MoS2/Au Heterojunction Catalyst for SERS Monitoring of a Fenton-like Reaction

Qian Wei; Beibei Lu; Qing Yang; Can Shi; Yulan Wei; Minmin Xu; Chenjie Zhang; Yaxian Yuan

doi:10.3390/ma16031169

MoS₂/Au Heterojunction Catalyst for SERS Monitoring of a Fenton-like Reaction

Materials (Basel). 2023 Jan 30;16(3):1169. doi: 10.3390/ma16031169.

Authors

Qian Wei¹, Beibei Lu¹, Qing Yang¹, Can Shi¹, Yulan Wei¹, Minmin Xu^{1

2}, Chenjie Zhang¹, Yaxian Yuan¹

Affiliations

¹ College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China.
² Suzhou Key Laboratory of Novel Semiconductor-Optoelectronics Materials and Devices, Soochow University, Suzhou 215123, China.

Abstract

Fenton technology is one of advanced oxidation process (AOP) methods to treat wastewater through chemical oxidation. Due to the limitations of classical iron-based catalysts, it is still challenging to find suitable catalysts for Fenton-like reactions. Here, MoS₂/Au heterojunctions were successfully synthesized by reduction of chloroauric acid in the solution of layered MoS₂ prepared by hydrothermal method. As a model molecule, methylene blue (MB) was used as the species to be degraded to evaluate the performance of the catalyst. It was determined by UV-visible spectra that the optimal catalyst can be obtained when MoS₂ (mg): HAuCl₄ (wt. % mL) is 2:2. The Fenton-like reaction process was monitored by introducing highly sensitive surface enhanced Raman spectroscopy (SERS). The results show that MB can be degraded by 83% in the first 10 min of the reaction, indicating that MoS₂/Au has good catalytic performance. In addition, as a fingerprint spectrum, SERS was used to preliminarily analyze the molecular structure changes during the degradation process. The result showed that C-N-C bond was easier to break than the C-S-C bond. NH₂ group and the fused ring were destroyed at the comparable speed at the first 30 min. In terms of application applicability, it was showed that MB degradation had exceeded 95% at all the three pH values of 1.4, 5.0, and 11.1 after the reaction was carried out for 20 min. The test and analysis of the light environment showed that the catalytic efficiency was significantly improved in the natural light of the laboratory compared to dark conditions. The possible mechanism based on ·OH and ·O₂^- from ESR data was proposed. In addition, it was demonstrated to be a first-order reaction from the perspective of kinetics. This study made a positive contribution to broaden of the applicable conditions and scope of Fenton-like reaction catalysts. It is expected to be used as a non-iron catalyst in practical industrial applications. From the perspective of detection method, we expect to develop SERS as a powerful tool for the in situ monitoring of Fenton-like reactions, and to further deepen our understanding of the mechanism.

Keywords: Fenton-like reaction; MoS2/Au heterojunctions; methylene blue; surface enhanced Raman spectroscopy.

Abstract

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