CdS/Sr_(2)Bi_(2)O_(5)复合光催化剂的制备、表征及性能测试

Preparation,characterization and performance test of CdS/Sr_(2)Bi_(2)O_(5) composite photocatalyst

在固相烧结制备单相Sr_(2)Bi_(2)O_(5)的基础上,利用化学沉淀法制备了一系列CdS/Sr_(2)Bi_(2)O_(5)复合光催化材料来解决环境污染中的有机污染物问题。采用XRD、SEM、TEM、EDS和XPS进行了复合光催化剂的表征,通过降解亚甲基蓝评估其光催化性能。实验结果表明,CdS/Sr_(2)Bi_(2)O_(5)复合光催化剂由CdS和Sr_(2)Bi_(2)O_(5)两相组成,形貌为团聚状的Sr_(2)Bi_(2)O_(5)颗粒并附着在不规则的CdS颗粒上,两相表面紧密接触在一起,形成明显的界线,相互耦合形成异质结;当CdS/Sr_(2)Bi_(2)O_(5)摩尔比为1/1时,可见光光催化性能最好,40 min降解亚甲基蓝的效率达95%。进一步循环测试发现,复合光催化剂具有良好的稳定性。显著改善的光催化性能主要归因于复合光催化剂中在CdS与Sr_(2)Bi_(2)O_(5)之间形成了异质结,在加快光生电子空穴对分离的同时,还有效抑制了光生电子空穴对的复合。

On the basis of solid phase sintering to prepare single-phase Sr_(2)Bi_(2)O_(5),a series of CdS/Sr_(2)Bi_(2)O_(5)composite photocatalytic materials were prepared by chemical precipitation method to solve the problem of organic pollutants in environmental pollution.The composite photocatalyst was characterized by XRD,SEM,TEM,EDS and XPS,and its photocatalytic performance was evaluated by degrading MB.After experiments,it is found that the CdS/Sr_(2)Bi_(2)O_(5)composite photocatalyst consists of two phases:CdS and Sr_(2)Bi_(2)O_(5).The morphology of agglomerated Sr_(2)Bi_(2)O_(5)particles is attached to the irregular CdS particles,and the surface of the two phases are in close contact with each other,forming an obvious boundary,and forming a heterojunction.When CdS/Sr_(2)Bi_(2)O_(5)mole ratio is 1/1,the visible photocatalytic performance is the best,the degradation efficiency of MB reached 95%in 40min,and three cycle tests show that the photocatalyst had good stability and repeatability.The significantly improved photocatalytic performance is mainly attributed to the formation of heterojunction between CdS and Sr_(2)Bi_(2)O_(5)phases in the composite photocatalyst,which accelerates the separation of photoelectron-generated hole pairs and effectively inhibits the recombination of photoelectron-generated hole pairs.