Low temperature preparation of nanocrystalline SrTiO3 and BaTiO3 from alkaline earth nitrates and TiO2 nanocrystals

Using low-melting-point Sr(NO3)2 (melting point: 570 °C) and high-reactive-activity TiO2 nanocrystals (Degussa P25 TiO2) as the raw materials, phase-pure SrTiO3 nanocrystals were prepared at 600 °C. X-ray diffraction and X-ray photoelectron spectroscopy revealed that the as-prepared products were cubic phase SrTiO3 with a surface composition of Sr0.97TiO2.92. Transmission electron microscopy image showed that the as-prepared SrTiO3 comprised nanocrystals with the size of about 24–44 nm. UV–vis absorption spectrum of the as-prepared SrTiO3 nanocrystals displayed a wide absorption peak centered at around 365 nm (3.4 eV), together with a tail at the lower energy side. This kind of low temperature and cost-effective method can also be extended to prepare BaTiO3 nanocrystals, simply by substituting Ba(NO3)2 for Sr(NO3)2.