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RESEARCH PRODUCT

Influence of platinum on catalytic activity of polycrystalline WO3 employed for phenol photodegradation in aqueous suspension

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Abstract A series of polycrystalline WO3 solids loaded with platinum (0.5; 1.0; 2.0 and 3.0 wt%) were prepared and characterised by X-ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy, specific surface areas determination, X-ray photoelectron spectroscopy. XPS and X-ray results indicate that the samples loaded with Pt up to 1 wt% contained on the surface mainly Pt(2+) species, while those loaded with higher amounts contained Pt(0). Moreover, the samples were employed for a probe reaction, i.e. phenol photooxidation in aqueous suspension, and their photoactivity was compared with that of two TiO2 commercial samples, mainly in the anatase phase. All the Pt–WO3 samples were more photoactive than the bare WO3 for the partial photooxidation of phenol and particularly those containing 2 and 3 wt% of platinum were also more photo active that the TiO2 samples used for comparison. On the contrary, as indicated by the total organic carbon analyses, the mineralisation (complete photooxidation) of phenol was faster on TiO2 samples. Cathecol, quinone and muconic acid were found as main intermediates, both in the presence of Pt–WO3 and TiO2 samples, while hydroquinone was found only when TiO2 samples were used.