Catalytic Combustion of Low-Concentration Methane over M_x-Cu/γ-Al₂O₃ (M = Mn/Ce) Catalysts

Abstract

Cu/Al2O3 modified by Mn and Ce catalysts for the catalytic combustion of low-concentration methane was studied by catalytic activity experiment and characterization. The results indicate that Mn improves the low-temperature (450–600 °C) catalytic activity. Compared with 10Cu/Al2O3, CH4 conversion of 3Mn–10Cu/Al2O3 is increased by 7% at 550 °C. This is because the interaction between Cu–Mn promotes the formation of CuMn2O4 and the dispersion of Cu, and increases the proportion of surface oxygen. Ce improves the high-temperature (600–700 °C) catalytic activity. Compared with 10Cu/Al2O3, CH4 conversion of 5Ce–10Cu/Al2O3 is increased by 8% at 700 °C. It is because Ce reduces Cu2+ to Cu+ with higher catalytic activity and inhibits CuAl2O4 production by Cu-support interaction. Cu–Mn–Ce three-component catalysts have the best catalytic activity. CH4 conversion of 3Mn–5Ce–10Cu/Al2O3 is increased by 11% at 600 °C. The synergy between Mn–Ce increases the proportion of surface oxygen and promotes the formation of the MnCeO x solid solution.

Catalytic Methane Combustion on the Hydrothermally Synthesized MnO2 Nanowire Catalysts

“…The use of an efficient heterogeneous catalyst can significantly reduce the light-off temperature and minimize the pollutant emission. The methane combustion at a low temperature is a promising technology for converting methane to carbon dioxide and water, which is very beneficial from the view of environmental protection and energy saving. , Generally, precious metals (Pd, Pt, Rh, and Au) supported on various metal oxides, − transition metal oxides (Mn, Co, Fe, Cr, and Cu), − spinels (AB 2 O 4 ), − perovskites (ABO 3 ), , and hexaaluminates (AB x Al 12– x O 19 ) , have been considered for methane combustion. Among the precious metals studied for lean methane catalytic combustion, Pd shows excellent activity and thermal stability, which has received significant consideration in recent years.…”