Probing the Reaction Mechanism of CO₂‐to‐Formic Acid Conversion on Bi and in Single‐Atom Alloys: A Solvation‐Corrected Theoretical Study

Bi‐ and In‐based catalysts, especially single‐atom alloys (SAAs), show great potential for CO 2 reduction to formic acid due to their favorable intermediate adsorption. However, complex solvent effects on reaction pathways and intermediate stability pose challenges for achieving high activity and selectivity, necessitating further study to guide efficient Bi/In SAA design. In this work, we combined density functional theory (DFT) and ab initio molecular dynamics (AIMD) to study the interaction between aqueous solvents and Bi(001), Bi(012), In(101), and In(002) surfaces. We developed solvation energy correction parameters for key intermediates involved in the CO 2 reduction reaction (CO 2 RR) to formic acid. Results indicate that due to the hydrogen‐bond effect, water molecules help stabilize reaction intermediates particularly on high‐index facets of metals with larger atomic radii. Applying these solvation corrections, we evaluated the free energy profiles of CO 2 reduction to HCOOH catalyzed by 49 SAAs of Bi and In doped with various d‐ and p‐block metals. Among them, Zn 1 Bi(012) ( U L = −0.14 V), Cu 1 Bi(001) ( U L = −0.21 V), Sb 1 In(101) ( U L = −0.26 V), and Bi 1 In(002) ( U L = −0.19 V) demonstrated the highest catalytic performance. This study provides crucial solvation parameters and theoretical insights to guide the rational design of highly active and selective Bi/In SAA catalysts for CO 2 electroreduction to formic acid.