Abstract：
Tubular Co9S8/CdS heterostructures have been successfully synthesized by in-situ growing CdS onto Co9S8 nanotubes through a simultaneous immobilization and in-situ reduction strategy. It turned out that the so-obtained heterostructure with Co9S8/CdS molar ratio of 1/10 can display a broad light absorption edge and especially much enhanced capacity for photocatalytic reduction of Cr(VI) under visible light. The characterization analysis and experimental results suggested that an interfacial electrostatic field between Co9S8 and CdS elements in the heterostructure could be constructed due to their different Fermi levels, allowing for more quantities of highly reductive electrons to participate in the photocatalytic reaction. Therefore, the so-obtained Co9S8/CdS (1/10) heterostructures could achieve the photocatalytic reduction efficiency of 100% within 20 min, which was more than two and four times larger than that of pristine CdS and Co9S8, respectively. Moreover, the possible photocatalytic reaction mechanism for reducing Cr(VI) was investigated and found to follow the direct Z-scheme charge transfer pathway. This novel fabrication route for composite photocatalysts with tubular heterostructures could lead to the widespread implementations for the elimination of various harmful pollutants in the process of environmental governance.
摘要：
管状Co9S8/CdS异质结构已通过同时固定和原位还原策略通过在Co9S8纳米管上原位生长CdS成功合成。结果表明，这样获得的Co9S8/CdS摩尔比为1/10的异质结构可以显示出宽的光吸收边缘，尤其是在可见光下光催化还原Cr（VI）的能力大大提高。表征分析和实验结果表明，异质结构中Co9S8和CdS元素之间的界面静电场可以由于它们不同的费米能级而被构造。允许更多的高度还原性电子参与光催化反应。因此,由此获得的Co9S8/CdS(1/10)异质结构在20min内可达到100%的光催化还原效率,分别是原始CdS和Co9S8的两倍和四倍以上。此外，研究了还原Cr（VI）的可能的光催化反应机理，并发现遵循直接Z方案电荷转移途径。这种具有管状异质结构的复合光催化剂的新颖制造路线可能导致在环境治理过程中消除各种有害污染物的广泛实施。
