Sandwich SrTiO3/TiO2/H-Titanate nanofiber composite photocatalysts for efficient photocatalytic hydrogen evolution

SrTiO3/TiO2/H-Titanate nanofiber composites were synthesized through facile thermal treatment of Sr(OH)(2) and H-titanate nanofibers in an ethanol/water solution and their photocatalytic activities for H-2 evolution from a methanol/water solution under simulated solar irradiation were evaluated. TiO2/H-titanate nanofiber composites were acquired without Sr(OH)(2) addition. At low Sr/Ti molar ratios, SrTiO3/TiO2/H-titanate nanofiber composites form. SrTiO3 nanoparticles were found to selectively grow on the surface of TiO2 nanoparticles, forming a unique SrTiO3-TiO2-H-titanate sandwich heterojunction. Upon increasing the Sr/Ti molar ratio, the fraction of TiO2 in the resultant composites decreases and eventually SrTiO3/H-titanate nanofiber composites form. SrTiO3/TiO2/H-titanate nanofiber composites are significantly more photocatalytically active than SrTiO3/H-titanate nanofiber and TiO2/H-titanate nanofiber composites due to the mitigated charge recombination and the accumulation of photo-excited electrons on the photocatalytically active TiO2 component. These results demonstrate an effective strategy of multi-heterojunctions with both appropriately-aligned band structures and appropriatelyarranged composite structures to fabricate efficient composite photocatalysts. (C) 2014 Elsevier B.V. All rights reserved.