碳纳米管辅助下ZnS光催化过程中光腐蚀机理的研究

Carbon nanotubes assisted investigation of photocorrosion mechanism of ZnS nanocrystals in the photocatalytic reaction

光腐蚀是困扰Ⅱ-Ⅵ半导体应用在光催化领域的一大难题。本论文以光催化降解亚甲基蓝为探针反应,研究了ZnS/碳纳米管复合物以及ZnS纳米晶体光催化过程中的光腐蚀机理。研究结果表明碳纳米管虽然不能避免ZnS的光腐蚀,但在每个循环实验中都可以提高ZnS的光催化效率。ZnS纳米晶体在光腐蚀过程中逐渐变小且相互融并,颗粒之间的界限逐渐模糊,并产生一些空腔结构。ZnS纳米晶体质量的损失与光腐蚀时间呈准线性关系,与所用的有机污染物亚甲基蓝的浓度没有关系。在本系统的富OH-体系中,光腐蚀的最终产物主要是ZnSO4。

The photocorrosion is bothersome when Ⅱ-Ⅵ semiconductors, such as ZnS and CdS etc. , are applied in photocatalytic reaction. The photocorrosion mechanism of ZnS/carbon nanotubes composites and ZnS nanocrystals was investigated using methylene blue （MB） photodegradation reaction as a probe. The results showed carbon nanotubes can promote the photocatalytic activity of ZnS in ME degradation behaviour although carbon nanotubes can not avoid the photocorrosion of ZnS nanocrystals. During the photocatalytic process, ZnS nanocrystals subsequently become small and mutually coalesce into together. In addition, some hollow structures were formed. We found there was a quasi-linear relationship between mass loss of ZnS nanocrystals and photocorrosion time. There was not relationship between mass loss of ZnS nanocrystals and the concentration of ME. The final photocorrosion products of ZnS nanocrystals were ZnSO4.