The influence of cobalt doping on photocatalytic nano-titania: Crystal chemistry and amorphicity

Journal Article · Mon Oct 15 00:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.08.021· OSTI ID:21049526

Ferraris, Cristiano ^[1]; Schreyer, Martin ^[1]; Shih, Kaimin; Leckie, James O ^[2]; White, T J ^[1]

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1. School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, 639798, Singapore (Singapore)
2. Department of Civil and Engineering, Stanford University, Terman Engineering Center, Stanford, CA 94305-4020 (United States)

Photocatalysts of nominal composition (Ti{sub 1-x}Co{sub x})O{sub 2-{delta}} with 0.001{<=}x{<=}0.05 were prepared via a sol-gel technique followed by air firing (200-1000 deg. C). The incorporation of cobalt inhibited crystal growth and slightly raised the anatase to rutile transformation temperature ({approx}700 deg. C). An amorphous component was invariably significant with the maximum content (41-53 wt%) appearing simultaneously with the removal of anatase, suggesting that rutile crystallizes via an aperiodic structure. While the introduction of cobalt shifted the apparent band gap to visible light energies this did not enhance performance as there was limited miscibility of cobalt in titania, non-catalytic secondary phases were present, and active Ti{sup 3+} sites were displaced by cobalt. - Graphical abstract: Cobaltiferous titania photocatalysts calcined at 200 deg. C contain up to 16 at% metal vacancies (V) and are significantly amorphous (up to 53 wt%). The presence of metal vacancies can be monitored by following the dilation of the 'c' lattice parameter as the crystallite size increases during calcination.

• OSTI ID: 21049526
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 10 Vol. 180; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CALCINATION
COBALT OXIDES
CRYSTAL GROWTH
CRYSTALS
DOPED MATERIALS
FORMIC ACID
LATTICE PARAMETERS
PHASE TRANSFORMATIONS
PHOTOCATALYSIS
RUTILE
SOL-GEL PROCESS
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
TITANIUM IONS
TITANIUM OXIDES
VACANCIES