Preparation and characterization of Ni based catalysts for the catalytic partial oxidation of methane: Effect of support basicity on H_2/CO ratio and carbon deposition

摘要

The catalytic partial oxidation of methane (CPOM) was studied on Ni based catalysts. Catalysts were prepared by wet impregnation method and characterized by using AAS, BET, XRD, HRTEM, TPR, TPO, Raman Spectroscopy and TPSR techniques. The prepared catalysts showed nearly 95% CH_4 conversion and nearly 96% H_2 selectivity under the flow of 157,500 (L kg~(-1) h~(-1)) with the ratio of CH_4/O_2 = 2 by using air as an oxidant at 1 atm and 800 ℃. Support basicity greatly influenced the H_2/CO ratio and carbon deposition. It was - found that the lowest carbon deposition occurred on Ni impregnated MgO catalyst. Considering the results, it was found that Ni/MgO catalyst with 10% Ni content would be the best catalyst amongst Ni/Al_2O_3, Ni/MgO/Al_2O_3, Ni/MgAl_2O_4 and Ni/Sorbacid for the CPOM only under more reductive conditions. Under optimum conditions, Ni/MgO showed poor performance and therefore Ni/Sorbacid would be the ideal catalyst because of its greater carbon resistance than the other catalysts.