Ni–MgO catalyst prepared by a sol-gel method for low temperature CO2 methanation

CO2 methanation presents a promising route to simultaneously reduce CO2 emissions and store renewable energy. Nickel supported on magnesium oxide (Ni–MgO) stands out as an effective catalyst for CO2 methanation, but suffers from low activity at temperatures below 300 °C. In this work, Ni–MgO prepared by a sol-gel method (Ni–MgO-SG) exhibited markedly higher activity at T ≤ 300 °C compared to catalysts prepared by other synthesis routes. Detailed characterizations revealed that the superior performance of the Ni–MgO-SG catalyst originated from smaller Ni nanoparticle size, higher surface area, higher low- and medium-strength basic sites, and abundant surface oxygen vacancies. The smaller Ni nanoparticles provided increased exposed active surface area, while the oxygen vacancies facilitated CO2 adsorption and activation at low temperatures. These features, combined with the intrinsic basicity of MgO and the moderate interactions between Ni and the support, led to a highly selective and stable catalyst that can operate at low temperatures. Overall, Ni–MgO-SG shows promise for sustainable fuel production processes.