溶剂对钨酸铋/石墨烯形貌结构和光催化性能的影响

Effect of Solvents on Morphology and Photocatalytic Performance of Bi_(2)WO_(6)/RGO

本工作采用溶剂热法通过乙二醇、乙二胺、水-乙二醇、水-乙二胺、水和水-乙酸不同溶剂制备可见光催化剂Bi_(2)WO_(6)/RGO,并对其形貌结构和光催化性能进行表征。研究结果表明,溶剂对Bi_(2)WO_(6)/RGO的形貌和光催化性能有显著影响。在可见光(λ>420 nm)照射下,以水为溶剂制备的样品对罗丹明B(RhB)的光催化降解性能最佳,20 min内降解率达到98%,且经过五次循环降解后光催化效果基本保持不变。Bi_(2)WO_(6)/RGO的光催化性能增强可归因于在水溶剂下形成的Bi_(2)WO_(6)分级结构微球为光催化反应提供更多的反应活性位点,同时石墨烯的引入增大了材料的比表面积,进一步促进了电子-空穴对的有效分离。自由基捕获实验表明,复合材料光降解RhB过程中光生空穴(h+)起主要作用,·O_(2)-和·OH起次要作用。

A series of visible-light-driven Bi_(2)WO_(6)/RGO photocatalysts were prepared by solvothermal processes with different kinds of solvents including ethylene glycol,ethylene diamine,deionized water-ethylene glycol,deionized water-ethylene diamine,deionized water and deionized water-aceticacid.The morphology,structure and photocatalytic performance of the obtained samples were characterized and analyzed.The results show that solvents have a great influence on the morphology and photocatalytic activity of Bi_(2)WO_(6)/RGO photocatalysts.Under visible light irradiation(λ>420 nm),the photocatalytic activities of Bi_(2)WO_(6)/RGO photocatalysts were evaluated by the decomposition of Rhodamine B(RhB).Among them,the sample prepared using deionized water as solvent exhibited the best photocatalytic performance.The degradation rate of RhB reached 98%within 20 minutes,and after five cycles the degradation of RhB remained approximately constant,suggesting the excellent chemical stability of the catalyst.The enhanced photocatalytic activity of Bi_(2)WO_(6)/RGO composite could be attributed to the formation of Bi_(2)WO_(6)hierarchical microspheres in aqueous solvents,which provide more reactive sites for photocatalytic reactions,and the introduction of graphene increases the specific surface area of the material,further promoting the effective separation of the electron-hole pairs.In addition,trapping experiments of the predominant radical species were conducted,which indicates the photo-generated holes(h+)played a major role in the photodegradation of RhB,and the effect of·O_(2)-and·OH on the photodegradation of RhB also cannot be ignored.