Photocatalytic Water Splitting under Visible Light by Mixed-Valence Sn3O4

A mixed-valence tin oxide, (Sn (2+) ) 2 (Sn (4+) ) O4, was synthesized via a hydrothermal route. The Sn3O4 material consisted of highly crystalline 110 flexes. The Sn3O4 material, when pure platinum (Pt) was used as a co-catalyst, significantly catalyzed water-splitting in aqueous solution under illumination of visible light (λ > 400 nm), whereas neither Sn (2+) O nor Sn (4+) O2 was active toward the reaction. Theoretical calculations have demonstrated that the co-existence of Sn (2+) and Sn (4+) in Sn3O4 leads to a desirable band structure for photocatalytic hydrogen evolution from water solution. Sn3O4 has great potential as an abundant, cheap, and environmentally benign solar-energy conversion catalyst.