Simulation Of Electronic Structure And Research On Photocatalytic And Optical Properties Of Zinc Gallium Oxide

As a new inorganic functional material,ZnGa₂O₄ shows high chemical stability,excellent fluorescence,superior photocatalytic performance,good lithium storage and microwave dielectric properties owing to its structural advantages,spontaneously,more and more researches on ZnGa₂O₄ have been reported in recent years.The establishment of density functional theory made it possible for researchers to accurately calculate and simulate the elementary properties of solid materials from the microscopic essence.It is undoubtedly a pretty efficient and convenient approach to use computational methods and experimental methods together to study the properties of materials.In this paper,some basic properties of ZnGa₂O₄ have been studied by adopting a combined technique of experiment and calculation,including electronic structure,photocatalytic and optical performance,and the completed research works are as follows:By operating VASP and its assistant softwares,the first-principles calculations of bulk ZnGa₂O₄ was carried out with GGA-PBE method.Firstly,the conventional cell structure of ZnGa₂O₄ was optimized and converted into primitive cell structure,then this primitive cell model exported by VASP was used to calculate the electronic structure and optical constants of ZnGa₂O₄.The calculation and simulation results show that ZnGa₂O₄ is an indirect bandgap semiconductor where electrons take a leading role in carrier transport,and its electrons in valence band could jump into the conduction band along the path in real space from O^2-to Zn²⁺ and Ga³⁺.ZnGa₂O₄ could exhitbit high photocatalytic activity and can be used as a potential TCO material and a possible microwave dielectric ceramics.It can also be applied to the field of optical ceramics as an ultraviolet window material.A new reusable film-like ZnGa₂O₄ photocatalyst for degrading organic dyes from aqueous solution has been successfully synthesized with a two-step hydrothermal method.The SEM characterization results indicated that as-prepared film-like ZnGa₂O₄ was composed of dense self-assembly nanostructures,and exhibited good photocatalytic activity due to its large surface area and low recombination rate of light-generated electrons and holes.From the photocatalytic experiment results under UV-light excitation,it was clear that the film-like ZnGa₂O₄ showed stronger physical adsorption for Rh B molecules than MO molecules,and the photocatalytic degradation rate of Rh B and MO after 1 h could reach 73.7% and 40.5%,respectively.The test results of reusability proved the stable photocatalysis of the film-like ZnGa₂O₄ for Rh B and MO.A white ZnGa₂O₄ powder was prepared via a facile one-step hydrothermal method.The optical band gap of this synthesized ZnGa₂O₄ powder was 4.8 e V calculated by using UV-Visible absorption spectrum with Tauc plot method.In addition,the absorption edge simulated by using PHS method was quite similar to the absorption spectrum measured in experiment.The excitation and emission spectra showed that ZnGa₂O₄ could emit blue-violet light through self-activation under the excitation of UV-light with the wavelength of 250 nm.