Basic Molten Salt Route to Prepare Porous SrTiO3 Nanocrystals for Efficient Photocatalytic Hydrogen Production

SrTiO3 nanocrystals with porous structures were synthesized by a basic molten salt method. TEM images confirmed that the SrTiO3 nanocrystals possess a cellular morphology. High-resolution TEM and selected-area electron diffraction (SAED) analysis proved the existence of pores even in single crystals. Time-dependent observations indicated that the formation of pores in the SrTiO3 nanocrystals resulted from the phase transformation of the TiO2 precursor in the basic solvent, and the process follows the dissolution-nucleation-aggregation growth mechanism. More importantly, the porous structure of the SrTiO3 nanocrystals is retained after the removal of the basic solvent by cool-water washing, as the cool water can efficiently dissipate the heat of dissolution for the dissolution of the strong base into the water. The as-prepared porous SrTiO3 nanocrystal photocatalysts exhibited a high rate of photocatalytic H-2 evolution, which is attributed to their large specific surface area and good crystallinity.