Rutile is much less active than anatase and brookite for the photocatalytic degradation of organic pollutants in aqueous solution. In this work, we found that addition of a trace amount of CuWO4 greatly accelerated phenol degradation in an aerated aqueous suspension of rutile. The increased rate was not only much higher than those of anatase and brookite, prepared at the same temperature (600 ℃), but also increased continuously with the sintering temperature of rutile from 150 to 800 ℃. These observations indicate that the high intrinsic photocatalytic activity of rutile produced at a high sintering temperature can be exploited by using co-catalyst CuWO4. Furthermore, as the amount of CuWO4 added to the suspension increased, the amount of H2O2 produced in the presence of excess phenol increased and then decreased; the trend was similar to that observed for phenol degradation. The observed positive effect of CuWO4 is mainly caused by solid CuWO4 rather than Cu2+ ions in aqueous solution. A (photo)electrochemical measurement showed that interfacial electron transfer occurred from the irradiated rutile to CuWO4. This would improve the charge-separation efficiency, and consequently increase the rates of O2 reduction and phenol degradation.
Received: 01 February 2016
Published: 28 March 2016
Bang-De LUO,Xian-Qiang XIONG,Yi-Ming XU. Improved Photocatalytic Activity for Phenol Degradation of Rutile TiO2 on the Addition of CuWO4 and Possible Mechanism. Acta Phys. -Chim. Sin., 2016, 32(7): 1758-1764.
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