溶剂热法制备CeO_(2)/BiOI复合光催化剂及性能

Preparation and Photocatalytic Dye Degradation Properties of CeO_(2)/BiOI Heterojunction

针对提高单体BiOI的可见光催化降解效率的问题,采用煅烧法在不同温度下制备出了CeO_(2)三维花型结构,然后将CeO_(2)加入到BiOI前驱体溶液中,通过溶剂热法制备出不同复合比例的BiOI/CeO_(2)复合光催化剂。运用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)、电化学等对制备样品进行表征,利用对罗丹明B(RhB)的降解实验评价了不同CeO_(2)煅烧温度、不同复合比例对光催化降解效率的影响,并通过自由基捕获实验对复合材料的光催化机理进行了分析。结果表明,当BiOI与CeO_(2)(煅烧温度为400℃)的质量比为1∶1时,复合材料对RhB的降解率最佳,约为38.1%。相比于BiOI(约为24%)和CeO_(2)(约为23%)其降解率有了一定的提高。这可能归因于两种材料复合后在界面处形成的异质结结构有效地抑制了光生电子-空穴的复合速率,实现了光催化性能的提高。

In order to improve the visible light catalytic degradation efficiency of monomer BiOI,the three-dimensional floral structure of CeO_(2) was prepared by calcination at different temperatures.Then,CeO_(2) was added to BiOI precursor solution and BiOI/CeO_(2) composite photocatalysts with different composite ratios were prepared by solvothermal method.X-ray powder diffraction(XRD),scanning electron microscope(SEM),ultraviolet-visible diffuse reflectance spectroscopy(UV-Vis DRS)and electrochemistry were used to characterize the prepared samples,and the effects of CeO_(2) calcination temperatures and different mass ratios on the photocatalytic degradation efficiency were evaluated by the degradation experiments of rhodamine B(RhB).The photocatalytic mechanism of the composites was analyzed by radical trapping experiments.The results showed that when the mass ratio of BiOI to CeO_(2)(400℃)was 1∶1,the degradation rate of RhB was the best,which was about 38.1%.Compared with BiOI(about 24%)and CeO_(2)(about 23%),the degradation rate was improved.This may be attributed to the heterojunction structure formed at the interface after the composite of the two materials,which effectively inhibits the photoelectron-hole recombination rate and improves the photocatalytic performance.