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

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.