Biogas reforming to syngas over cu‐modified Ni‐Al‐LDH catalysts

Abstract

Ni-Al-LDH catalyst was modified with Cu to improve catalyst activity and deactivation resistance in biogas reforming. The samples were obtained by impregnation of Cu on Ni-Al previously prepared by coprecipitation, and characterized by X-ray diffractometry, N2 physisorption, temperature-programmed reduction, CO2 temperature-programmed desorption, and temperature-programmed oxidation. Catalytic tests were performed with CH4/CO2 = 1.5 at 600 and 700°C in a fixed bed reactor. The characterization results revealed that the presence of Cu facilitates the reduction of Ni2+ to Ni°. The washing step influences the properties of the catalyst, since samples with low Cu content showed greater activity and stability than catalysts with high Cu content. At 700°C, the best results were obtained with the unreduced catalyst, with CH4 conversions above 75%, because the reduction with H2 at such condition causes catalyst sintering. No deactivation was observed at 600°C. The results achieved by the unreduced catalysts show potential for the production of H2 as they do not require theactivation with H2. A mechanism for activating the catalyst with CH4 was proposed.