SnS-modified platinum electrode for electrocatalytic hydrazine oxidation: mechanistic insights and electrochemical sensing.
Abstract
Hydrazine (HZ) is a highly toxic and carcinogenic chemical widely used in industrial, agricultural, and pharmaceutical applications, making its rapid and reliable determination essential for environmental monitoring and public health protection. In this work, a Pt/SnS-modified electrode was developed as an electrochemical sensing platform for sensitive HZ detection. Tin sulfide (SnS) particles were synthesized via a hydrothermal method and immobilized onto a Pt surface using a thin PTFE binder layer. The morphology and chemical composition of the modified electrode were characterized by SEM, EDX, Raman spectroscopy, XPS, and XRD confirming the successful formation of the SnS catalyst. Electrochemical investigations revealed that the Pt/SnS electrode exhibited enhanced electrocatalytic activity toward HZ oxidation in alkaline medium compared with bare Pt, producing more than a twofold increase in oxidation current and improved HZ adsorption. Chronoamperometry and convolution potential sweep voltammetry indicated an overall four-electron oxidation process to nitrogen, while kinetic analysis suggested an irreversible multistep oxidation mechanism with an apparent anodic electron-transfer coefficient (β) of 0.30-0.32. Differential pulse voltammetry enabled HZ determination over two linear concentration ranges of 5-35 µM and 50-3500 µM, with a limit of detection of 2.68 µM and a limit of quantification of 8.13 µM. The sensor further exhibited good operational stability, reproducibility, selectivity against common interfering species, and satisfactory recoveries of 81.0-99.3% for simulated industrial water samples. These results demonstrate that the Pt/SnS-modified electrode is a prospective electrochemical sensing platform for HZ detection, while the mechanistic electrochemical studies provide fundamental insight into its potent electrocatalytic performance.
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