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.

Graphical abstractPhase-pure SrTiO3 and BaTiO3 nanocrystals were prepared from low-melting alkaline earth nitrates (Sr(NO3)2 or Ba(NO3)2) and high reactive P25 TiO2 nanocrystals at 600 °C, and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and UV-vis absorption spectra. The proposed method may serve as a general strategy to prepare nanocrystalline titanates.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Phase-pure SrTiO3 and BaTiO3 nanocrystals were prepared at 600 °C. ► The raw materials were low-melting Sr(NO3)2 or Ba(NO3)2 and high reactive P25 TiO2. ► The products were characterized by XRD, TEM, XPS and UV–vis absorption spectra. ► This method may serve as a general strategy to prepare nanocrystalline titanates.