Dynamic Te-OH Proton Relay Enables Industrial-Level Acidic CO2 Electroreduction on Single-Atom Catalysts.

Electrochemical CO2 reduction reaction (CO2RR) in acidic media can suppress carbonate formation and boost CO2 utilization efficiency. However, at high current densities, rapid proton consumption induces localized alkalization, causing insufficient proton supply and limiting reaction kinetics. Here we report a dynamic proton-relay strategy that enables rapid and selective CO2RR by integrating atomically dispersed Ni-N sites on carbon with adjacent Te species (Ni-N/Te-C). The incorporated Te centers form reversible Te-OH/Te-O- couples that simultaneously promote water activation and mediate controlled proton delivery, thereby synchronizing hydrogen supply with intermediate protonation while suppressing competitive hydrogen evolution. As a result, Ni-N/Te-C achieves a CO Faradaic efficiency above 94.8% across a wide potential window from -0.8 to -1.4 V versus the reversible hydrogen electrode. Ni-N/Te-C delivers an industrial CO current density of 562.5 mA cm-2 and a turnover frequency of 16291.9 h-1 at -1.4 V, significantly higher than that of Ni-N/C. The catalyst also demonstrates remarkable durability, maintaining 93.8% selectivity for 300 h at 100.0 mA cm-2. In situ spectroscopic characterization and theoretical calculations reveal that the Te-OH-mediated proton relay modulates the reaction pathway of water dissociation and CO2 protonation with significantly lower energy barriers, thus accelerating *COOH formation.