Preparation and characterization of carbon supported platinum nanocatalysts with different surfactants for C1 to C3 alcohol oxidations

Ertan, Salih
In this thesis, carbon supported platinum nanoparticles have been prepared by using PtCl4 as a starting material and 1-octanethiol, 1-decanethiol, 1-dodecanethiol and 1-hexadecanethiol as surfactants for methanol, ethanol and 2-propanol oxidation reactions. The structure, particle sizes and surface morphologies of the platinum were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). XRD and TEM results indicate that all prepared catalysts have a face centered cubic structure and are homogeneously dispersed on the carbon support with a narrow size distribution (2.0 to 1.3 nm). X-ray photoelectron spectra of the catalysts were examined and it was found that platinum has two different oxidation state, Pt (0) and Pt (IV), oxygen and sulfur compounds are H2Oads and OHads, bounded and unbounded thiols. The electrochemical and electrocatalytic properties of those catalysts were investigated towards C1 to C3 alcohol oxidations by cyclic voltammetry (CV) and chronoamperometry (CA). The highest electrocatalytic activity was obtained from catalyst I which was prepared with 1-octanethiol. This may be attributed to decrease in the ratio of bounded to unbounded thiol species and increase in Pt (0)/Pt (IV), H2Oads/OHads ratios, electrochemical surface area, CO tolerance and percent platinum utility.