Ceria imparts superior low temperature activity to nickel catalysts for CO2 methanation

Abstract

Carbon dioxide methanation is well known to achieve the catalytic conversion of the CO₂ molecule into value-added chemicals. At present, the important challenge is the development of efficient methanation catalysts at low reaction temperature. In this study, Ni–Al layered double hydroxides (LDHs) were used as catalyst precursors and modified by CeO₂ for CO₂ methanation. By the optimization of CeO₂ loading, the reaction activity was improved, especially at low temperature. Among the prepared catalysts, the NiAl-MO/CeO₂-5 catalyst exhibited the highest catalytic activity with a CO₂ conversion of 91% at 250 °C. The addition of CeO₂ was beneficial to the formation of small particles with good dispersion and provided appropriate basic sites and oxygen vacancies, which were conducive to the catalytic performance. DFT calculation and in situ DRIFTS results further verified that the catalyst with an appropriate amount of CeO₂ was favorable for CO₂ adsorption and conversion. The reaction mechanism results demonstrated that the high amount of formate intermediate species can accelerate the reaction and a certain amount of ceria in the catalyst could provide a suitable metal–support interaction, which was beneficial for CO₂ methanation. The LDH as a catalyst precursor integrated with CeO₂ shows a promising effect on CO₂ methanation at low temperature.