(569bw) 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 a markedly higher activity at temperature ≤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.