Efficiency enhancement of methanol/ethanol oxidation reactions on Ptnanoparticles prepared using a new surfactant, 1,1-dimethyl heptanethiol

• Published in: Physical chemistry chemical physics : PCCP 2011-01, Vol.13 (4), p.1676-1684
• Main Authors: en, Fatih, en, Selda, Göka aç, Gülsün
• Format: Article
• Language: English
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c0cp01212b

In this study, carbon-supported platinum nanoparticlecatalysts were prepared using PtCl 4 and H 2 PtCl 6 as starting materials and 1-heptanethiol, 1,1-dimethyl heptanethiol, 1-hexadecanethiol and 1-octadecanethiol as surfactants. These nanoparticles can be used as catalysts for methanol and ethanol oxidation reactions in methanol and ethanolfuelcells. 1,1-Dimethyl heptanethiol was used for the first time in this type of synthesis; other surfactants were used to synthesize nanoparticles for comparison of the catalyst's performance. Cyclic voltammetry, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to characterize the catalysts. It should also be stressed that AFM was employed for the first time in determining the surface topography of these catalysts. XRD, TEM and AFM height results indicate that the platinum crystallizes into a face-centered cubic structure and the surfactant plays an important role in determining the size of the platinum nanoparticles. XPS data revealed that the platinum was found in two different oxidation states, Pt(0) and Pt(IV) with a ratio of about 7.5 : 2.5, respectively. Electrochemical studies showed catalystIIa to be the most active sample towards methanol/ethanol oxidation reactions (∼342 A g −1 Pt at 0.612 V for methanol (4.6 times more active than the commercial catalyst), ∼309 A g −1 Pt at 0.66 V for ethanol, (15.4 times more active than the commercial catalyst)). AFM techniques and the surfactant 1,1-dimethyl heptanethiol were used for the first time in the synthesis and study of Pt nanoparticle catalysts.