Deciphering Pyridinic N-Mediated Inhibition Mode in Platinum Nanozymes for Pesticide Distinction

Developing high-performance nanozymes with efficient H₂O₂ activation capacity for biosensing still faces a great challenge. Here, Pt nanoparticles on a porous nitrogen-doped carbon carrier (Pt─N_p─C) are prepared as efficient nanozymes. By optimizing the pyridinic N content in the carbon carrier, a positive correlation has been found between the pyridinic N content and the peroxidase-like activity of Pt─N_p─C nanozymes. Additionally, chlorpyrifos, a common pesticide, exerts reversible mixed inhibition on the peroxidase-like activity of Pt─N_p─C nanozymes, characterized by inhibition constants K_I' of 0.180 mM and K_I of 0.147 mM. By combining the inhibition effect with array technology, a three-channel colorimetric sensor array capable of precisely discrimination five pesticides is constructed. The study provides fundamental insights into nanozyme inhibition modes and advanced pesticide sensing applications.