Improved photocatalytic activity and stability for organic pollutant degradation and hydrogen production by both Ag doping and deposition:the case of CdS
Modified CdS samples by both Ag doping and simultaneous deposition (denoted as Ag-CdS thereafter) are simply prepared by one-step hydrothermal method.The prepared Ag-CdS samples have enhanced photocatalytic activity under simulated sunlight compared with pure CdS for organic pollutant degradation and H2 production from water splitting.The sample with molar ratio of Ag/Cd =1∶50 shows the best photocatalytic activity.The main reason for the enhanced activity is due to the fast transfer of photogenerated electrons from the conduction band of CdS to Ag nanoparticles on the surface,which suppresses the recombination of photogenerated electrons and holes.Additionally,the best Ag-CdS sample is much more stable than only Ag deposited CdS.The stability is improved because of Ag+ doping.On one hand,Ag doping creates acceptor energy level near the valence band of CdS.The holes can inject into the acceptor energy level freely,leading to the weak oxidative ability of holes in the excitated semiconductor,which may not oxidize S2-.On the other hand,the more stable and easier formed chemical bond between Ag+ substituted for Cd2+ in hexagonal crystal lattice and S2-may make the doped sample much more stable than Ag deposited CdS.The detailed mechanism for the improvement of activity and stability is proposed and discussed based on experimental data.This study provides a facile preparation method for photocatalysts with high activity and stability able to be used in future application.
Sheng Huang Yu Lin Xiangru Li Jun Zhang Jiaguo Yu Fenglong Shi Wenzhong Wang Ying Yu
College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University School of Science, Minzu University of China, Beijing 100081, China
国际会议
2013 International Symposium on Environmental Science and Technology(2013环境科学与技术国际会议)
大连
英文
764-764
2013-06-04（万方平台首次上网日期，不代表论文的发表时间）