Interfacial Solvation and Spin-Selective Electron Transfer Govern CO/MeOH Selectivity at a Graphene–CoPc Interface

Electrochemical CO2-to-methanol conversion over noncopper single-atom catalysts is limited by competition between further *CO reduction and CO desorption. Here, constant-potential ab initio molecular dynamics and nonadiabatic molecular dynamics elucidate how applied potential, interfacial solvation, and spin-resolved electron transfer control CO/MeOH selectivity at a graphene-supported cobalt phthalocyanine interface. At −0.6 V versus the reversible hydrogen electrode, frequent Co–C bond elongation favors CO release. By contrast, −1.0 V strengthens *CO retention and extends the hydrogen-bond-network lifetime from 171.0 to 282.1 fs, establishing a persistent proton-delivery pathway for subsequent proton-coupled electron transfer. Unsupported CO@CoPc exhibits predominantly spin-down electron transfer, whereas graphene coupling enhances nonadiabatic coupling and activates an ultrafast spin-up channel with an injection time of 20.3 fs at −1.0 V. Thus, potential-dependent *CO residence, solvent organization, and spin-selective charge injection act cooperatively to govern CO/MeOH selectivity, with graphene serving as an active regulator of interfacial dynamics.