(678h) Interfacial Electric Field Modulated Catalysis

A high local electric field can rearrange the electronic orbitals of chemical species and alter the electronic interactions between adsorbates and catalytic surfaces, which influences the thermodynamics, kinetics, and mechanisms of (electro)catalytic reactions.¹ The local high electric field could be generated by the different charges between the metal complex molecule (i.e., metal phthalocyanines, MPc = CoPc, FePc, NiPc, and Pc) and the Cu metallic surface, and could further be enhanced by the electrode/electrolyte interfacial electric field.

Density functional theory (DFT) calculations show that all MPc molecules induce a strong confined electric field on the order of ~2 to 3 V/Å. The favorability of C-C coupling is linearly correlated to the confined electric field strength (Figure 1a) generated at the MPc/Cu interface. To validate our DFT predictions, we conformally coated a thin layer of MPc molecules on a Cu-based gas diffusion electrode and evaluated the related CO₂RR performance in a flow cell electrolyzer using neutral electrolytes (Figure 1b). The CoPc/Cu electrode showed an ethylene selectivity of 72% from CO₂reduction, exceeding the ethylene selectivity on bare Cu by two-fold. With the aid of in-situ spectroscopic analysis, we confirmed that the CoPc/Cu catalyst performs the best for C-C coupling as it induces the strongest confined interfacial electric field among all examined MPc/Cu catalysts, consistent with our DFT results (Figure 1c).³ This project will advance the mechanism understanding at the organic-inorganic interface, accelerating the electrochemical CO₂conversion to ethylene and beyond.