Dynamic Surface Restructuring Driven Formation of a Highly Polarized CO Species on a Defected Copper Surface

The catalytic versatility of the copper surface calls for a fundamental understanding of the formation and reactivity of key intermediates in various C₁ catalytic conversions such as water-gas shift reaction, CO/CO₂ hydrogenation, and electrochemical reduction reactions. Here, based on in situ spectroscopic and morphological evidence, we demonstrate the formation of a bridge CO* species through the adsorption-induced restructuring of a defect-rich Cu surface and its reactivity toward C-O bond dissociation and C-C coupling under hydrogenation reaction conditions. In corroboration with computational simulations, we attribute the unexpected reactivity to its enhanced adsorption strength and polarity with respect to commonly observed on-top CO* species. Our findings provide new insights into the strong correlation between the surface defect density and the selectivity toward methane, C₂ hydrocarbons, and oxygenates over Cu-based catalysts. The marked impact on reactivity highlights the crucial role of dynamic surface restructuring in determining the reaction selectivity over copper-based catalysts.