Modulation of Local Electronic Structure in Double-Shell Hollow Cu2O via Pyridyl Ligands for Efficient CO2-to-Ethylene Conversion.

The electrochemical reduction of CO2 to ethylene (C2H4) offers an attractive route for carbon valorization to bulk chemicals by using sustainable energy. However, its practical application is hindered by sluggish C─C coupling kinetics and poor C2H4 selectivity at high current densities. While hollow-structured Cu2O can enrich *CO intermediates, further enhancing C─C coupling on such structures remains challenging. In this context, we developed a ligand modulation strategy to tailor the catalytic properties of double-shell hollow Cu2O by anchoring π-conjugated 1,4-bis(4-pyridyl)benzene (BPB) onto the Cu2O surface via Cu─N coordination bonds. Concentration‑dependent studies identify 10 mM BPB as the optimal balance between electronic modulation and surface accessibility. In situ ATR‑SEIRAS and density functional theory calculations collectively demonstrate that the electron donation from pyridinic N donors to Cu+ sites promotes CO2 activation and *COOH formation, while the strengthened *CO adsorption is expected to facilitate C─C coupling. As a result, the optimized Cu2O-BPB-10 catalyst delivered a C2H4 Faradaic efficiency (FE) of 61.6% and a total C2+ FE of 85.1% at a current density of 600 mA cm-2. This work provides a facile and versatile ligand engineering strategy for designing high-performance Cu-based catalysts for practical electrochemical CO2 reduction under industrially relevant conditions.