Photoelectric Property And Photocatalytic Property Of Wide Bandgap Metal Oxide Semiconductor

On the basis of combinatorial and the idea of equilateral ingredient triangle,TiO₂/ZnO/Fe₂O₃composite system consist of66ingredient points was designed. Thephotocurrents under different light sources and bias voltages were measured through ahigh-throughput screening platform. The photocurrent amplitude was chosen as aparameter to evaluate the photoelectric response of the composite. In order to assess thecomposition effect of the composite material, the quantitative formula of compositioneffect was provided for the first time. We expect this quantitative formula of compositioneffect may provide a means for the evaluation of photoelectric properties andphotocatalytic properties of the composite.In order to compare the photocatalytic properties of TiO₂, ZnO and their composite ingas phase, different mole ratios of TiO₂/ZnO nanocomposite were designed to degradegaseous formaldehyde. Through comprehensive analysis of UV-vis diffuse reflectance（UV-vis） spectra, photoluminescence （PL） spectra and energy band diagram, we found thatthe difference of photocatalytic properties of ZnO and TiO₂may mainly come from themuch more recombination of photoinduced charges of ZnO which was part of thephotocatalytic physics process.Six prism （SP）, short six pyramid （SSP） and long six pyramid （LSP） shape ZnO withdifferent defect percentages were prepared at low temperatures by chemical method andheat-treated in the Ar and H₂mixed atmosphere at500℃for several hours. Bycomparisons, the degradation efficiency under ultraviolet illumination of LSP ZnO afterheat-treated in gas mixture of Ar and H₂for10h was larger than that of TiO₂. Percentagesof donor-related defect （Zn_i+V_O） of as-prepared ZnO increased with heat-treated from0h to10h, which was in accordance with the tendency of relative degradation efficiency ofas-prepared ZnO with heat-treated from0h to10h. This phenomenon indicates thatdonor-related defects have a favorable effect to photocatalysis. In addition, thephotocatalytic performances of as-prepared ZnO were different, which resulted from thedifferences of morphologies and defect percentages together.