Pt/MWCNT and Pt/f-MWCNT Catalysts Preparation by Hydrogen Reduction and Impregnation Method: The Application to Methanol Oxidation Reaction

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2016
Zabara, Mohammed Ahmed M
In this thesis, multi-walled carbon nanotubes supported platinum nanoparticles (Pt/MWCNT) and functionalized multi-walled carbon nanotubes supported platinum nanoparticles (Pt/f-MWCNT) catalysts in different Pt percentages were prepared using impregnation method and hydrogen gas reduction. Firstly, multi-walled carbon nanotubes were functionalized using sonochemical method and characterized by Fourier transform infra-red spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and acid base back titration. Secondly, Pt/MWCNT and Pt/f-MWCNT were prepared and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma mass spectrometry (ICP-MS). Their electrochemical properties and performance toward methanol oxidation reaction were examined by cyclic voltammetry (CV). FTIR and XPS studies showed the formation of carboxylic acid, carbonyl, and hydroxyl groups on the surface of f-MWCNT. XRD and TEM works indicated the formation of faced center cubic structure platinum nanoparticles for all catalysts and the average particle size of Pt nanoparticles were little larger for Pt/f-MWCNT (~3nm) than Pt/MWCNT (~2nm) when only the nanoparticles were considered. Agglomeration of Pt nanoparticles was detected for Pt/MWCNT, while narrow particle size distribution was noticed for Pt/f-MWCNT which specifies the positive effect of the functional groups on MWCNT. XPS data revealed three oxidation states of platinum, 0, +2 and +4, with a percentage of ~ 65, 20 and 15, respectively. CV analysis displayed that 14 wt% Pt/f-MWCNT has the highest performance toward methanol oxidation reaction, which is 4.8 times more than commercial E-TEK Pt/Vulcan XC72 catalyst, because it has the highest electrochemical surface area (72.30 m2/g), percent Pt utility (70.9%), and roughness factor (134.9) compared to other catalysts.
Citation Formats
M. A. M. Zabara, “Pt/MWCNT and Pt/f-MWCNT Catalysts Preparation by Hydrogen Reduction and Impregnation Method: The Application to Methanol Oxidation Reaction,” M.S. - Master of Science, Middle East Technical University, 2016.