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

Abstract

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. CuNi/PCN with low-coordinated N3-Ni-Cu-N2 dual-atom sites achieves selective C2H6 production with a 1.15% AQE in dilute flue gas CO2. Synergistic dual sites promote C-C coupling and endow the catalyst with strong resistance to NOx and SO2 poisoning.