Improving Coking Resistance and Catalytic Performance of Ni Catalyst from LaNiO3 Perovskite by Dispersion on SBA-15 Mesoporous Silica for Hydrogen Production by Steam Reforming of Ethanol

A strategic option for the production of H-2 from renewable resources is use of the ethanol steam reforming reaction. Catalysts based on nickel have been widely investigated for this reaction, offering the advantages of low cost and high activity. However, a difficulty is that nickel may be strongly deactivated by coke formation. Perovskite-type mixed oxides are promising precursors for nickel-based catalysts, since their reduction leads to the formation of highly dispersed metal particles that can mitigate carbon deposition. However, high calcination temperatures are required for perovskite structure formation, resulting in low surface areas and limiting the effectiveness of this method. In order to address this difficulty, the present work proposes a novel strategy whereby the perovskite-type oxide LaNiO3 is supported on SBA-15. Characterization of the catalysts was performed using XRF, XRD, SEM, TPR, TEM, BET, H-2-TPD, and TGA techniques. Their performances were then evaluated in catalysis of the ethanol steam reforming reaction to produce hydrogen. Calcination at 750 degrees C resulted in formation of highly dispersed perovskite on a support that presented high specific surface area. The catalyst obtained from reduced LaNiO3/SBA-15 with 33 wt% perovskite was the most active in the reaction. Analyses using TGA and SEM showed the formation of carbon mainly over Ni catalysts obtained from bulk LaNiO3 perovskite, while supporting LaNiO3 on SBA-15 led to lower deposition of carbon. The superior performance of this material in catalysis could be attributed to the dispersion of the perovskite on SBA-15, resulting in smaller size of the Ni metal particles formed during the reduction, compared to the catalyst derived from bulk perovskite. This promising method could be used in the production of a wide range of other catalysts.