Revealing the Mechanisms behind SnO2 Nanoparticle Formation and Growth during Hydrothermal Synthesis: An In Situ Total Scattering Study

Journal Article · Thu Mar 15 04:00:00 EDT 2012 · Journal of the American Chemical Society

OSTI ID:1049251

J, Billinge S; Jensen, K M.O.; Christensen, M; Juhas, P; Tyrsted, C; Bojesen, E D; Lock, N; Iversen, B B

The formation and growth mechanisms in the hydrothermal synthesis of SnO{sub 2} nanoparticles from aqueous solutions of SnCl{sub 4} {center_dot} 5H{sub 2}O have been elucidated by means of in situ X-ray total scattering (PDF) measurements. The analysis of the data reveals that when the tin(IV) chloride precursor is dissolved, chloride ions and water coordinate octahedrally to tin(IV), forming aquachlorotin(IV) complexes of the form [SnCl{sub x}(H{sub 2}O){sub 6-x}]{sup (4-x)+} as well as hexaaquatin(IV) complexes [Sn(H{sub 2}O){sub 6-y}(OH){sub y}]{sup (4-y)+}. Upon heating, ellipsoidal SnO{sub 2} nanoparticles are formed uniquely from hexaaquatin(IV). The nanoparticle size and morphology (aspect ratio) are dependent on both the reaction temperature and the precursor concentration, and particles as small as 2 nm can be synthesized. Analysis of the growth curves shows that Ostwald ripening only takes place above 200 C, and in general the growth is limited by diffusion of precursor species to the growing particle. The c-parameter in the tetragonal lattice is observed to expand up to 0.5% for particle sizes down to 2-3 nm as compared to the bulk value. SnO{sub 2} nanoparticles below 3-4 nm do not form in the bulk rutile structure, but as an orthorhombic structural modification, which previously has only been reported at pressures above 5 GPa. Thus, adjustment of the synthesis temperature and precursor concentration not only allows control over nanoparticle size and morphology but also the structure.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1049251
• Report Number(s): BNL--98201-2012-JA; KC0202010
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 15 Vol. 134; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AQUEOUS SOLUTIONS
CHLORIDES
DIFFUSION
HEATING
HYDROTHERMAL SYNTHESIS
MORPHOLOGY
PARTICLE SIZE
PRECURSOR
RIPENING
RUTILE
SCATTERING
SYNTHESIS
TETRAGONAL LATTICES
WATER
hydrothermal synthesis
in situ x-ray total scattering (PDF) measurements
metal oxide nanoparticles