Effect of surface properties controlled by Ce addition on CO2 methanation over Ni/Ce/Al2O3 catalyst

Abstract

Ce-promoted Ni/Al2O3 catalysts with Ce contents of 0, 5, 10, 15, and 20 wt% were investigated for CO2 methanation. Ni/15Ce/Al2O3 showed good selectivity and catalytic performance in CO2 methanation and remained stable at 350 degrees C for 80 h with minor fluctuations. Interactions between Ni and the Ce/Al2O3 support was characterized using X-ray diffraction, temperature-programmed reduction of H-2, temperature-programmed desorption of CO2, X-ray photoelectron spectroscopy, Raman spectroscopy, and thermogravimetric analysis. Addition of Ce did not increase the catalytic surface area, which can significantly enhance the heterogeneous catalytic activity. However, XPS analysis showed that the Ce on the Ni/Al2O3 catalyst changed the surface electron states of Ni, Ce, and O. Additionally, CO2 adsorption/desorption was confirmed to be related to the amount of Ce present on Ni/ Al2O3 by TGA and CO2-TPD. The Ce addition thus played an important role in determining the CO2 adsorption, desorption, and conversion. (c) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.