Nickel Oxide Catalysts for Partial Oxidation of Methane to Synthesis Gas

Abstract

Nickel catalysts supported on different carriers (θ-Al2O3, γ-Al2O3, HZSM-5 with γ-Al2O3, HZSM-5, and NaX) have been investigated for the partial oxidation of methane. All the supported nickel catalysts showed a high activity for the formation of synthesis gas, and γ-Al2O3 was the most effective among all the tested carriers. The effect of the heat-treatment temperature of the 3 wt.% Ni/γ-Al2O3 catalyst on its catalytic activity was studied, and a considerable decrease in its activity was observed by the heat-treatment of the catalyst at 1000 °C compared with the catalysts prepared by the 300–800 °C – calcination. The XRD analysis suggested the formation of NiAl2O4 that is a non-reducible compound at the high calcination temperature. The addition of a modifier (Co, Ce, or La) to the 3 wt.% Ni/γ-Al2O3 catalyst increased the selectivity to H2 and CO with the decreasing selectivity to CO2, and the highest selectivity to H2 was obtained by the 5 wt.% NiLa/γ-Al2O3. The developed 5 wt.% NiLa/γ-Al2O3 catalyst showed a high stability for 30 h for the partial oxidation of methane at 750 °C. The methane conversion reached 95%, selectivity to hydrogen 83% and 52% to carbon monoxide.

Keywords

• partial oxidation of methane, synthesis gas, supported nickel catalysts