The colloids of ZnO and WO 3 were synthesized and ZnO colloid with different mass fractions was added into the WO 3 colloid to get WO 3/ZnO composite colloids. The experimental results indicate that the UV-light color...The colloids of ZnO and WO 3 were synthesized and ZnO colloid with different mass fractions was added into the WO 3 colloid to get WO 3/ZnO composite colloids. The experimental results indicate that the UV-light coloration of WO 3 nanoparticles could be improved greatly after the addition of ZnO. When the molar ratio of ZnO to WO 3 is about 1∶100, the magnitude of the difference of absorbance(ΔOD) at 900 nm after and before the coloration for WO 3/ZnO colloids is as about 135 times as that of WO 3 colloids. The surface photovoltaic spectra show that the state density of the surface state of WO 3 increases greatly after the addition of ZnO, thus, under the UV-light irradiation more electrons from ZnO nanoparticles can be captured in the surface state and those electrons can be excited to a higher energy level, resulting in the improved coloration.展开更多
Core–shell nanoparticles containing plasmonic metals（Ag or Au） have been frequently reported to enhance performance of photo-electrochemical（PEC） devices. However, the stability of these particles in water-splitt...Core–shell nanoparticles containing plasmonic metals（Ag or Au） have been frequently reported to enhance performance of photo-electrochemical（PEC） devices. However, the stability of these particles in water-splitting conditions is usually not addressed. In this study we demonstrate that Ag@SiOcore–shell particles are instable in the acidic conditions in which WO-based PEC cells typically operate, Ag in the core being prone to oxidation, even if the SiOshell has a thickness in the order of 10 nm. This is evident from in situ voltammetry studies of several anode composites. Similar to the results of the PEC experiments, the Ag@SiOcore–shell particles are instable in slurry-based, Pt/ZnO induced photocatalytic water-splitting. This was evidenced by in situ photodeposition of Ag nanoparticles on the Pt-loaded ZnO catalyst, observed in TEM micrographs obtained after reaction. We explain the instability of Ag@SiOby OH-radical induced oxidation of Ag, yielding dissolved Ag+. Our results imply that a decrease in shell permeability for OH-radicals is necessary to obtain stable, Ag-based plasmonic entities in photo-electrochemical and photocatalytic water splitting.展开更多
文摘The colloids of ZnO and WO 3 were synthesized and ZnO colloid with different mass fractions was added into the WO 3 colloid to get WO 3/ZnO composite colloids. The experimental results indicate that the UV-light coloration of WO 3 nanoparticles could be improved greatly after the addition of ZnO. When the molar ratio of ZnO to WO 3 is about 1∶100, the magnitude of the difference of absorbance(ΔOD) at 900 nm after and before the coloration for WO 3/ZnO colloids is as about 135 times as that of WO 3 colloids. The surface photovoltaic spectra show that the state density of the surface state of WO 3 increases greatly after the addition of ZnO, thus, under the UV-light irradiation more electrons from ZnO nanoparticles can be captured in the surface state and those electrons can be excited to a higher energy level, resulting in the improved coloration.
基金part of the research programme of the Foundation for Fundamental Research on Matter(FOM,project 10TBSC07-1),which is part of the Netherlands Organisation for Scientific Research(NWO)
文摘Core–shell nanoparticles containing plasmonic metals（Ag or Au） have been frequently reported to enhance performance of photo-electrochemical（PEC） devices. However, the stability of these particles in water-splitting conditions is usually not addressed. In this study we demonstrate that Ag@SiOcore–shell particles are instable in the acidic conditions in which WO-based PEC cells typically operate, Ag in the core being prone to oxidation, even if the SiOshell has a thickness in the order of 10 nm. This is evident from in situ voltammetry studies of several anode composites. Similar to the results of the PEC experiments, the Ag@SiOcore–shell particles are instable in slurry-based, Pt/ZnO induced photocatalytic water-splitting. This was evidenced by in situ photodeposition of Ag nanoparticles on the Pt-loaded ZnO catalyst, observed in TEM micrographs obtained after reaction. We explain the instability of Ag@SiOby OH-radical induced oxidation of Ag, yielding dissolved Ag+. Our results imply that a decrease in shell permeability for OH-radicals is necessary to obtain stable, Ag-based plasmonic entities in photo-electrochemical and photocatalytic water splitting.
