Fabrication of BiFeO3-g-C3N4-WO3 Z-scheme heterojunction as highly efficient visible-light photocatalyst for water reduction and 2,4-dichlorophenol degradation: Insight mechanism

Sher Ali; Muhammad Humayun; Wenbo Pi; Yang Yuan; Mei Wang; Abbas Khan; Pang Yue; Lang Shu; Zhiping Zheng; Qiuyun Fu; Wei Luo

doi:10.1016/j.jhazmat.2020.122708

Fabrication of BiFeO₃-g-C₃N₄-WO₃ Z-scheme heterojunction as highly efficient visible-light photocatalyst for water reduction and 2,4-dichlorophenol degradation: Insight mechanism

J Hazard Mater. 2020 Oct 5:397:122708. doi: 10.1016/j.jhazmat.2020.122708. Epub 2020 Apr 20.

Authors

Sher Ali¹, Muhammad Humayun², Wenbo Pi¹, Yang Yuan¹, Mei Wang¹, Abbas Khan³, Pang Yue⁴, Lang Shu¹, Zhiping Zheng¹, Qiuyun Fu¹, Wei Luo⁵

Affiliations

¹ Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China.
² Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China; China-EU Institute for Clean and Renewable Energy, HuazhongUniversity of Science and Technology, Wuhan 430074, PR China.
³ Department of Chemistry, Abdul Wali Khan University Mardan, Mardan 23200, Khyber Pakhtunkhwa, Pakistan.
⁴ College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, PR China.
⁵ Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China; China-EU Institute for Clean and Renewable Energy, HuazhongUniversity of Science and Technology, Wuhan 430074, PR China. Electronic address: luowei@mail.hust.edu.cn.

PMID: 32361672
DOI: 10.1016/j.jhazmat.2020.122708

Abstract

In this work, a Z-scheme BiFeO₃-g-C₃N₄-WO₃ (BFO-CN-WO) photocatalyst has been synthesized via a wet chemical method and utilized in photocatalysis for hydrogen generation and 2,4-dichlorophenol (2,4-DCP) degradation under visible light irradiation. The resultant photocatalyst showed 90 μmol·h^-1 g^-1 H₂ evolution activity and 63% 2,4-DCP degradation performance, which is 12 and 4.2 times higher than the pristine g-C₃N₄ respectively. The fascinating photocatalytic performance is attributed to the strong interfacial contact between g-C₃N₄ and the coupled BiFeO₃ and WO₃ component, which greatly improved the visible light absorption and charge carriers' separation. The designed Z-scheme heterojunction is a successful strategy for enhancing the separation efficiency of photo-induced charge carriers at the interface while retaining outstanding redox ability. During 2,4-DCP degradation, LC/MS technique was used to detect the reaction intermediates. According to the LC/MS results, several new intermediates such as 2,3-dichloro-6-(2,4-dichlorophenoxy)phenol (m/z = 306), 2,4-dichlorophenyl hydrogen carbonate (m/z = 207), 2,4-dichlorobenzen-1,3-diol (m/z = 177) and phenyl hydrogen carbonate (m/z = 137) were detected. Based on these intermediates, 2,4-DCP degradation pathway is proposed. The fluorescence (FL) and electron paramagnetic resonance (EPR) results reveal that the •OH plays an important role in the 2,4-DCP degradation. The fabricated photocatalyst can be utilized in the field of photocatalysis for practical applications.

Keywords: 2,4-dichlorophenol; H(2) evolution; LC/MS intermediates; Z-scheme; electron; mechanism; paramagnetic; resonance.