Preparation And Optical And Electrocatalytic Properties Of Nanosized Selenide And Its Composites

In recent years, due to the suitable band structures, good optical properties,electrical properties, electro-optical synergy and electromagnetics properties, selenide nanoparticles and composites were widely used in optical, electro-Catalysis and electronic devices. Therefore, the synthesis and properties of selenide nanoparticles and composites have been hot topic of current research.In this paper, Na HSe precursor as the selenium source, obtained three composite of nano-selenium by hydrothermal synthesis method of controlled growth. The main contents of this paper are as follows:The Bi₂Se₃ ultrathin nanasheet was prepared by one-step hydrothermal method using bismuth chloride as bismuth source, selenium powder as selenium source, sodium borohydride as reductant, and deionized water and acetone as solvent. One-step hydrothermal synthesis could produce the Bi₂Se₃ ultrathin nanasheet with 2 nm thickness. Added surfactant PVP into system to regulate the thickness of ultrathin nanosheets and speculated the growth mechanism by varying the reaction time. We screened out the optimal structure via a series of characterization. And the Bi₂Se₃ ultrathin nanasheet exhibited excellent photocatalytic performance in degradating the methyl orange solution with a 78% degradation rate in 30 min.The ZnO\ZnSe nanonail heterogeneous array was prepared via in situ controlled synthesis onto the surface of FTO substrates. First off, dipped the FTO glass into solution of crystal seeds repeatedly and then annealed it to obtain ZnO seed layer. In the next place, ZnO nanorod array was grown on the FTO with ZnO seeds by using further hydrothermal process. ZnO\ZnSe nanonail heterogeneous array was obtained by selenizing the ZnO nanorod array and was tested the photoelectrochemical water oxidation performance as photoelectrode material. As-prepared ZnO\ZnSe nanonail heterogeneous array exhibited excellent photoelectrochemical catalytic performance due to its unique structure. We speculated the growth mechanism by varying the reaction time and confirmed the electrons moving direction by using time-resolved and steady-state photoluminescence spectroscopy, work function and valence band spectrum.We also did in-depth study of the role of hetero-nanoarchitecture in enhancingphotoelectrochemical water oxidation.A novel MoS_{2（1-x）}Se_2x/r GO composite material was synthesized by two-step hydrothermal method. First off, we mixed the ultrathin, curling MoSe₂ nanosheets with GO. During this process, we used thiurea to substitute sulfur atoms. Compared with MoSe₂ and MoS₂, as-prepared Mo S_{2（1-x）}Se_2x/r GO exhibited enhanced electro-catalytic hydrogen evolution performance. Different compositions of MoS_{2（1-x）}Se_2x/r GO were obtained by varying the ratio of Se/S. By measuring the electro-catalytic hydrogen evolution performance of different compositions, we confirmed MoS_0.8Se_1.2/r GO displayed enhanced electro-catalytic hydrogen generation performance.