The Nanocrystalline SnO2-TiO2 System-Part I: Structural Features

• Published in: Journal of the American Ceramic Society Vol. 99; no. 2; pp. 631 - 637
• Main Authors: Miagava, Joice, Rubbens, Annick, Roussel, Pascal, Navrotsky, Alexandra, Castro, Ricardo H. R., Gouvêa, Douglas
• Format: Journal Article
• Language: English
• Published: Columbus Blackwell Publishing Ltd 01.02.2016; Wiley Subscription Services, Inc
• Subjects: Catalysis; Crystal structure; Electron energy; Electron energy loss spectroscopy; Fourier transforms; Infrared spectroscopy; Microstructure; Nanocrystals; Nanoparticles; Nucleation; Phases; Raman spectra; Solubility; Spectrum analysis; Surface area; Tin dioxide; Titanium dioxide; Titanium oxides; X-ray diffraction; X-rays
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.13790

The phases present and their crystal structure and microstructure in the nanocrystalline SnO2–TiO2 system were studied in the compositional range Sn1−xTixO2 (0.0 ≤ x ≤ 0.9). There is an apparent increase in the solubility limits in the solid solution compared to bulk crystalline SnO2–TiO2. No two phase region was observed with increasing TiO2 content. Electron energy loss spectroscopy, infrared spectroscopy (FTIR), and X‐ray diffraction (XRD) of the nanopowders showed that the apparent increase in solubility is related to the systematic Ti4+ segregation on the particle surface (surface excess) at the SnO2‐rich side, avoiding the nucleation of a second phase even at high Ti4+ contents. Is this finding in accord with Raman spectra, which suggest localized Ti‐rich sites in the absence of a second crystalline phase. Ti4+ surface excess is also lead to a modification of the surface hydroxyls and a decrease in the crystallite size of the nanoparticles (with a concomitant increase in surface area), with expected implications to catalytic and sensorial properties of these nanoparticles.