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Photocatalytic Characteristics of Zinc Oxide Particles Precipitated from Concentrated Solutions at Low Temperatures
|Jean-Francois Hochepied 1, Ana Paula Almeida de Oliveira 1, Véronique Guyot Ferreol 2, Jean François Tranchant 2|
1. Laboratoire de Systemes Colloidaux dans le Processus Industriels (SCPI), Ecole des Mines de Paris, Paris F - 75272, France
Zinc oxide particles of different morphologies (sand roses and prickly spheres) were directly obtained at soft conditions (T=25 °C, 40 °C, 60 °C) by double-jet precipitation using 0.5 mol.dm-3 zinc nitrate and 1.0 mol.dm-3 NaOH at two different pH values, 9.5 and 10.5. Increasing precipitation temperature changed continuously particle morphology from two-dimensional (sand roses, 12m2/g) to three-dimensional (prickly spheres, 3m2/g) features. The interest of the method, in spite of a relatively low surface area, is to provide a morphology control without templates nor surface treatments, facilitating further comparisons. Particles result from different oriented aggregation of similar nanocrystals, exhibiting in the final architecture more or less polar vs non polar crystal faces of the zincite structure. Phenol photodegradation / ZnO weight is superior for sand-roses morphology due to their higher specific surface area, whereas phenol photodegradation / ZnO specific surface area is superior for prickly spheres, which can be interpreted by a better activity of zincite non-polar surfaces for phenol photodegradation.
Presentation: Poster at E-MRS Fall Meeting 2008, Symposium D, by Jean-Francois Hochepied
See On-line Journal of E-MRS Fall Meeting 2008
Submitted: 2008-04-11 17:59 Revised: 2009-06-07 00:48