A novel Pd-Fe3O4/PEDOT:PSS/nitrogen and sulfur doped-Ti3C2Tx frameworks as highly sensitive sensing platform toward parathion-methyl residue in nature

Excessive pesticide residues (e.g., parathion-methyl, PM) not only threaten human health but also cause serious environmental pollution. Herein, a palladium-magnetic iron/poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonic acid)/nitrogen and sulfur co-doped titanium carbide (Pd-Fe3O4/PEDOT:PSS/NS-Ti3C2Tx) composite frameworks was fabricated, hoping to provide an interesting strategy for the design of PM sensor. First, the NS-Ti3C2Tx was synthesized through N and S co-doped modification of Ti3C2Tx to improve its electrical properties. The hierarchical PEDOT:PSS/NS-Ti3C2Tx composite, as catalytic supports of Pd-Fe3O4, was constructed with PEDOT:PSS inserting between the NS-Ti3C2Tx nanolayers to enhance the dispersibility and continuity of the layers. The components and structure of composites were well identified by various characterization and analysis methods. More importantly, the Pd-Fe3O4/PEDOT:PSS/NS-Ti3C2Tx/GCE sensing platform indicates an outstanding electrocatalytic activity in the electro-reduction of PM with sensitivity of 517.08 μA mM−1 cm−2, linear detection range of 0.01–140 μM, limit of detection as 3.3 nM, and ks as 3.585 s−1. Moreover, this sensing platform was successfully applied to PM residue detection in vegetable, surface water and soil, showing high accuracy and promising feasibility in application.