Study of Organic Sulfide Oxidation on the Modified Graphite Electrodes by Co, Fe and Ni Nano Particles

Abstract

Electro-oxidation of methyl phenyl sulfide with the aim of producing sulfoxide and sulfone was investigated over Ni, Co, Fe, and their alloys on graphite electrodes in the acetic acid as a non-toxic solvent. The modified electrodes were prepared by cyclic voltammetry technique. The surface morphology of electrodes was investigated by scanning electron microscopy and the presence of metal nanoparticles on the graphite was investigated by X-ray diffraction. The catalytic treatment and synergistic effects of the modified electrodes were studied by electrochemical techniques such as cyclic voltammetry (CV) and chronoamperometry (CA). It was found the performance of all the modified electrodes is successful. In the attendance of methyl phenyl sulfide, the graphite/CoFe modified electrode (G/CoFe) showed the highest performance for electro-oxidation also there was a linear relationship between the square root of the scan rate and anodic current in low scan rates, that indicates a diffusion controlled process. The diffusion coefficient, heterogeneous electron transfer rate constant and electron transfer coefficient were determined for methyl phenyl sulfide electrochemical oxidation. Electro-oxidation of methyl phenyl sulfide by electrolysis method was investigated and its results were studied by gas chromatograph (GC). Based on GC studies, the electro-oxidation of methyl phenyl sulfide by electrolysis produced methyl phenyl sulfoxide and methyl phenyl sulfone. Also, a mechanism for electro-oxidation of sulfide was proposed. The using of non-noble metals as the electrocatalyst for the first time for the organic sulfide electro-oxidation, the very easy, affordable and fast preparation of the modified electrode, high performance of the modified electrode, no need of using oxidant and co-catalyst and designing a homogeneous media with proper conductivity for oxidation of insoluble in water compounds demonstrate important items for the use of this procedure and electrode in the subsequent investigation of sulfides.