Mixed-phase Mg Ti O3/Mg Ti2O5 microspheres were prepared through a salicylic acid precursor method and further calcined in air. The microspheres were formed through coordination, polymerization, and aggregation processes. Salicylic acid acted as a ligand in coordinating with metal ions, in addition to acting as a structure-directing agent in the polymerization and aggregation of the titanate precursor microspheres via chemical bonds and electrostatic attraction. The mixed-phase Mg Ti O3/Mg Ti2O5 microspheres prepared by this method showed excellent photocatalytic hydrogen production efficiencies that were two and four times higher than mixed-phase nanoparticles and pure-phase nanoparticles, respectively, owing to their closed phase junctions and sphere-like morphologies. This versatile and facile salicylic acid precursor method was also used to prepare a number of other bivalent metal-based titanate microspheres, including Ba TiO3, ZnTiO3, CoTiO3, NiTiO3, and CdTiO3.
