助催化剂NiCoP修饰改性增强半导体TiO2的光催化性能

Enhanced Photocatalytic Property of TiO2 Semiconductor by Modification of Cocatalyst NiCoP

为了增强半导体TiO2的光催化性能,采用相对简便的磷酸盐还原法制备了双金属磷化物NiCoP,并且首次将NiCoP作为助催化剂对半导体光催化剂TiO2进行修饰改性。以罗丹明B(RhB)染料溶液为污染物模型,对NiCoP/TiO2复合材料的光催化活性进行测试。实验结果表明,与纯TiO2和纯NiCoP相比,适量的NiCoP修饰使TiO2催化剂的光催化降解性能明显增强;其中,NiCoP的负载量为0.25%时,NiCoP/TiO2复合材料光催化活性最高,对RhB的降解效果最佳。电化学测试表明,复合材料活性增强的主要原因是NiCoP与TiO2发生相互作用,促进了光生电荷的分离,提高了其迁移效率。紫外-可见漫反射光谱证实,NiCoP负载后使得半导体催化剂的光谱响应范围稍有拓宽。同时,自由基捕获实验证明·OH、·O2-为该降解反应的主要活性物种。

AAiming at enhancing the photocatalytic property of TiO 2,we synthesized the bimetal phosphide NiCoP by a relatively simple approach of phosphate reduction,and utilized the well dispersed NiCoP as cocatalyst to modify the photocatalyst TiO 2 for the first time. Then,the mea-surement of photocatalytic activity of NiCoP/TiO 2 composites were conducted,taking rhodamine B (RhB) dye solution as a contaminant model. It could be found from the results that there was an obvious enhancement in photocatalytic degradation performance of NiCoP/TiO 2 composites after loading proper amount of NiCoP,compared with either pure TiO 2 or pure NiCoP. The NiCoP/TiO 2 composite with NiCoP loading amount of 0.25% exhibited the highest photocatalytic activity and optimal degradation effect to RhB. Electrochemical test demonstrated that the reason for the improved photocatalytic activity of NiCoP/TiO 2 composites lay in the interaction of loaded NiCoP with host catalyst TiO 2,promoting the separation and migration of photogenerated charge. The results of UV-vis diffuse reflectance spectra confirmed that after loading phosphides the slightly broadened spectrum response range of TiO 2 were derived from the loading of NiCoP. In addition,the free radical capture experiment proved ·OH and·O 2 - as the main active species in the degradation reaction.