Effects Of Alkali Metal Ions On The Synthesis And Performance Of WO₃ Photocatalysts

Design and synthesis of efficient semiconductor photocatalyst is the basic way to resolve the energy crisis and environmental pollution problems which human being confronts. Solar energy because of its rich, clean, renewable and other advantages, play a decisive role in the development of new energy. How to improve the conversion efficiency of solar energy is a core problem in the photocatalysis research field at present. In this paper, we illustrate the existing problems of photogeneration carriers recombination, narrow light absorption range and so on in the researches on the semiconductor photocatalytic leading to the of low efficiency of photocatalysis and coping strategies in detail. Based on WO3 as the research subject, different morphology of tungsten oxide will bring different catalytic effect. This article revolves around how to improve the efficiency of WO3 photocatalytic starting our experimental work.First of all, in order to improve the separation efficiency of tungsten oxide photogeneration electrons and holes, we designed and synthesized a kind of carbon materials and semiconductor materials controlled assembly of MWCNTs @ Cs2W3O10 core- shell structure, and it is the first time to successfully construct MWCNTs@Cs2W3O10 core-shell structure. It shows that Cs+ pre-adsorbed on the surface of MWCNTs by electrostatic force can direct the crystallization of Cs2W3O10. This core-shell arrangement allows the Cs2W3O10 particles to be sufficiently accessible for catalytic reactions and the electron storage ability of MWCNTs to be sufficiently used. Compared to samples that in the absence of MWCNTs and that without layer formation, the photoactivity of the core-shell composites are greatly enhanced by more than one order.Secondly, because of the light catalytic reaction occurring on the surface of the catalyst, so how to increase the specific surface area exposed to more active sites is undoubtedly the key to improve the photocatalytic activity. In the presence of Na+, with WCl6 as tungsten source, we get a kind of white powder, and the white powder can dissolve in water, which forms quantum size colloid nanowires. Combined with the gel has good solubility in water, we try to splitting water in the presence of homogeneous cocatalysis. This material has not only brought the advantages of the one-dimensional materials and quantum size effect, but also can realize the homogeneous photocatalysis reaction in aqueous systems, so as to achieve efficient catalytic efficiency of the homogeneous catalyst.Finally, based on the energy level matching with Ta3N5, Ta ON and tungsten oxide, and our perious work emphasizes the role of alkali metal ions in preparation in the synthesis. We try to prepare tungsten oxide composite material with Ta3N5 or Ta ON, that is, WO3 grow on the surface of tantalum nitride material in the presence of alkali metal ions. To build a Z-scheme system, which can carry out water splitting without any sacrificing reagent.