Pressure-Enhanced CO₂-to-CO Electroreduction on Ag-Based Catalysts: Industrially Relevant Rates and Mechanistic Insights

Electrochemical carbon dioxide reduction (CO₂RR) has emerged as a promising strategy for CO₂ utilization and as a means of storing surplus renewable electricity in chemical form. Among the possible CO₂RR products, CO is particularly significant because it serves as a key platform molecule for the downstream synthesis of hydrocarbons and oxygenates. However, CO₂RR in aqueous systems is fundamentally constrained by limited interfacial CO₂ availability and the challenge of stabilizing key reaction intermediates, especially in conventional H-type cell configurations, which restricts achievable activity and selectivity. Here, we report a comprehensive investigation of Ag-based catalysts operated in conventional high-pressure H-type cells, demonstrating their high intrinsic activity for CO production. Under 5.0 MPa CO₂, oxide-derived Ag (OD-Ag) electrode achieves a total current density of −200 mA cm^–2 and a Faraday efficiency of CO (FE_CO) of 90.0% at a low overpotential of −1.3 V (vs. RHE), representing one of the highest performances reported under similar reactor configurations. Mechanistic insights reveal that CO formation proceeds through a *COOH-mediated pathway, with elevated pressure substantially enhancing intermediate coverage and suppressing the competing hydrogen evolution reaction. These findings highlight the critical role of CO₂ pressure in modulating both reaction pathways and catalytic selectivity. Overall, this work demonstrates that high-pressure CO₂RR conditions markedly improve CO selectivity and activity over Ag electrodes, providing a powerful and industrially relevant route toward high-rate CO production and offering valuable guidance for the design of next-generation high-pressure electrochemical CO₂ conversion systems.