Rational synthesis of SrTiO3 nanodots anchored mesocrystalline anatase TiO2 submicrospheres for photocatalytic reduction of CrVI

Mesoporous anatase TiO 2 sphere based materials has long been the focus of intensive research dealing with environmental-related issues due to their significant advantages in terms of structural isotropy, high surface area, structural stability, and low cost. However, in most cases, the employed mesoporous anatase spheres were comprised of nanocrystalline subunits with random crystalline orientations, which means that numerous grain boundaries exist in the sphere-shaped particles, suppressing their performance in various applications. Herein, by using mesocrystalline anatase submicrospheres that were synthesized via utilizing SO 4 2- ions to modulate the growth dynamics of anatase crystals in the green mixed solvents of PEG-400 and H 2 O as both template and reactant, novel sphere-shaped anatase mesocrystal/SrTiO 3 nanodot heterostructures were successfully produced. These spherical anatase mesocrystal/SrTiO 3 heterostructures exhibited noticeably enhanced activity toward reduction of hexavalent chromium (Cr VI ) under stimulated solar light irradiation, which was largely attributed to their favored adsorption of Cr VI , bolstered photogenerated charge carrier separation and well-preserved reduction capability due to the construction of a well-defined type-II heterojunction with tight interfacial contacts and strong interactions. This work will be useful for the designed fabrication of micro/nanostructured TiO 2 based photocatalysts with complex spherical morphologies for photocatalytic applications in environmental purification.