Modulating Interfacial Molecular Vibration for Enhanced CO Electrolysis via Coated-Carbon Layers

The regulation mechanism of interfacial coatings on CO electroreduction has not yet been unraveled even though high CO-to-C 2+ conversion is observed. In this work, in situ spectroscopy techniques were employed to decouple the regulatory rules of carbon coatings on the hydrogen-bonding network and adsorbed carbon monoxide at the copper-based catalytic interface for CO electroreduction. The coated-carbon layers could promote the CO-to-C 2+ conversion efficiency, as the C 2+ selectivity increased from below 66% (for pure Cu) to above 77% in alkaline electrolyte. Combined with in situ electrochemical infrared spectroscopy, online mass spectrometry, and theoretical calculations, it was found that the carbon coating could reconstruct the interfacial hydrogen-bonding network and enhances its orderliness, thereby inducing more favorable hydrogenation steps for intermediates compared to hydrogen evolution. Meanwhile, the Cu–C interface tunes the vibrational state of linearly adsorbed CO, strengthens Cu–CO interactions, and lowers the energy barrier for C–C coupling toward C 2+ products. To further demonstrate the practical relevance of this mechanism, a self-designed compact integrated CORR prototype was developed, which maintained an ethylene Faradaic efficiency above 40% over 24 h at 15 A. These findings provide molecular-level insight and practical guidance for the design of interfacial-modified Cu catalysts for efficient CO electro-conversion.