Fabrication Of GaN/ZnO Composites And The Photocatalytic Performance

As an important wastewater treatment method, photocatalytic has attractedextensive attention and research due to many advantages such as high efficiency, lowcost and no secondary pollution etc. Both Zinc oxide (ZnO) and gallium nitride (GaN)are typical direct band gap semiconductors, which have the same wurtzite structureand similar band gap. These excellent features make them have some potentialapplications in photocatalysis.In this study, we focus on the photocatalytic properties of GaN and ZnOnano-materials. The photocatalytic enhancement mechanism of GaN/ZnO compositeswas researched via the preparation, characterization and catalytic propertiesmeasurement of GaN/ZnO composites. The purpose of this research is to explore amethod which can improve the photocatalytic performance of GaN and ZnOnano-materials. The details are as follows:(1) GaN powder was synthesized by the sol-gel method. And then, GaN/ZnOcomposites were synthesized by solid phase method. The microstructure, composition,and photoluminescence properties of the composites were characterized by usingX-Ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersivespectrometer (EDS), high-resolution transmission electron microscopy (HRTEM) andphotoluminescence (PL) spectra. The results show that the GaN/ZnO material iscomposed of the wurtzite GaN and wurtzite ZnO and the main morphology arenanoparticle (GaN) and short nanorod (ZnO). In addition, the heterojunction wasobserved in the contact site of GaN and ZnO. The composite of GaN and ZnO makesweakened light emitting peak, and the weakest light emitting peak was obtained whenthe the ratio of GaN and ZnO was1:2, which means that the heterojunction of GaNand ZnO inhibits the recombination of optical electronic-hole.(2) The photocatalytic properties of six kinds of GaN/ZnO composites withdifferent compositions were researched by the degradation of methylene blue aqueoussolution under the white light and UV light, respectively. The effect of composition tophotocatalytic properties was researched. The results show that the photocatalyticproperty of GaN/ZnO composites is improved obviously compared with the pureGaN and ZnO powders. Under the irradiation of white light and ultraviolet, thechanging trends of photocatalytic performance are consistent. The photocatalytic activity was analyzed by pseudo-first-order kinetics equation. Under the white lightand UV light, the best photodegradation rate constant k is0.11072min-1and0.12843min-1, respectively. By comparison with visible light and ultraviolet light,found that the ultraviolet light play a leading role in the whole process ofphotocatalytic reaction.In this study, GaN/ZnO composites were synthesized by using GaN and ZnOnanomaterials. To a certain extent, the photocatalytic performance is improved.GaN/ZnO composites have potential application value for using the sun lightdegradation organic pollutants of waste water.