Turning a Methanation Co Catalyst into an In–Co Methanol Producer

Abstract

The direct hydrogenation of CO 2 to methanol using hydrogen is regarded as a potential technology to reduce greenhouse gas emissions and the dependence on fossil fuels. For this technology to become feasible, highly selective and productive catalysts that can operate under a wide range of reaction conditions near thermodynamic conversion are required. Here we combine a CO-producing In oxide catalyst with a methane-producing Co catalyst to obtain an In/Co catalyst for CO 2 reduction to methanol. Density functional (DFT) simulations demonstrate that the charge transfer between the Co support and the In oxide film leads to enrichment of the surface of indium oxide with O vacancies, which serve as active sites for selective conversion of CO 2 to methanol. Moreover, our simulations suggest that CO 2 reduction on Co-supported In 2 O 3– x films will preferentially yield methanol, rather than CO and methane. As a result, the prepared In@Co catalysts produce methanol from CO 2 with high selectivity (>80%) and productivity (0.86 g CH 3 OH g catalyst –1 h –1 ) at conversion levels close to thermodynamic equilibrium, even at temperatures as high as 300 °C and at moderate pressures (50 bar).