Rational Regulation of Surface Free Radicals on TiO(2) Nanotube Arrays via Ag(2)O–AgBiO(3) towards Enhanced Selective Photoelectrochemical Detection

Due to integrated advances in photoelectrochemical (PEC) functionalities for environment detection applications, one-dimensional (1D) TiO(2) nanostructures provide a new strategy (PEC sensors) towards organics detection in wastewater. However, the unidealized selectivity to the oxidation of water and organics limits the PEC detection performance. Herein, we designed a ternary photoanode consisting of Ag(2)O–AgBiO(3)/TiO(2) nanotube arrays (NTAs) to solve this issue by using a facile one-step precipitation reaction. High oxidation capacity for organics is achieved by regulating the surface free radicals properly through the heterostructure formed between the interface of TiO(2) and AgBiO(3). More importantly, as a trap for electron capture, Ag(2)O in this ternary system could not only further improve the separation efficiency of charge carriers, but also capture electrons transferred to the TiO(2) conduction band, thus reducing the electrons transferred to the external circuit and the corresponding background photocurrent when detecting organics. As a result, the reconstructed TiO(2) NTAs decrease their photocurrent response to water and enhance their response to organics, thus presenting lower oxidation activity to water and higher activity to organics, that is, highly selective oxidation characteristics. This work provides more insights into the impact of charge transfer and surface free radicals on developing promising and efficient PEC sensors for organics.