Photoelectrocatalytic microfluidic reactors utilizing hierarchical TiO2 nanotubes for determination of chemical oxygen demand

Abstract

In this work, a hierarchical TiO₂ nanotube (H-TNTs) electrode was successfully fabricated via the anodization of a titanium sheet followed by a hydrothermal process. TiO₂ nanoparticles were successfully deposited on the surface of the TiO₂ nanotubes (TNTs) which can enhance the light-harvesting capability and surface area of TNTs. In comparison with the pure TNTs, the H-TNT electrode showed a great enhancement in the photocurrent response. Subsequently, the H-TNT electrode was put into a microfluidic device made from polymethyl methacrylate (PMMA) for mineralization of organic compounds. Photocatalytic results showed that a COD detection limit of 1 mg L⁻¹ COD and a linear range of 0–300 mg L⁻¹ COD were achieved by the microfluidic device.