Rational Regulation of Surface Free Radicals on TiO2 Nanotube Arrays via Ag2O–AgBiO3 towards Enhanced Selective Photoelectrochemical Detection

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.

Sequential‐Dependent Synthesis of Bimetallic Silver‐Chromium Nanoparticles for Multichannel Sensing, Logic Computing, and 3 in 1 Information Protection

“…The TEM results suggested that after the addition of ClO − , the surface of the nanoparticles was wrapped by a membrane (whose chemical composition mainly includes Cl, O, and Cr elements), causing agglomeration of the nanoparticles (Figure 4B). And high-resolution TEM analysis showed that the lattice fringe spacings of Ag-Cr NPs and ClO − mixtures were 0.171, 0.243, 0.251 (Figure 4Bb), and 0.278 nm (Figure S4, Supporting Information), corresponding to the (220) plane of Ag 2 O, [63,73] the (111) plane of Ag, [74] the (110) plane of Cr 2 O 3 , [75] and (200) plane of AgCl, [76] respectively. Compared to the crystal planes of Ag-Cr NPs, this result showed that ClO − clearly leaded to the oxidation of Ag-Cr NPs.…”