ACr_2O_4尖晶石氧化物(A=Co,Zn,Mn,Cu)上二氯甲烷的催化燃烧:A位阳离子的影响

采用溶胶-凝胶法制备4种不同ACr_2O_4尖晶石氧化物(A=Co,Zn,Mn,Cu),考察A位阳离子对ACr_2O_4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、H_2-TPR、NH_3-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CoCr_2O_4Zn Cr_2O_4Mn Cr_2O_4CuCr_2O_4。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。CoCr_2O_4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CuCr_2O_4由于具有最低的表面酸性导致其催化活性最低。

Catalytic combustion of dichloromethane over ACr2O4 spinel oxides (A=Co,Zn,Mn,Cu):the effects of A site cations

Four Cr-containing spinel oxides ACr₂O₄ (A=Co,Zn,Mn,Cu) were prepared by sol-gel method.The influence of A site cations on the properties of spinel oxides ACr₂O₄ 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 CoCr₂O₄>ZnCr₂O₄>MnCr₂O₄>CuCr₂O₄.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,CoCr₂O₄ had the best reducibility and high surface acidity,therefore the best catalytic activity,while CuCr₂O₄ possessed the lowest catalytic activity due to its lowest surface acidity.