Polyoxometalates-doped TiO2/Ag hybrid heterojunction: removal of multiple pollutants and mechanism investigation?

Environmental Science: Nano Pub Date: 2021-11-11 DOI: 10.1039/D1EN00827G

Abstract

Photocatalysis is considered to be an effective and sustainable way to purify a variety of refractory pollutants. However, the construction of a versatile efficient photocatalyst is still an arduous challenge. Herein, a series of mesoporous TiO2-doped with polyoxometalates [PMo10V2O40]5? (PMV) and loaded with Ag nanoparticle composite photocatalysts PMV-TiO2/Agx (x represented the mass of AgNO3) are presented. In this composite, polyoxoanions PMV are uniformly dispersed in mesoporous TiO2, which not only acts as a dopant to effectively expand the visible light absorption of TiO2 but also acts as a component to form the S-scheme heterojunction with modified TiO2 to promote the separation of the photogenerated carrier. Furthermore, the Schottky junction between Ag nanoparticles and PMV-doped TiO2 further enhances its carrier separation. The synergistic effect of the above factors endows PMV-TiO2/Agx with excellent photocatalytic activity. PMV-TiO2/Ag0.1 can completely degrade 10 ppm of 2,4-dichlorophenol in 180 minutes (λ ≥ 420 nm), which is about 8.3 times higher than that of traditional TiO2. In addition, PMV-TiO2/Ag0.1 also exhibits ultrahigh photocatalytic performance and durability for the photocatalytic removal of 2,4-difluorophenol, 2,4-dibromophenol, hexafluorobisphenol A, tetracycline, K2Cr2O7, methyl orange, which is an excellent photocatalyst with high efficiency and universal application.

Graphical abstract: Polyoxometalates-doped TiO2/Ag hybrid heterojunction: removal of multiple pollutants and mechanism investigation
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