镁铝水滑石衍生复合氧化物的COS水解性能

Hydrolysis of COS over MgAl Mixed Oxides Derived from Hydrotalcites

采用共沉淀的方法制备了系列镁铝水滑石衍生复合氧化物,分别考察了煅烧温度、反应温度、水蒸气体积分数以及碱金属添加对材料COS水解反应活性的影响.通过X射线衍射仪(XRD)、气体吸附仪(BET)、程序升温脱附(TPD)和X射线光电子能谱(XPS)等对复合氧化物的晶体结构、比表面积、孔结构和碱性位分布等进行表征.结果表明,水解反应活性随煅烧温度的增加先升高后减小,650℃煅烧制备的复合氧化物材料具有最佳的水解反应活性(COS完全转化的维持时间为180min).反应温度的升高有利于水解活性的提高,从70℃起水解反应就具有很高的活性和稳定性.此外,Cs的添加有利于水解反应活性的提高,掺杂后材料COS完全转化的维持时间达到了480 min.

A series of MgAl hydrotalcite-derived composite oxides were prepared by co-precipitation methods.The effects of calcination temperature,reaction temperature,water vapor volume fraction,and alkali metal addition on the hydrolysis activity of the samples were investigated.The crystal structure,specific surface area,pore structure,and basic position distribution of the composite oxides were characterized using XRD,BET,TPD,and XPS.The results shown that the catalytic activity firstly increased and then decreased with the rise of calcination temperature.Furthermore,the sample that calcined at 650℃can achieve the best catalytic activity(complete removal of COS lasted for 180 min).Increasing the reaction temperature improved the catalytic activity,which can present excellent catalytic activity and stability at temperatures above 70℃.In addition,the doping of the alkali metal Cs improved the catalytic activity,the complete removal time for COS can be maintained for 480 min.