Covalently Integrated Selenoviologen-N-Heterocyclic Carbene-Pt Nanoparticles for Visible-Light-Driven Hydrogen...

To overcome the kinetic charge-transfer barriers imposed by traditional insulating protecting agents in nanoparticle photocatalysis, we synthesized a covalently integrated, single-component photocatalyst via a thermally induced reduction method. In this architecture, a hydrophilic selenoviologen (SeV²⁺) moiety, which intrinsically provides multiple redox capabilities, a narrow energy gap, and strong visible light absorption, is directly tethered to Platinum nanoparticles (PtNPs) via Nitrogen heterocyclic carbene (NHC) ligands, yielding the SeV²⁺- NHC-PtNPs. The resulting Pt─C covalent linkages serve a bifunctional role: acting as a structural scaffold for nanoparticle stabilization without introducing insulating layers and providing a direct electronic pathway. Consequently, this design not only preserves the photochemical advantages of the SeV²⁺ moiety but also drives efficient, directional intramolecular electron transfer (IET) to the catalytic Pt core, as confirmed by ultrafast spectroscopic and photoelectrochemical studies. By unifying the photosensitizer, electron mediator, and catalyst into a single entity, the system achieves a high hydrogen production rate (2706 µmol·h^-1·g^-1), turnover number (169), and apparent quantum yield (0.9%), demonstrating the potential of this covalent integration strategy for solar energy conversion.