【摘要】 通过共沉淀方法制备了AMnxAl12-xO19 (A=La或Ba) (x=0 5、1、2、3 )系列六铝酸盐催化剂。利用XRD、BET、TPR等方法考察了La3+、Ba2+作为镜面阳离子对六铝酸盐结构、热稳定性和甲烷催化燃烧活性的影响。结果表明,La3+、Ba2+作为镜面阳离子时六铝酸盐分别具有磁铅石 (MP)结构、β Al2O3结构;La3+作为镜面阳离子可以在较低温度下形成六铝酸盐,因而有利于维持较高的比表面积;此外La3+作为镜面阳离子可以明显提高六铝酸盐的结构稳定性和活性组分Mn的氧化态,因而具有较高的催化活性;Mn取代量为 2时具有最佳的活性。更多还原

【Abstract】 The co-precipitation method was employed to prepare barium and lanthanum he xaaluminate catalysts AMn_xAl₁2-xO₁9（A=La or Ba） （x=0.5,1,2,3） for methane combustion. The influences of La3+ and Ba 2+ as mirror plane cations on the structure and thermal stability of hexaa luminates and the catalytic activity for methane combustion over them were i nvestigated by means of XRD, BET, TPR techniques. The results show that the hexa aluminates possessed MP and β-Al₂O₃ structures when La3+ and Ba2+ were taken as mirror plane cations. Taking La3+ as mirro r plane cation can avoid decreasing the surface area of the catalysts, enhance t he structural stability of the catalysts, increase the oxidation state of active component Mn, the catalytic activity is thus improved. The catalysts po ssess optimal catalytic activity as x is equal to 2.更多还原