No description available.

This study investigated the applicability of various analytical tools for the qualitative and quantitative characterization of nanophase electrocatalysts.

No description available.

No description available.

The success of Solid Oxide Fuel Cells (S.O.F.C) rests heavily on material selection. The performances of several compounds were investigated as possible anode materials, starting with reduced titanates such as the magnesium titanate and zirconium titanate. These compositions, although possessing many qualities beneficial for use as an anode material, were found to be too unstable for practical use. For this reason further work concentrated on stable, zirconia based, compounds with exhibited mixed conduction under reducing atmospheres. The mobility of electronic carriers is considered to be much higher than that of ionic defects, therefore, promising mixed conductors can be formed by doping a good ionic conductor with a small concentration of transition metal ions. Zirconia based mixed conductors were studied for two reasons. Firstly, zirconia stabilised in the cubic defect fluorite structure, exhibits a high level of ionic conductivity. Secondly, it is the most common electrolyte material for an S.O.F.C. An anode based on zirconia would, therefore, be expected to offer a good physical compatibility with the electrolyte material and to exhibit a high ionic contribution to total conductivity. Large defect fluorite solid solutions in the systems Y<SUB>2</SUB>O<SUB>3</SUB>-ZrO<SUB>2</SUB>-Nb<SUB>2</SUB>O<SUB>5</SUB>, Yb<SUB>2</SUB>O<SUB>3</SUB>-ZrO<SUB>2</SUB>-Nb<SUB>2</SUB>O<SUB>5</SUB> and CaO-ZrO<SUB>2</SUB>-Nb<SUB>2</SUB>O<SUB>5</SUB> were established, which enabled the effects of composition, dopant size and charge on conduction to be investigated. These effects were shown to be linked to structure. From these results and comparisons with the Y<SUB>2</SUB>O<SUB>3</SUB>-ZrO<SUB>2</SUB>-TiO<SUB>2</SUB> system, optimum, mixed conducting, compositions were established. The sample Y<SUB>0.25</SUB>Ti<SUB>0.15</SUB>Zr<SUB>0.60</SUB>O<SUB>1.875</SUB> exhibited the best mixed conducting properties to date, obtained for compositions based on zirconia.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2004. / Includes bibliographical references.

<p>The main objective of this work it to produce membrane electrode assemblies (MEAs) that have improved performance over MEAs produced by the conventional manner, by producing highly efficient, electroactive, uniform catalyst layers with lower quantities of platinum electrocatalyst. The catalyst coated membrane (CCM) method was used to prepare the MEAs for the PEM fuel cell as it has been reported that this method of MEA fabrication can improve the performance of PEM fuel cells. The MEAs performances were evaluated using polarisation studies on a single cell. A comparison of polarisation curves between CCM MEAs and MEAs produced in the conventional manner illustrated that CCM MEAs have improved performance at high current densities (&gt / 800 mA/cm2).</p>

Thesis (M.S.)--Tennessee Technological University, 2009. / Title from title page screen (viewed on Feb. 5, 2010). Bibliography: leaves 93-100.

Thesis (Ph. D.)--Lehigh University, 2003. / Includes vita. Includes bibliographical references (leaves 110-117).

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: process based cost model; cost model; fuel cell; PBCM; multi-layer ceramics; sofc; solid oxide fuel cell. Includes bibliographical references.