Table S6.

Work function (in electronvolts) of the initial state (Φ₀), transition state (Φ_TS), and final state (Φ₁) for various reduction steps of C₂H₄ formation on Cu(100) at pH 7 and 298 K

ID	Reaction equation	Φ0, eV	ΦTS, eV	Φ1, eV
0	$\text{*CO}+\text{*CO}+\mathrm{\delta }\cdot e^{-}\to {\text{*CO–CO}}^{\mathrm{\delta -}}$	3.39 (0.24)	3.47 (0.28)	3.67 (0.3)
1	${\text{*OC–CO}}^{\mathrm{\delta -}}+{\text{H}}_2\text{O}+\left(1-\mathrm{\delta }\right)\mathrm{\cdot }{e}^{-}\to \text{*CO–COH}+{\text{OH}}^{-}$	3.67 (0.3)	3.75 (0.21)	3.74 (0.25)
2	$\text{*CO–COH}+{\text{H}}_2\text{O}+e^{-}\to \text{*COH–COH}+{\text{OH}}^{-}$	3.32 (0.30)	3.43 (0.35)	3.68 (0.29)
2a	${\text{*OC–CO}}^{\mathrm{\delta -}}+\text{H*}\to {\text{*CHO–CO}}^{\mathrm{\delta -}}$	3.67 (0.3)	3.76 (0.26)	3.83 (0.28)
3	$\text{*COH–COH}+e^{-}\stackrel{{\text{H}}_2\text{O}}{\to }\text{*C–COH}+{\text{OH}}^{-}$	3.13 (0.28)	3.27 (0.22)	3.50 (0.24)
3a	$\text{*COH–COH}+\text{H*}\to \text{*CHOH–COH}$	3.13 (0.28)	3.28 (0.28)	3.19 (0.25)
4	$\text{*C–COH}+{\text{H}}_2\text{O}+e^{-}\to \text{*CH–COH}+{\text{OH}}^{-}$	3.43 (0.31)	3.61 (0.34)	3.80 (0.22)
4a	$\text{*C–COH}+\text{H*}\to \text{*CH–COH}$	3.43 (0.31)	3.55 (0.35)	3.56 (0.35)
4b	$\text{*C–COH}+e^{-}\stackrel{{\text{H}}_2\text{O}}{\to }\text{*C–C}+{\text{OH}}^{-}$	3.43 (0.31)	3.48 (0.24)	3.72 (0.25)
4c	$\text{*C–COH}+\text{H*}\to \text{*C–CHOH}$	3.43 (0.31)	3.56 (0.22)	3.60 (0.27)
5	$\text{*CH–COH}+e^{-}\stackrel{{\text{H}}_2\text{O}}{\to }\text{*C–CH}+{\text{OH}}^{-}$	3.28 (0.27)	3.42 (0.35)	3.65 (0.35)
5a	$\text{*CH–COH}+\text{H*}\to {\text{*CH}}_2\text{–COH}$	3.28 (0.27)	3.36 (0.32)	3.40 (0.21)
5b	$\text{*CH–COH}+\text{H*}\to \text{*CH–CHOH}$	3.28 (0.27)	3.29 (0.35)	3.38 (0.20)
6	$\text{*C–CH}+{\text{H}}_2\text{O}+e^{-}\to {\text{*C–CH}}_2+{\text{OH}}^{-}$	3.43 (0.36)	3.60 (0.35)	3.85 (0.26)
6a	$\text{*C–CH}+\text{H*}\to {\text{*C–CH}}_2$	3.43 (0.36)	3.46 (0.27)	3.57 (0.21)
6b	$\text{*C–CH}+{\text{H}}_2\text{O}+e^{-}\to \text{*CH–CH}+{\text{OH}}^{-}$	3.43 (0.36)	3.64 (0.25)	3.88 (0.29)
6c	$\text{*C–CH}+\text{H*}\to \text{*CH–CH}$	3.43 (0.36)	3.48 (0.28)	3.60 (0.29)
7	${\text{*C–CH}}_2+{\text{H}}_2\text{O}+e^{-}\to {\text{*CH–CH}}_2+{\text{OH}}^{-}$	3.26 (0.30)	3.45 (0.27)	3.64 (0.36)
7a	${\text{*C–CH}}_2+\text{H*}\to {\text{*CH–CH}}_2$	3.26 (0.30)	3.32 (0.25)	3.44 (0.23)
7b	${\text{*C–CH}}_2+\text{H*}\to {\text{*C–CH}}_3$	3.26 (0.30)	3.35 (0.29)	3.48 (0.26)
8	${\text{*CH–CH}}_2+{\text{H}}_2\text{O}+e^{-}\to {\text{C}}_2{\text{H}}_4+{\text{OH}}^{-}$	3.24 (0.21)	3.38 (0.35)	3.65 (0.30)
8a	${\text{*CH–CH}}_2+\text{H*}\to {\text{C}}_2{\text{H}}_4$	3.24 (0.21)	3.30 (0.29)	3.43 (0.24)
8b	${\text{*CH–CH}}_2+{\text{H}}_2\text{O}+e^{-}\to {\text{*CH–CH}}_3+{\text{OH}}^{-}$	3.24 (0.21)	3.44 (0.20)	3.67 (0.32)
8c	${\text{*CH–CH}}_2+\text{H*}\to {\text{*CH–CH}}_3$	3.24 (0.21)	3.34 (0.26)	3.44 (0.28)