Simultaneous Realization of Direct Photoinduced Deposition\nand Improved H₂‑Evolution Performance of Sn-Nanoparticle-Modified\nTiO₂ Photocatalyst

Abstract

The exploitation\nand preparation of novel non-noble-metal cocatalysts\nare particularly crucial to develop high-activity photocatalytic hydrogen-generation\nmaterials. In this study, metallic Sn nanoparticle, a new hydrogen-generation\ncocatalyst, was effectively integrated with the conventional TiO₂ photocatalyst to greatly boost the hydrogen-production reaction\nvia a direct photoinduced method. Herein, the direct photoinduced\nsynthesis of Sn nanoparticle-deposited TiO₂ photocatalysts\nand their enhanced H₂-generation activity can be easily\nand simultaneously realized in an ethylene glycol–ethanol system.\nThe Sn nanoparticles were very small (ca. 2 nm) and uniformly deposited\nonto the TiO₂ surface to synthesize highly efficient Sn/TiO₂ photocatalysts via the formation of Sn­(II)-EG complex molecules\nand their following in situ photoreduction method. Photocatalytic\nresults indicated that metallic Sn cocatalyst could dramatically promote\nthe H₂-generation activity of TiO₂ photocatalyst,\nand the resultant Sn/TiO₂(3 wt %) presented the highest\nH₂-production rate with a value of 553.1 μmol h^–1 g^–1, which is 43.9 times as that\nof pure TiO₂ (12.6 μmol h^–1 g^–1). Thus, an electron-cocatalyst-mediated mechanism\nis raised to explain the promoted H₂-generation efficiency\nof TiO₂ photocatalyst, namely, the metallic Sn cocatalyst\ncan act as the electron receiver to quickly capture photoexcited electrons\nand serve as the interfacial hydrogen-generation site to enhance the\nhydrogen-generation rate. Considering the facile synthetic route,\nearth abundance, and high activity, the metallic Sn cocatalyst would\nhave enormous prospect for the development of efficient photocatalysts\napplied in different fields.