Photoelectrocatalysis reactivity of independent titania nanotubes

Two types of independent titania nanotube arrays with the separated tube wall structure have been fabricated by a controlled anodization process and used for photoelectrocatalysis (PEC) applications. The photocatalysis degradation efficiency of the organic pollutant is improved from 6.0 to 9.2% through increasing tube length and inter-tube space. The PEC degradation efficiency is 20.4% at an applied potential of 2.885 V for titania long nanotube array. An electro-Fenton-assisted PEC reaction system has been developed using titania long nanotube array and an iron sheet as two anodes in a parallel connection and a multiporous carbon as one cathode. The current distribution among three functional electrodes is conducted to optimize titania PEC reaction and electro-Fenton reaction. Accordingly, the degradation efficiency is improved from 20.4% in PEC to 60.2% in electro-Fenton-assisted PEC, and the mineralization efficiency is also improved from 8.1 to 37.4%. The corresponding reaction rate constant of 5.19 × 10⁻³ min⁻¹ is even higher than that of 3.98 × 10⁻³ min⁻¹ for the sum of individual oxidation reactions of titania PEC, electro-Fenton, and anodic electrolysis.