异质结型光催化剂ZnO/AgBr/AgI的制备及其性能分析

Analysis on the preparation and properties of heterojunction photocatalyst ZnO/AgBr/AgI

本文探究制备一种ZnO/AgBr/AgI异质结型光催化剂,并对其结构和性能进行了分析。首先应用沉积-沉淀法制备ZnO/AgBr复合光催化剂,由于AgBr和AgI的溶度积不同,以离子交换的方法制备异质结型光催化剂ZnO/AgBr/AgI;利用X射线粉末衍射(XRD)、透射电镜(TEM)、能谱分析(EDX)、X射线光电子能谱(XPS)、紫外-可见漫反射光谱(UV-visDRS)等手段对该催化剂进行表征,并以可见光(500 W、λ>420 nm)为光源,评价该光催化剂光催化降解亚甲基蓝(MB)的活性,考察了不同AgI含量对ZnO/AgBr/AgI催化活性的影响。结果表明:AgI拓展了该催化剂的吸收光谱范围且当AgI生成量为AgBr的10%(质量分数)时,异质结型光催化剂ZnO/AgBr/AgI的催化活性最高;ZnO外层AgI/AgBr异质结的形成有利于快速分离光生电子和空穴,提高ZnO/AgBr/AgI的催化活性。

In this paper,a novel heterogeneous catalyst ZnO/AgBr/AgI was prepared and characterized.At first,ZnO/AgBr was prepared via deposition-precipitation method,and then a novel heterojunction structure ZnO/AgBr/AgI photocatalyst was synthesized by ion exchange because of the difference in Ksp.The prepared photocatalysts were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),energy dispersive X-ray spectroscopy(EDX),X-ray photoelectron spectroscopy(XPS) and UV-vis diffuse reflectance spectra(UV-vis DRS),respectively.The photocatalytic activity of ZnO/AgBr/AgI was measured with methylene blue(MB) as dye model under the visible light condition(500 W,λ >420 nm) and the different Agl content in the composite photocatalyst were studied.The results showed that Agl broadened the light absorption range of ZnO/AgBr/AgI catalyst in visible light area and the maximum photocatalytic activity of ZnO/AgBr/AgI could be obtained when the Agl was 10% of AgBr.Agl/AgBr heterojunction was beneficial to separate the photogenerated electrons and holes,also enhanced the photocatalytic activity of ZnO/AgBr/AgI.