Activated CdS/ sulfur doped g-C3N4 photocatalyst for dye and antibiotic degradation: Experimental and DFT verification of S-scheme heterojunction

Xu Duan; Jian Yang; Jiaqing Zhu; Hongbin Li; Yujie Fang; Runxue Liu; Chen Yang; Weizao Liu; Chunlian Ding; Qingcai Liu; Jiangling Li; Shan Ren

doi:10.1016/j.envres.2024.120487

Activated CdS/ sulfur doped g-C₃N₄ photocatalyst for dye and antibiotic degradation: Experimental and DFT verification of S-scheme heterojunction

Environ Res. 2024 Nov 29:120487. doi: 10.1016/j.envres.2024.120487. Online ahead of print.

Authors

Xu Duan¹, Jian Yang², Jiaqing Zhu¹, Hongbin Li¹, Yujie Fang¹, Runxue Liu¹, Chen Yang¹, Weizao Liu¹, Chunlian Ding¹, Qingcai Liu¹, Jiangling Li¹, Shan Ren³

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 State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.

PMID: 39617154
DOI: 10.1016/j.envres.2024.120487

Abstract

To alleviate situation caused by azo dyestuff and antibiotics, a series of CdS/sulfur doped carbon nitride (GCNS) S-scheme heterojunction photocatalysts have been successfully fabricated by a pretty facile solid-state diffusion (SSD) method,. Under visible light, the optimal sample called CdS/GCNS-1:2 presented the best photodegradation rate of nearly 100% over methyl orange (MO), of which the reaction constant k was about 9.67 and 5.39 times higher than that of pure GCNS and CdS, respectively. Degradation rate of 91% over tetracycline hydrochloride (TCH) was achieved within 60 min as well. The DFT calculations, XPS and charge flow tracking tests clarified the surge of C-S linkages and the construction of interfacial S-scheme heterojunction. The former promoted the fixation and conversion of adsorbed oxygen, while the latter accelerated the separation/transport of charge carriers. These tuning eventually collaborates on the promotion of •O₂^- reactive species, which confirmed as the predominant role of photoreaction. Furthermore, the plausible degradation pathways of MO/TCH and photocatalytic optimization mechanism were thoroughly elucidated.

Keywords: C-S linkages; CdS; Interfacial electric field; S-scheme; carbon nitride.