Au-Cu dual-single-atom sites on Bi₂WO₆ with oxygen vacancy for CO₂ photoreduction towards multicarbon products

CO₂ photoreduction into high-value-added C₂₊ products struggles with energetic challenges in forming critical intermediates and multiple C−C bonds. Herein, an effectively synthesized photocatalyst, Bi₂WO₆ nanosheets with oxygen vacancies anchoring Au and Cu dual single atoms on the surface, can convert CO₂ and H₂O vapour into C₃H₆ and C₂H₄. The high product selectivity of 18.2 % for C₃H₆ and 65.4 % for total C₂₊ hydrocarbons are achieved under concentrated light irradiation (2.4 W·cm⁻²). Au-Cu dual-single-atom sites and defect engineering strategies exhibit synergistic effects on optimizing the reaction thermodynamics and charge kinetics for CO₂ conversion. Theoretical calculations provide reference values for reaction pathways of C₃H₆ and C₂H₄ formation, with the C−C couplings being potential determining steps of multicarbon product formation. Our work offers a promising strategy with a combination of concentrated light irradiation technology and catalyst modification to achieve high selectivity of C₂₊ products.