The analysis developed in the previous sections demonstrates that the cation effect on Aucatalyzed CO2RR be described by two experimentally accessible variables (|𝜎| and ∆𝐺 /0& , Fig. ), which determine key terms for the cation effect on the thermodynamics (𝐸 * * ) and kinetics (𝜆, 𝐻 78 and 𝑆 *. ) of the RDS. For alkali metal cations, larger cations with less negative hydration free energy tend to exhibit higher surface charge density due to shorter distance to the electrode , which is beneficial to both ET and PT. The slightly anomalous behavior of |𝜎| with Cs could be due to partial electron transfer from the electrode to Cs . Comparing with alkali metal cations, organic cations exhibit much less negative hydration free energy and lower |𝜎|, suggesting that although organic cations promote PT and lower the reorganization energy in PCET, their positive effect is more than offset by the weak electronic coupling in ET.