AgI-AgBr/硅藻土复合光催化剂的制备及其光催化性能

采用一步法制备了AgBr/硅藻土、Ag-AgBr/硅藻土、AgI-AgBr/硅藻土3种复合光催化剂,采用SEM,XPS,UV-VisDRS,BET,XRD技术对复合材料进行了表征,并以其为光催化剂,在可见光下降解水中罗丹明B(RhB)。表征结果显示,AgI-AgBr/硅藻土具有最大的比表面积,且在可见光区的光吸收效率最高。实验结果表明:AgI-AgBr/硅藻土表现出最强的光催化活性,光反应40min时的RhB去除率即可达99.8%;该催化剂具有优异的稳定性,5次重复使用时的RhB去除率仍可达90%以上;AgI和AgBr形成异质结,有效抑制了光生电子-空穴对的复合,提高了AgI-AgBr/硅藻土的光催化活性;空穴是光催化降解RhB过程中起主要作用的活性物种。

Preparation of AgI-AgBr/diatomite composite photocatalyst and its photocatalytic activity

Three kinds of composite photocatalysts,AgBr/diatomite,Ag-AgBr/diatomite,AgI-AgBr/diatomite,were prepared by one-step process and characterized by SEM,XPS,UV-Vis DRS,BET and XRD. The photocatalysts were used to degrade rhodamine B（Rh B）in water under visible light. The characterization results showed that AgI-AgBr/diatomite has the largest specific surface area and the highest light absorption efficiency under visible light. The experimental results showed that：AgI-AgBr/diatomite exhibited the strongest photocatalytic activity,and the removal rate of Rh B reached 99.8% after 40 min of light reaction;The catalyst had excellent stability,and the Rh B removal rate could reach 90% above after 5 times of reuse;The heterostructure formed with AgI and AgBr effectively inhibited the recombination of photoelectron-hole pair and improved the photocatalytic activity of AgI-AgBr/diatomite;Holes were active species that played a major role in photocatalytic degradation of Rh B.