Study of photoelectrocatalytic degradation behavior of p-nitrophenol with nano-TiO2 modified film at a rotating ring-disk electrode

The photoelectrocatalytic degradation behavior of p-nitrophenol (pNP) was investigated by using hydrodynamic differential pulse voltammetry (HDPV) technique. The method was applied on a nano-TiO2 modified platinum rotating ring-disk electrode (RRDE) as versatile working electrode. The voltammetric response of the intermediate product was recorded instantly at the rotating platinum-ring electrode under hydrodynamic conditions via compulsive transport during the photoelectrocatalytic degradation process of pNP. A distinct anodic peak at about 0.55 V is mainly attributed to the result of the formation of electroactive intermediate product, namely hydroquinone (HQ), through the direct reaction between photo-generated powerful oxidant (hydroxyl radicals, (OH)-O-center dot) and pNP. The present work has demonstrated that HDPV can be effectively used to in situ monitor the formation of intermediate product at nano-TiO2 modified RRDE, providing a promising approach to investigate the photoelectrocatalytic degradation mechanism of organic pollutants like toxic nitrophenols. (C) 2009 Elsevier B.V. All rights reserved.