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Language: English

Conflict of Interest: In relation to this article, we declare that there is no conflict of interest.

Publication history: Received July 14, 2016
Accepted October 11, 2016

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Formation of intermediate band and low recombination rate in ZnO-BiVO4 heterostructured photocatalyst: Investigation based on experimental and theoretical studies

Sonal Singh Rishabh Sharma¹ Girdhar Joshi^2† Jitendra Kumar Pandey^†

University of Petroleum and Energy Studies (UPES), VPO Bidholi, PO Prem Nagar, Dehradun 248007, India ¹Thin Film Laboratory, Department of Physics, Indian Institute of Technology, New Delhi-110016, India ²Department of Chemistry, Government Post Graduate College, Gopeshwar, Uttarakhand, India

Korean Journal of Chemical Engineering, February 2017, 34(2), 500-510(11), 10.1007/s11814-016-0284-2

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Abstract

We present systematic investigations on the relationship between interface formation and enhanced photocatalytic activity of ZnO-BiVO4 nanocomposite based on experimental techniques supported by theoretical calculations. The interaction between ZnO (101) nanosheet and BiVO4 surface at the heterojunction was explored to study the charge transfer and separation mechanism responsible for enhanced photocatalytic response. XPS results and DFT computations mutually validate the reasonable existence of ZnO-BiVO4 interface. The nanocomposite photocatalytic activity, tested for various weight ratios, was found to be highest for ZnO-BiVO4 (1 : 1) under visible-light irradiation. Moreover, the percentage removal of MB was found to be greater than RhB for the same time duration. Steady state and time resolve photoluminescence were employed to understand the carrier lifetime and emissivity. Visible light driven high photoactivity exhibited by ZnO-BiVO4 (1 : 1) was ascribed to the formation of intermediate band and comparatively low recombination rate, which facilitates the separation of electron-hole pairs. Based on the theoretical outcome, we found that valence band maximum was occupied by Bi s orbital and conduction band minimum was occupied by Zn s orbital, which indicates the maximum electron transition from BiVO4 valence band to ZnO conduction band in ZnO-BiVO4 composite. These results demonstrated that heterojunction semiconductors are an effective strategy that can be successfully applied to develop photocatalysts that respond to visible light for organic pollutant degradation.

Keywords

Zinc Oxide Monoclinic-bismuth Vanadate Intermediate Band DFT Time Resolved PL

References

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