Efficient charge separation and improved photocatalytic activity in Type-II & Type-III heterojunction based multiple interfaces in BiOCl0.5Br0.5-Q: DFT and Experimental Insight

Document Type

Article

Publication Date

6-1-2022

Abstract

The nanostructured, inner-coupled Bismuth oxyhalides (BiOX0.5X'(0.5); X, X' = Cl, Br, I; X/=X') heterostructures were prepared using Quercetin (Q) as a sensitizer. The present study revealed the tuning of the band properties of as-prepared catalysts. The catalysts were characterized using various characterization techniques for evaluating the superior photocatalytic efficiency and a better understanding of elemental interactions at interfaces formed in the heterojunction. The material (BiOCl0.5Br0.5-Q) reflected higher degradation of MO (about 99.85%) and BPA (98.34%) under visible light irradiation than BiOCl0.5I0.5-Q and BiOBr0.5I0.5-Q. A total of 90.45 percent of total organic carbon in BPA was removed after visible light irradiation on BiOCl(0.5)Br0.5-Q. The many-fold increase in activity is attributed to the formation of multiple interfaces between halides, conjugated p-electrons and multiple -OH groups of quercetin (Q). The boost in degradation efficiency can be attributed to the higher surface area, 2-D nanostructure, inhibited electron-hole recombination, and appropriate band-gap of the heterostructure. Photo-response of BiOCl0.5Br0.5-Q is higher compared to BiOCl0.5I0.5-Q and BiOBr0.5I0.5-Q, indicating better light absorption properties and charge separation efficiency in BiOCl0.5Br0.5-Q due to band edge position. First-principles Density Functional Theory (DFT) based calculations have also provided an insightful understanding of the interface formation, physical mechanism, and superior photocatalytic performance of BiOCl0.5Br0.5-Q heterostructure over other samples.

Keywords

Bismuth oxyiodide, Bismuth oxychloride, Bismuth oxybromide, Interface formation, Quercetin invasion, Type-II heterojunction, Type-III heterojunction

Publication Title

Chemosphere

Divisions

nanotechnology

Funders

Department of Science & Technology (India) Science Engineering Research Board (SERB), India (Grant No. TAR/2021/000100)

Volume

297

Publisher

Pergamon-Elsevier Science Ltd

Publisher Location

THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND

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