Pressure‐Induced Forward‐Shift of Proton‐Coupled Electron Transfer Step Boosts CO‐to‐Acetate Throughput

ABSTRACT Regulating the rate‐determining step (RDS) constitutes the central challenge in catalysis science, as it governs both reaction efficiency and pathway selectivity. In CO/CO 2 electroreduction, the voltage‐insensitive * CO‐ * CO dimerization — a non‐proton‐coupled electron transfer (PCET) step — critically limits multi‐carbon production rates by restricting accessible current densities below industrial demands. Traditional catalyst modification strategies often induce undesired perturbations to downstream pathways while addressing this bottleneck. Here, we demonstrate a physical microenvironment engineering strategy that reconfigures reaction sequences through pressure modulation. Elevated CO pressure enriches surface * CO coverage, redirecting proton reaction pathways to preferentially hydrogenate * CO intermediates rather than coupling for hydrogen evolution, evidenced by a reduced Tafel slope for acetate and hydrogenated intermediates resolved from high‐pressure operando Raman spectroscopy. When integrated with a synthetic Cu–Pd single‐atom alloy (SAA) catalyst, the CO‐to‐acetate conversion system is selective with a Faradaic efficiency of 85%, energy‐efficient with an energy efficiency of 33%, and selective with an operation duration of 700 h. Interestingly, our system can maintain a high acetate selectivity (>75%) across an exceptionally broad current density range from 3 to 1500 mA cm − 2 , potentially compatible with intermittent renewable power sources.