Fig. 2
From: Theoretical insights into selective electrochemical conversion of carbon dioxide
a–b (Reproduced with permission from [20], copyright 2017 American Chemical Society. c Reproduced with permission from [37], copyright 2017 National Academy of Sciences)
The direct observation of subsurface oxygens (Osub) and their effects on intermediate binding. a In situ O 1 s APXPS spectra of Cu foil depending on electrochemical reduction/oxidation treatments. Oxidation of the reduced Cu foil leads to the formation of a thick water overlayer and oxidized compounds such as CuCO3, Cu(OH)2, and Cu2O. Initially oxidized and then reduced Cu foil contains more adventitious oxygen (green). b Illustration of CO binding on Cu and oxide-derived Cu (OD-Cu) with Osub. c Predicted structures of bent CO2 (b-CO2) and H2O molecules on Cu(111) with different levels of Osub. Free energies for CO2 activation to b-CO2 are calculated to be +1.07, − 0.06, +0.28 eV on pristine Cu(111), Cu(111) with 1/4 ML Osub, and Cu(111) with 1/2 ML Osub