Aggregation-Induced Equidistant Dual Pt Atom Pairs for Effective CO2 Photoreduction to C2H4

The photocatalytic conversion of CO2 into high value-added ethylene (C2H4) is challenging due to the unsuitable active sites and the significant energy barrier associated with the C–C coupling process. Single-atom catalysts are advantageous for their high atom utilization efficiency, yet enhancing C–C coupling efficiency requires strategic engineering of the active site environment. Traditional approaches often result in the random spacing of active atom pairs, which can hinder C–C coupling facilitation. Dual-atom pairs with precise geometrical modulation and well-defined spacing can improve the generation of C2 products and enhance the mechanistic understanding. Herein, we present an equidistant dual Pt atom pair assembly on the Bi3O4Br surface via Pt-TCPP aggregation. Using this strategy, the spacing between neighboring Pt atoms in each atom pair is confined through intermolecular van der Waals forces, and such a geometrically well-defined site significantly facilitates the C–C coupling process. Consequently, the atom pair configuration achieves a C2H4 yield over 8 times higher than that of the single atom structure, with an improved TOF of site enhancement of about 10 times. Our work highlights an effective strategy for fabricating well-defined dual-atom catalysts, offering a promising pathway for efficient CO2 photoreduction to C2H4 by precisely designing the photocatalytic environment.