Influence of Indium as a Promoter on the Stability and Selectivity of the Nanocrystalline Cu/CeO₂ Catalyst for CO₂ Hydrogenation to Methanol

Stable catalyst development for CO₂ hydrogenation to methanol is a challenge in catalysis. In this study, indium (In)-promoted Cu nanoparticles supported on nanocrystalline CeO₂ catalysts were prepared and explored for methanol production from CO₂. In-promoted Cu catalysts with ∼1 wt % In loading showed a methanol production rate of 0.016 mol g_Cu^–1 h^–1 with 95% methanol selectivity and no loss of activity for 100 h. It is found that the addition of indium remarkably increases Cu dispersion and decreases Cu particle size. In addition led to an increased metal–support interaction, which stabilizes Cu particles against sintering during the reaction, leading to high stability and activity. In addition, density functional theory calculations suggested that the reaction is proceeding via reverse water gas shift (RWGS) mechanism where the presence of In stabilized intermediate species and lowered CO₂ activation energy barriers.