Mechanochemical synthesis of nanoparticulate ZnO–ZnWO4 powders and their photocatalytic activity

✍ Scribed by Aaron Dodd; Allan McKinley; Takuya Tsuzuki; Martin Saunders

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 889 KB
• Volume: 29
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2008.05.027

✦ Synopsis

In this study, mechanochemical reaction systems with H 2 WO 4 as a precursor were investigated for the synthesis of nanoparticulate powders of WO 3 , ZnWO 4 , and dual-phase (ZnWO 4 ) x (ZnO) 1-x . The objective was to establish whether mechanochemical processing can be used to manufacture high activity photocatalysts in the ZnO-WO 3 system. Milling and heat treatment of H 2 WO 4 + 12NaCl was found to result in the formation of irregularly shaped platelets of a sodium tungstate rather than nanoparticles of WO 3 . Powders of single-phase ZnWO 4 and dual-phase (ZnWO 4 ) x (ZnO) 1-x were successfully synthesised by incorporating H 2 WO 4 into the ZnCl 2 + Na 2 CO 3 + 4NaCl reactant mixture. The photocatalytic activity of these powders was evaluated using the spin-trapping technique with electron paramagnetic resonance spectroscopy. It was found that the photocatalytic activity decreased with the ZnWO 4 content. This decrease in activity was attributed to the larger average particle size of the ZnWO 4 component compared to the ZnO, which reduced the surface area available for interfacial transfer of the photogenerated charge carriers.