Abstract
Due to integrated advances in photoelectrochemical (PEC) functionalities for environment detection applications, one-dimensional (1D) TiO2 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 Ag2O–AgBiO3/TiO2 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 TiO2 and AgBiO3. More importantly, as a trap for electron capture, Ag2O in this ternary system could not only further improve the separation efficiency of charge carriers, but also capture electrons transferred to the TiO2 conduction band, thus reducing the electrons transferred to the external circuit and the corresponding background photocurrent when detecting organics. As a result, the reconstructed TiO2 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.
Highlights
Global concerns over water pollution and its impact on the environment are becoming increasingly prominent, which has become a bottleneck problem in the current rapid development of the world
It is reasonable to believe that Bi-containing materials will significantly regulate the surface free radicals of TiO2, thereby changing the surface electrochemical reaction and the complicated PEC process. We introduce both Ag bismuthate (AgBiO3) and Ag2O nanoparticles as co-catalysts to TiO2 nanotube arrays (NTAs) by a one-step precipitation method
The nanostructure of the as-prepared samples in each step was investigated by using scanning electron microscopy (SEM)
Summary
Global concerns over water pollution and its impact on the environment are becoming increasingly prominent, which has become a bottleneck problem in the current rapid development of the world. Water pollution issues are related directly to human health, and seriously affect both economic and social development. To this end, water research has been included as one of the most momentous topics in modern environmental issues. The traditional methods, such as the potassium dichromate oxidation method, the potassium permanganate oxidation method, etc., have been widely used. These methods still have some shortcomings, including unsatisfactory reflux time and sensitivity, limited detection limit, secondary pollution, and high cost, which can no longer meet the increasing environmental requirements
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