DFT study of CO2 conversion on InZr3(110) surface

Abstract

Methanol and methane synthesis from CO₂ hydrogenation on a InZr₃(110) surface has been studied using density functional theory calculations. The CO₂ can be chemically adsorbed via a polydentated configuration and the H₂ molecule can dissociate to H atoms spontaneously. The methanol is primarily formed via the HCOO route instead of the RWGS route, due to its higher activation barrier of 1.35 eV for HCO hydrogenation. In the HCOO route, the adsorbed CO₂ consecutively hydrogenates to form HCOO, H₂COO and the H₃CO species. The H₃COH is produced via the reaction of H₃CO with a surface OH group. Furthermore, the C–O bonds of CO, CHO, CH₂O and CH₃O species prefer to dissociate to C, CH, CH₂ CH₃ and surface O species. Methane is formed via the hydrogenation of CH_x (x = 0–3) monomers with the highest activation barrier of 1.19 eV for CH₃ hydrogenation, which is higher than that of the hydrogenation of H₂COO in methanol synthesis via the HCOO route. The surface O species formed during CO₂ hydrogenation reacts with the adsorbed H₂ molecule to produce an OH group which reacts with a surface H atom to form H₂O with an activation barrier of 1.13 eV, which then desorbs to the gas phase. Our calculated results indicate that the InZr₃ alloy is a potential candidate catalyst for CO₂ utilization and conversion.