Cu₂O@Cu@NiAl-LDH with Cu⁰/Cu⁺ Valence Synergy and Core-Shell Structure for Highly Selective Generation of C₂H₆

Photocatalytic CO₂ reduction to produce C₂ products remains a challenge. Herein, Cu₂O@Cu@NiAl-LDH composites with three-dimensional ordered core-shell structures were successfully prepared, and the effects of Cu₂O with different exposed surfaces on CO₂ photoreduction were investigated. The synergistic effect of zero-valent Cu and Cu⁺ as intermediate electron mediators retains more photogenerated electrons and the Z-scheme heterojunction formed between Cu₂O and NiAl-LDH leads to the enhancement of C₂ selectivity. The best sample, Cu₂O@Cu@NiAl-LDH-2, achieved a C₂H₆ yield of 22.17 μmol g^-1 h^-1 with 63.89 % electron selectivity. The evolution pathways and photocatalytic mechanisms of CO₂ were investigated by in-situ DRIFTS and theoretical calculations. This study provides references and suggestions for the further development of experimental and theoretical calculations of Cu₂O-based photocatalysts for the reduction of CO₂ to C₂ products.