In this study, mechanochemical reaction systems withH2WO4 as a precursor were investigated for the synthesis of nanoparticulate powders ofWO3,ZnWO4, and dual-phase (ZnWO4)x(ZnO)1–x. The objective was to establish whether mechanochemical processing can be used to manufacture highactivity photocatalysts in the ZnO–WO3 system. Milling and heat treatment of H2WO4 + 12NaCl was found to result in the formation of irregularlyshaped platelets of a sodium tungstate rather than nanoparticles ofWO3. Powders of single-phase ZnWO4 and dual-phase (ZnWO4)x(ZnO)1–x weresuccessfully synthesised by incorporating H2WO4 into the ZnCl2 +Na2CO3 + 4NaCl reactant mixture. The photocatalytic activity of these powderswas evaluated using the spin-trapping technique with electron paramagnetic resonance spectroscopy. It was found that the photocatalytic activitydecreased with the ZnWO4 content. This decrease in activity was attributed to the larger average particle size of the ZnWO4 component comparedto the ZnO, which reduced the surface area available for interfacial transfer of the photogenerated charge carriers.
|Journal||Journal of the European Ceramic Society|
|Publication status||Published - 2009|