One-Dimensional Mesoporous Anatase-TiO 2 /Rutile-TiO 2 /ZnTiO 3 Triphase Heterojunction with Boosted Photocatalytic Hydrogen Production Activity

The rational design of heterojunction photocatalysts with unique mesoporous structure is of significant importance for obtaining enhanced conversion efficiency of solar energy to hydrogen energy. In present work, for the first time, anatase-TiO 2 /rutile-TiO 2 /ZnTiO 3 (TiO 2 (A-R)/ZnTiO 3 ) heterojunction photocatalysts with a unique mesoporous structure were synthetized by a foaming agent assisted electrospinning method. The obtained mesoporous TiO 2 (A-R)/ZnTiO 3 nanofibers photocatalyst showed the highest hydrogen generation rate (887.7 μmol·g −1 ·h −1 ) without use of any co-catalytic noble metals, which was approximately 2.0, 2.2 and 1.4 times higher than those of ordinary solid TiO 2 (A-R)/ZnTiO 3 , mesoporous TiO 2 (A-R) and mesoporous TiO 2 (A)/ZnTiO 3 nanofibers, respectively. Significantly, the archived hydrogen generation rate is also better or comparable to the some ever reported 1D TiO 2 based photocatalysts. The unique 1D mesoporous nanostructure would make the reactants and products migrating easily into/out of the photocatalyst while the closely-coupled triphase heterojunction can significantly favor the separation of photogenerated electron–hole pairs, thus synergistically contributing to the improved photocatalytic activity. We also proposed that three types of charge transfer routes over the heterojunction photocatalysts, named “waterfall”, “concave” and “convex”, might concurrently promote the separation of photoinduced electrons and holes in this triphase photocatalyst system, thereby efficiently boost the photocatalytic hydrogen production activity. Graphic Abstract