Photoelectrocatalytic degradation of organic pollutants in wastewater using titania nanotube arrays: a proof-of-concept study

This study explored the application of highly ordered TiO 2 nanotube arrays in photoelectrocatalytic degradation of organic pollutants.In this proof-of-concept study, model compounds such as ethylene glycol and oxalic acid were used as organics representing pollutants in wastewater.The primary objective of the research was to demonstrate the unique photoelectrocatalytic activity of TiO 2 nanotube arrays in degrading organic compounds with an added benefit of hydrogen production that takes place in a same unit of operation.The TiO 2 nanotube arrays with controllable properties were synthesized by anodization approach.The TiO 2 nanotube arrays possess excellent separation and transport properties for photo-generated electron/hole pair and hence exhibit enhanced photocurrent response and photocatalytic properties for organic compound degradation and hydrogen production.Factors affecting degradation performance were investigated.Results have shown that the pH of electrolyte solution, the chemical property of electrolyte, initial concentration of model pollutants, the redox property of the pollutants, and bias potential were all interrelated that affect the photoelectrocatalytic performance of TiO 2 nanotube arrays.For example, when 0.1 M KOH was used as electrolyte in the presence of 0.5 M ethylene glycol solution, the highest current density of 0.04 mA/cm 2 was achieved at bias potential of 0.45 V.