高效光催化分解水产氢Ni_(2)P/Cd_(0.5)Zn_(0.5)S复合材料的共催化效应

Co-catalytic Effect of Ni_(2)P/Cd_(0.5)Zn_(0.5)S Photocatalyst for Efficient Hydrogen Evolution by Water Splitting

采用沉淀-水热法和低温热磷化法分别制备了Cd_(0.5)Zn_(0.5)S纳米颗粒和Ni_(2)P纳米片,利用超声空化效应合成了价格低廉、分散良好、高效的非贵金属磷化物助催化的Ni_(2)P/Cd_(0.5)Zn_(0.5)S复合材料。通过XRD、SEM、UV-vis、PL以及电化学测试等手段进行了表征测试。以Na_(2)S-Na_(2)SO_(3)为牺牲剂,在可见光(λ≥420 nm)照射下对样品的光催化分解水产氢性能进行评价。结果表明,Ni_(2)P显著提高了Cd_(0.5)Zn_(0.5)S的光催化产氢活性。当Ni_(2)P含量为10%时,复合材料的光催化产氢速率达到19.133 mmol/(g·h),为Cd_(0.5)Zn_(0.5)S产氢速率[7.865 mmol/(g·h)]的2.4倍,且七次光催化循环实验后的产氢速率仍为初始值的91%。这可以归因于复合材料在具有更好的光吸收性能和较低的禁带宽度的同时,Ni_(2)P为Cd_(0.5)Zn_(0.5)S提供的活性中心和界面效应有效地促进了光生载流子的有效分离和快速迁移。

Cd_(0.5)Zn_(0.5)S nanoparticles and Ni_(2)P nano-lamellar were prepared by precipitation-hydrothermal and low temperature thermal phosphating method,respectively.Low-cost,well-dispersed,efficient non-noble metal phosphide-assisted Ni_(2)P/Cd_(0.5)Zn_(0.5)S composites were synthesized by using ultrasonic cavitation effect.The samples were characterized via XRD,SEM,UV-vis,PL,and electrochemical testing.Using Na_(2)S-Na_(2)SO_(3)as sacrificial agent,the photocatalytic activity of the samples was evaluated under visible light(λ≥420 nm)irradiation.The results showed that Ni_(2)P significantly improved the photocatalytic hydrogen evolution of Cd_(0.5)Zn_(0.5)S.For 10%Ni_(2)P/Cd_(0.5)Zn_(0.5)S,the photocatalytic hydrogen generation rates is 19.133 mmol/(g·h),which is 2.4 times higher than that of Cd_(0.5)Zn_(0.5)S[7.865 mmol/(g·h)].Additionally,the hydrogen generation rate keeps 91%of the initial value after seven photocatalytic cycles,which can be attributed to the fact that the composite material has better light absorption ability and lower band gap,while the active center and interface effect provided by Ni_(2)P effectively promote the rapid migration and effective separation of photo-generated carriers.