ACr2 O4尖晶石氧化物(A=Co,Zn,Mn,Cu)上r二氯甲烷的催化燃烧:A位阳离子的影响

摘要

采用溶胶-凝胶法制备4种不同ACr2 O4尖晶石氧化物(A=Co,Zn,Mn,Cu),考察A位阳离子对ACr2 O4尖晶石氧化物的性质以及对二氯甲烷催化燃烧性能的影响,并对催化剂进行SEM、HRTEM、H2-TPR、NH3-TPD以及XPS等表征.结果表明,A位离子显著影响催化剂的可还原性和表面酸性,催化剂催化活性顺序为CoCr2 O4>ZnCr2 O4>MnCr2 O4>CuCr2 O4.结合表征结果,认为催化剂活性与其可还原性能和表面酸性存在密切关系.CoCr2 O4由于具有最佳的可还原性和较高的表面酸性,具有最高的催化活性;而CuCr2 O4由于具有最低的表面酸性导致其催化活性最低.%Four Cr-containing spinel oxides ACr2 O4 (A = Co,Zn,Mn,Cu ) were prepared by sol-gel method. The influence of A site cations on the properties of spinel oxides ACr2 O4 and their performance for dichloromethane catalytic combustion was investigated. The catalysts were characterized by SEM, HRTEM,H2-TPR,NH3-TPD and XPS techniques. The results showed that A site cations had obviously effects on catalyst reducibility and surface acidity. The catalitic activity of the catalysts followed the order of CoCr2 O4 >ZnCr2 O4 >MnCr2 O4 >CuCr2 O4 . Based on the characterization results,it was believed that the activity of the catalyst was closely related to its reducibility and surface acidity. Among the catalysts, CoCr2 O4 had the best reducibility and high surface acidity,therefore the best catalytic activity,while CuCr2 O4 possessed the lowest catalytic activity due to its lowest surface acidity.