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Solar water splitting over Rh <sub/>0.5</sub> Cr <sub/>1.5</sub> O <sub/>3</sub> -loaded AgTaO <sub/>3</sub> of a valence-band-controlled metal oxide photocatalyst
摘要： Improvement of water splitting performance of AgTaO3 (BG 3.4 eV) of a valence-band-controlled photocatalyst was examined. Survey of cocatalysts revealed that a Rh0.5Cr1.5O3 cocatalyst was much more effective than Cr2O3, RuO2, NiO and Pt for water splitting into H2 and O2 in a stoichiometric amount. The optimum loading amount of the Rh0.5Cr1.5O3 cocatalyst was 0.2 wt%. The apparent quantum yield (AQY) at 340 nm of the optimized Rh0.5Cr1.5O3(0.2 wt%)/AgTaO3 photocatalyst reached to about 40%. Rh0.5Cr1.5O3(0.2 wt%)/AgTaO3 gave a solar to hydrogen conversion efficiency (STH) of 0.13% for photocatalytic water splitting under simulated sunlight irradiation. Bubbles of gasses evolved by the solar water splitting were visually observed under atmospheric pressure at room temperature.
关键词： Rh0.5Cr1.5O3 cocatalyst,valence-band-controlled photocatalyst,solar water splitting,apparent quantum yield,AgTaO3,solar to hydrogen conversion efficiency
更新于2025-11-19 16:51:07
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Effects of annealing conditions on the oxygen evolution activity of a BaTaO2N photocatalyst loaded with cobalt species
摘要： Precise engineering of the cocatalyst-photocatalyst interface and optimization of the cocatalyst dispersion are essential for improving the activity of particulate semiconductor photocatalysts. Herein, we report the effects of varying the conditions used to load cobalt oxide (CoOx) as a cocatalyst on the O2 evolution activity of a particulate BaTaO2N photocatalyst, based on trials in an aqueous silver nitrate solution under visible light irradiation. Annealing under an N2 flow after loading the Co species increased the O2 evolution rate threefold compared to that obtained following conventional annealing under an NH3 flow. Subsequent annealing under an H2 atmosphere exposed the BaTaO2N surface as a result of the aggregation of CoOx particles, and further enhanced the photocatalytic O2 evolution by a factor of two, yielding an apparent quantum efficiency of 0.55% at 420 nm. These results indicate the importance of intimate contact between cocatalyst particles and the photocatalyst, as well as the necessity of exposing the photocatalyst surface to make it available for reduction reactions during photocatalytic water oxidation.
关键词： Cocatalyst,Dispersion,Oxynitride,Visible light
更新于2025-11-19 16:51:07
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A high-performance photoelectrochemical water oxidation system with phosphorus doping g-C3N4 and simultaneous metal phosphide cocatalyst formation via a gas treatment
摘要： Graphitic carbon nitride (g-C3N4) has been widely explored as photocatalyst for water splitting. The anodic water oxidation reaction (WOR) remains the major obstacle for such process, with particular issues on low surface area of g-C3N4, poor light absorption as well as low charge transfer efficiency. In this work, such longtime concerned issues have been partially addressed with band gap and surface engineering of nanostructured graphitic C3N4. Specifically, surface area and charge transfer efficiency are significantly enhanced via architecturing g-C3N4 on nanorod TiO2 to avoid the aggregation of layered g-C3N4. Moreover, a simple phosphide gas treatment of TiO2/g-C3N4 configuration not only narrows the band gap of g-C3N4 by 0.57 eV into visible range, but also in-situ generates a metal phosphide (M=Fe, Cu) water oxidation cocatalyst. This TiO2/g-C3N4/FeP configuration significantly improves charge separation and transfer capability. As a result, our photoelectrochemical system yields outstanding visible light (> 420 nm) photocurrent: ca. 0.3 mA·cm-2 at 1.23 V and 1.1 mA·cm-2 at 2.0 V vs RHE, the highest using g-C3N4 as photoanode. We expect that our TiO2/g-C3N4/FeP configuration generating via simple phosphide gas treatment will bring in new insight for robust g-C3N4 for water oxidation.
关键词： doping,photoelectrochemical,cocatalyst,g-C3N4,high performance
更新于2025-09-23 15:23:52
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Au as a cocatalyst loaded on solid solution Bi0.5Y0.5VO4 for enhancing photocatalytic CO2 reduction activity
摘要： Au as a cocatalyst was deposited on the surface of solid solution Bi0.5Y0.5VO4 by a photodeposition method for photocatalytic reduction of CO2. Au particles loaded on the surface of Bi0.5Y0.5VO4 apparently enhanced the photocatalytic activity of CO2 reduction toward CO evolution. The highest rate of CO evolution was obtained over 1.0 wt% Au/Bi0.5Y0.5VO4, reaching 3.5 times of that of bare Bi0.5Y0.5VO4. The improved photocatalytic performance was assigned to the lower overpotential of Au/Bi0.5Y0.5VO4 for CO evolution than that of bare Bi0.5Y0.5VO4 as well as the formation of Schottky barrier, which promotes the separation of photogenerated electron–hole pairs.
关键词： Semiconductors,Au cocatalyst,Nanocomposites,CO2 reduction,Charge separation
更新于2025-09-23 15:23:52
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Improved charge separation of NiS nanoparticles modified defect-engineered black TiO2 hollow nanotubes for boosting solar-driven photocatalytic H2 evolution
摘要： NiS nanoparticles (NPs) modified black TiO2 hollow nanotubes (NBTNs) are successfully synthesized via surface hydrogenation and facile solvothermal method. The unique structure with intensified surface and interface characteristic endow NBTNs with more catalytic sites, and increase charge carrier separation efficiency with a extended charge lifetime, overwhelmingly promoting its photocatalytic performance. The resultant NBTNs possess a relatively high surface area and pore size of ~89 m2 g-1 and ~9.8 nm, respectively. The resultants NBTNs exhibit an excellent solar-driven photocatalytic hydrogen rate (3.17 mmol h-1 g-1), which almost as high as that of Pt as cocatalyst, in which the apparent quantum (AQE) yield of 5.4 % (420 nm) is recorded for the NBTNs sample. Moreover, the turnover number (TON) can be up to 116000 within 48 h. And the turnover frequency (TOF) is 2400 for NiS. This novel strategy could provide a better understanding of cocatalyst photocatalytic mechanism, and a scheme simultaneously regulating the morphology and structure of photocatalyst for promoting H2 generation.
关键词： Mesoporous TiO2 nanotube,Oxygen vacancy defect,NiS cocatalyst,Photocatalysis,Ti3+ self-doping
更新于2025-09-23 15:23:52
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Ni doped noble-metal-free CdZnNiS photocatalyst for high-efficient photocatalytic hydrogen evolution reduction by visible light driving
摘要： In this paper, we report a method that the transition element nickel is doped into the interstitial position of CdZnS (CZS) nanoparticles for their photocatalytic hydrogen evolution activity boosting. It is demonstrated that CdZnNiS nanocrystalline materials (with 0.5 wt% of Ni) could achieve the highest photocatalytic H2-evolution activity of 25.4 mmol·g?1·h?1 in sulfide and sulfite solution under visible light which value is 1.16 times higher than that of Pt modified CdZnS particles (with 3 wt% of Pt). This work evidences the possibility of substitution of noble metal cocatalyst by adding a suitable inexpensive Ni to achieve high-efficient visible light driven water splitting hydrogen production.
关键词： Semiconductors,CdZnNiS nanocrystalline materials,Noble-metal-free cocatalyst,Gap doping,Nanocomposites,Water splitting
更新于2025-09-23 15:22:29
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Integrating non-precious-metal cocatalyst Ni3N with g-C3N4 for enhanced photocatalytic H2 production in water under visible-light irradiation
摘要： Photocatalytic H2 production via water splitting in a noble-metal-free photocatalytic system has attracted much attention in recent years. In this study, noble-metal-free Ni3N was used as an active cocatalyst to enhance the activity of g-C3N4 for photocatalytic H2 production under visible-light irradiation (λ > 420 nm). The characterization results indicated that Ni3N nanoparticles were successfully loaded onto the g-C3N4, which accelerated the separation and transfer of photogenerated electrons and resulted in enhanced photocatalytic H2 evolution under visible-light irradiation. The hydrogen evolution rate reached ~305.4 μmol h?1 g?1, which is about three times higher than that of pristine g-C3N4, and the apparent quantum yield (AQY) was ~0.45% at λ = 420 nm. Furthermore, the Ni3N/g-C3N4 photocatalyst showed no obvious decrease in the hydrogen production rate, even after five cycles under visible-light irradiation. Finally, a possible photocatalytic hydrogen evolution mechanism for the Ni3N/g-C3N4 system is proposed.
关键词： Hydrogen evolution,g-C3N4,Cocatalyst,Ni3N,Photocatalysis
更新于2025-09-23 15:22:29
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Noble-metal-free MOF derived hollow CdS/TiO2 decorated with NiS cocatalyst for efficient photocatalytic hydrogen evolution
摘要： Noble-metal-free hollow NiS/CdS/TiO2 (NS/CT) nanohybrid photocatalyst was prepared by a facile hydrolysis combining sulfidation process using metal-organic framework (MOF) as a template. The as-prepared composites were characterized by SEM, TEM, XRD, XPS, UV-vis, and photoelectrochemical techniques. It is found that NS/CT composites with porous hollow structure show significantly enhanced photocatalytic efficiency compare to TiO2, or CdS/TiO2, or even Pt decorated CdS/TiO2 photocatalysts, for hydrogen evolution from water upon visible light irradiation. Significantly, NS/CT composite with optimum amount of 30% CdS and 0.3% NiS exhibits the highest photoactivity, with H2 production rate of 2149.15 μmol·g-1·h-1, which is 23.9 and 2.3 times higher than that of the pure CdS particles and the CdS/TiO2 nanocomposites, respectively. The superiority of the composites arises from the synergistic effect of the heterojunction for rapid charge separation and the NiS cocatalyst for accelerated surface redox reaction.
关键词： NiS cocatalyst,H2 production,CdS/h-TiO2,heterojunction,photocatalysis.
更新于2025-09-23 15:22:29
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Single Nickel Atoms Anchored on Nitrogen-Doped Graphene as a Highly Active Co-Catalyst for Photocatalytic H2 Evolution
摘要： Earth abundant nickel is a typical non-noble-metal cocatalyst used for photocatalytic hydrogen evolution (PHE). Ni nanoparticles, however, tend to aggregate during the hydrogen production process, significantly lowering their PHE activity. In this research, we report single nickel atoms anchored on nitrogen-doped graphene (Ni-NG) as a cocatalyst for PHE. We have demonstrated that Ni-NG is a robust and highly active cocatalyst for PHE from water. With only 0.0013 wt.% of Ni loading, the PHE activity of composite Ni-NG/CdS photocatalyst is 3.4 times greater than that of NG/CdS. The quantum efficiency of Ni-NG/CdS for PHE reaches 48.2% at 420 nm, one of the highest efficiencies for non-noble-metal based cocatalysts reported in literature. Photoluminescence spectral analyses and electrochemical examinations have indicated that Ni-NG coupled to CdS can serve not only as an electron storage medium to suppress electron-hole recombination, but also as an active catalyst for proton reduction reaction. Density functional theory calculation shows that the high activity of Ni-NG/CdS composite results from the single Ni atoms trapped in NG vacancies, which significantly reduces the activation energy barrier of the hydrogen evolution reaction. This approach may be valuable for developing robust and highly active noble-metal free cocatalysts for solar hydrogen production.
关键词： Non-noble Metal Cocatalyst,CdS,Photocatalytic Hydrogen Evolution,Nitrogen-Doped Graphene,Single Ni Atom Catalysts
更新于2025-09-23 15:21:21
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Role of Pt Loading in the Photocatalytic Chemistry of Methanol on Rutile TiO2(110)
摘要： As a cocatalyst, Pt is well-known for accepting photoexcited electrons and lowering the overpotential of hydrogen production in photocatalysis, being responsible for the enhanced photocatalytic efficiency. Despite the above existing knowledge, the adsorption of reactants on the Pt/photon-absorber (for example, Pt/TiO2) interface, a prerequisite to understand the photocatalytic chemistry, is extremely difficult to investigate mainly due to the complexity of the powdered material and solution environment. Combining ultrahigh vacuum and well-ordered single crystals, we study the photocatalytic chemistry of methanol on Pt loaded rutile TiO2(110) using temperature-programmed desorption (TPD) and ultraviolet photoelectron spectroscopy (UPS). Despite the same photocatalytic chemical products, i.e., formaldehyde and surface hydrogen species, as on Pt-free TiO2(110), the subsequent chemistry of surface hydrogen species and the photocatalytic reaction rate are much different. The bridging hydroxyls desorb as water molecules around 500 K on Pt-free TiO2(110) surface, by contrast, this desorption channel disappears completely and water and molecular hydrogen desorb at much lower temperature (<300 K) after Pt deposition, which can prevent the recombination of hydrogen species with formaldehyde. More importantly, methanol dissociates into methoxy at the Pt/TiO2(110) interface, which is crucial in the photocatalytic chemistry of methanol on TiO2 surfaces since methoxy is a more effective hole scavenger than methanol itself. The photocatalytic chemical reaction rate is increased by nearly one order of magnitude after 0.12 monolayer Pt deposition. This work suggests that Pt loading can promote the dissociation of methanol into methoxy and lower the desorption barrier of molecular hydrogen, which may work cooperatively with separating photoexcited charges to enhance the photocatalytic efficiency. Our work implies the importance of the cocatalysts in affecting the surface structure and adsorption of reactants and products and then improving the photoactivity, in addition to the well-known role in charge separation.
关键词： Titanium Dioxide,Charge Separation,Pt Cocatalyst,Hydrogen Production,Methanol to Methoxy Conversion
更新于2025-09-23 15:21:21