络合浸渍法制备Ag/Al_(2)O_(3)-TiO_(2)催化剂及其催化燃烧丙烷性能

Catalytic Performance of Ag/Al_(2)O_(3)-TiO_(2) Catalyst Prepared by Complexing Impregnation Method for Propane Combustion

研究了制备过程中不同络合剂乙醇胺(ETA)、二乙醇胺(DTA)、三乙醇胺(TEA)及柠檬酸(CA)等对Ag/Al_(2)O_(3)-TiO_(2)催化剂理化性质的影响,并考察了其催化丙烷燃烧的活性。结果表明,络合浸渍法能够显著提高催化剂催化活性,其活性顺序依次为:Ag/Al_(2)O_(3)-TiO_(2)(IM,传统浸渍法)<Ag/Al_(2)O_(3)-TiO_(2)(TEA)<Ag/Al_(2)O_(3)-TiO_(2)(DTA)<Ag/Al_(2)O_(3)-TiO_(2)(ETA)<Ag/Al_(2)O_(3)-TiO_(2)(CA),表明CA作为络合剂效果最好。当CA与Ag的物质的量比为1:1时,催化剂的催化活性最佳。与Ag/Al-Ti(IM)催化剂相比,Ag/Al_(2)O_(3)-TiO_(2)催化剂的T_(90)(丙烷转化率为90%的反应温度)下降了81℃。由催化剂的结构分析发现,络合浸渍法制备的催化剂银物种的粒径明显变小、银的分散度提高、表面Ag^(0)物种和表面吸附氧的含量增加,进而促进了丙烷催化燃烧性能的提升。

In this paper,the effects of different complexing agents such as ethanolamine(ETA),diethanolamine(DTA),triethanolamine(TEA)and citric acid(CA)on the physicochemical properties of Ag/Al_(2)O_(3)-TiO_(2)catalysts were studied,and their catalytic activity for propane combustion was investigated.It was found that the complexing impregnation method could significantly improve the catalytic activity of the catalysts,and the activity sequence was as follows:Ag/Al_(2)O_(3)-TiO_(2)(IM,Traditional impregnation)<Ag/Al_(2)O_(3)-TiO_(2)(TEA)<Ag/Al_(2)O_(3)-TiO_(2)(DTA)<Ag/Al_(2)O_(3)-TiO_(2)(ETA)<Ag/Al_(2)O_(3)-TiO_(2)(CA),which prepared by citric acid(CA)as complexing agent has the best catalytic performance.In addition,when the molar ratio of citric acid is 1:1,the catalytic activity of Ag/Al_(2)O_(3)-TiO_(2)(CA)is the best.Compared with Ag/Al-Ti(IM)catalyst,T_(90) decreased by 81℃.The structure analysis showed that the particle size of silver species in the catalysts prepared by the complex impregnation method decreased obviously,the dispersion of silver increased,and the content of Ag^(0) and species surface adsorbed oxygen on the surface increased,which resulted in improving the catalytic performance of Ag/Al_(2)O_(3)-TiO_(2)(CA)catalyst for propane combustion.