study demonstrates that tailoring the number of contact points to the electrode-surface may help realize commercial-grade stability in the highly active electrocatalysts.
Collapse
Affiliation(s)
- Lipipuspa Sahoo
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Sector 81, Mohali, SAS Nagar, Punjab 140306, India
| | - Reeya Garg
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Sector 81, Mohali, SAS Nagar, Punjab 140306, India
| | - Komalpreet Kaur
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Sector 81, Mohali, SAS Nagar, Punjab 140306, India
| | - C P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-NCL, Pune 411008, India
| | - Ujjal K Gautam
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Sector 81, Mohali, SAS Nagar, Punjab 140306, India
| |
Collapse
|
14
|
Vaidhyanathan R, Singh HD, Nandi S, Chakraborty D, Singh K, Vinod CP. Coordination flexibility aided CO2-specific gating in an Iron Isonicotinate MOF. Chem Asian J 2021; 17:e202101305. [PMID: 34972258 DOI: 10.1002/asia.202101305] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/23/2021] [Indexed: 11/10/2022]
Abstract
Coordination flexibility assisted porosity has been introduced into an Iron-isonicotinate metal organic framework (MOF), (Fe(4-PyC) 2 .(OH). The framework showed CO 2 -specific gate opening behavior, which gets tuned as a function of temperature and pressure. The MOF's physisorptive porosity towards CO 2 , CH 4 , and N 2 was investigated; it adsorbed only CO 2 via a gate opening phenomenon. The isonicotinate, representing a borderline soft base, is bound to the hard Fe 3+ centre through monodentate carboxylate and pyridyl nitrogen. This moderately weak binding enables isonicotinate to spin like a spindle under the CO 2 pressure opening the gate for a sharp increase in CO 2 uptake at 333 mmHg (At 298K, the CO 2 uptake increases from 0.70 to 1.57 mmol/g). We investigated the MOF's potential for CO 2 /N 2 and CO 2 /CH 4 gas separation aided by this gating. IAST model reveals that the CO 2 /N 2 selectivity jumps from 325 to 3131 when the gate opens, while the CO 2 /CH 4 selectivity increases three times. Interestingly, this Fe-isonicotinate MOF did not follow the trend set by our earlier reported Hard-Soft Gate Control (established for isostructural M 2+ -isonicotinate MOFs (M = Mg, Mn)). However, we account for this discrepancy using the different oxidation state of metals confirmed by X-ray photoelectron spectroscopy and magnetism.
Collapse
Affiliation(s)
- Ramanathan Vaidhyanathan
- Indian Institute of Science Education and Research, Chemistry, Main Building, IISER, Dr. Homi Bhabha Rd. Pashan Pune Maharashtra, 411008, Pune, INDIA
| | - Himan Dev Singh
- IISER P: Indian Institute of Science Education Research Pune, Chemistry, INDIA
| | - Shyamapada Nandi
- IISER Pune: Indian Institute of Science Education Research Pune, Chemistry, INDIA
| | - Debanjan Chakraborty
- IISER Pune: Indian Institute of Science Education Research Pune, Chemistry, INDIA
| | - Kirandeep Singh
- CSIR-NCL: National Chemical Laboratory CSIR, Physical and Materials Chemistry, INDIA
| | - Chathakudath P Vinod
- CSIR-NCL: National Chemical Laboratory CSIR, Catalysis and Inorganic Chemistry, INDIA
| |
Collapse
|
15
|
Sarkar S, Rawat A, Das T, Gaboardi M, Chakraborty S, Vinod CP, Peter SC. Structure-Tailored Non-Noble Metal-based Ternary Chalcogenide Nanocrystals for Pt-like Electrocatalytic Hydrogen Production. ChemSusChem 2021; 14:3074-3083. [PMID: 34038021 DOI: 10.1002/cssc.202100967] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/19/2021] [Indexed: 06/12/2023]
Abstract
A facile microwave-assisted strategy was employed to synthesize Ni3 Bi2 S2 nanocrystals. Variation in the synthesis conditions tuned the composition of monoclinic and orthorhombic phases of Ni3 Bi2 S2 . The electrochemical hydrogen evolution activity of the catalyst with highest percentage of monoclinic phase demonstrated a negligible onset potential of only 24 mV close to that of state-of-the-art Pt/C with an overpotential as low as 88 mV. Density functional theory calculations predicted the monoclinic phase exhibit the lowest adsorption free energy corresponding to hydrogen adsorption ( Δ G ads H * ) and, therefore, the highest hydrogen evolution activity amongst the considered phases. The quasi-2D structure of monoclinic phase facilitated an increased charge-transfer between Ni and Bi, favoring the downward shift of the d-band center to enhance the catalytic activity.
Collapse
Affiliation(s)
- Shreya Sarkar
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Abhishek Rawat
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | - Tisita Das
- Materials Theory for Energy Scavenging (MATES) Lab, Harish Chandra Research Institute (HRI), Chhatnag Road, Jhunsi, Prayagraj, Allahabad, Uttar Pradesh, 211019, India
| | - Mattia Gaboardi
- Elettra-Sincrotrone Trieste, Strada Statale 14, km 163.5 in Area Science Park, Basovizza, Italy
| | - Sudip Chakraborty
- Materials Theory for Energy Scavenging (MATES) Lab, Harish Chandra Research Institute (HRI), Chhatnag Road, Jhunsi, Prayagraj, Allahabad, Uttar Pradesh, 211019, India
| | - C P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical laboratory, Pune, 411008, India
| | - Sebastian C Peter
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
- School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| |
Collapse
|
16
|
Sarkar S, Varghese M, Vinod CP, Peter SC. Correction: Conductive interface promoted bifunctional oxygen reduction/evolution activity in an ultra-low precious metal based hybrid catalyst. Chem Commun (Camb) 2021; 57:2824. [PMID: 33660727 DOI: 10.1039/d1cc90088a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Correction for 'Conductive interface promoted bifunctional oxygen reduction/evolution activity in an ultra-low precious metal based hybrid catalyst' by Shreya Sarkar et al., Chem. Commun., 2021, 57, 1951-1954, DOI: 10.1039/D0CC08225B.
Collapse
Affiliation(s)
- Shreya Sarkar
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India. and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
| | - Merin Varghese
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India. and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
| | - C P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune, 411008, India
| | - Sebastian C Peter
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India. and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
| |
Collapse
|
17
|
Sarkar S, Varghese M, Vinod CP, Peter SC. Conductive interface promoted bifunctional oxygen reduction/evolution activity in an ultra-low precious metal based hybrid catalyst. Chem Commun (Camb) 2021; 57:1951-1954. [PMID: 33502398 DOI: 10.1039/d0cc08225b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ultra low PtPd alloy deposited on Ni12P5 nanostructures (PtPd/Ni12P5) exhibited enhanced ORR activity (onset: 1.003 V and E1/2:0.95 V) on par with commercial Pt/C and superior OER activity with 81% reduction of the precious metal compared to the commercial catalyst.
Collapse
Affiliation(s)
- Shreya Sarkar
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
| | - Merin Varghese
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
| | - C P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune, 411008, India.
| | - Sebastian C Peter
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune, 411008, India.
| |
Collapse
|
18
|
Belgamwar R, Maity A, Das T, Chakraborty S, Vinod CP, Polshettiwar V. Lithium silicate nanosheets with excellent capture capacity and kinetics with unprecedented stability for high-temperature CO 2 capture. Chem Sci 2021; 12:4825-4835. [PMID: 34168759 PMCID: PMC8179639 DOI: 10.1039/d0sc06843h] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An excessive amount of CO2 is the leading cause of climate change, and hence, its reduction in the Earth's atmosphere is critical to stop further degradation of the environment. Although a large body of work has been carried out for post-combustion low-temperature CO2 capture, there are very few high temperature pre-combustion CO2 capture processes. Lithium silicate (Li4SiO4), one of the best known high-temperature CO2 capture sorbents, has two main challenges, moderate capture kinetics and poor sorbent stability. In this work, we have designed and synthesized lithium silicate nanosheets (LSNs), which showed high CO2 capture capacity (35.3 wt% CO2 capture using 60% CO2 feed gas, close to the theoretical value) with ultra-fast kinetics and enhanced stability at 650 °C. Due to the nanosheet morphology of the LSNs, they provided a good external surface for CO2 adsorption at every Li-site, yielding excellent CO2 capture capacity. The nanosheet morphology of the LSNs allowed efficient CO2 diffusion to ensure reaction with the entire sheet as well as providing extremely fast CO2 capture kinetics (0.22 g g−1 min−1). Conventional lithium silicates are known to rapidly lose their capture capacity and kinetics within the first few cycles due to thick carbonate shell formation and also due to the sintering of sorbent particles; however, the LSNs were stable for at least 200 cycles without any loss in their capture capacity or kinetics. The LSNs neither formed a carbonate shell nor underwent sintering, allowing efficient adsorption–desorption cycling. We also proposed a new mechanism, a mixed-phase model, to explain the unique CO2 capture behavior of the LSNs, using detailed (i) kinetics experiments for both adsorption and desorption steps, (ii) in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy measurements, (iii) depth-profiling X-ray photoelectron spectroscopy (XPS) of the sorbent after CO2 capture and (iv) theoretical investigation through systematic electronic structure calculations within the framework of density functional theory (DFT) formalism. Capturing CO2 before its release. Lithium silicate nanosheets showed high CO2 capture capacity (35.3 wt%) with ultra-fast kinetics (0.22 g g−1 min−1) and enhanced stability at 650 °C for at least 200 cycles, due to mixed-phase-model of CO2 capture.![]()
Collapse
Affiliation(s)
- Rajesh Belgamwar
- Department of Chemical Sciences, Tata Institute of Fundamental Research (TIFR) Mumbai India
| | - Ayan Maity
- Department of Chemical Sciences, Tata Institute of Fundamental Research (TIFR) Mumbai India
| | - Tisita Das
- Harish-Chandra Research Institute, HBNI Allahabad Uttar Pradesh India
| | - Sudip Chakraborty
- Materials Theory for Energy Scavenging (MATES) Lab, Department of Physics, Indian Institute of Technology Simrol Indore India
| | - Chathakudath P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory (NCL) Pune India
| | - Vivek Polshettiwar
- Department of Chemical Sciences, Tata Institute of Fundamental Research (TIFR) Mumbai India
| |
Collapse
|
19
|
Garg R, Mondal S, Sahoo L, Vinod CP, Gautam UK. Nanocrystalline Ag 3PO 4 for Sunlight- and Ambient Air-Driven Oxidation of Amines: High Photocatalytic Efficiency and a Facile Catalyst Regeneration Strategy. ACS Appl Mater Interfaces 2020; 12:29324-29334. [PMID: 32484649 DOI: 10.1021/acsami.0c05961] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Selective oxidation of amines to imines using sunlight as clean and renewable energy source is an important but challenging chemical transformation because of high reactivity of the generated imines and lack of visible light-responsive materials with high conversion rates. In addition, oxygen gas has to be purged in the reaction mixture in order to increase the reaction efficiency which, in itself, is an energy-consuming process. Herein, we report, for the first time, the use of Ag3PO4 as an excellent photocatalyst for the oxidative coupling of benzyl amines induced by ambient air in the absence of any external source of molecular oxygen at room temperature. The conversion efficiency for the selective oxidation of benzyl amine was found to be greater than 95% with a selectivity of >99% after 40 min of light irradiation indicating an exceptionally high conversion efficiency with a rate constant of 0.002 min-1, a turnover frequency of 57 h-1, and a quantum yield of 19%, considering all of the absorbed photons. Ag3PO4, however, is known for its poor photostability owing to a positive conduction band position and a favorable reduction potential to metallic silver. Therefore, we further employed a simple catalyst regeneration strategy and showed that the catalyst can be recycled with negligible loss of activity and selectivity.
Collapse
Affiliation(s)
- Reeya Garg
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Sector 81, SAS Nagar, Mohali, Punjab 140306, India
| | - Sanjit Mondal
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Sector 81, SAS Nagar, Mohali, Punjab 140306, India
| | - Lipipuspa Sahoo
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Sector 81, SAS Nagar, Mohali, Punjab 140306, India
| | - C P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR-NCL, Pune 411008, India
| | - Ujjal K Gautam
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Sector 81, SAS Nagar, Mohali, Punjab 140306, India
| |
Collapse
|
20
|
Pandey DK, Ankade SB, Ali A, Vinod CP, Punji B. Nickel-catalyzed C-H alkylation of indoles with unactivated alkyl chlorides: evidence of a Ni(i)/Ni(iii) pathway. Chem Sci 2019; 10:9493-9500. [PMID: 32110305 PMCID: PMC7017866 DOI: 10.1039/c9sc01446b] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 08/17/2019] [Indexed: 11/21/2022] Open
Abstract
A mild and efficient nickel-catalyzed method for the coupling of unactivated primary and secondary alkyl chlorides with the C-H bond of indoles and pyrroles is described which demonstrates a high level of chemo and regioselectivity. The reaction tolerates numerous functionalities, such as halide, alkenyl, alkynyl, ether, thioether, furanyl, pyrrolyl, indolyl and carbazolyl groups including acyclic and cyclic alkyls under the reaction conditions. Mechanistic investigation highlights that the alkylation proceeds through a single-electron transfer (SET) process with Ni(i)-species being the active catalyst. Overall, the alkylation follows a Ni(i)/Ni(iii) pathway involving the rate-influencing two-step single-electron oxidative addition of alkyl chlorides.
Collapse
Affiliation(s)
- Dilip K Pandey
- Organometallic Synthesis and Catalysis Group , Chemical Engineering Division , CSIR-National Chemical Laboratory (CSIR-NCL) , Dr. Homi Bhabha Road , Pune 411 008 , Maharashtra , India .
- Academy of Scientific and Innovative Research (AcSIR) , CSIR-NCL , Dr. Homi Bhabha Road , Pune , India
| | - Shidheshwar B Ankade
- Organometallic Synthesis and Catalysis Group , Chemical Engineering Division , CSIR-National Chemical Laboratory (CSIR-NCL) , Dr. Homi Bhabha Road , Pune 411 008 , Maharashtra , India .
- Academy of Scientific and Innovative Research (AcSIR) , CSIR-NCL , Dr. Homi Bhabha Road , Pune , India
| | - Abad Ali
- Organometallic Synthesis and Catalysis Group , Chemical Engineering Division , CSIR-National Chemical Laboratory (CSIR-NCL) , Dr. Homi Bhabha Road , Pune 411 008 , Maharashtra , India .
| | - C P Vinod
- Catalysis Division , CSIR-NCL , Dr. Homi Bhabha Road , Pune , India
| | - Benudhar Punji
- Organometallic Synthesis and Catalysis Group , Chemical Engineering Division , CSIR-National Chemical Laboratory (CSIR-NCL) , Dr. Homi Bhabha Road , Pune 411 008 , Maharashtra , India .
- Academy of Scientific and Innovative Research (AcSIR) , CSIR-NCL , Dr. Homi Bhabha Road , Pune , India
| |
Collapse
|
21
|
Pandey AM, Agalave SG, Vinod CP, Gnanaprakasam B. MnO 2 @Fe 3 O 4 Magnetic Nanoparticles as Efficient and Recyclable Heterogeneous Catalyst for Benzylic sp 3 C-H Oxidation. Chem Asian J 2019; 14:3414-3423. [PMID: 31418537 DOI: 10.1002/asia.201900810] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 08/01/2019] [Indexed: 11/08/2022]
Abstract
Herein, we report a highly chemoselective and efficient heterogeneous MnO2 @Fe3 O4 MNP catalyst for the oxidation of benzylic sp3 C-H group of ethers using TBHP as a green oxidant to afford ester derivatives in high yield under batch/continuous flow module. This catalyst was also effective for the benzylic sp3 C-H group of methylene derivatives to furnish the ketone in high yield which can be easily integrated into continuous flow condition for scale up. The catalyst is fully characterized by spectroscopic techniques and it was found that 0.424 % MnO2 @Fe3 O4 catalyzes the reaction; the magnetic nanoparticles of this catalyst could be easily recovered from the reaction mixture. The recovered catalyst was recycled for twelve cycles without any loss of the catalytic activity. The advantages of MnO2 @Fe3 O4 MNP are its catalytic activity, easy preparation, recovery, and recyclability, gram scale synthesis with a TOF of up to 14.93 h-1 and low metal leaching during the reaction.
Collapse
Affiliation(s)
- Akanksha M Pandey
- Department of Chemistry, Indian Institute of Science Education and Research, Pune-, 411008, India
| | - Sandip G Agalave
- Department of Chemistry, Indian Institute of Science Education and Research, Pune-, 411008, India
| | | | - Boopathy Gnanaprakasam
- Department of Chemistry, Indian Institute of Science Education and Research, Pune-, 411008, India
| |
Collapse
|
22
|
Chakraborty D, Nandi S, Illathvalappil R, Mullangi D, Maity R, Singh SK, Haldar S, Vinod CP, Kurungot S, Vaidhyanathan R. Carbon Derived from Soft Pyrolysis of a Covalent Organic Framework as a Support for Small-Sized RuO 2 Showing Exceptionally Low Overpotential for Oxygen Evolution Reaction. ACS Omega 2019; 4:13465-13473. [PMID: 31460475 PMCID: PMC6705268 DOI: 10.1021/acsomega.9b01777] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 07/25/2019] [Indexed: 05/23/2023]
Abstract
Electrochemical water splitting is the most energy-efficient technique for producing hydrogen and oxygen, the two valuable gases. However, it is limited by the slow kinetics of the anodic oxygen evolution reaction (OER), which can be improved using catalysts. Covalent organic framework (COF)-derived porous carbon can serve as an excellent catalyst support. Here, we report high electrocatalytic activity of two composites, formed by supporting RuO2 on carbon derived from two COFs with closely related structures. These composites catalyze oxygen evolution from alkaline media with overpotentials as low as 210 and 217 mV at 10 mA/cm2, respectively. The Tafel slopes of these catalysts (65 and 67 mV/dec) indicate fast kinetics compared to commercial RuO2. The observed activity is the highest among all RuO2-based heterogeneous OER catalysts-a touted benchmark OER catalyst. The high catalytic activity arises from the extremely small-sized (∼3-4 nm) RuO2 nanoparticles homogeneously dispersed in a micro-mesoporous (BET = 517 m2/g) COF-derived carbon. The porous graphenic carbon favors mass transfer, while its N-rich framework anchors the catalytic nanoparticles, making it highly stable and recyclable. Crucially, the soft pyrolysis of the COF enables the formation of porous carbon and simultaneous growth of small RuO2 particles without aggregation.
Collapse
Affiliation(s)
- Debanjan Chakraborty
- Department
of Chemistry and Centre for Energy Science, Indian Institute
of Science Education and Research, Pune 411008, India
| | - Shyamapada Nandi
- Department
of Chemistry and Centre for Energy Science, Indian Institute
of Science Education and Research, Pune 411008, India
| | - Rajith Illathvalappil
- Physical
and Materials Chemistry Division, CSIR-National
Chemical Laboratory, Pune 411008, India
| | - Dinesh Mullangi
- Department
of Chemistry and Centre for Energy Science, Indian Institute
of Science Education and Research, Pune 411008, India
| | - Rahul Maity
- Department
of Chemistry and Centre for Energy Science, Indian Institute
of Science Education and Research, Pune 411008, India
| | - Santosh K. Singh
- Physical
and Materials Chemistry Division, CSIR-National
Chemical Laboratory, Pune 411008, India
| | - Sattwick Haldar
- Department
of Chemistry and Centre for Energy Science, Indian Institute
of Science Education and Research, Pune 411008, India
| | | | - Sreekumar Kurungot
- Physical
and Materials Chemistry Division, CSIR-National
Chemical Laboratory, Pune 411008, India
| | - Ramanathan Vaidhyanathan
- Department
of Chemistry and Centre for Energy Science, Indian Institute
of Science Education and Research, Pune 411008, India
| |
Collapse
|
23
|
Chakraborty D, Nandi S, Mullangi D, Haldar S, Vinod CP, Vaidhyanathan R. Cu/Cu 2O Nanoparticles Supported on a Phenol-Pyridyl COF as a Heterogeneous Catalyst for the Synthesis of Unsymmetrical Diynes via Glaser-Hay Coupling. ACS Appl Mater Interfaces 2019; 11:15670-15679. [PMID: 30964266 DOI: 10.1021/acsami.9b02860] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Covalent organic frameworks (COFs) are a new class of porous crystalline polymers with a modular construct that favors functionalization. COF pores can be used to grow nanoparticles (nPs) with dramatic size reduction, stabilize them as dispersions, and provide excellent nP access. Embedding substrate binding sites in COFs can generate host-guest synergy, leading to enhanced catalytic activity. In this report, Cu/Cu2O nPs (2-3 nm) are grown on a COF, which is built by linking a phenolic trialdehyde and a triamine through Schiff bonds. Their micropores restrict the nP to exceptionally small sizes (∼2-3 nm), and the pore walls decorated with strategically positioned hydrogen-bonding phenolic groups anchor the substrates via hydrogen-bonding, whereas the basic pyridyl sites serve as cationic species to stabilize the [CuclusterCl2]2- type reactive intermediates. This composite catalyst shows high activity for Glaser-Hay heterocoupling reactions, an essential 1,3-diyne yielding reaction with widespread applicability in organic synthesis and material science. Despite their broad successes in homocoupled products, preparation of unsymmetrical 1,3-diynes is challenging due to poor selectivity. Here, our COF-based Cu catalyst shows elevated selectivity toward heterocoupling product(s) (Cu nP loading 0.0992 mol %; turn over frequency: ∼45-50; turn over number: ∼175-190). The reversible redox activity at the Cu centers has been demonstrated by carrying out X-ray photoelectron spectroscopy on the frozen reactions, whereas the crucial interactions between the substrates and the binding sites in their optimized configurations have been modeled using density functional theory methods. This report emphasizes the utility of COFs in developing a heterogeneous catalyst for a truly challenging organic heterocoupling reaction.
Collapse
|
24
|
Nayak C, Jain P, Vinod CP, Jha SN, Bhattacharyya D. Operando X-ray absorption spectroscopy study of the Fischer-Tropsch reaction with a Co catalyst. J Synchrotron Radiat 2019; 26:137-144. [PMID: 30655478 DOI: 10.1107/s1600577518015588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 11/03/2018] [Indexed: 06/09/2023]
Abstract
This article describes the setting up of a facility on the energy-scanning EXAFS beamline (BL-09) at RRCAT, Indore, India, for operando studies of structure-activity correlation during a catalytic reaction. The setup was tested by operando X-ray absorption spectroscopy (XAS) studies performed on a Co-based catalyst during the Fischer-Tropsch reaction to obtain information regarding structural changes in the catalyst during the reaction. Simultaneous gas chromatography (GC) measurements during the reaction facilitate monitoring of the product gases, which in turn gives information regarding the activity of the catalyst. The combination of XAS and GC techniques was used to correlate the structural changes with the activity of the catalyst at different reaction temperatures. The oxide catalyst was reduced to the metallic phase by heating at 400°C for 5 h under H2 at ambient pressure and subsequently the catalytic reaction was studied at four different temperatures of 240, 260, 280 and 320°C. The catalyst was studied for 10 h at 320°C and an attempt has been made to understand the process of its deactivation from the XANES and EXAFS results.
Collapse
Affiliation(s)
- Chandrani Nayak
- Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Preeti Jain
- Catalysis and Inorganic Chemistry Division, CSIR - National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411008, India
| | - C P Vinod
- Catalysis and Inorganic Chemistry Division, CSIR - National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411008, India
| | - S N Jha
- Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - D Bhattacharyya
- Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| |
Collapse
|
25
|
Soni Y, Kavya I, Ajithkumar TG, Vinod CP. Correction: One pot ligand exchange method for a highly stable Au-SBA-15 catalyst and its room temperature CO oxidation. Chem Commun (Camb) 2018; 54:12892. [PMID: 30394461 DOI: 10.1039/c8cc90494d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Correction for 'One pot ligand exchange method for a highly stable Au-SBA-15 catalyst and its room temperature CO oxidation' by Yogita Soni et al., Chem. Commun., 2018, DOI: 10.1039/c8cc06887a.
Collapse
Affiliation(s)
- Yogita Soni
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India.
| | | | | | | |
Collapse
|
26
|
Soni Y, Kavya I, Ajithkumar TG, Vinod CP. One pot ligand exchange method for a highly stable Au-SBA-15 catalyst and its room temperature CO oxidation. Chem Commun (Camb) 2018; 54:12412-12415. [PMID: 30307460 DOI: 10.1039/c8cc06887a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A modified deposition precipitation (DP) method has been developed to address a fundamental issue of supporting well dispersed Au nanoparticles on silica. Ammonium chloride (NH4Cl) plays an important role in in situ modifying the gold precursor (HAuCl4·3H2O) solution allowing facile deposition of gold NPs in the channels of SBA-15. The Au-SBA-15 catalyst (2.8 wt%) synthesized by this procedure showed 100% conversion for CO oxidation at room temperature with excellent stability at room temperature and high temperature.
Collapse
Affiliation(s)
- Yogita Soni
- Catalysis and Inorganic Chemistry Division, Anusandhan Bhavan, 2 Rafi Marg, New Delhi 110001, India.
| | | | | | | |
Collapse
|
27
|
Mullangi D, Chakraborty D, Pradeep A, Koshti V, Vinod CP, Panja S, Nair S, Vaidhyanathan R. Highly Stable COF-Supported Co/Co(OH) 2 Nanoparticles Heterogeneous Catalyst for Reduction of Nitrile/Nitro Compounds under Mild Conditions. Small 2018; 14:e1801233. [PMID: 30062759 DOI: 10.1002/smll.201801233] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/18/2018] [Indexed: 05/22/2023]
Abstract
Ordered nanoporosity in covalent organic framework (COF) offers excellent opportunity for property development. Loading nanoparticles (nPs) onto them is one approach to introducing tailor-made properties into a COF. Here, a COF-Co/Co(OH)2 composite containing about 16 wt% of <6 nm sized Co/Co(OH)2 nPs is prepared on a N-rich COF support that catalyzes the release of theoretical equivalence of H2 from readily available, safe, and cheap NaBH4 . Furthermore, the released H2 is utilized for the hydrogenation of nitrile and nitro compounds to amines under ambient conditions in a facile one-pot reaction. The COF "by choice" is built from "methoxy" functionalized dialdehydes which is crucial in enabling the complete retention of the COF structure under the conditions of the catalysis, where the regular Schiff bonds would have hydrolyzed. The N-rich binding pockets in the COF ensure strong nP-COF interactions, which provides stability and enables catalyst recycling. Modeling studies reveal the crucial role played by the COF in exposing the active facets and thereby in controlling the activation of the reducing agent. Additionally, via density functional theory, we provide a rational explanation for how these COFs can stabilize nanoparticles which grow beyond the limiting pore size of the COF and yet result in a truly stable heterogeneous catalyst - a ubiquitous observation. The study underscores the versatility of COF as a heterogeneous support for developing cheap and highly active nonnoble metal catalysts.
Collapse
Affiliation(s)
- Dinesh Mullangi
- Department of Chemistry, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Debanjan Chakraborty
- Department of Chemistry, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Anu Pradeep
- Department of Chemistry, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Vijay Koshti
- Polyolefin Lab, Polymer Science and Engineering Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Chathakudath P Vinod
- CSIR-NCL Catalysis and Inorganic Chemistry Division, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Soumendranath Panja
- Department of Physics, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Sunil Nair
- Department of Physics, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Ramanathan Vaidhyanathan
- Department of Chemistry, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, 411008, India
| |
Collapse
|
28
|
Betsy KJ, Nayak C, Lazar A, Krishnan A, Bhattacharyya D, Jha SN, Vinod CP. Selective Oxidation of Cyclohexane to Cyclohexanone Using Chromium Oxide Supported Mesoporous MCM-41 Nanospheres: Probing the Nature of Catalytically Active Chromium Sites. ChemCatChem 2018. [DOI: 10.1002/cctc.201800309] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Kurisingal J. Betsy
- Catalysis and Inorganic Chemistry Division; CSIR-National Chemical Laboratory; Dr. Homi Bhabha Road, Pashan Pune- 411008 India
| | - Chandrani Nayak
- Atomic and Molecular Physics Division; Bhabha Atomic Research Centre; Mumbai- 400085 India
| | - Anish Lazar
- Catalysis and Inorganic Chemistry Division; CSIR-National Chemical Laboratory; Dr. Homi Bhabha Road, Pashan Pune- 411008 India
- Academy of Scientific and Innovative Research (AcSIR); Anusandhan Bhawan, 2, Rafi Marg, New Delhi- 110001 India
| | - Athira Krishnan
- Catalysis and Inorganic Chemistry Division; CSIR-National Chemical Laboratory; Dr. Homi Bhabha Road, Pashan Pune- 411008 India
| | - Dibyendu Bhattacharyya
- Atomic and Molecular Physics Division; Bhabha Atomic Research Centre; Mumbai- 400085 India
| | - Shambhu N. Jha
- Atomic and Molecular Physics Division; Bhabha Atomic Research Centre; Mumbai- 400085 India
| | - Chathakudath P. Vinod
- Catalysis and Inorganic Chemistry Division; CSIR-National Chemical Laboratory; Dr. Homi Bhabha Road, Pashan Pune- 411008 India
- Academy of Scientific and Innovative Research (AcSIR); Anusandhan Bhawan, 2, Rafi Marg, New Delhi- 110001 India
- Center of Excellence on Surface Science; CSIR-National Chemical Laboratory; Dr Homi Bhabha Road Pune- 411 008 India
| |
Collapse
|
29
|
Bharathan VA, Yadukiran V, Lazar A, Singh AP, Vinod CP. Synthesis of Au@Ni bimetallic core shell nanoparticle and nanochains in soyabean oil and their catalytic hydrogenation reactions. ChemistrySelect 2016. [DOI: 10.1002/slct.201500006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Vysakh A. Bharathan
- Catalysis Division; CSIR-National Chemical Laboratory; Dr. Homi Bhabha Road Pune INDIA
- Academy of Scientific and Innovative Research (AcSIR); Anusandhan Bhawan; 2 Rafi Marg, New Delhi Delhi 110001
| | - V. Yadukiran
- Catalysis Division; CSIR-National Chemical Laboratory; Dr. Homi Bhabha Road Pune INDIA
| | - Anish Lazar
- Catalysis Division; CSIR-National Chemical Laboratory; Dr. Homi Bhabha Road Pune INDIA
- Academy of Scientific and Innovative Research (AcSIR); Anusandhan Bhawan; 2 Rafi Marg, New Delhi Delhi 110001
| | - Anand. P. Singh
- Catalysis Division; CSIR-National Chemical Laboratory; Dr. Homi Bhabha Road Pune INDIA
| | - Chathakudath P. Vinod
- Catalysis Division; CSIR-National Chemical Laboratory; Dr. Homi Bhabha Road Pune INDIA
- Academy of Scientific and Innovative Research (AcSIR); Anusandhan Bhawan; 2 Rafi Marg, New Delhi Delhi 110001
- Center of Excellence on Surface Science; CSIR-National Chemical Laboratory; Pune INDIA
| |
Collapse
|
30
|
Lazar A, Vinod CP, Singh AP. A simple, phosphine free, reusable Pd(ii)–2,2′-dihydroxybenzophenone–SBA-15 catalyst for arylation and hydrogenation reactions of alkenes. NEW J CHEM 2016. [DOI: 10.1039/c5nj02686e] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient, phosphine and co-catalyst free Pd(ii)–DHBP@SBA-15 catalyst for arylation and hydrogenation reactions of alkenes was synthesized and characterized.
Collapse
Affiliation(s)
- Anish Lazar
- Catalysis Division
- CSIR-National Chemical Laboratory
- Pune-411008
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Chathakudath P. Vinod
- Catalysis Division
- CSIR-National Chemical Laboratory
- Pune-411008
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Anand Pal Singh
- Catalysis Division
- CSIR-National Chemical Laboratory
- Pune-411008
- India
| |
Collapse
|
31
|
Sreedhala S, Vinod CP. Surfactant assisted formation of ruthenium nanochains under mild conditions and their catalytic CO oxidation activity. Chem Commun (Camb) 2015; 51:10178-81. [PMID: 26015996 DOI: 10.1039/c4cc09430a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spontaneous formation of ruthenium nanochains is accomplished in aqueous medium under mild conditions using a seed mediated protocol with cetyl trimethylammonium bromide (CTAB) as the capping agent. They are formed due to the random self-assembly of Ru seeds of ∼3.5 nm size. These 1D nanostructures exhibit better catalytic activity towards the oxidation of CO relative to the ∼3.5 nm seeds and 6 nm Ru nanospheres. The synthesis strategy adopted here is found to be simple, facile and environmentally friendly.
Collapse
Affiliation(s)
- S Sreedhala
- Catalysis Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune, India - 411 008
| | | |
Collapse
|
32
|
Sunil Sekhar AC, Ziyad K, Soni Y, Vinod CP. Activity Enhancement upon the Incorporation of Titanium: Au@Ti-SiO2Core-Shell Nanocatalysts for the CO Oxidation Reaction. ChemCatChem 2015. [DOI: 10.1002/cctc.201402954] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
33
|
Sreedhala S, Sudheeshkumar V, Vinod CP. Structure sensitive chemical reactivity by palladium concave nanocubes and nanoflowers synthesised by a seed mediated procedure in aqueous medium. Nanoscale 2014; 6:7496-7502. [PMID: 24882223 DOI: 10.1039/c4nr01283f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Palladium nanocubes and their transformation to concave nanocubes and nanoflowers are realised by a seed mediated procedure in aqueous medium and at room temperature using cationic surfactants. The concave nanocubes and nanoflowers were found to be enclosed by high index facets. The under co-ordinated atoms present on the high index facets make these nanostructures chemically more active towards Suzuki coupling and Heck coupling reactions compared to the conventional nanocubes and spherical nanoparticles of similar size.
Collapse
Affiliation(s)
- S Sreedhala
- Catalysis Division CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune, 411 008, India.
| | | | | |
Collapse
|
34
|
Anderson BG, Fierro-Gonzalez JC, Ramesh K, Vinod CP, Niemantsverdriet JW, Gates BC. Tricarbonyls of low-coordinated Au(0) atoms in zeolite-supported gold nanoparticles: Evidence from infrared and X-ray absorption spectroscopies. Langmuir 2006; 22:4310-4. [PMID: 16618180 DOI: 10.1021/la0526535] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Mononuclear gold complexes in zeolite NaY were synthesized from initially physisorbed Au(CH3)2(C5H7O2) and characterized by X-ray absorption and infrared spectra recorded as the samples were exposed to flowing CO. X-ray absorption spectra demonstrate the formation of zero-valent gold nanoparticles during the CO treatment. Three new nu(CO) bands grew in during this treatment, at 2070, 2033, and 2000 cm(-1), characteristic of carbonyls of Au0. Because the relative intensities of these bands decreased monotonically when the flow of CO was replaced by flowing He, it is inferred that they correspond to a single Au0(CO)3 species, on low-coordinated Au atoms. This is the first example of an Au0(CO)3 species.
Collapse
Affiliation(s)
- Bruce G Anderson
- Schuit Institute of Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | | | | | | | | | | |
Collapse
|
35
|
Weststrate CJ, Bakker JW, Rienks EDL, Lizzit S, Petaccia L, Baraldi A, Vinod CP, Nieuwenhuys BE. NH3 adsorption and decomposition on Ir(110): A combined temperature programmed desorption and high resolution fast x-ray photoelectron spectroscopy study. J Chem Phys 2005; 122:184705. [PMID: 15918745 DOI: 10.1063/1.1893690] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The adsorption and decomposition of NH3 on Ir(110) has been studied in the temperature range from 80 K to 700 K. By using high-energy resolution x-ray photoelectron spectroscopy it is possible to distinguish chemically different surface species. At low temperature a NH3 multilayer, which desorbs at approximately 110 K, was observed. The second layer of NH3 molecules desorbs around 140 K, in a separate desorption peak. Chemisorbed NH3 desorbs in steps from the surface and several desorption peaks are observed between 200 and 400 K. A part of the NH3ad decomposes into NH(ad) between 225 and 300 K. NH(ad) decomposes into N(ad) between 400 K and 500 K and the hydrogen released in this process immediately desorbs. N2 desorption takes place between 500 and 700 K via N(ad) combination. The steady state decomposition reaction of NH3 starts at 500 K. The maximum reaction rate is observed between 540 K and 610 K. A model is presented to explain the occurrence of a maximum in the reaction rate. Hydrogenation of N(ad) below 400 K results in NH(ad). No NH2ad or NH3ad/NH3 were observed. The hydrogenation of NH(ad) only takes place above 400 K. On the basis of the experimental findings an energy scheme is presented to account for the observations.
Collapse
Affiliation(s)
- C J Weststrate
- Leids Instituut voor Chemisch Onderzoek, Universiteit Leiden, P.O. Box 9502, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
36
|
Guzman J, Anderson BG, Vinod CP, Ramesh K, Niemantsverdriet JW, Gates BC. Synthesis and reactivity of dimethyl gold complexes supported on MgO: characterization by infrared and X-ray absorption spectroscopies. Langmuir 2005; 21:3675-3683. [PMID: 15807620 DOI: 10.1021/la0470434] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Dimethyl gold complexes bonded to partially dehydroxylated MgO powder calcined at 673 K were synthesized by adsorption of Au(CH3)2(acac) (acac is C5H7O2) from n-pentane solution. The synthesis and subsequent decomposition of the complexes by treatment in He or H2 were characterized with diffuse reflectance Fourier transform infrared (DRIFT), X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) spectroscopies. The XANES results identify Au(III) in the supported complexes, and the EXAFS and DRIFTS data indicate mononuclear dimethyl gold complexes as the predominant surface gold species, consistent with the lack of Au-Au contributions in the EXAFS spectrum and the presence of nu(as)(CH3) and nu(s)(CH3) bands in the IR spectrum. EXAFS data show that each complex is bonded to two oxygen atoms of the MgO surface at an Au-O distance of 2.16 angstroms. The DRIFT spectra show that reaction of Au(CH3)2(acac) with MgO at room temperature also formed Mg(acac)2 and H(acac) species on the support. Treatment of the dimethyl gold complexes in He or H2 at increasing temperatures varying from 373 to 573 K removed CH3 ligands and caused aggregation forming zerovalent gold nanoclusters of increasing size, ultimately with an average diameter of about 30 angstroms. Analysis of the gas-phase products during the genesis of the gold clusters indicated formation of CH4 (consistent with removal of CH3 groups) and CO2 at 473-573 K, associated with decomposition of the organic ligands derived from acac species. O2 and CO2 were also formed in the decomposition of ubiquitous carbonates present on the surface of the MgO support.
Collapse
Affiliation(s)
- Javier Guzman
- Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616, USA
| | | | | | | | | | | |
Collapse
|
37
|
Weststrate CJ, Bakker JW, Rienks EDL, Vinod CP, Lizzit S, Petaccia L, Baraldi A, Nieuwenhuys BE. The role of Oad in the decomposition of NH3 adsorbed on Ir(110): a combined TPD and high-energy resolution fast XPS study. Phys Chem Chem Phys 2005; 7:2629-34. [PMID: 16189574 DOI: 10.1039/b502350e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High energy resolution fast XPS combined with TPD experiments were used to study the effect of chemisorbed oxygen on the adsorption and dissociation of NH(3) on Ir(110). Below 250 K the presence of O(ad) does not influence NH(3) decomposition. Above 250 K O(ad) enhances NH(3) dissociation, which results in three times as much N(2) formation and less molecular NH(3) desorption compared to the experiments without O(ad). The effect of O(ad) can be attributed to destabilization of NH(ad) on the surface, resulting in a further dehydrogenation towards N(ad). The presence of O(ad) on the surface lowers the temperature at which the N(ad) combination reaction takes place by as much as 200 K, due to repulsive interaction between N(ad) and O(ad). NO is formed above 450 K if both N(ad) and O(ad) are present on the surface.
Collapse
Affiliation(s)
- C J Weststrate
- Leids instituut voor chemisch onderzoek, Universiteit Leiden, P.O. Box 9502, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|