Low-coordinated CuNi dual-atom catalyst for efficient flue gas CO₂-to-C₂H₆ photoreduction

Efficient photoreduction of flue gas CO₂ to high-value C₂ products is challenging due to low CO₂ concentrations, sluggish kinetics, and susceptibility to catalyst poisoning. To tackle this, CuNi/PCN photocatalysts with low-coordinated N₃-Ni-Cu-N₂ dual-atom active sites were synthesized by in-situ thermal polymerization method. The optimized catalyst drives CO₂ photoreduction, with C₂H₆ formed as the major product at a rate of 254.3 μmol h^-1 g^-1 alongside CO and CH₄. Notably, it retains ~50% yield with ~63% electron selectivity of C₂H₆ under 15% diluted CO₂ and exhibits robust anti-poisoning capability and stability in complex flue gas. Integrated studies reveal that low coordinated CuNi dual-atom sites synergistically modulates active site electronics, enhancing CO₂ adsorption and lowering barriers for C-C coupling to form C₂H₆. The formed Cu-Ni bonds further reinforce the catalyst's structural and photocatalytic stability. Overall, this work offers a promising strategy for efficient solar C₂ production from industrial exhaust gases.