研磨-焙烧法制备BiOI/BiOBr异质结光催化剂及其光催化性能

Preparation of BiOI/BiOBr hetero-structured photocatalyst by grinding-calcination route and its photocatalytic performance

首先通过沉淀法制备BiOBr和BiOI纳米粉体,然后在主体BiOBr光催化剂中掺杂不同含量的共催化剂BiOI,充分研磨后在不同温度下进行煅烧3h,制备了BiOI/BiOBr系列复合物,其中BiOI的质量分数分别为1%,2%,4%和8%.采用氮气物理吸附、X射线粉末衍射(XRD)、扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)、紫外-可见(UV-Vis)漫反射(DRS)和光电流测试等技术对所制备的样品进行表征.以酸性橙II为模拟污染物,在可见光下考察了煅烧温度和BiOI复合含量对BiOBr主体光催化剂的光催化性能的影响.研究表明,当复合BiOI的含量为4%,煅烧温度为400℃时所制备的复合光催化剂表现出最高光催化性能,其降解效率分别是纯BiOBr和BiOI的1.7和1.9倍.复合BiOI促进了催化剂对可见光的吸收,同时经过研磨和煅烧形成的BiOI/BiOBr异质相结,促进了光生电子(e-)和空穴(h+)的分离,提高了光催化活性.

Pure BiOBr and BiOI nanopowders were first synthesized by precipitation method.BiOBr main photocatalyst and BiOI cocatalyst with different contents were mixed and grinded.After grinding, the composite powder was calcined at different temperatures.The produced BiOI/BiOBr hetero-structured photocatalysts（BiOI mass fraction content：1 %, 2 %, 4 %, 8 %） were characterized by N2-physical adsorption, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, Fourier translation infrared spectroscopy（FT-IR）, and UV-Vis diffuse reflectance spectroscopy（DRS） and photoelectrochemical measurements.Acid orange II dye was selected as degradation target pollutant under visible light irradiation.The effects of BiOI coupling concentration and calcination temperature on the photocatalytic performance were investigated.The results show that the BiOI/BiOBr composite photocatalyst with 4 % mass fraction of BiOI and calcination at 400 ℃show about 0.7 and 0.9 times of increasement in degradation rate compared to pure BiOBr and BiOI,respectively.Coupling of BiOI cocatalyst promoted the visible light absorption.Moreover, the formation of BiOI/BiOBr hetero-structure could restrain the recombination rate of photogenerated electrons（e-） and holes（h＋）.These two reasons could mainly account for the boosting of photocatalytic activity.