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The effect of platinum on the performance of WO 3 nanocrystal photocatalysts for the oxidation of Methyl Orange and iso‐propanol
Author(s) -
Joshi Upendra A.,
Darwent James R.,
Yiu Humphrey H. P.,
Rosseinsky Matthew J.
Publication year - 2011
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.2612
Subject(s) - photocatalysis , methyl orange , nanocrystalline material , materials science , catalysis , platinum , visible spectrum , oxide , photochemistry , inorganic chemistry , chemistry , nanotechnology , organic chemistry , metallurgy , optoelectronics
BACKGROUND: This research investigated the effect of platinum (Pt) on the reactivity of tungsten oxide (WO 3 ) for the visible light photocatalytic oxidation of dyes. RESULTS: Nanocrystalline tungsten oxide (WO 3 ) photocatalysts were synthesised by a sol‐gel process and employed for the photocatalytic degradation of Methyl Orange under visible light. For comparison commercial bulk WO 3 materials were also studied for the same reaction. These materials were fully characterised using X‐ray diffraction (XRD), UV‐visible diffuse reflection spectroscopy and transmission electron microscopy (TEM). The photocatalytic oxidation of iso‐propanol was used as a model reaction to follow the concomitant reduction of molecular oxygen. No reactions occured in the absence of platinum, which is an essential co‐catalyst for the multi‐electron reduction of oxygen. The platinised WO 3 catalysts were stable for multiple oxidation–reduction cycles. The results from the catalytic activity measurements showed that platinised nanocrystalline WO 3 is a superior oxidation photocatalyst when compared with bulk WO 3 . Methyl Orange was completely decolourised in 4 h. CONCLUSIONS: The enhanced performance of nanocrystalline Pt‐WO 3 is attributed to improved charge separation in the nanosized photocatalyst. Platinum is an essential co‐catalyst to reduce oxygen. This photocatalyst could be applied to the treatment of organic pollutants in wastewater, with the advantage of using visible light compared with the widely studied TiO 2 , which requires UV light. Copyright © 2011 Society of Chemical Industry