Carbon dioxide methanation over Ni-M/Al_2O_3 (M: Fe, CO, Zr, La and Cu) catalysts synthesized using the one-pot sol-gel synthesis method

摘要

In this paper, a series of mesoporous supported nickel based catalysts on nanocrystalline alumina carrier promoted with various metals (Fe, CO, Zr, La and Cu) were prepared and employed in carbon dioxide methanation reaction. The samples were characterized by XRD, BET, TPR and SEM techniques. The BET results showed that the incorporation of promoters into nickel based catalysts decreased the surface area. The results showed that among the prepared catalysts, 30 wt.%Ni-5 wt.%La/Al2O3 and 30 wt.%Ni-5 wt.%Fe/Al(2)O(3 )possessed the highest surface area and the largest pore volume, respectively. Likewise, there was a slight decrease in the pore volume and the average pore diameters of the promoted samples. The TPR results depicted that the incorporation of the promoters enhanced the reducibility of the catalysts and shifted the reduction of NiO species to a lower reduction temperature. The CO2 conversions of all promoted catalysts except Cu-promoted sample were higher peculiarly at low temperatures compared to those attained for the unpromoted catalyst. 30 wt.%Ni-5 wt.%Fe/Al2O3 catalyst exhibited the best catalytic performance (70.63% CO2 conversion and 98.87% CH4 selectivity at 350 degrees C), high stability and desirable resistance against sintering. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.