A strategy for degradation of 2,5dichlorophenol using its photoelectrocatalytic oxidation on the TiO2/Ti thin film electrode

In this work, the photoelectrocatalytic (PEC) degradation of 2,5dichlorophenol can be used for its removal from aqueous solution. To study this activity, a TiO lt;sub gt;2 lt;/sub gt; thin film modified titanium sheet (TiO lt;sub gt;2 lt;/sub gt;/Ti) was fabricated by anodizing Ti plates using a two electrode system under the constant bias voltage of 20 V for 20 min in a solution of 0.2% (v/v) HF followed by calcination at 500 lt;sup gt;o lt;/sup gt;C for 2 h. Then, the electrochemical properties of 2,5dichlorophenol were compared on the surface of the TiO lt;sub gt;2 lt;/sub gt;/Ti and unmodified Ti electrodes. Consequently, the TiO lt;sub gt;2 lt;/sub gt;/Ti was applied for PEC degradation of 2,5dichlorophenol. It was found that 2,5dichlorophenol could be degraded more efficiently by this photoelectrocatalysis process than the sum of degradation obtained by photocatalytic (PC) and electrochemical (EC) oxidation so that the amount of 2,5dichlorophenol degraded by PEC, PC and EC oxidation were equal to 51%, 39% and 5% respectively under the 0.4 V voltage in 60 min. The effect of various parameters was studied and the highest degradation percentage of 2,5dichlorophenol was obtained at pH 6.0, the initial 2,5dichlorophenol concentration of 7.0 mg L lt;sup gt;1 lt;/sup gt;and applied potential of 1.2 V.