【摘要】 采用共浸渍和不同分步浸渍的方法制备了8%(质量分数)Ag/CeO2-SiO2催化剂,运用XRD,UV-Vis和BET等手段对催化剂的结构进行表征,考察了其对CO氧化的活性,并初步探讨了助剂CeO2对催化剂结构及活性物种的影响.结果表明,添加质量分数为1%CeO2的8%Ag/SiO2催化剂表现出较好的低温CO催化活性,氢气预处理能明显提高催化剂的反应活性.XRD和UV-Vis分析结果表明,少量的CeO2(1%)有利于金属银物种的形成,并且能够提高Ag粒子的稳定性,高温处理不易聚集.高CeO2负载量下的催化剂中银物种主要以银簇(Agδn+)形式存在.更多还原

【Abstract】 8%(mass fraction) Ag/CeO2-SiO2 catalysts were prepared by an incipient wetness co-impregnation and two-step impregnation methods.XRD,UV-Vis and BET were used for the characterization of the catalysts and the catalytic activity for CO oxidation was studied.The effects of CeO2 on the structure of catalysts and the silver active species were discussed.The results indicate that 8%Ag/1%CeO2-SiO2 show better catalytic activity for CO oxidation,and the activity is further increased after hydrogen treatment.XRD and UV-Vis characterization results show that CeO2 favored the dispersion of Ag particles on the surface of SiO2,and silver cluster is the main silver species when more CeO2 is supported on the surface of SiO2.更多还原