Photocatalytic activity of MTiO_3 (M = Ca, Ni, and Zn) nanocrystals for water decomposition to hydrogen

摘要

MTiO_3 (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 CaTiO_3 and NiTiO_3 are orthorhombic phase, while the ZnTiO_3 is orthorhombic phase. The activity of the CaTiO_3 nanocrystals for water splitting into H_2 was obviously higher than those of the NiTiO_3 and ZnTiO_3 nanocrystals, which could be attributed to the more negative conduction band position of CaTiO_3 than NiTiO_3 and ZnTiO_3. The Brunauer-Emmett-Teller system-based surface areas of samples are 19.03, 21.13, and 4.17 m~2/g for CaTiO_3, NiTiO_3, and ZnTiO_3 nanocrystals, respectively. In addition, the activity of the CaTiO_3 nanocrystals increased with increase in the sintering temperature of samples.