Theoretical Insights into Amido Group-Mediated Enhancement of CO2 Hydrogenation to Methanol on Cobalt Catalysts

Catalytic reduction of carbon dioxide into high-value-added products, such as methanol, is an effective approach to mitigate the greenhouse effect, and improving Co-based catalysts is anticipated to yield potential catalysts with high performance and low cost. In this study, based on first-principles calculations, we elucidate the promotion effects of surface *NH_x (x = 1, 2, and 3) on the carbon dioxide hydrogenation to methanol from both activity and selectivity perspectives on Co-based catalysts. The presence of *NH_x reduced the energy barrier of each elementary step on Co(100) by regulating the electronic structure to alter the binding strength of intermediates or by forming a hydrogen bond between surface oxygen-containing species and *NH_x to stabilize transition states. The best promotion effect for different steps corresponds to different *NH_x. The energy barrier of the rate-determining step of CO₂ hydrogenation to methanol is lowered from 1.55 to 0.88 eV, and the product selectivity shifts from methane to methanol with the assistance of *NH_x on the Co(100) surface. A similar phenomenon is observed on the Co(111) surface. The promotion effect of *NH_x on Co-based catalysts is superior to that of water, indicating that the introduction of *NH_x on a Co-based catalyst is an effective strategy to enhance the catalytic performance of CO₂ hydrogenation to methanol.