Photocatalytic peroxydisulfate activation over Zn0.5Cd0.5S/g-C3N4 S-scheme heterojunction: “One Stone and two Birds” strategy to improve the photocatalytic activity and stability

• Published in: Separation and purification technology 2025-07, Vol.360, p.131116, Article 131116
• Main Authors: Li, Chunxue, Cheng, Bohan, Shen, Jyunhong, Wang, Haoshuai, Yi, Mingxiu, Gu, Panyang, Liu, Renyu, Liao, Guangfu, Jiang, Zhuwu
• Format: Article
• Language: English
• Subjects: Ciprofloxacin; Photocatalytic peroxydisulfate activation; Photocorrosion behavior; S-scheme heterojunction; ZCS/g-C3N4
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2024.131116

[Display omitted] •The photocatalyst solves two urgent problems simultaneously, that is, it has the properties of “One Stone and Two Birds”.•The S-scheme charge transfer pathway is proposed.•The 1:2 ZCS/g-C3N4 possesses comparable photocatalytic activity and excellent chemical stability.•The degradation path of CIP is proposed.•The degradation mechanism is proved by theoretical calculation, in-suit XPS, KPFM, and LC-MS, etc. Photocatalytic peroxydisulfate (PDS) activation is considered as a promising strategy for antibiotic degradation due to it possesses abundant active species, but the activation effect is limited by low redox capacity and carrier separation efficiency. Herein, a Zn0.5Cd0.5S/g-C3N4 (ZCS/g-C3N4) S-scheme heterojunction with high carrier separation efficiency is synthesized for the degradation of ciprofloxacin (CIP). The reaction rate constant of 1:2 ZCS/g-C3N4 + PDS (0.0461 min−1) is approximately 4.43 times and 5.36 times that of ZCS + PDS (0.0104 min−1) and g-C3N4 + PDS (0.0086 min−1). In addition to comparable photocatalytic activity, the photocatalyst also shows good chemical stability, which can be attributed to that the S-scheme heterojunction inhibits the photocorrosion behavior of ZCS. Based on in-situ X-ray photoelectron spectroscopy (XPS), theoretical calculation, and photoassisted Kelvin probe force microscopy (KPFM) results, S-scheme electron migration pathway is proposed. The constructed S-scheme heterojunction with the properties of “One Stone and Two Birds”, which solve two important problems simultaneously including low carrier migration rate and severe photocorrosion. Finally, the constructed photocatalyst possesses comparable catalytic activity and excellent chemical stability. This study proves the practicality of 1:2 ZCS/g-C3N4 + PDS for CIP degradation, which provides a theoretical basis for further research on water environmental remediation.