High selectivity and stability of nickel catalysts for CO₂ Methanation: Support effects

In this work, we present an investigation concerning the evaluation of the catalytic properties of Ni nanoparticles supported on ZrO₂, SiO₂, and MgAl₂O₄ for CO₂ hydrogenation to methane. The supports were prepared by coprecipitation and sol-gel, while Ni was incorporated by impregnation (10–20 wt %). X-ray diffraction, nitrogen physisorption, temperature-programmed reduction, H₂ pulse chemisorption, Raman spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy were the main characterization techniques employed. A laboratory fixed-bed reactor operated at atmospheric pressure, a temperature range of 350–500°C, and a stoichiometric H₂/CO₂ molar ratio was used for catalyst evaluation. The most outstanding results were obtained with nickel catalysts supported on ZrO₂ with CO₂ conversions of close to 60%, and selectivity to methane formation was 100% on a dry basis, with high stability after 250 h of reaction time. The majority presence of tetragonal zirconia, as well as the strong Ni–ZrO₂ interaction, were responsible for the high catalytic performance of the Ni/ZrO₂ catalysts.