Lean methane catalytic combustion over the mesoporous MnO_x-Ni/MgAl_2O_4 catalysts: Effects of Mn loading

摘要

In the current investigation, the textural features and catalytic efficiency of the Mn-promoted Ni/MgAl_2O_4 catalysts were evaluated in the catalytic combustion of lean methane. The results demonstrated that adding manganese oxide up to 5 wt.% to the catalyst improved the structural features and light-off temperatures due to the increase of the reduction degree and oxygen vacancies. The role of the T_(calcination) and processing factors on the methane conversion of the 5%Mn-20%Ni/MgAl_2O_4 catalyst was also studied. The results indicated that the CH_4 conversion decreased with the increment of O_2/CH_4 molar ratio and GHSV value. The stability test revealed that the prepared sample exhibited high stability during 10 h time on stream. Furthermore, the obtained results indicated that the BET area, reduction degree, oxygen mobility, and catalytic performance increased with decreasing the calcination temperature from 700 to 500 ℃.