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

In this work, the photoelectrocatalytic (PEC) degradation of 2,5-dichlorophenol can be used for its removal from aqueous solution. To study this activity, a TiO2 thin film modified titanium sheet (TiO2/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 oC for 2 h. Then, the electrochemical properties of 2,5-dichlorophenol were compared on the surface of the TiO2/Ti and unmodified Ti electrodes. Consequently, the TiO2/Ti was applied for PEC degradation of 2,5-dichlorophenol. It was found that 2,5-dichlorophenol 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 2,5-dichlorophenol 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 2,5-dichlorophenol was obtained at pH 6.0, the initial 2,5-dichlorophenol concentration of 7.0 mg L-1 and applied potential of 1.2 V.