The Studies Of Structure And Photoelectrochemistry Performance On Transition Metal Oxides Nanomaterials

The global energy shortage and environment problem make it more important to develop an renewable energy materials to meet human energy needs.Solar energy is a inexhaustible natural resource,with the magnitude of the avaible solar power striking the earth's surface at any one instant equal to 130 million 500MW power plants.However,how to absorption,storage,and distribution the solar energy is the most important problems to solve to fully utilize it for the global energy demand.Transition metal oxides has fascinationg electronic,optic and magnetic properties,moreover its abundant-storge,low manufacture cost and excellent-stability that lead it to a potential material in the research field and application of optoelectron and magnetism.As a photoelectronic catalyst,transition metal oxides exist a problem that the shorter charge cattier diffusion length and the slower electron transger rate decrease the recombination of photogenerated electron-hole pairs.In this thesis,we used a hydrothermal method to synthesize a plasmonic and amorphous oxygen-vacancy MoO3-x nanosphere as a highly active photoanode for water oxidation.The plasmonic resonance induced by oxygen vacancies in MoO3-X nanospheres leads to a strong absorption in visible-near-infrared wavelength for photoelectrocatalysis which can effectively suppress electron-hole recombination and thus enhance the photocuttent resonance.A thickness Cu₂O nanosheet is also successfully synethesized by a hyrothermal method.In order to investigate a deep cognize the intrinsic relationship between structure and performance we used a combination of X-ray absorption spectroscopy?XAS?,X-ray diffraction?XRD?patterns,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?and X-ray photoelectron spectroscopy?XPS?to measure these materials.The works are exhibited as follows in detail:1.We have used a simple hydrothermal method to synethsize a plasmonic and amorphous MoO3-x nanospheres.The M0O3-x nanosphere exhibits strong plasmon absorption at visible-near-infrared wavelength,thus substantially enhancing the utilization of sunlight.In the photoelectron-catalyst water oxidation performance texts,compared to the commercial bulk MoO3 nanoparticles,the A-MoO3-x has a much stronger photocurrent.Moreover,as the XAFS results displayed that the oxygen-vacancy derived amorphous nature of MoO3-x lead to the formation of a metastable hexagonal structure in the short-range order,which greatly improves the charge-separation efficiency.The synergistic effect of plasmonic absorption and amorphous structure results in the improved solar water-oxidation activity of the MoO3-x photoanodes.2.Cu₂O nanosheet was synthesized by one-pot hydrothermal method.The Cu₂O nanosheet morphology was characterized by TEM,SEM,and the results shows that Cu₂O nanosheet was uniform In the photoelectron-catalyst water oxidation performance texts,compared to the commercial Cu₂O nanoparticles,the Cu₂O nanosheet has a much stronger photocurrent?It shows that the Cu₂O nanosheet has a better photo-electro-catalytic performance than the commercial one.