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Low‐cost transition‐metal chalcogenides (MSx) are demonstrated to be potential candidate cocatalyst for photocatalytic H2 generation. However, their H2‐generation performance is limited by insufficient quantities of exposed sulfur (S) sites and their strong bonding with adsorbed hydrogen atoms (SHads). To address these issues, an efficient coupling strategy of active‐site‐enriched regulation and electronic structure modification of active S sites is developed by rational design of core–shell Au@NiS1+x nanostructured cocatalyst. In this case, the Au@NiS1+x cocatalyst can be skillfully fabricated to synthesize the Au@NiS1+x modified TiO2 (denoted as TiO2/Au@NiS1+x) by a two‐step route. Photocatalytic experiments exhibit that the resulting TiO2/Au@NiS1+x(1.7:1.3) displays a boosted H2‐generation rate of 9616 µmol h−1 g−1 with an apparent quantum efficiency of 46.0%  at 365 nm, which is 2.9 and 1.7 times the rate over TiO2/NiS1+x and TiO2/Au, respectively. In situ/ex situ XPS characterization and density functional theory calculations reveal that the free‐electrons of Au can transfer to sulfur‐enriched NiS1+x to induce the generation of electron‐enriched Sδ− active centers, which boosts the desorption of Hads for rapid hydrogen formation via weakening the strong SHads bonds. Hence, an electron‐enriched Sδ−‐mediated mechanism is proposed. This work delivers a universal strategy for simultaneously increasing the active site number and optimizing the binding strength between the active sites and hydrogen adsorbates.

The exploitation and preparation of novel non-noble-metal cocatalysts are particularly crucial to develop high-activity photocatalytic hydrogen-generation materials. In this study, metallic Sn nanoparticle, a new hydrogen-generation cocatalyst, was effectively integrated with the conventional TiO2 photocatalyst to greatly boost the hydrogen-production reaction via a direct photoinduced method. Herein, the direct photoinduced synthesis of Sn nanoparticle-deposited TiO2 photocatalysts and their enhanced H2-generation activity can be easily and simultaneously realized in an ethylene glycol–ethanol system. The Sn nanoparticles were very small (ca. 2 nm) and uniformly deposited onto the TiO2 surface to synthesize highly efficient Sn/TiO2 photocatalysts via the formation of Sn­(II)-EG complex molecules and their following in situ photoreduction method. Photocatalytic results indicated that metallic Sn cocatalyst could dramatically promote the H2-generation activity of TiO2 photocatalyst, and the resultant Sn/TiO2(3 wt %) presented the highest H2-production rate with a value of 553.1 μmol h–1 g–1, which is 43.9 times as that of pure TiO2 (12.6 μmol h–1 g–1). Thus, an electron-cocatalyst-mediated mechanism is raised to explain the promoted H2-generation efficiency of TiO2 photocatalyst, namely, the metallic Sn cocatalyst can act as the electron receiver to quickly capture photoexcited electrons and serve as the interfacial hydrogen-generation site to enhance the hydrogen-generation rate. Considering the facile synthetic route, earth abundance, and high activity, the metallic Sn cocatalyst would have enormous prospect for the development of efficient photocatalysts applied in different fields.

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