Electrochemical Redox Behaviors of Sulfur Mustard at Different Platinum Electrodes

Abstract

A bare platinum (Pt) plate electrode, two composite Pt electrodes of Pt/polypyrrole/glassy carbon electrode (Pt/pPy/GCE) and Pt nanoparticles/CeO2 microspheres/GCE (Pt NPs/CeO2/GCE) were prepared to investigate the electrochemical redox behaviors of sulfur mustard (HD). Cyclic voltammetry (CV) measurements revealed two irreversible oxidation peaks and an irreversible reduction peak. All three Pt electrodes had two oxidation peaks at 1.02 V (vs. saturated calomel electrode (SCE)) and 1.26 V (vs. SCE), indicating the formation of bis(2-chloroethyl) sulfoxide and bis(2-chloroethyl) sulfone on all the electrode surfaces. The reduction peak at 1.16 V (vs. SCE) attributed to the cleaving of HD was observed on both Pt/pPy/GCE and Pt NPs/CeO2/GCE, but not on the bare Pt-plate electrode, which revealed that Pt/pPy and Pt NPs/CeO2 materials were more conducive for catalyzing degradation of HD. Fourier transform infrared (FT-IR) and high performance liquid chromatography-mass spectrometry (HPLC-MS) measurements were taken, which further supported the presence of sulfoxide, sulfone, hydroxyl structure, and 2,2′-sulfonyldi[ethanol]. Furthermore, this work proposes the integral redox process of HD on Pt NPs/CeO2.