Enhanced low-temperature CO2 methanation over a Ni-based catalyst supported on La2O3–Al2O3 composite supports

Despite the substantial efforts in the conversion of carbon dioxide (CO2) into high value-added products, directly transforming CO2 into CH4 at low temperatures still poses a formidable challenge. In this study, we report a bottom-up strategy to synthesize supported Ni catalysts on a doped Al2O3 support. LaAl mixed oxide was first synthesized via a co-precipitation method, followed by Ni species loaded using a deposition precipitation method. The CO2 conversion of the Ni/LaAl catalyst is found to be greatly enhanced, two times higher than that of the Ni/Al2O3 catalyst at 250 °C. The characterization results show that the introduction of La promotes the dispersion of Ni, reduces the reduction temperature of NiO and facilitates the adsorption of CO2 by increasing the basic sites. Temperature-programmed reduction with H2 demonstrated that La2O3 promotes the reducibility of NiO. Furthermore, kinetic analysis, in situ DRIFTS and CO methanation tests evidenced that La2O3 promotes the activation of CO2 and accelerates the CO hydrogenation step.