Synthesis of a carbon dots modified g-C3N4/SnO2 Z-scheme photocatalyst with superior photocatalytic activity for PPCPs degradation under visible light irradiation

Daguang Li; Jiaxing Huang; Ruobai Li; Ping Chen; Danni Chen; Meixuan Cai; Haijin Liu; Yiping Feng; Wenying Lv; Guoguang Liu

doi:10.1016/j.jhazmat.2020.123257

Synthesis of a carbon dots modified g-C₃N₄/SnO₂ Z-scheme photocatalyst with superior photocatalytic activity for PPCPs degradation under visible light irradiation

J Hazard Mater. 2021 Jan 5:401:123257. doi: 10.1016/j.jhazmat.2020.123257. Epub 2020 Jun 21.

Authors

Daguang Li¹, Jiaxing Huang², Ruobai Li¹, Ping Chen³, Danni Chen¹, Meixuan Cai¹, Haijin Liu⁴, Yiping Feng¹, Wenying Lv⁵, Guoguang Liu⁶

Affiliations

¹ School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
² School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Petrochemical Pollution Processes and Control, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming, Guangdong, 525000, China.
³ School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China; School of Environment, Tsinghua University, Beijing, 100084, China.
⁴ School of Environment, Henan Normal University, Key Laboratory for Yellow River and Huaihe River Water Environment and Pollution Control, Xinxiang, 453007, China.
⁵ School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China. Electronic address: lvwy612@163.com.
⁶ School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China. Electronic address: liugg615@163.com.

PMID: 32659572
DOI: 10.1016/j.jhazmat.2020.123257

Abstract

As an emerging carbon nanomaterial, carbon dots (CDs) have superior prospects for applications in the area of photocatalysis due to their unique optical and electronic properties. In this study, a novel CDs modified g-C₃N₄/SnO₂ photocatalyst (CDs/g-C₃N₄/ SnO₂) was successfully synthesized by the thermal polymerization. Under visible light irradiation, the resulting CDs/g-C₃N₄/SnO₂ photocatalyst exhibited excellent photocatalytic activity for the degradation of indomethacin (IDM). It was demonstrated that a 0.5 % loading content of CDs led to the highest IDM degradation rate, which was 5.62 times higher than that of pristine g-C₃N₄. This improved photocatalytic activity might have been attributed to the unique up-conversion photoluminescence (PL) properties and efficient charge separation capacities of the CDs. Moreover, the combination of g-C₃N₄ with SnO₂ improved the separation of photoinduced carriers and augmented the specific surface area. Reactive species (RSs) scavenging experiments and electron spin resonance (ESR) revealed that superoxide radical anions (O₂^·-) and photogenerated holes (h⁺) played critical roles during the photocatalytic process. The results of the detection of H₂O₂ and ESR confirmed that CDs/g-C₃N₄/ SnO₂ was a Z-scheme heterojunction photocatalyst. Further, HRAM LC-MS/MS was employed to identify the byproducts of IDM, and the major IDM degradation pathways of the CDs/g-C₃N₄/SnO₂ photocatalyst were proposed. This study provides new ideas for the design of novel CDs modified photocatalysts for environmental remediation.

Keywords: Carbon dots; Reactive species; SnO(2); Transformation pathway; g-C(3)N(4).

Publication types

Research Support, Non-U.S. Gov't