Comparison of the photoelectrochemical performance of particulate and nanotube TiO2 photoanodes

The aim of this work has been the comparison of the photoelectrocatalytic properties of two types of TiO2-based photoanodes. Sol-gel particulate TiO2 (SGT) layers were grown on Ti substrates (using an isopropoxide precursor) and TiO2 nanotubes (TNTs) were formed by appropriate anodization of the same substrate in glycerin solutions. EIS spectroscopy was employed to determine the intrinsic photoelectrocatalytic activity and surface area of the photoanodes. The intrinsic catalytic activity was assessed by the product R(ct)Q(dl) (where R-ct is the charge transfer resistance). Photovoltammetry experiments showed that the incident photon-to-current efficiency (IPCE) of the TNTs electrodes was 3.5 times higher than that of the SGT ones due to a higher surface area and lower recombination rates. Furthermore, the photoelectrodes were tested against the photoelectrolysis of an antibiotic, where the TNTs showed a 4-fold enhancement in the Chloramphenicol photo-electrolytic degradation rate under +0.5 V reverse bias compared to the SGT. (C) 2016 Elsevier B.V. All rights reserved.