Platinum nanocatalysts prepared with different surfactants for C1–C3 alcohol oxidations and their surface morphologies by AFM

In this study, platinum nanoparticle catalysts have been prepared 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 catalysts were characterized by X-ray diffraction (XRD), atomic force microscopy 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 (2.0–1.3 nm). X-ray photoelectron spectra of the catalysts were examined and it is found that platinum has two different oxidation states, Pt (0) and Pt(IV), oxygen and sulfur compounds are H₂O_ads and OH_ads, bound and unbound thiols. The electrochemical and electrocatalytic properties of these catalysts were investigated with respect to C1–C3 alcohol oxidations by cyclic voltammetry and chronoamperometry. The highest electrocatalytic activity was obtained from catalyst I which was prepared with 1-octanethiol. This may be attributed to a decrease in the ratio of bound to unbound thiol species increase in Pt (0)/Pt(IV), H₂O_ads/OH_ads ratios, electrochemical surface area, CO tolerance and percent platinum utility.