Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains vii, 156 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 71).

Thesis (M.S.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains ix, 71 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 52-53).

Thesis (M.S)--Ohio University, March, 2005. / Title from PDF t.p. Includes bibliographical references (leaves 129-132)

The doctoral thesis deals with investigation of the catalysts and ionexchanege membranes for fuel cells H2-O2. The work contains the basic principles of chemical reactions, thermodynamic aspects and kinetic properties in PEM fuel cells.Ion-exchagers based on fluorinated polymer sulfonic acids known as NAFION are used in most cases. These compounds are very expensive. Also a strong corrosive attribute requires platinum as a catalysator. These facts make the membrane fuel cells fully non-competetive with e.g. internal combustion engine in spite of all ecological advantages of this electrical power source. The subject of doctoral thesis is research and development of compounds for the composite electrode materials base on NiOx, Ni-Pd and Raney Ni suitable as catalysts a nd alkaline or bipolar ionexchange membranes for electrochemical fuel cells.

In this work, two groups of carbon supported Pt-Pd catalysts have been prepared in order to investigate the effect of Pd, as a second metal, and surfactants on the catalytic activity towards methanol and ethanol oxidation reactions used in the direct methanol and ethanol fuel cells. In the first group (group a), 1- hexanethiol was used as a stabilizing agent while in the second group (group b), 1,1 dimethyl hexanethiol was utilized. Cyclic voltammetry (CV), chronoamperometry (CA), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were used in order to determine the nature of the catalysts. The average crystalline size of the metal particles in the catalysts was explored by XRD and TEM. TEM results revealed the uniform distribution of the metal nanoparticles on carbon support with a narrow size distribution in the range of 3.0 to 3.7 nm and the average crystalline sizes of metal particles for group &ldquo / b&rdquo / catalysts were larger than that of group &ldquo / a&rdquo / catalysts which can be explained by the surfactant effect. These results were in good agreement with XRD data. The oxidation states of platinum (Pt(0) and Pt(IV)) and palladium (Pd(0) and Pd(II)) and their ratios were investigated by XPS and for the most active catalyst, catalyst Ib, these ratios were found to be as 6.94 and 13.7, respectively. Electrochemical activities of the catalysts towards methanol and ethanol oxidation reactions were recorded and compared with that of Pt/C and the commercial Pt (ETEK 20 %wt) catalysts. The results indicated that the group &lsquo / b&rsquo / catalyst has greater catalytic activities than that of group &lsquo / a&rsquo / catalysts. Catalyst Ib comes into prominence as the most active catalyst due to its superior characteristics that it possess such as highest extent of alloying with respect to the palladium amount used, active surface area, CO-tolerance, stability and Pt (0) to Pt (IV) and Pd (0) to Pd (II) ratios.

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.