Highly Selective Electrocatalytic CO2 Reduction to Methanol on Iridium Dioxide with CO* Spectators

Abstract

AbstractIridium dioxide has emerged as a promising anode family for electrocatalytic reduction of CO2. Herein, the catalytic mechanism of CO2 reduction reaction (CO2RR) on the IrO2 (110) electrocatalyst model has been assessed using density functional theory (DFT) calculations. The CO* spectator on the IrO2 (110) is the crucial factor, which directly affects the binding free energy of the reaction intermediates by means of the different ratios of CO* spectator models. Our results showed that the CO* spectator may have a great promotion effect on the methanol production, and it always maintains low sensitivity on the CO2 reduction to methane reaction. The onset potentials for reducing to methanol and methane are −0.32 V‐RHE and −0.68 V‐RHE, respectively, at a CO* coverage of 50 %, which means that providing an appropriate CO* coverage can improve the selectivity of CO2 catalytic reduction to methanol tremendously. It is worth noting that the intermediate CH3O*+OH*, which plays a vital role in the major pathways to produce methanol and methane, is a branch point that led to the formation of two products. Although both subsequent protonation processes are exothermic, the path to methanol production is more favorable than that of CH4 formation. These results demonstrate that iridium dioxide should be a good CO2RR catalyst, and the CO* spectator also exhibits an enhanced effect on the selectivity of CO2 reduced to alcohol products.