CO₂ Reduction Mechanism on the Pb(111) Surface: Effect of Solvent and Cations

The Pb electrode is the most efficient and selective catalyst in reducing CO₂ into HCOOH; however, the reaction mechanism remains elusive. Herein, we have investigated the mechanism of CO₂ electroreduction to HCOOH on the Pb(111) surface using density functional theory calculations. We find that the effects of solvation and cations lead to different active intermediates for CO₂ electroreduction (HCOO in gas-phase condition, both HCOO and COOH in solvent condition, and COOH in cation solution). In particular, the size and hydrophilic/hydrophobic nature of the cations are found to significantly affect the reaction selectivity and efficiency of CO₂ electroreduction at different overpotentials. These findings rationalize several experimental observations and contribute to a thorough understanding of CO₂ electroreduction