The influence of nickel content on the performance of hydrotalcite-derived catalysts in CO2 methanation reaction

Abstract

A series of mixed oxides obtained by thermal decomposition of hydrotalcites containing different amounts of Ni and constant MII+/MIII+ molar ratio were characterized by XRD, XANES, XES, H2-TPR, CO2-TPD, elemental analysis and low temperature nitrogen sorption technique. The results confirm the formation of periclase-like structured materials after thermal treatment, with nickel present as NiO in octahedral coordination environment. As proven by H2-TPR with increasing Ni content the interaction between Ni and hydrotalcite matrix weakens, which has a positive influence on the catalytic performance. The catalysts containing different amounts of nickel (10.3, 16.2, 27.3, 36.8, 42.5 wt.%) showed at 300 °C a very good catalytic performance in carbon dioxide methanation, with CO2 conversion of 36 (Ni10.3)–82% (Ni42.5) and CH4 selectivity of 98–99%.