Constructing C-O bridged CeO2/g-C3N4 S-scheme heterojunction for methyl orange photodegradation：Experimental and theoretical calculation

Chen Yang; Jian Yang; Shuangshuang Liu; Mingxue Zhao; Xu Duan; Hongli Wu; Lang Liu; Weizao Liu; Jiangling Li; Shan Ren; Qingcai Liu

doi:10.1016/j.jenvman.2023.117608

Constructing C-O bridged CeO₂/g-C₃N₄ S-scheme heterojunction for methyl orange photodegradation：Experimental and theoretical calculation

J Environ Manage. 2023 Jun 1:335:117608. doi: 10.1016/j.jenvman.2023.117608. Epub 2023 Mar 1.

Authors

Chen Yang¹, Jian Yang², Shuangshuang Liu¹, Mingxue Zhao¹, Xu Duan¹, Hongli Wu¹, Lang Liu³, Weizao Liu¹, Jiangling Li¹, Shan Ren¹, Qingcai Liu¹

Affiliations

¹ College of Materials Science and Engineering, Chongqing University, Chongqing, 400044, China.
² College of Materials Science and Engineering, Chongqing University, Chongqing, 400044, China. Electronic address: skyinjune@cqu.edu.cn.
³ School of Materials and Environment, Guangxi Minzu University, Nanning, Guangxi, 530006, China. Electronic address: l.liu@git.edu.cn.

PMID: 36867902
DOI: 10.1016/j.jenvman.2023.117608

Abstract

Owing to its feasibility, efficiency in light-harvesting and effectiveness in the interfacial charge transfer between two n-type semiconductors, constructing heterojunction photocatalysts have been identified as an effective way for enhancing the photocatalytic properties. In this research, a C-O bridged CeO₂/g-C₃N₄ (cCN) Step-scheme (S-scheme) heterojunction photocatalyst was constructed successfully. Under visible light irradiation, the cCN heterojunction exhibited the photocatalytic degradation efficiency of methyl orange, which was about 4.5 and 1.5 times higher than that of pristine CeO₂ and CN, respectively. The DFT calculations, XPS and FTIR analyses demonstrated the formation of C-O linkages. And the calculations of work functions revealed the electrons would flow from g-C₃N₄ to CeO₂ due to the difference in Fermi levels, resulting in the production of internal electric fields. Benefiting from the C-O bond and internal electric field, the photo-induced holes in the valence band of g-C₃N₄ and the photo-induced electrons from conduction band of CeO₂ would be recombined when exposed to visible light irradiation, while leaving the electrons with higher redox potential in the conduction band of g-C₃N₄. This collaboration accelerated the separation and transfer rate of photo-generated electron-hole pairs, which promoted the generation of superoxide radical (•O₂^-) and improved the photocatalytic activity.

Keywords: CeO(2); C–O linkages; Electron transfer mechanism; G-C(3)N(4); Internal electric field.

MeSH terms

Azo Compounds*
Electricity*
Electrons
Photolysis

Substances

methyl orange
Azo Compounds