Electromethanation of CO2 has received intensive attention due to its high calorific value and convenient storage along with transportation to accommodate industrial demands. However, it is limited by sluggish multi-step proton-coupled electron transfer kinetics and undesired *H coupling under high current density, posing great challenges to its commercialization. Herein, carbon nitride (CN) with superior hydrogen adsorption ability is used as an active-hydrogen adsorption and supply material. Through a facile liquid-assisted exfoliation and electrostatic self-assembly strategy to strengthen its interfacial contacts with Cu2O catalysts, yielding a strengthened CH4 production 52 times higher than that of pristine Cu2O. Flow-cell test ultimately achieved FECH4 and remarkably CH4 partial current density of 61% and 561 mA cm-2, respectively. With in situ ATR-FTIR spectra and DFT calculations, it is established that strengthened interfaces enabled abundant *H tethered by ─C─N═C─ sites in CN nanosheets and oriented to the *CO hydrogenation to *CHO and *CHx on Cu species. This work reveals the profound influence of fine-expanded interfaces with dimensional materials on the product distribution and yield through the active-hydrogen management, which is of reference value for other small-molecule electro-polarization dominated by the proton-coupled electron transfer (PCET) process (e.g., N2, O2, etc.).
Keywords: CO2 electrolysis; active‐hydrogen supply; industrial‐level current; process intensification.
© 2024 Wiley‐VCH GmbH.