High-performance photocatalytic peroxymonosulfate activation by carbon quantum dots via precise surface chemistry regulation: Insight into the structure-function relations

Wenyuan Han; Degang Li; Yifan Kong; Wei Liu; Wenwu Qin; Shaobin Wang; Xiaoguang Duan

doi:10.1016/j.jcis.2023.05.092

High-performance photocatalytic peroxymonosulfate activation by carbon quantum dots via precise surface chemistry regulation: Insight into the structure-function relations

J Colloid Interface Sci. 2023 Sep 15:646:633-648. doi: 10.1016/j.jcis.2023.05.092. Epub 2023 May 18.

Authors

Wenyuan Han¹, Degang Li², Yifan Kong², Wei Liu³, Wenwu Qin⁴, Shaobin Wang⁵, Xiaoguang Duan⁶

Affiliations

¹ Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry and Key Laboratory of Special Function Materials and Structure Design (MOE), College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China.
² School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, PR China.
³ School of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, ZiGong 643000, PR China.
⁴ Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry and Key Laboratory of Special Function Materials and Structure Design (MOE), College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China; Academy of Plateau Science and Sustainability, People's Government Of Qinghai Province & Beijing Normal University, Xining, 810016, China. Electronic address: qinww@lzu.edu.cn.
⁵ School of Chemical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia.
⁶ School of Chemical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia. Electronic address: xiaoguang.duan@adelaide.edu.au.

PMID: 37216711
DOI: 10.1016/j.jcis.2023.05.092

Abstract

Carbon quantum dots (CQDs) are considered promising metal-free green catalysts for the activation of persulfates, but direct experimental evidence to identify the true active sites on the surface of CQDs is still lacking. We prepared CQDs with different oxygen contents by controlling the carbonisation temperature, using a simple pyrolysis method. Photocatalytic activity experiments show that CQDs₂₀₀ exhibits the best PMS activation performance. By investigating the relationship between the oxygen functional groups on CQDs surface and photocatalytic activity, it was postulated that the C=O groups might be the predominant active site, which was confirmed by selective chemical titrations of the C=O, C-OH and COOH groups. Furthermore, limited to the weak photocatalytic properties of the pristine CQDs, ammonia and phenylhydrazine were used to precisely nitrogen-modify the o-CQD surface. We found that phenylhydrazine-modified o-CQDs-PH promoted the absorption of visible light and the separation of photocarriers, thus enhancing the activation of PMS. Theoretical calculations provide more insights from different levels of the pollutant, fine-tuned CQDs, and their interactions.

Keywords: Carbon quantum dots (CQDs); Carbonyl group; DFT; Electronic structure; Peroxymonosulfate; Photocatalytic.