Photocatalytic activity of MTiO₃ (M = Ca, Ni, and Zn) nanocrystals for water decomposition to hydrogen

MTiO3(M = Ca, Ni, and Zn) nanocrystals were prepared via a facile ethylene glycol-mediated synthesis route followed by calcination in air. The structures and morphologies of nanocrystals were characterized by x-ray diffraction, Raman spectroscopy, transmission electron microscopy, and scanning electron microscopy. The results indicated that CaTiO3and NiTiO3are orthorhombic phase, while the ZnTiO3is orthorhombic phase. The activity of the CaTiO3nanocrystals for water splitting into H2was obviously higher than those of the NiTiO3and ZnTiO3nanocrystals, which could be attributed to the more negative conduction band position of CaTiO3than NiTiO3and ZnTiO3. The Brunauer-Emmett-Teller system-based surface areas of samples are 19.03, 21.13, and 4.17 m2/g for CaTiO3, NiTiO3, and ZnTiO3nanocrystals, respectively. In addition, the activity of the CaTiO3nanocrystals increased with increase in the sintering temperature of samples.