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Studies on Nanostructured Bi 2 WO 6 : Convenient Hydrothermal and TiO 2 ‐Coating Pathways

2009; Wiley; Volume: 635; Issue: 12 Linguagem: Inglês

10.1002/zaac.200900187

1521-3749

Ying Zhou, Kathrin Vuille, André Heel, Greta R. Patzke,

Transition Metal Oxide Nanomaterials

Abstract Bismuth tungstate is an important conductor and photocatalyst that keeps attracting research interest due to its promising catalytic activity under visible light irradiation. The 2D Aurivillius‐type structure of Bi 2 WO 6 promotes its tendency towards the formation of nanosheets that can be converted into hierarchically structured Bi 2 WO 6 microspheres. As their formation mechanism varies strongly with the preparative parameters and further investigations are required, we present studies on the most direct and convenient access to Bi 2 WO 6 nano‐architectures developed hitherto. Our one‐step approach towards this key material is based on the immediate hydrothermal reaction of Bi(NO 3 ) 3 ·5H 2 O with K 2 WO 4 that proceeds through a mechanism that differs from the previously observed routes. These insights are essential for the development of straightforward technical processes in order to produce nanomaterials without complicated parameter adjustments. The resulting Bi 2 WO 6 nanostructures display high photocatalytic activity under visible light irradiation. For the first time, the influence of an inorganic additive, K 2 SO 4 , is investigated in the Bi(NO 3 ) 3 ·5H 2 O/K 2 WO 4 hydrothermal system. This paved the way to the synthesis and stabilization of other bismuth oxide‐based materials at lower temperatures. Furthermore, we developed a flexible and efficient solution‐based coating process to cover the hierarchical Bi 2 WO 6 arrangements with a thin layer of anatase TiO 2 nanoparticles.