Carbon dioxide reforming of methane on Ni–MgO–Al2O3 catalysts prepared by sol–gel method: Effects of Mg/Al ratios

Abstract Carbon dioxide reforming of methane on Ni–MgO–Al 2 O 3 catalysts has been investigated systematically at various Mg/Al ratios, focusing on catalytic activity and coke resistance. Ni catalysts supported on MgO–Al 2 O 3 were prepared by sol–gel method using citric acid as a gelling agent. The characterization of the catalyst was carried out by XRD, TEM, TPR, N 2 adsorption, H 2 chemisorption, O 2 titration, CO 2 -TPD and TGA. In the comparison with a catalyst prepared by coprecipitation method, it was found that the catalyst prepared by the sol–gel method showed higher coke resistance. In the variation of Mg/Al ratios, high coke resistance was obtained with increasing MgO loading, while high catalytic activity was observed with the catalysts of medium MgO/(MgO + Al 2 O 3 ) ratio (0.44–0.86), of which the superior catalytic activity is likely attributed to high specific surface area and well dispersed Ni particles.