A surface precleaning strategy intensifies the interface coupling of the Bi2O3/TiO2 heterostructure for enhanced photoelectrochemical detection properties

Abstract

The interfacial coupling effect plays a crucial role in tailoring the photoelectrochemical performance of heterostructured photocatalysts. However, it is an urgent need but challenging to intensify the interfacial coupling effect of heterojunctions. Herein, we proposed the surface precleaning of n-type TiO₂via a facile low-temperature hydrogenation to facilitate strong coupling with p-type Bi₂O₃ (Bi₂O₃/c-TiO₂) and thus disruptively accelerate the electron transfer and electron–hole pair separation. The comparative studies of uncleaned Bi₂O₃/TiO₂ and Bi₂O₃/c-TiO₂ heterostructures by X-ray photoelectron spectroscopy revealed an unneglected valence change and thus a highly strong coupling effect between Bi₂O₃ and the cleaned TiO₂ originating from a possible weakening role of the nitrogen species adsorbed on the surface of pristine TiO₂ for the interfacial coupling effect. When integrated into a photoelectrochemical sensor, Bi₂O₃/c-TiO₂ presented both significantly high detection photocurrent response and selectivity for organics in a buffer solution. The current response of the as-built Bi₂O₃/c-TiO₂ was two-fold higher than that of uncleaned Bi₂O₃/TiO₂ and was even almost five-fold that of bulk TiO₂. We believe that this work will provide new perspectives and insights into the construction of efficient heterojunctions for impressive applications in photoelectrochemical detection.