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

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 (O_v), while residual Al stabilizes Cu⁺ species and F-O_v 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.