Fig. 5: DFT calculations and in-situ ATR-IRAS.

a Free energy diagram for CO2RR to form CH4. b Free energy diagram for *CO-*CHO coupling. In-situ ATR-IRAS spectra of CO2RR over c, d Al2O3-CuSAC and e CeO2-CuSAC. In-situ ATR-IRAS of O-H stretching vibration for f Al2O3-CuSAC, g CeO2-CuSAC, and h TiO2-CuSAC. i Fraction of free H2O in the electrode-electrolyte interface. c–i No iR correction was applied to calculate the applied potential. Relevant source data are provided as a Source Data file.