Preparation and Characterization of Bismuth Tungstate Polycrystalline Flake-Ball Particles for Photocatalytic Reactions

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• 作者：Fumiaki Amano ; Kohei Nogami ; Ryu Abe ; Bunsho Ohtani
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：June 26, 2008
• 年：2008
• 卷：112
• 期：25
• 页码：9320 - 9326
• 全文大小：661K
• 年卷期：v.112,no.25(June 26, 2008)
• ISSN：1932-7455

文摘

Micrometer-sized spherical polycrystalline particles of bismuth tungstate (Bi₂WO₆) of a hierarchical “flake-ball” shape were prepared by a facile hydrothermal reaction without using any surfactants and polymers as structure-directing agents. The flake-ball particles were assemblies of polycrystalline flakes composed of rectangular platelets with a lateral size of a few hundred nanometers and thickness of 20−35 nm. An excess amount of a tungstate precursor (10%) and an acidic condition (pH 1.2) during the hydrothermal reaction were required to obtain a high yield of uniform particles with the flake-ball architecture. The mechanism by which the flake-ball particles are formed is discussed. The photocatalytic activities under ultraviolet light irradiation were investigated by using oxygen liberation from water, oxidative decomposition of acetic acid in an aqueous solution, and oxidative decomposition of gaseous acetaldehyde. The photocatalytic activity level of the flake-ball particles was higher than the photocatalytic activity levels of other Bi₂WO₆ samples prepared by conventional solid-state and hydrothermal reactions using a stoichiometric amount of a tungstate precursor. It was revealed that the 10% excess amount of tungsten plays a key role in the high level of photocatalytic activity of flake-ball particles.