Decorating Thermodynamically Stable (101) Facets of TiO2 with MoO3 for Multifunctional Sustainable Hydrogen Energy and Ammonia Gas Sensing Applications

Unprecedented Hydrogen Evolution Reactions Based on the Accelerating Effect of [Co-Tb]-Supramolecular Complex-Anchored CdS Heterojunctions

This study presents a series of 1-Tb/CdS binary heterojunctions, synthesized by combining 1-Tb (a Co3+-Tb3+-based supramolecular complex) and CdS in various weight ratios via a solvothermal process. These heterojunctions have been thoroughly characterized to elucidate their chemical, structural, and optoelectronic properties. The catalytic effectiveness of these heterojunctions was evaluated with respect to the hydrogen evolution reaction (HER), spanning photocatalytic, electrocatalytic, and photoelectrocatalytic processes. Significantly outperforming individual photocatalysts (CdS and 1-Tb) and other binary heterostructures, the 7.5-1-Tb/CdS heterojunction exhibited the highest catalytic HER efficiency. The exceptional catalytic performance of 7.5-1-Tb/CdS is attributed to a synergistic integration of 1-Tb and CdS, enabling a highly efficient Z-scheme heterojunction. This unique architecture enhances charge separation and transfer by leveraging the complementary electronic properties of the individual CdS and 1-Tb semiconductors while minimizing recombination losses. X-ray photoelectron spectroscopy, band structure analysis, photoluminescence, and electrochemical impedance spectroscopy further validated the Z-scheme mechanism, highlighting the optimal alignment of energy levels. Overall, this study highlights the potential of 1-Tb/CdS binary heterojunctions as robust and efficient catalysts for the HER. The simplicity of the synthesis process, coupled with the exceptional catalytic activity, offers a significant advancement in clean energy technologies, paving the way for sustainable hydrogen production.

Highly Selective Oxidation of Benzene to Phenol Mediated by KHCO3 in the Bimetallic Mo-Cu/NC-H2O2 System

Although selective oxidation of benzene to phenol (SOBP) by H2O2 is an important chemical process, overoxidation of benzene by the produced nonselective •OH during the activation of H2O2 inevitably reduces the oxidation selectivity. We, therefore, attempt to mediate the oxidation selectively by using electrophilic KHCO3 in the oxidation system. In this study, Mo-Cu/NC has been successfully synthesized via ball-milling bimetallic Mo-Cu and N-doped carbon, which exhibits high reactivity in SOBP by H2O2 and KHCO3 with a desirable phenol yield of 25.1% and selectivity of 100%. A series of characterizations and DFT calculations reveal that the reaction between H2O2 and KHCO3 produces HCO4-, which is then moderately activated on Mo1Cu2/NC via the nonradical pathway with the formation of Mo-(η2-O2) peroxo. Meanwhile, Ov at Mo1Cu2/NC facilitates the adsorption of benzene, which is then selectively oxidized by Mo-(η2-O2) peroxo to phenol via the oxygen atom transfer pathway. This study provides new insights on the importance of Mo-(η2-O2) peroxo mediated by H2O2-KHCO3 in selective oxidation of aromatic C-H bond via the nonradical pathway.

Enhancing xylene degradation by core-shell TS-1@TiO2 in a bubble reactor with ultraviolet/H2O2

Volatile organic compounds (VOCs) in the atmosphere pose a critical global challenge due to their detrimental health effects. The ultraviolet (UV)/Fenton-like system has shown promise for VOC degradation. However, maintaining long-term catalytic efficiency by minimizing intermediate byproduct accumulation remains key challenges. In this study, a novel core-shell catalyst is developed which composed of anatase-phase titanium dioxide (TiO2) nanoparticles deposited on titanium silicalite-1 (TS-1) via a Stöber method in an ethanol/ammonia mixture. The TS-1@TiO2 structure promotes efficient spatial separation of photogenerated electrons and holes under UV irradiation, enhancing the activation of H2O2 to yield highly reactive free radicals (OH, OOH and O2-) for effective xylene degradation. In a UV/H2O2 bubble reactor, the TS-1@TiO2 catalyst demonstrates stable xylene degradation efficiency (75 % over 200 min), surpassing the performance of standalone TS-1 (53.2 %) and TiO2 (57.1 %). This design addresses critical challenges in sustained radical generation and intermediate suppression, offering a robust strategy to improve the longevity and efficiency of UV/H2O2 systems for environmental remediation.

CeF3-Accelerated surface reconstruction of MoO2 nanosheets into coral-like CeF3/MoO2 composites enhances the oxygen evolution reaction for efficient water splitting

Developing efficient and cost-effective rare earth element-based electrocatalysts for water splitting remains a significant challenge. To address this, interface engineering and charge modulation strategies were employed to create a three-dimensional coral-like CeF3/MoO2 heterostructure electrocatalyst, grown in situ on the multistage porous channels of carbonized sugarcane fiber (CSF). Integrating abundant CeF3/MoO2 heterostructure interfaces and numerous oxygen vacancy defects significantly enhanced the catalyst's active sites and molecular activation capabilities. The prepared coral-like CeF3/MoO2/CSF catalyst achieves overpotentials as low as 29 mV and 210 mV for hydrogen evolution reaction and oxygen evolution reaction at 10 mA cm-2 current density, respectively. Notably, the CeF3/MoO2@CSF||CeF3/MoO2@CSF electrolyzer demonstrates a superior overall water splitting ability having a voltage of 1.53 V at 10 mA cm-2 and retains outstanding stability for 100 h operating in 1.0 M KOH electrolyte. The exceptional catalytic performance of CeF3/MoO2@CSF is attributed to the reduction in the water dissociation energy barrier, optimal adsorption/desorption behavior of H/O intermediates, and rapid mass transfer facilitated by the multistage porous channels. These findings, supported by experimental results and density functional theory (DFT) calculations, provide a novel approach for designing rare-earth metal heterojunctions and biomass-derived synergistic electrocatalysts for efficient water splitting.

From materials to applications: a review of research on artificial olfactory memory

Olfactory memory forms the basis for biological perception and environmental adaptation. Advancing artificial intelligence to replicate this biological perception as artificial olfactory memory is essential. The widespread use of various robotic systems, intelligent wearable devices, and artificial olfactory memories modeled after biological olfactory memory is anticipated. This review paper highlights current developments in the design and application of artificial olfactory memory, using examples from materials science, gas sensing, and storage systems. These innovations in gas sensing and neuromorphic technology represent the cutting edge of the field. They provide a robust scientific foundation for the study of intelligent bionic devices and the development of hardware architectures for artificial intelligence. Artificial olfaction will pave the way for future advancements in intelligent recognition by progressively enhancing the level of integration, understanding of mechanisms, and application techniques of machine learning algorithms.

Oxygen Evolution Enhancement of Nickel (Hydr)Oxide via Iron Coordination Compound in Alkaline Conditions

This study investigates the complex dynamics of the oxygen-evolution reaction (OER) in systems involving Ni(Fe) (hydr)oxides and the iron coordination compound Fe phthalocyanine-4,4',4″,4‴-tetrasulfonate. It offers a novel perspective on the interaction between nickel hydroxide and the Fe compound during the OER process. The Fe complex facilitates the controlled release of trace Fe ions into the Ni (hydr)oxides as it undergoes degradation or demetalation within the Ni(II)/(III) potential range. Once the electrode surface reaches saturation with Fe, additional contributions from Fe have minimal impact on OER activity, and the turnover frequency rapidly reaches its maximum value (approximately 1 s-1) under cyclic voltammetry. In situ Raman spectroscopy reveals that the interaction between the iron complex and the electrode surface, as well as the amount of complex deposited or adsorbed, depends on the applied potential of the electrode. Changes in the electrode's potential influence how the Fe complex binds to the surface, through mechanisms such as electrostatic attraction, chemical bonding, or other interactions. This underscores the critical role of potential control in optimizing electrode surface modifications and enhancing the efficiency of electrochemical processes involving the iron complex.

Physicochemical Modulations in MXenes for Carbon Dioxide Mitigation and Hydrogen Generation: Tandem Dialogue between Theoretical Anticipations and Experimental Evidences

The dawn of MXenes has fascinated researchers under their intriguing physicochemical attributes that govern their energy and environmental applications. Modifications in the physicochemical properties of MXenes pave the way for efficient energy-driven operations such as carbon capture and hydrogen generation. The physicochemical modulations such as interface engineering through van der Waals coupling with homo/hetero-junctions render the tunability of optoelectronic variables driving the photochemical and electrochemical processes. Herein, we have reviewed the recent achievements in physicochemical properties of MXenes by highlighting the role of intercalants/terminal groups, atomic defects, surface chemistry and few/mono-layer formation. Recent findings of MXenes-based materials are systematically surveyed in a tandem manner with the future outlook for constructing next-generation multi-functional catalytic systems. Theoretical modelling of MXenes surface engineering proffers the mechanistic comprehension of surface phenomena such as termination, interface formation, doping and functionalization, thereby enabling the researchers to exploit them for targeted applications. Therefore, theoretical anticipations and experimental evidences of electrochemical/photochemical carbon dioxide reduction and hydrogen evolution reactions are synergistically discussed.

Green light all the way: Triple modification synergistic modification effect to enhance the photoelectrochemical water oxidation performance of BiVO4 photoanode

The recombination of photogenerated electron-hole pairs of the photoanode seriously impairs the application of bismuth vanadate (BiVO4) in photoelectrochemical water splitting. To address this issue, we prepared a Yb:BiVO4/Co3O4/FeOOH composite photoanode by employing drop-casting and soaking methods to attach Co3O4/FeOOH cocatalysts to the surface of ytterbium-doped BiVO4. The prepared Yb:BiVO4/Co3O4/FeOOH photoanode demonstrates a high photocurrent density of 4.89 mA cm-2 at 1.23 V versus the reversible hydrogen electrode (RHE), which is 5.1 times that of bare BiVO4 (0.95 mA cm-2). Detailed characterization and testing demonstrated that Yb doping narrows the band gap and significantly enhances the carrier density. Furthermore, Co3O4 serves as a hole transfer layer to expedite hole migration and diminish recombination, while FeOOH offers additional active sites and minimizes surface trap states, thus boosting stability. The synergistic effects of Yb doping and Co3O4/FeOOH cocatalyst significantly improved the reaction kinetics and overall performance of PEC water oxidation. This work provides a strategy for designing efficient photoanodes for PEC water oxidation.

Self-Supported Porous Carbon Monoliths for Electrocatalytic Hydrogen Evolution in Alkaline Freshwater and Seawater

Developing efficient catalysts for seawater electrolysis hydrogen evolution reaction (HER) is crucial for producing green hydrogen. Carbonized wood (CW), a porous carbon monolith, is a promising self-supporting electrocatalytic electrode owing to its environmentally friendly, sustainable, and hierarchically porous properties. However, the impact of different tree species on the hydrogen evolution performance remains unclear. In this study, various types of CWs, including carbonized poplar (PoCW), carbonized balsa (BaCW), carbonized fir (FiCW), and carbonized pine (PiCW), have been selected to investigate their electrocatalytic performance in hydrogen evolution. Among these, the PoCW exhibits superior electrocatalytic HER performance compared to the other CWs, attributed to its electrochemically active surface area, resistance, and the content of oxygen-containing functional groups. PoCW demonstrates a low overpotential of 284 mV and 356 mV at 10 mA cm-2 in alkaline freshwater and seawater, respectively. Moreover, PoCW shows long-term durability for 100 h in both alkaline freshwater and seawater. This work guides the selection of wood-based carbon monoliths and demonstrates that metal-free, CW-based self-supporting electrodes hold great potential for electrocatalytic hydrogen evolution in both freshwater and seawater.

Ultrafast Hole Trapping in Te-MoTe2-MoSe2/ZnO S-Scheme Heterojunctions for Photochemical and Photo-/Electrochemical Hydrogen Production

Te-MoTe2-MoSe2/ZnO S-scheme heterojunctions are engineered to ascertain the advanced redox ability in sustainable HER operations. Photo-physical studies have established the steady state transfer of photo-induced charge carriers whereas an improved transfer dynamics realized by state-of-art ultrafast transient absorption and irradiated-XPS analysis of optimized 5wt% Te-MoTe2-MoSe2/ZnO heterostructure. 2.5, 5, and 7.5wt% Te-MoTe2-MoSe2/ZnO photocatalysts (2.5MTMZ, 5MTMZ and 7.5MTMZ) exhibited 2.8, 3.3, and 3.1-fold higher HER performance than pristine ZnO with marvelous apparent quantum efficiency of 35.09%, 41.42% and 38.79% at HER rate of 4.45, 5.25, and 4.92 mmol/gcat/h, respectively. Electrochemical water splitting experiments manifest subdued 583 and 566 mV overpotential values of 2.5MTMZ and 5MTMZ heterostructures to achieve 10 mA cm-2 current density for HER, and 961 and 793 mV for OER, respectively. For optimized 5MTMZ photocatalyst, lifetime kinetic decay of interfacial charge transfer step is evaluated to be 138.67 ps as compared to 52.92 ps for bare ZnO.

Biofunctionalized magnetic nanoparticles incorporated MoS2 nanocomposite for enhanced n-butanol sensing at room temperature

N-butanol is well known to be a flammable and harmful liquid that is a potential threat to human health and property. Therefore, it is important to monitor the concentration of n-butanol in the surroundings. The need for highly efficient toxic gas detection is urgent and has been driving the research on gas sensors for practical applications. Molybdenum disulfide (MoS2) has been attracting significant interest for gas detection at room temperature. Herein, we report biofunctionalized magnetic nanoparticles incorporated MoS2 for sensing n-butanol. The biosynthesized magnetite nanoparticles (CT-Fe3O4) were synthesized by the addition of Cinnamomum Tamala (CT) leaf extract, and subsequently, the nanocomposite was synthesized using a hydrothermal method. Highly sensitive sensors based on MoS2-CT-Fe3O4 were fabricated and tested for sensing different concentrations of n-butanol. The nanocomposites showed a good sensing performance ( Δ R/Rair %) of 72% towards 20 ppm of n-butanol, indicating the potential use of MoS2-CT-Fe3O4 nanocomposite for sensing n-butanol at room temperature.

Polyoxometalate Cluster-Guided Dynamic Nucleation and Hierarchical Growth of Branched WO3 Nanofibers with Ultrafine Pt Nanoparticles for Advanced Gas Sensing

In the food industry, 2,3-butanedione is a significant volatile organic compound valued for its unique aroma and flavor. Real-time detection of its concentration during food preparation is crucial for ensuring optimal taste and food safety. However, accurately detecting low concentrations of 2,3-butanedione requires highly sensitive sensing materials. Herein, we present a novel synthesis of branched WO3 nanofibers decorated with ultrafine Pt nanoparticles (Pt NPs-WO3 NFs), templated by polyoxometalate (POM) clusters, through a combination of electrospinning and thermal oxidation strategies for advanced gas sensing applications. This Pt NPs-WO3 NFs-based sensor exhibits impressive sensitivity (Ra/Rg = 2.25 vs 500 ppb), a low detection limit of 10 ppb, high selectivity, excellent repeatability, and stable performance over a period of 25 days. Using POM clusters as templates offers significant advantages over the traditional WCl6 salt in synthesizing WO3 NFs with smooth surfaces. Specifically, the POM clusters guide the dynamic nucleation and hierarchical growth of branched NFs, enhancing the concentration of oxygen vacancies and increasing the number of active adsorption sites. Furthermore, the uniform dispersion of ultrafine Pt NPs (≈ 4 nm) within the WO3 NFs further enhances the catalytic activation of 2,3-butanedione, significantly improving the gas sensing performance. This study introduces an efficient method to synthesize Pt NPs-WO3 NFs with potential for manufacturing advanced nanostructured sensing materials using POM clusters as templates, paving the way for high-performance gas sensing technologies.

Ceria nanocatalyst-supported oxidative organic transformations of aromatic alcohols andp-nitrotoluene

Hydrothermally derived nanocubes of CeO2(10 nm) were explored as an efficient heterogeneous catalyst in the partial oxidation of aromatic alcohols to the corresponding aldehydes and aerobic oxidation ofp-nitrotoluene top-nitrobenzoic acid. The CeO2nanocatalyst was characterized by x-ray diffraction, transmission electron microscopy (TEM), energy dispersive spectroscopy, x-ray photoelectron spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis, Fourier transform infrared spectroscopy, thermal gravimetric analysis and ultraviolet-visible spectroscopy. TEM/high-resolution TEM micrographs reveal a morphology of mostly cubic nanostructures with exposed highly active {100} and {110} facets. The surface area of nanoceria was determined by BET analysis and found to be 33.8 m2g-1. To demonstrate the universality of the catalytic system, the selective oxidation of different substrates of benzylic alcohol and complete oxidation ofp-nitrotoluene was investigated under mild conditions. Absolute selectivity towards their respective aldehydes was found to be 99.50% (benzaldehyde), 90.18% (p-chlorobenzaldehyde), 99.71% (p-nitrobenzaldehyde), 98.10% (p-fluorobenzaldehyde), 94.66% (p-anisaldehyde) and 86.14% (cinnamaldehyde). Moreover, the catalytic oxidative transformation of nitrotoluene results in 100% conversion with 99.29% selectivity towards nitrobenzoic acid.

Photoelectrocatalytic Hydrogen Generation: Current Advances in Materials and Operando Characterization

Photoelectrochemical (PEC) hydrogen generation is a promising technology for green hydrogen production yet faces difficulties in achieving stability and efficiency. The scientific community is pushing toward the development of new electrode materials and a better understanding of the underlying reactions and degradation mechanisms. Advances in photocatalytic materials are being pursued through the development of heterojunctions, tailored crystal nanostructures, doping, and modification of solid-solid and solid-electrolyte interfaces. Operando and in situ techniques are utilized to deconvolute the charge transfer mechanisms and degradation pathways. In this review, both materials development and Operando characterization are covered for advancing PEC technologies. The recent advances made in the PEC materials are first reviewed including the applied improvement strategies for transition metal oxides, nitrites, chalcogenides, Si, and group III-V semiconductor materials. The efficiency, stability, scalability, and electrical conductivity of the aforementioned materials along with the improvement strategies are compared. Next, the Operando characterization methods and cite selected studies applied for PEC electrodes are described. Operando studies are very successful in elucidating the reaction mechanisms, degradation pathways, and charge transfer phenomena in PEC electrodes. Finally, the standing challenges and the potential opportunities are discussed by providing recommendations for designing more efficient and electrochemically stable PEC electrodes.

Structural, Optical, Electrical and Photocatalytic Investigation of n-Type Zn2+-Doped α-Bi2O3 Nanoparticles for Optoelectronics Applications

Herein, n-type pure and Zn2+-doped monoclinic bismuth oxide nanoparticles were synthesized by the citrate sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) analysis, ultraviolet-visible (UV-vis) spectroscopy, and Hall effect measurements were used to study the effect of Zn2+ on the structural, optical, and electrical properties of nanoparticles. XRD revealed the monoclinic stable phase (α-Bi2O3) of all synthesized samples and the crystallite size of nanoparticles increased with increasing concentration of dopant. Optical analysis illustrated the red shift of absorption edge and blue shift of band gap with increasing concentration of dopant. Hall Effect measurements showed improved values (2.79 × 10-5 S cm-1 and 6.89 cm2/V·s) of conductivity and mobility, respectively, for Zn2+-doped α-Bi2O3 nanoparticles. The tuned optical band gap and improved electrical properties make Zn2+-doped α-Bi2O3 nanostructures promising candidates for optoelectronic devices. The degradation of methylene blue (MB, organic dye) in pure and zinc-doped α-Bi2O3 was investigated under solar irradiation. The optimum doping level of zinc (4.5% Zn2+-doped α-Bi2O3) reveals the attractive photocatalytic activity of α-Bi2O3 nanostructures due to electron trapping and detrapping for solar cells.

MBenes for Energy Conversion: Advances, Bottlenecks, and Prospects

The advent of two-dimensional layered materials has bolstered the development of catalytic endeavors for energy conversion and storage. MXenes (transition metal carbides/nitrides) have already consolidated their candidature in the past decade due to their enhanced compositional and structural tunabilities through surface modifications. Perseverant research in engineering MXene based materials has led to the inception of MBenes (transition metal borides) as promising catalytic systems for energy-driven operations. Physicochemical superiorities of MBenes such as escalated conductivity and hydrophilicity, unique surface and geometrical domains, and higher stability and modulus of elasticity provide the reaction-friendly milieu to exploit these materials. Nevertheless, the research on MBenes is embryonic and requires the thorough realization of their scientific significance. Herein, we aim to discuss the advancements, challenges, and outlooks of MBenes with respect to their energy conversion HER, CO2RR, and NRR applications.

Superlative Porous Organic Polymers for Photochemical and Electrochemical CO2 Reduction Applications: From Synthesis to Functionality

To mimic the carbon cycle at a kinetically rapid pace, the sustainable conversion of omnipresent CO2 to value-added chemical feedstock and hydrocarbon fuels implies a remarkable prototype for utilizing released CO2. Porous organic polymers (POPs) have been recognized as remarkable catalytic systems for achieving large-scale applicability in energy-driven processes. POPs offer mesoporous characteristics, higher surface area, and superior optoelectronic properties that lead to their relatively advanced activity and selectivity for CO2 conversion. In comparison to the metal organic frameworks, POPs exhibit an enhanced tendency toward membrane formation, which governs their excellent stability with regard to remarkable ultrathinness and tailored pore channels. The structural ascendancy of POPs can be effectively utilized to develop cost-effective catalytic supports for energy conversion processes to leapfrog over conventional noble metal catalysts that have nonlinear techno-economic equilibrium. Herein, we precisely surveyed the functionality of POPs from scratch, classified it, and provided a critical commentary of its current methodological advancements and photo/electrochemical achievements in the CO2 reduction reaction.

Revolutionizing Glucose Monitoring: Enzyme-Free 2D-MoS2 Nanostructures for Ultra-Sensitive Glucose Sensors with Real-Time Health-Monitoring Capabilities

The growing requirement for real-time monitoring of health factors such as heart rate, temperature, and blood glucose levels has resulted in an increase in demand for electrochemical sensors. This study focuses on enzyme-free glucose sensors based on 2D-MoS2 nanostructures explored by simple hydrothermal route. The 2D-MoS2 nanostructures were characterized by powder X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and XPS techniques and were immobilized at GCE to obtain MoS2-GCE interface. The fabricated interface was characterized by electrochemical impedance spectroscopy which shows less charge transfer resistance and demonstrated superior electrocatalytic properties of the modified surface. The sensing interface was applied for the detection of glucose using amperometry. The MoS2-GCE-sensing interface responded effectively as a nonenzymatic glucose sensor (NEGS) over a linearity range of 0.01-0.20 μM with a very low detection limit of 22.08 ng mL-1. This study demonstrates an easy method for developing a MoS2-GCE interface, providing a potential option for the construction of flexible and disposable nonenzymatic glucose sensors (NEGS). Moreover, the fabricated MoS2-GCE electrode precisely detected glucose molecules in real blood serum and urine samples of diabetic and nondiabetic persons. These findings suggest that 2D-MoS2 nanostructured materials show considerable promise as a possible option for hyperglycemia detection and therapy. Furthermore, the development of NEGS might create new prospects in the glucometer industry.

Influence of nano-BN inclusion and mechanism involved on aluminium-copper alloy

Taking advantage of the high specific surface area of the nanoparticles, boron nitride (BN) nanoparticles were incorporated into the semi-solidified aluminium-copper alloy Al-5Cu-Mn (ZL201) system during the casting process, and its properties and enhancement mechanism were studied. The results shown that the BN in the new composite material is more uniformly distributed in the second phase (Al2Cu), which can promote grain refinement and enhance the bonding with the aluminium-based interface, and the formation of stable phases such as AlB2, AlN, CuN, etc. makes the tensile strength and hardness of the material to be significantly improved (8.5%, 10.2%, respectively). The mechanism of the action of BN in Al2Cu was analyzed by establishing an atomic model and after calculation: BN can undergo strong adsorption on the surface of Al2Cu (0 0 1), and the adsorption energy is lower at the bridge sites on the two cut-off surfaces, which makes the binding of BN to the aluminum base more stable. The charge transfer between B, N and each atom of the matrix can promote the formation of strong covalent bonds Al-N, Cu-N and Al-B bonds, which can increase the dislocation density and hinder the grain boundary slip within the alloy.

Catalytic CO Oxidation on the Cu+-Ov-Ce3+ Interface Constructed by an Electrospinning Method for Enhanced CO Adsorption at Low Temperature

It is crucial to eliminate CO emissions using non-noble catalysts. Cu-based catalysts have been widely applied in CO oxidation, but their activity and stability at low temperatures are still challenging. This study reports the preparation and application of an efficient copper-doped ceria electrospun fiber catalyst prepared by a facile electrospinning method. The obtained 10Cu-Ce fiber catalyst achieved complete CO oxidation at a temperature as low as 90 °C. However, a reference 10Cu/Ce catalyst prepared by the impregnation method needed 110 °C to achieve complete CO oxidation under identical reaction conditions. Asymmetric oxygen vacancies (ASOV) at the interface between copper and cerium were constructed, to effectively absorb gas molecules involved in the reaction, leading to the enhanced oxidation of CO. The exceptional ability of the 10Cu-Ce catalyst to adsorb CO is attributed to its unique structure and surface interaction phase Cu+-Ov-Ce3+, as demonstrated by a series of characterizations and DFT calculations. This novel approach of using electrospinning offers a promising technique for developing low-temperature and non-noble metal-based catalysts.

Enhanced Photo/Electrocatalytic Hydrogen Evolution by Hydrothermally Derived Cu-Doped TiO2 Solid Solution Nanostructures

Highly efficient nanocatalysts with a high specific surface area were successfully synthesized by a cost-effective and environmentally friendly hydrothermal method. Structural and elemental purity, size, morphology, specific surface area, and band gap of pristine and 1 to 5% Cu-doped TiO2 nanoparticles were characterized by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), energy dispersive X-ray analysis (EDAX), inductively coupled plasma mass spectrometry (ICP-MS), liquid chromatography-high resolution mass spectrometry (LC-HRMS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET surface area, Raman spectroscopy, photoluminescence spectroscopy (PL) and UV-visible diffused reflectance spectroscopy (UV-DRS) studies. The XPS and EPR findings indicated the successful integration of Cu ions into the TiO2 lattice. UV-DRS and BET surface area investigations revealed that with an increase in dopant concentration, Cu-doped TiO2 NPs show a decrease in band gap (3.19-3.08 eV) and an increase in specific surface area (169.9-188.2 m2/g). Among all compositions, 2.5% Cu-doped TiO2 has shown significant H2 evolution with an apparent quantum yield of 17.67%. Furthermore, the electrochemical water-splitting study shows that 5% Cu-doped TiO2 NPs have superiority over pristine TiO2 for H2 evolution reaction. It was thus revealed that the band gap tuning with the desired dopant concentration led to enhanced photo/electrocatalytic sustainable energy applications.

Boosted Electrocatalytic Degradation of Levofloxacin by Chloride Ions: Performances Evaluation and Mechanism Insight with Different Anodes

As chloride (Cl-) is a commonly found anion in natural water, it has a significant impact on electrocatalytic oxidation processes; yet, the mechanism of radical transformation on different types of anodes remains unexplored. Therefore, this study aims to investigate the influence of chlorine-containing environments on the electrocatalytic degradation performance of levofloxacin using BDD, Ti4O7, and Ru-Ti electrodes. The comparative analysis of the electrode performance demonstrated that the presence of Cl- improved the removal and mineralization efficiency of levofloxacin on all the electrodes. The enhancement was the most pronounced on the Ti4O7 electrode and the least significant on the Ru-Ti electrode. The evaluation experiments and EPR characterization revealed that the increased generation of hydroxyl radicals and active chlorine played a major role in the degradation process, particularly on the Ti4O7 anode. The electrochemical performance tests indicated that the concentration of Cl- affected the oxygen evolution potentials of the electrode and consequently influenced the formation of hydroxyl radicals. This study elucidates the mechanism of Cl- participation in the electrocatalytic degradation of chlorine-containing organic wastewater. Therefore, the highly chlorine-resistant electrocatalytic anode materials hold great potential for the promotion of the practical application of the electrocatalytic treatment of antibiotic wastewater.