Biogas Dry Reforming Over Ni–Mg–La–Al Catalysts: Influence of La/Mg Ratio

Abstract

La/Mg ratio was evaluated in Ni–Mg–La–Al catalysts for the biogas dry reforming. The reactions were carried out in a fixed bed tubular reactor using synthetic biogas (70% CH4 and 30% CO2). The catalyst characterization showed that the increase of La/Mg ratio decreased the specific surface area of the catalyst and the average crystallite size of Ni0, but increased the acid strength of sites identified by NH3-TPD analysis. These properties contributed to improving the activity and catalytic stability for CH4 conversion at 700 °C. The Mg presence increased the strength of basic sites of the catalysts and plays an important role in CO2 conversion. The catalyst with La/Mg = 4 presented the best activity and stability for the reaction at 700 °C, due to the greater resistance to sintering associated with de small size of Ni0, and a proper combination of acid and basic sites. H2/CO ratios higher than 1 were obtained due to the contribution of the CH4 decomposition reaction.