Developing Dual-Atom Catalysts with Tunable Electron Synergistic Effect via Photoinduced Ligand Exchange Strategy

Dual-atom catalysts (DACs) are promising for various catalytic reactions. However, synthesis challenges have hindered their development. Herein, we propose a universal approach using photoinduced ligand exchange (PILE) to create DACs with high proportions of dual-atom pairs, fixed interatomic distances, and tunable metal ratios and types. By cocrystallizing two metal acetylacetonates on graphitic carbon nitride (CN) nanosheets, the metal types and ratios in DACs can be precisely controlled. Remarkably, over 90% of dual-atom pairs follow the metal atom distances of 2.4 and 7.3 Å. During the photocatalytic H₂ production, the heteronuclear DAC (Pt₁Pd₂/CN) delivers a performance of ∼15.9 mmol·g^–1·h^–1 under AM1.5 light irradiation due to the electron synergistic effect, which overperforms not only the single-atom catalysts (Pt/CN and Pd/CN) but also the homonuclear DACs (PtPt/CN and PdPd/CN). X-ray photoelectron spectroscopy (XPS), X-ray absorption near-edge structure (XANES), and density functional theory (DFT) calculations reveal that Pt draws electrons from Pd, modulating its charge state, lowering the d-orbital center and approaching the more proper H adsorption free energy, thereby enhancing H₂ production. As a pioneering strategy, PILE offers a straightforward and powerful route to synthesize both homonuclear and heteronuclear DACs, holding immense promise for revolutionizing a broad spectrum of catalytic applications.