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

Abstract

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-1h-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.

Keywords: CO2 photoreduction; Cu2O@Cu@NiAl-LDH photocatalyst; valence synergy; zero-valent copper.