This study presents the fabrication and application of a graphene-assisted voltammetry platform for the sensitive detection of nitrate ions in PM2.5 (atmospheric aerosols with a maximum diameter of 2.5 μm). The MoS2/ reduced graphene oxide/ glassy carbon electrode ( MoS2/rGO/GCE) was prepared using a simple and efficient electrochemical deposition method. The rationale behind selecting MoS2/ rGO stems from their individual properties that, when combined, can enhance the electrode’s performance. MoS2 offers excellent electro-catalytic activity and selectivity for nitrate ion detection, while rGO provides high conductivity and a large surface area for enhanced sensitivity. The electrochemical performance of MoS2/ rGO/GCE was investigated and compared with MoS2/ GCE and bare GCE using cyclic voltammetry and electrochemical impedance spectroscopy. The results demonstrated that MoS2/ rGO/GCE exhibited enhanced electro-catalytic activity, high conductivity, and improved selectivity for nitrate ion detection. The optimal pH value for detecting nitrate ions was determined to be 8.0. Differential pulse voltammetry (DPV) was employed to investigate the linear range and detection limit of nitrate ions on MoS2/ rGO/GCE, resulting in a linear range from 1 to 300 μM and a detection limit of 0.35 μM. The reproducibility and the stability of MoS2/ rGO/GCE were assessed, showing satisfactory performance. Real sample analysis from Chengdu City showed a strong correlation between the results obtained using MoS2/ rGO/GCE and ion chromatography, highlighting its potential application in monitoring nitrate ions in PM2.5. The findings of this study contribute to the development of a graphene-assisted voltammetry platform for sensitive nitrate ion detection in PM2.5, offering potential benefits for real-time air pollution monitoring and environmental health assessments.

Fabrication of graphene-assisted voltammetry platform for the detection of nitrate ions in PM2.5
    Abstract
    1 Introduction
    2 Experimental
        2.1 Preparation of MoS2rGO composite
        2.2 Electrochemical characterizations
        2.3 NO3− collection and processing of actual samples
    3 Results and discussion
    4 Conclusion
    References

• Huadong Li(School of Architecture and Civil Engineering, Xihua University, Chengdu 610039, Sichuan, China)
• Yang Zhang(School of Architecture and Civil Engineering, Xihua University, Chengdu 610039, Sichuan, China)
• Kaiwen Feng(School of Architecture and Civil Engineering, Xihua University, Chengdu 610039, Sichuan, China)
• Chuan Wei(School of Architecture and Civil Engineering, Xihua University, Chengdu 610039, Sichuan, China)