Fabrication of nitrogen-carbon mediated γ-Mo2N nanocomposite based electrochemical sensor for rapid and sensitive determination of antioxidant 6-PPD in the environment

The rapid and sensitive determination of antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-henylenediamine (6-PPD) in the environment is crucial for early intervention to prevent its adverse effects. Here, a reliable electrochemical sensor based on a N-C mediated γ-Mo2N nanocomposite (γ-Mo2N@N-C) modified carbon paste electrode (CPE) was developed and applied for selective and sensitive determination of 6-PPD. Benefiting from the superior stability and faster electron diffusion coefficient, the peak current responded to 6-PPD on the sensor linearly over a concentration range from 5 × 10-8 mol L-1 to 1.0 × 10-5 mol L-1 with a detection limit of 1.67 × 10-8 mol L-1 (4.48 ng mL-1). Moreover, the sensor maintained good anti-interference ability in the determination of 6-PPD in soil samples from different regions in Zhengzhou City. Furthermore, the density functional theory (DFT) calculations combined with kinetics analysis proved that the enhanced basicity of the γ-Mo2N@N-C facilitated the deprotonation of 6-PPD, with the preferred orientation facet of (200) in γ-Mo2N playing a vital role in inducing the dissociation of 6-PPD, thereby improving the sensor's response. Such an electrochemical sensor, with its good stability and superior sensitivity, has the potential to be applied for real-time evaluation and monitoring of environmental pollutants.