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TiO2 nanoarrays modification by a novel Cobalt-heteroatom doped graphene complex for photoelectrochemical water splitting: An experimental and theoretical study. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Sitaaraman SR, Nirmala Grace A, Sellappan R. Photoelectrochemical performance of a spin coated TiO 2 protected BiVO 4-Cu 2O thin film tandem cell for unassisted solar water splitting. RSC Adv 2022; 12:31380-31391. [PMID: 36349021 PMCID: PMC9627459 DOI: 10.1039/d2ra05774c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 10/25/2022] [Indexed: 11/07/2022] Open
Abstract
A tandem cell consisting of a Mo-BiVO4/TiO2/FeOOH photoanode–Cu2O/TiO2/MoS2 photocathode was prepared for unassisted solar water splitting. The protective TiO2 layer was prepared by a cost-effective spin coating technique. The individual Mo-BiVO4/TiO2/FeOOH photoanode and the Cu2O/TiO2/MoS2 photocathode yielded a current density of ∼0.81 mA cm−2 at 1.23 V vs. RHE and ∼−1.88 mA cm−2 at 0 V vs. RHE, respectively under 100 mW cm−2 xenon lamp illumination. From the individual photoelectrochemical analysis, we identify the operating points of the tandem cell as 0.66 V vs. RHE and 0.124 mA cm−2. The positive current density from the operating points proves the possibility of non-zero operation of the tandem cell. Finally, a two-electrode Mo-BiVO4/TiO2/FeOOH-Cu2O/TiO2/MoS2 tandem cell was constructed and analysed for unassisted operation. The obtained unassisted current density of the tandem cell was ∼65.3 μA cm−2 with better stability compared to the bare BiVO4-Cu2O tandem cell. The results prove that the spin coated TiO2 protective layer can be a viable approach to protect the photoelectrodes from photocorrosion with better stability and enhanced photoelectrochemical (PEC) performance. Mo-BiVO4/TiO2/FeOOH photoanode–Cu2O/TiO2/MoS2 photocathode tandem cells with photoelectrochemical stability testing.![]()
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Affiliation(s)
- S. R. Sitaaraman
- School of Electronics Engineering, Vellore Institute of Technology, Vellore 632014, India
| | - Andrews Nirmala Grace
- Centre for Nanotechnology Research, Vellore Institute of Technology, Vellore 632014, India
| | - Raja Sellappan
- Centre for Nanotechnology Research, Vellore Institute of Technology, Vellore 632014, India
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Wang HT, Chiou JW, Chen KH, Shelke AR, Dong CL, Lai CH, Yeh PH, Du CH, Lai CY, Asokan K, Hsieh SH, Shiu HW, Pao CW, Tsai HM, Yang JS, Wu JJ, Ohigashi T, Pong WF. Role of Interfacial Defects in Photoelectrochemical Properties of BiVO 4 Coated on ZnO Nanodendrites: X-ray Spectroscopic and Microscopic Investigation. ACS APPLIED MATERIALS & INTERFACES 2021; 13:41524-41536. [PMID: 34436855 DOI: 10.1021/acsami.1c08522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Synchrotron-based X-ray spectroscopic and microscopic techniques are used to identify the origin of enhancement of the photoelectrochemical (PEC) properties of BiVO4 (BVO) that is coated on ZnO nanodendrites (hereafter referred to as BVO/ZnO). The atomic and electronic structures of core-shell BVO/ZnO nanodendrites have been well-characterized, and the heterojunction has been determined to favor the migration of charge carriers under the PEC condition. The variation of charge density between ZnO and BVO in core-shell BVO/ZnO nanodendrites with many unpaired O 2p-derived states at the interface forms interfacial oxygen defects and yields a band gap of approximately 2.6 eV in BVO/ZnO nanocomposites. Atomic structural distortions at the interface of BVO/ZnO nanodendrites, which support the fact that there are many interfacial oxygen defects, affect the O 2p-V 3d hybridization and reduce the crystal field energy 10Dq ∼2.1 eV. Such an interfacial atomic/electronic structure and band gap modulation increase the efficiency of absorption of solar light and electron-hole separation. This study provides evidence that the interfacial oxygen defects act as a trapping center and are critical for the charge transfer, retarding electron-hole recombination, and high absorption of visible light, which can result in favorable PEC properties of a nanostructured core-shell BVO/ZnO heterojunction. Insights into the local atomic and electronic structures of the BVO/ZnO heterojunction support the fabrication of semiconductor heterojunctions with optimal compositions and an optimal interface, which are sought to maximize solar light utilization and the transportation of charge carriers for PEC water splitting and related applications.
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Affiliation(s)
- Hsiao-Tsu Wang
- Department of Physics, Tamkang University, New Taipei City 251301, Taiwan
| | - Jau-Wern Chiou
- Department of Applied Physics, National University of Kaohsiung, Kaohsiung 811726, Taiwan
| | - Kuan-Hung Chen
- Department of Physics, Tamkang University, New Taipei City 251301, Taiwan
| | - Abhijeet R Shelke
- Department of Physics, Tamkang University, New Taipei City 251301, Taiwan
| | - Chung-Li Dong
- Department of Physics, Tamkang University, New Taipei City 251301, Taiwan
| | - Chun-Hao Lai
- Department of Physics, Tamkang University, New Taipei City 251301, Taiwan
| | - Ping-Hung Yeh
- Department of Physics, Tamkang University, New Taipei City 251301, Taiwan
| | - Chao-Hung Du
- Department of Physics, Tamkang University, New Taipei City 251301, Taiwan
| | - Chun-Yen Lai
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Kandasami Asokan
- Inter-University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Shang-Hsien Hsieh
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Hung-Wei Shiu
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Chih-Wen Pao
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Huang-Ming Tsai
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Jih-Sheng Yang
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Jih-Jen Wu
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | | | - Way-Faung Pong
- Department of Physics, Tamkang University, New Taipei City 251301, Taiwan
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Chen YA, Wang YT, Moon HS, Yong K, Hsu YJ. Yolk-shell nanostructures: synthesis, photocatalysis and interfacial charge dynamics. RSC Adv 2021; 11:12288-12305. [PMID: 35423745 PMCID: PMC8696994 DOI: 10.1039/d1ra00803j] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/16/2021] [Indexed: 12/18/2022] Open
Abstract
Solar energy has long been regarded as a promising alternative and sustainable energy source. In this regard, photocatalysts emerge as a versatile paradigm that can practically transform solar energy into chemical energy. At present, unsatisfactory conversion efficiency is a major obstacle to the widespread deployment of photocatalysis technology. Many structural engineering strategies have been proposed to address the issue of insufficient activity for semiconductor photocatalysts. Among them, creation of yolk-shell nanostructures which possess many beneficial features, such as large surface area, efficient light harvesting, homogeneous catalytic environment and enhanced molecular diffusion kinetics, has attracted particular attention. This review summarizes the developments that have been made for the preparation and photocatalytic applications of yolk-shell nanostructures. Additional focus is placed on the realization of interfacial charge dynamics and the possibility of achieving spatial separation of charge carriers for this unique nanoarchitecture as charge transfer is the most critical factor determining the overall photocatalytic efficiency. A future perspective that can facilitate the advancement of using yolk-shell nanostructures in sophisticated photocatalytic systems is also presented.
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Affiliation(s)
- Yi-An Chen
- Department of Materials Science and Engineering, National Chiao Tung University Hsinchu 30010 Taiwan
| | - Yu-Ting Wang
- Department of Materials Science and Engineering, National Chiao Tung University Hsinchu 30010 Taiwan
| | - Hyun Sik Moon
- Surface Chemistry Laboratory of Electronic Materials, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH) Pohang 790-784 Korea
| | - Kijung Yong
- Surface Chemistry Laboratory of Electronic Materials, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH) Pohang 790-784 Korea
| | - Yung-Jung Hsu
- Department of Materials Science and Engineering, National Chiao Tung University Hsinchu 30010 Taiwan
- Center for Emergent Functional Matter Science, National Chiao Tung University Hsinchu 30010 Taiwan
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University Hsinchu 30010 Taiwan
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Abbas M. Factors influencing the adsorption and photocatalysis of direct red 80 in the presence of a TiO2: Equilibrium and kinetics modeling. JOURNAL OF CHEMICAL RESEARCH 2021. [DOI: 10.1177/1747519821989969] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Among the different photocatalysts, TiO2 ( Eg = 3.1 eV, zero charge point (pHpzc = 6.3), and surface = 55 m2/g) is currently the most efficient and the most studied semiconductor due to its strong photocatalytic activity, non-toxicity, and chemical stability. The elimination of DR-80 on TiO2 is studied by adsorption in batch mode and by application of heterogeneous photocatalysis onto TiO2 under UV irradiation. The effects of contact time (0–60 min), initial pH (3–11), dose of the adsorbent (0.5–3 g L−1), and DR-80 concentration (40–60 mg L−1) on the adsorption of DR-80 by TiO2 are studied for optimization of these parameters. The kinetic parameters, rate constants, and equilibrium adsorption capacities are calculated and discussed for each applied theoretical model. The adsorption of DR-80 is well described by the pseudo-first-order kinetic model. The fitting of the adsorption isotherms shows that the models of Langmuir and Temkin offering a better fit and an adsorption 64.102 mg/g at 25 °C of DR-80 are eliminated. The results showed that the photocatalytic efficiency strongly depends on the pH while the initial rate of photodegradation is proportional to the catalyst dose, and becomes almost constant above a threshold value. It was found that the photodegradation is favored at low DR-80 concentrations in accordance with the Langmuir–Hinshelwood model with the constants Kad = 6.5274 L/mg and KL–H = 0.17818 mg L−1 min. However, the adsorption is improved for high DR-80 concentrations. It is found that the degradation depends on both the temperature and the pH with a high elimination rate at high temperature. The photocatalyst TiO2 has a better activity for the degradation of DR-80, compared to some commercial catalysts that have been described in the literature.
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Affiliation(s)
- Moussa Abbas
- Laboratory of Soft Technologies, Valorization, Physicochemistry of Biological Materials and Biodiversity (LTDVPMBB), Science Faculty, University M’hamed Bougara of Boumerdes, Figuier, Boumerdes, Algeria
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Strategic Surface Modification for the Enhanced Photocatalyic Activity: Synergistic Promotion for Energy Utilization in TiO2–Cu2O–Au. Catal Letters 2020. [DOI: 10.1007/s10562-020-03431-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Shao Z, Zhang Y, Yang X, Zhong M. Au-Mediated Charge Transfer Process of Ternary Cu 2O/Au/TiO 2-NAs Nanoheterostructures for Improved Photoelectrochemical Performance. ACS OMEGA 2020; 5:7503-7518. [PMID: 32280894 PMCID: PMC7144151 DOI: 10.1021/acsomega.0c00299] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/18/2020] [Indexed: 05/05/2023]
Abstract
Based on a facile three-step preparation method, Cu2O/Au/TiO2-NAs ternary heterojunction nanocomposites have been successfully synthesized by electrodepositing a Cu2O layer on the surface of Au nanoparticles (NPs) decorated highly ordered TiO2 nanotube arrays (NAs). The structure, surface morphology, chemical composition, and optical and intrinsic defects properties of the as-prepared samples are characterized by transmission and scanning electron microscopy (TEM and SEM), X-ray diffraction (XRD), UV-vis light absorbance spectra, Raman scattering, and X-ray photoelectron spectroscopy (XPS). Simultaneously, the Cu2O/Au/TiO2-NAs ternary nanohybrids exhibited progressively improved photoelectrocatalytic (PEC) performance compared with the dual Cu2O/TiO2-NAs type-II nanoheterojunctions, confirming by the photocurrent density versus testing time curve (amperometric I-t curve), open-circuit potential versus testing time curve (V oc-t curve), and electrochemical impedance spectroscopy (EIS) measurements, which were mainly ascribed to the synergistic effect of reduced interfacial charge transfer resistance and boosted energetic charge carriers generation associated with embedding Au NPs. Furthermore, the self-consistent charge transfer mechanism of Z-scheme and interband transitions mediated with Au NPs for Cu2O/Au/TiO2-NAs triple nanocomposites is proposed, which was evaluated by nanosecond time-resolved transient photoluminescence (NTRT-PL) spectra excited by 266 and 400 nm, respectively. Following this scheme, UV-vis light photocatalytic activities of Cu2O/Au/TiO2-NAs ternary nanohybrids were elaborated toward photodegradation of methyl orange (MO) in aqueous solution, and the photodegradation rate of optimum triple nanocomplex was found to be 90%.
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Affiliation(s)
- Zhufeng Shao
- College of New Energy, Bohai University, Jinzhou, Liaoning, 121000 China
| | - Yufeng Zhang
- College of New Energy, Bohai University, Jinzhou, Liaoning, 121000 China
| | - Xiujuan Yang
- College of New Energy, Bohai University, Jinzhou, Liaoning, 121000 China
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Saffari R, Shariatinia Z, Jourshabani M. Synthesis and photocatalytic degradation activities of phosphorus containing ZnO microparticles under visible light irradiation for water treatment applications. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 259:113902. [PMID: 31918149 DOI: 10.1016/j.envpol.2019.113902] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/12/2019] [Accepted: 12/29/2019] [Indexed: 06/10/2023]
Abstract
A series of phosphorus containing ZnO (P-ZnO) photocatalysts with various percentages of phosphorus were successfully synthesized using the hydrothermal method. The structural, physical and optical properties of the obtained microparticles were investigated using diverse techniques such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible diffusion reflectance spectroscopy (UV-Vis DRS), photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and N2 adsorption-desorption analysis. The photocatalytic activities of the pure and P-ZnO samples were evaluated for the degradation of Rhodamine B (RhB) under visible light irradiation. The parameters such as pH, catalyst dosage, contaminant concentration and effect of persulfate as an oxidant were studied. It was found that the P-ZnO1.8% photocatalyst could destroy 99% of RhB (5 ppm) in 180 min at pH = 7; furthermore, it degraded ∼100% of 5 and 10 ppm of the RhB pollutant in 120 and 180 min, respectively, only by adding 0.01 g of persulfate into the reaction solution. To determine the photocatalytic mechanism, 2-propanol, benzoquinone and EDTA were used and it was indicated that hydroxyl radicals, superoxide ions and holes, all had major roles in the photocatalytic degradation but the hydroxyl radical effect was the most significant. The phenol degradation was also investigated using the P-ZnO1.8% optimum photocatalyst which could destroy 53% of the phenol (5 ppm) in 180 min. According to the reusability test, it was proved that after 5 cycles, the catalyst activity was not highly changed and it was potentially capable of pollutant degradation.
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Affiliation(s)
- Reyhaneh Saffari
- Department of Chemistry, Amirkabir University of Technology (Tehran Polytechnic), P.O.Box:15875-4413, Tehran, Iran
| | - Zahra Shariatinia
- Department of Chemistry, Amirkabir University of Technology (Tehran Polytechnic), P.O.Box:15875-4413, Tehran, Iran.
| | - Milad Jourshabani
- Department of Chemistry, Amirkabir University of Technology (Tehran Polytechnic), P.O.Box:15875-4413, Tehran, Iran
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Dong Y, Meng F. Effect of polyethylene glycol on crystal growth and photocatalytic activity of anatase TiO 2 single crystals. RSC Adv 2020; 10:12511-12518. [PMID: 35497631 PMCID: PMC9051215 DOI: 10.1039/d0ra01796e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 03/20/2020] [Indexed: 11/21/2022] Open
Abstract
In order to evaluate the effect of polyethylene glycol (PEG) on the growth of TiO2 crystals, anatase TiO2 crystals with different morphologies and structures were synthesized by controlling the content and type of PEG in a solvothermal system. Then, their morphology and structure were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Characterization results show that hydrofluoric acid can promote the formation of high activity (001) facets. Experiments on the effect of PEG on crystal growth show that the low molecular weight PEG (PEG400) can accelerate crystal differentiation and relieve the agglomeration of crystals in the presence of hydrofluoric acid. Besides, according to the experimental results, we found that PEG400 can reduce the agglomeration size and number of TiO2 polycrystalline particles. Research on the photocatalytic activity proposed that the independence of single crystal and the integrity of (001) facets are the critical factors in advanced oxidation reaction. The resultant anatase TiO2 single crystals could produce more hydroxyl radicals (˙OH) in the photocatalytic system, which exhibited remarkable photocatalytic performance for the degradation of Acid Red B. Anatase TiO2 crystals with different structures were synthesized. Experiments on the effect of polyethylene glycol show that the low molecular weight PEG (PEG400) can accelerate crystal differentiation and relieve the agglomeration of crystals.![]()
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Affiliation(s)
- Yeshuo Dong
- School of Environmental and Municipal Engineering, Qingdao University of Technology Qingdao 266033 China
| | - Fanjun Meng
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University Jinan 250014 China
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Gao Z, Sun P, Fang Y, Li C, Yuan X, Zheng X, Gao J. Effect of heat treatment under vacuum on structure and visible-light photocatalytic activity of nano-TiO 2. RSC Adv 2019; 9:32691-32698. [PMID: 35529763 PMCID: PMC9073092 DOI: 10.1039/c9ra03556g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 09/25/2019] [Indexed: 11/21/2022] Open
Abstract
Nano-TiO2 is known as a photocatalyst with high catalytic activity. However, it should be emphasized that the bandgap of nano-TiO2 is wide, which limits its photocatalytic efficiency in response to visible light and thus hinders its potential application. Improving the photocatalytic activity of nano-TiO2 under visible light by the strategy of heat treatment under vacuum was investigated in this study. The structure and photocatalytic activity of nano-TiO2 before and after heat treatment under vacuum were compared and analyzed by XRD, TEM, HRTEM, XPS and UV-Vis-NIR, respectively. The results show that oxygen vacancies were introduced into the crystal structure of nano-TiO2 to change its inherent energy band structure. Particularly, the samples after heat treatment under vacuum exhibited high photocatalytic activity under visible light. In addition, the formation mechanism of non-stoichiometric compound TiO2−x and the mechanism of oxygen vacancy defects to expand the wavelength of light that nano-TiO2 absorbs to the visible portion of the spectrum have also been addressed in this paper. Nano-TiO2 is known as a photocatalyst with high catalytic activity.![]()
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Affiliation(s)
- Zhengyuan Gao
- School of Mechatronics and Automotive Engineering, Chongqing Jiaotong University Chongqing China 400074
| | - Pengfei Sun
- School of Mechatronics and Automotive Engineering, Chongqing Jiaotong University Chongqing China 400074
| | - Yiliu Fang
- School of Mechatronics and Automotive Engineering, Chongqing Jiaotong University Chongqing China 400074
| | - Chuanqiang Li
- School of Materials Science and Engineering, Chongqing Jiaotong University Chongqing China 400074
| | - Xiaoya Yuan
- School of Materials Science and Engineering, Chongqing Jiaotong University Chongqing China 400074
| | - Xuxu Zheng
- School of Mechatronics and Automotive Engineering, Chongqing Jiaotong University Chongqing China 400074.,School of Materials Science and Engineering, Chongqing Jiaotong University Chongqing China 400074
| | - Jiacheng Gao
- School of Materials Science and Engineering, Chongqing University Chongqing China 400044
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