CuS纳米片修饰Bi_(5)O_(7)I复合材料用于光催化还原Cr(Ⅵ)水溶液

CuS Nanosheet Decorated Bi_(5)O_(7)I Composite for the Enhanced Photocatalytic Reduction Activity of Aqueous Cr(Ⅵ)

光催化技术以其高效、安全、低成本的优势,被广泛研究用于去除污水中有毒副作用的重金属Cr(Ⅵ)。制备半导体复合材料是一种可以有效提高半导体光催化性能的途径。本研究通过简单的水热法合成了CuS纳米片修饰的Bi_(5)O_(7)I复合材料,并且表征和评估了其在可见光下对Cr(Ⅵ)的光催化还原活性。与纯Bi_(5)O_(7)I微米棒及纯CuS样品相比,CuS/Bi_(5)O_(7)I复合催化剂对Cr(Ⅵ)水溶液具有更高的光催化降解活性。在相同的可见光辐照条件下,15wt%CuS修饰的复合样品,光催化降解Cr(Ⅵ)的反应常数是纯/Bi_(5)O_(7)I样品的20倍,纯CuS样品的4.3倍。对比样品的比表面积、光致发光谱和电化学阻抗谱的测试结果发现,复合样品表现出更高的催化效率是由于CuS/Bi_(5)O_(7)I具有更大的比表面积、更宽的光吸收区域及更高的光生电子–空穴对的分离和传输效率。本研究还提出了CuS/Bi_(5)O_(7)I复合材料光催化降解Cr(Ⅵ)的机理。

Photocatalytic approach has been extensively explored to remove toxic Cr(Ⅵ)in wastewater owing to its high efficient,safe and low cost features.Fabricating semiconductor composite is supposed to be an effective approach to improve the poor photocatalytic activity of single component.In this work,we prepared CuS nanosheets decorated Bi_(5)O_(7)I composites by a simple hydrothermal method,and characterized and evaluated its photoatalytic reduction activity of Cr(Ⅵ)under the visible-light irradiation.Compared to pure Bi_(5)O_(7)I microrods and CuS nanoparticles,the as-prepared CuS/Bi_(5)O_(7)I composites exhibits more efficient photocatalytic reduction of aqueous Cr(Ⅵ).The reaction rate constant of 15wt%CuS/Bi_(5)O_(7)I catalyst was 20 times and 4.3 times of that of pristine Bi_(5)O_(7)I and CuS,respectively.BET,photoluminescence and EIS spectra measurement demonstrate that the improved photocatalytic activity may be attributed to their higher surface areas,broader light absorption region,improved separation,and transfer efficiency of photo-induced electron-hole pairs.Moreover,a possible photocatalytic mechanism of CuS/Bi_(5)O_(7)I catalyst is also proposed.