Dual Locking of Cu+/Cu0 Interface and Vacancy Defects via Al‐Doping for Efficient Electroreduction of CO2 to C2+ Products

Multi-carbon (C2+) products from the electrochemical CO2 reduction reaction (CO2RR) are highly desirable due to their energy density and commercial value. Cu-based catalysts are the only known materials capable of producing C2+ products with appreciable efficiency. However, the low *CO intermediate coverage and sluggish C-C coupling kinetics hinder their selectivity. Herein, an Al-doped copper hydroxyfluoride (Al-CuOHF) catalyst that combines dynamic reconstruction with electronic modulation is reported. In/ex situ CO2RR characterization confirm that partial Al dissolution drives in situ reconstruction of porous Cu2O/Cu heterostructures with abundant oxygen vacancies (Ov), while residual Al stabilizes Cu+ species and F-Ov Lewis acid-base pairs. In situ Raman spectroscopy directly evidences enhanced *CO adsorption on restructured surfaces. These synergistic effects facilitate CO2 activation, elevate *CO coverage, and reduce the energy barrier for C-C coupling. Consequently, Al-CuOHF delivers a remarkable C2+ Faradaic efficiency of 83.3% and a partial current density of -93.03 mA cm-2 at -1.0 V (vs. RHE). This work provides a strategy for constructing multifunctional interfaces via dopant-guided structural evolution and electronic field engineering, offering new insights into high-efficiency CO2 electroreduction.