Fig. 1. Schematic illustration and DFT prediction of the Cu faceting process.

a Schematics of the in situ Cu(111) formation from weak CO adsorption during CO₂R. b Schematics of the in situ Cu(100) formation from the co-adsorption of CO&OHˉ during CO₂R. c The surface energies of Cu(111) and Cu(100) at different CO* and OHˉ surface coverages. d A contour plot of the surface energy difference between Cu(100) and Cu(111) by changing the surface coverages of CO* and OHˉ. e, Wulff construction clusters of copper without and with (co-)adsorption of CO* and OHˉ.