Local Electric Fields at Organic-Inorganic Hybrid Interfaces Drive Electrocatalysis

The local electric field generated at organic-inorganic hybrid interfaces can profoundly influence electrocatalytic reactions, yet how molecular interfaces regulate local field distributions and reaction pathways remains poorly understood. Here, we combine grand-canonical density functional theory with in situ surface-enhanced Raman spectroscopy to investigate CO2 reduction at cobalt phthalocyanine-copper (CoPc-Cu) interfaces. Density functional theory calculations show that CoPc creates a confined interfacial microenvironment and modifies the charge distribution at the Cu surface, producing non-uniform local electric fields that are experimentally probed using the vibrational Stark effect of adsorbed CO. Theory and experiment reveal that this field heterogeneity modifies CO adsorption across neighboring Cu sites and increases the adsorption-energy difference between adjacent CO intermediates, thereby lowering the barrier for C–C coupling. Consistent with this mechanism, CoPc-Cu exhibits an enhanced C2+/C1 product ratio, particularly at modest cathodic potentials where the confined hybrid interface is preserved. This work provides direct in situ evidence that organic-inorganic hybrid interfaces can regulate electrocatalytic selectivity through local electric-field engineering, offering design principles for field-enhanced CO2 electroreduction.