CO2 Hydrogenation to Methanol on CoIn2/In2O3: The Role of the Alloy/Oxide Interface in Driving Catalytic Activity and Selectivity

Abstract

CO₂ catalytic hydrogenation to methanol is promising for CO₂ utilization. In₂O₃-based catalysts are attracting much attention because of their high methanol selectivity. However, a low CO₂ conversion rate limits the overall methanol yield. Herein, we developed the interface of the CoIn₂ alloy and In₂O₃ oxide as a CoIn₂/In₂O₃ catalyst and successfully achieved high performance for the hydrogenation of CO₂ to methanol. Experimental and theoretical results indicated that the alloy/oxide interface is stable during the reaction atmosphere; the high performance arising from the electronic interaction between CoIn₂ and In₂O₃, which improves the electron density at the CoIn₂ interface, facilitates H₂ dissociation, CO₂ adsorption, and the hydrogenation of formate intermediates to methanol, which justifies the sustained high methanol selectivity and production rate. The optimized catalyst showed a methanol selectivity up to 74% and a high methanol space-time yield up to 0.69 g_MeOHg_cat^–1h^–1 at 5.0 MPa, H₂/CO₂ = 3:1, 300 °C and 36,000 mLg_cat^–1h^–1.