Photoelectrocatalytic property of microporous Pt-TiO2/Ti electrodes

Abstract

This study investigates the photoelectrocatalytic (PEC) property of microporous WO3-loaded TiO2/Ti layer, prepared via micro-arc oxidation (MAO) of Ti plate, followed by sputtering deposition of a thin Pt layer as a Pt-TiO2/Ti electrode. The WO3-loaded TiO2 layer which is associated with a more acidic surface forms many local electrochemical cells on its micro-pores immersed in cationic dye solution. The electrocatalytic (EC) reactions can take place in the local cells by the applied electrons. A low resistivity that is accomplished by MAO technique and by platinization offers an easy path for the electron motions in the Pt-TiO2/Ti electrode. All these features make the EC oxidation of aqueous dye pollutants practically feasible without using counter electrodes and supporting electrolytes. Our experiments demonstrate that, under PEC condition, the Pt-TiO2/Ti shows the highest degradation rate constant of 0.83h−1 at an applied bias of 1.0V and exhibits significantly high PEC and EC oxidation activities at a low applied bias of 0.25V. This is attributable to high anodic currents generated in the Pt-TiO2/Ti even at low bias. The modified microporous electrodes conclusively reveal a very interesting EC property as a two double-sided device that functions the PEC and EC oxidation simultaneously without a need of supporting electrolyte and expensive Pt cathode.