Facile preparation of apatite-type lanthanum silicate by a new water-based sol–gel process

Journal Article · Sat Jun 01 04:00:00 EDT 2013 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2013.02.041· OSTI ID:22341689

Yamagata, Chieko ^[1]; Elias, Daniel R.; Paiva, Mayara R.S.; Misso, Agatha M.

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1. Nuclear and Energy Research Institute – Instituto de Pesquisas Energéticas e Nucleares – CCTM (Centro de Ciência e Tecnologia de Materiais), São Paulo (Brazil)

Highlights: ► We use a Na{sub 2}SiO{sub 3} waste solution as source of Si. ► We present a simple, rapid and low temperature method of lanthanum silicate apatite preparation. ► TEOS, a high cost reagent, was successfully substituted by a cheap price Na{sub 2}SiO{sub 3}, to obtain pure La{sub 9.56}(SiO{sub 4})6O{sub 2.33} lanthanum silicate apatite. - Abstract: In recent years, apatite-type lanthanum silicates ([Ln{sub 10−x}(XO{sub 4})6O{sub 3–1.5x}] (X = Si or Ge)) have been studied for use in SOFC (solid oxide fuel cells), at low temperature (600–800 °C), due to its ionic conductivity which is higher than that of YSZ (Yttrium Stabilized Zirconia) electrolyte. For this reason they are very promising materials as solid electrolyte for SOFCs. Synthesis of functional nanoparticles is a challenge in the nanotechnology. In this work, apatite-type lanthanum silicate nanoparticles were synthesized by a water-based sol–gel process, i.e., sol–gel technique followed by chemical precipitation of lanthanum hydroxide on the gel of the silica. Na{sub 2}SiO{sub 3} waste solution was used as silica source. Spherical aerogel silica was prepared by acid catalyzed reaction, followed by precipitation of lanthanum hydroxide to obtain the precursor of apatite-type lanthanum silicate. Powders of apatite-type lanthanum silicate achieved from the precursor were characterized by thermal analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area measurements (BET). The apatite phase was formed at 900 °C.

• OSTI ID: 22341689
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 6 Vol. 48; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
APATITES
ELECTROLYTES
GELS
LANTHANUM HYDROXIDES
LANTHANUM SILICATES
NANOPARTICLES
SCANNING ELECTRON MICROSCOPY
SILICA
SILICON OXIDES
SODIUM SILICATES
SOL-GEL PROCESS
SOLID OXIDE FUEL CELLS
SYNTHESIS
THERMAL ANALYSIS
X-RAY DIFFRACTION
YTTRIUM OXIDES
ZIRCONIUM OXIDES