A First-Principles-Based Microkinetic Study of CO2 Reduction to CH3OH over In2O3(110)

Methanol synthesis from catalytic recycling of CO2 is one viable route to produce fuel and a stock chemical from a greenhouse gas. Herein, hydrogenation of CO2 to CH3OH is investigated with density functional theory calculations combined with mean-field microkinetic modeling. The model explores the direct route for CO2 hydrogenation (HCOOH route) and the competing reverse water-gas shift (RWGS) reaction. The predicted temperature dependence of turnover frequencies, selectivities, and reaction orders are in good agreement with previous experimental results. The formation of methanol at relevant reaction temperatures (470-670 K) is found to be kinetically controlled by H2COOH dissociation to H2CO + OH, whereas the RWGS reaction is solely controlled by CO2 hydrogenation to COOH. An analysis of the kinetic behavior reveals that the stabilization of hydrogen adsorption should be one way to improve the catalyst performance.