Renewable hydrogen from glycerol steam reforming using Co-Ni-MgO based SBA-15 nanocatalysts

摘要

Steam reforming of glycerol was carried out using Si-based mesoporous SBA-15 catalysts. Different mesoporous catalysts- Co-SBA-15, Ni-SBA-15, Co-MgO-SBA-15, Ni-MgO-SBA-15, and Co-Ni-SBA-15 were prepared using a one-pot hydrothermal method. An incipient wetness impregnation method was used only for the bimetallic Co-Ni-SBA-15 catalyst (catalyst designated as Co-Ni-SBA-15-IMPG) to compare its activity to that prepared by the one-pot method. The catalysts were characterized using XRD, TPR, TEM, TGA-DSC, ICP-OES and N-2 adsorption-desorption analytical techniques. A high surface area in the range of 540 -750 m(2)/g was observed depending on the catalyst composition. The glycerol steam reforming (GSR) activity of the catalysts was studied in the reaction temperature range of 450 degrees C-700 degrees C for hydrogen production. Results from the GSR studies for continuous 40 h showed that both Co-Ni-SBA-15-IMPG (impregnation) and Co-Ni-SBA-15 (one-pot) were resistant to deactivation, and both yielded 100% glycerol conversion for the entire 40 h. 10% Co-5%Ni-SBA-15 and 10%Co-5%Ni-SBA-15-IMPG produced (70-78) % and (60-78) % H-2 selectivity, respectively. Addition of MgO to Co-SBA-15 and Ni-SBA-15 increased the activity and stability of the catalysts. The catalyst stability performance followed the trend 10%Co-5%Ni 10%Co-5%MgO 10%Co-5%Ni-IMPG. 15%Co 10%Ni-5%MgO 15%NiSBA-15. Thermal analyses of the spent catalyst showed a substantial amount of coke deposition which could be the major factor responsible for catalysts deactivation. Bimetallic catalysts prepared by one-pot method (10%Co-5%Ni-SBA-15) and incipient wetness impregnation (10%Co-5%Ni-SBA-15-IMPG) exhibited remarkable GSR activity compared to their monometallic counterparts. The GSR activity was observed in the order: 10%Co-5% Ni-IMPG 10%Co-5%Ni 10%Co-5%MgO 15%Co 15%Ni 10%Ni-5%MgO. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.