Core-shell structured Cu2O@NiAl-LDH/CQDs photocatalysts for efficient photocatalytic reduction of CO2 to C2 products

Photocatalytic CO2 reduction to high-value C2 fuels is considered a promising technology, but still challenging due to the complex multi-electronic steps and C-C coupling involved. In this paper, a Cu2O@NiAl-LDH/CQDs composite with a core-shell structure is designed for the highly selective photoreduction of CO2 to C2H6. A series of characterizations show that the construction of Cu2O@NiAl-LDH heterojunctions accelerates the transfer of photogenerated electrons from NiAl-LDH to Cu2O which improves the yield and selectivity of C2H6. The C2H6 yield of the best sample, Cu2O@NiAl-LDH/CQDs-10, is as high as 8.18 mu mol g-1 h-1, and the electron selectivity is 69.85 %, which is 15.7 times higher than Cu2O. In-situ DRIFTS showed that the Cu2O@NiAl-LDH/CQDs composites were able to promote the adsorption of CO* and the generation of COCO*, and facilitate the C-C coupling to generate C2H6.