Insights into the photocatalysis mechanism of the novel 2D/3D Z-Scheme g-C3N4/SnS2 heterojunction photocatalysts with excellent photocatalytic performances

Wei Zhao; Yajuan Li; Pushu Zhao; Lili Zhang; Benlin Dai; Haibao Huang; Jianli Zhou; Yukun Zhu; Kuirong Ma; Dennis Y C Leung

doi:10.1016/j.jhazmat.2020.123711

Insights into the photocatalysis mechanism of the novel 2D/3D Z-Scheme g-C₃N₄/SnS₂ heterojunction photocatalysts with excellent photocatalytic performances

J Hazard Mater. 2021 Jan 15:402:123711. doi: 10.1016/j.jhazmat.2020.123711. Epub 2020 Aug 20.

Authors

Wei Zhao¹, Yajuan Li², Pushu Zhao², Lili Zhang², Benlin Dai³, Haibao Huang⁴, Jianli Zhou⁵, Yukun Zhu⁶, Kuirong Ma², Dennis Y C Leung⁷

Affiliations

¹ Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian, China; Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China; School of Materials Engineering, Changshu Institute of Technology, Changshu, China.
² Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian, China.
³ Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian, China. Electronic address: benlindai@hytc.edu.cn.
⁴ School of Environmental Science and Engineering, Sun Yat-Sen University, China.
⁵ Harbin Institute of Technology, Shenzhen, China. Electronic address: wonderkc@live.com.
⁶ School of Environmental Science and Engineering, Qingdao University, Qingdao, China.
⁷ Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China. Electronic address: ycleung@hku.hk.

PMID: 33254755
DOI: 10.1016/j.jhazmat.2020.123711

Abstract

A novel 2D/3D Z-scheme g-C₃N₄/SnS₂ photocatalyst was successfully fabricated via self-assembly forming 3D flower-like SnS₂ microspheres on the surface of the 2D g-C₃N₄ nanosheets. The photocatalytic performances of the samples were systematically explored through catalytic reduction of Cr⁶⁺ and oxidation of Bisphenol S (BPS) under the illumination of visible light, and the photocatalytic degradation pathway of BPS was also proposed based on the degradation products confirmed by GCMS. Among the as-prepared samples, 0.4-g-C₃N₄/SnS₂ exhibited the most efficient photocatalytic performances, and the apparent quantum efficiency (QE) for the removal of Cr⁶⁺ could achieve 30.3 %, which is 2.8 times higher than that of the SnS₂. The enhancing photocatalytic activities originated from the efficient interfacial charge migration and separation obtained in g-C₃N₄/SnS₂, which was firstly verified via the photoluminescence spectra, time-resolved photoluminescence spectra and photoelectrochemical characterizations. Importantly, the DFT calculated shows that the band distribution of the g-C₃N₄/SnS₂ sample is staggered near the forbidden, which can facilitate the efficient interfacial charge migration and separation as well as result in the improvement of the catalytic activity. Finally, we put forward a more reasonable Z-scheme charge transfer mechanism, it was verified by analysing the results of free radical scavenging tests, EPR experiments and theoretical calculations.

Keywords: Carbon nitride; Photocatalytic degradation; Removal of Cr(6+); Z-scheme photocatalyst.