Parallel Interface Engineering of Single-Atom Pt/g-C₃N₄ and Selenoviologen for Durable Photocatalysis via Efficient Directional Electron Flow

Photocatalysis offers a sustainable route for clean energy conversion, yet its efficiency is frequently constrained by uncontrolled charge-carrier recombination and sluggish interfacial electron transfer. Here, we address this challenge by constructing a parallel photocatalytic interface through the dual covalent binding of selenoviologen electron mediators to defective g-C₃N₄ which is anchored with single-atom Pt. This architecture forms a highly stable “electron overpass” that directs electron flow with exceptional efficiency. Ultrafast spectra and DFT calculations confirm that this overpass channels electrons from both photoexcited g-C₃N₄ and selenoviologen radical intermediates directly to the Pt catalytic sites. The system achieves a forward electron transfer rate of 0.043 L·g⁻¹·s⁻¹, four times that of the single covalent binding control, and extends the charge carrier lifetime to 7998.8 ps. As a result, the photocatalyst delivers a remarkable hydrogen evolution rate of 3231.9 µmol·h⁻¹g⁻¹, while the concurrent anaerobic oxidation of benzylamine proceeds at 1390.6 µmol·h⁻¹g⁻¹. Crucially, the dual covalent binding affords outstanding durability, retaining 92% of the initial activity after six 24 h cycles, a nearly tenfold improvement over the conventional system. This work establishes parallel interface engineering as a general paradigm for directing electron flow, paving the way for advanced solar fuel production and artificial photosynthesis.