CO2 chemistry of Cu(100) regulated by Ni deposition and pressure

Modification of copper-based catalysts by incorporating a second metal is prevailing in developing high-performance catalysts for CO2 hydrogenation. In particular, the insight into how the reaction is influenced is key to understanding the nature of the strategy. Herein, we show that both intermediates and reaction pathways of CO2 over Cu(100) are conspicuously regulated by Ni deposition and CO2 pressure. CO2 exposure to Cu(100) at room temperature mainly yields surface oxygen and gas phase CO, whereas the deposited Ni functions in two ways: either to stabilize the surface carbonate species or to dissociate CO, leading to surface carbon and oxygen deposition. Interestingly, the pathways depend strongly on the pressure of CO2, which essentially induces surface roughening and alters the competition of CO/CO2 to react with Ni. Density functional theory simulations reveal that both factors have a notable influence on the adsorption/desorption kinetics and the stability of intermediates, hence leading to varied pathways.