Fabrication of nitrogen-carbon mediated -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 (6PPD) in the environment is crucial for early intervention to prevent its adverse effects. Here, a reliable electrochemical sensor based on a N-C mediated gamma-Mo2N nanocomposite (gamma-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 x 10 (-8) mol L (-1) to 1.0 x 10 (-5) mol L (-1) with a detection limit of 1.67 x 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 gamma-Mo2N@N-C facilitated the deprotonation of 6-PPD, with the preferred orientation facet of (200) in gamma-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.