Hydrogenated TiO2/SrTiO3 porous microspheres with tunable band structure for solar-light photocatalytic H2 and O2 evolution

The production of H-2 and O-2 from solar-light photocatalytic water splitting has attracted significant research attention as a clean and renewable source of energy. In this study, hydrogenated TiO2/SrTiO3 porous microspheres were prepared as a high-performance photocatalyst. Titanium glycerolate and then strontium complex precursors were first prepared via a two-step solvothermal process, then, after calcination in air and subsequent H-2/Ar reduction treatments, hydrogenated TiO2/SrTiO3 porous microspheres with controllable defects and band positions were prepared. Several characterization techniques were used to demonstrate that the catalyst heterostructures, the oxygen-vacancy content, and the unique porous structures synergistically enhanced the visible-light harvesting abilities and photogenerated charge separation, and resulted in improved photocatalytic efficiency for H-2 and O-2 evolution. As expected, the optimum treatment conditions provided hydrogenated TiO2/SrTiO3 porous microspheres that showed excellent photocatalytic activity with H-2 and O-2 evolution rates of 239.97 and 103.79 mu mol h(-1) (50 mg catalyst, under AM 1.5 irradiation), respectively, which were ca. 5.9 and 6.6 times higher, respectively, than those of solid TiO2/SrTiO3 materials. Thus, this type of hydrogenated TiO2/SrTiO3 porous microsphere catalyst shows great potential as a photocatalyst for solar-energy conversion applications.