Synergetic Effect of Pt and Borate on the TiO2-Photocatalyzed Degradation of Phenol in Water

Abstract

It has been reported that Pt and borate can promote the TiO2-photocatalyzed degradation of phenol in an aerated aqueous suspension, respectively. Herein, we report a synergism between Pt and borate greatly improving the photocatalytic activity of anatase TiO2. The rate of phenol degradation was dependent on Pt loading, borate concentration, and solution pH. A maximum rate of phenol degradation was observed at 0.52 wt % Pt, 3.0 mM Na2B4O7, and initial pH 9.0, respectively. Under such conditions, the rates of phenol degradation, upon the addition of Pt, borate, and Pt plus borate, were increased by 1.34, 0.22, and 4.87 times, respectively. This mutual action of Pt and borate were also observed from the photocatalytic degradation of 4-chlorphenol, and 2,4-dichlrophenol. A separate experiment with the TiO2 and Pt/TiO2 film electrodes showed that borate could mediate the hole oxidation of phenol, but not water. Furthermore, the electrochemical reduction of O2 over TiO2 and Pt/TiO2, upon addition of borate, bec...