Currently in fuel cell state-of-the-art research, studies are divided on separate improvements of electrocatalyst and ionomeric materials. In this work, the synthesis of a novel composite material that combines both components-ionomer and electrocatalyst is presented. This composite material preserves both ionic and electronic conductivities, making this a unique material for fuel cells and other electrochemical devices.

Gallium-doped zinc oxide spin-coated thin films have been prepared by the sol-gel method. The influence of two solvents, isopropanol and 2-methoxyethanol (2-ME), and two chelating agents, monoethanolamine (MEA) and diethanolamine (DEA), was investigated. X-ray diffraction shows preferential (002) c-axis orientation of the crystallites influenced by the doping content and starting solution composition. Better orientation was obtained with 2-ME as a solvent because of a slower evaporation rate during the spin coating. Better orientation was also obtained using MEA as a stabilizer due to the weaker bonds formed with the Zn 2+ ions. Typical film thickness was 550 nm. The transparency of the films was greater than 85% in the entire visible range. A sheet resistance of 68 X/u was obtained for the ZnO film doped with 2 at.% of Ga using 2-ME and MEA as a solvent and stabilizer, respectively. The results show that the denser packing created using a high boiling temperature solvent and a low organic content stabilizer improved the layer's electrical and optical properties.

Anion conductive nanofiber mats from FAA-3 ionomers are obtained by electrospinning. Depending on the solvent used in the precursor solution, nanofibers with either nonhollow cylindrical or flat ribbon-like cross-sections are prepared. The anion conductivity and water uptake of the ionomeric nanofiber mats are measured as a function of the relative humidity in the 10-90% range and compared to that of a solid membrane cast from the same ionomer. In addition, the anion conductivity of an isolated single fiber of the ionomer is measured for the first time. The anion conductivity of the electrospun single fiber is found to be higher than that of the mats, which is, in turn, one order of magnitude higher than that of the solid ionomer membrane. The higher conductivity of the mats relative to the solid membrane (in both inplane and through-plane directions) is found to be related to the variation in water uptake, which stems from the morphological distinctions. These results increase the understanding of the electrospinning process of ionomers, toward the development and design of new anion conductive ionomer fibers, useful for high performance electrochemical devices.

Oxide-based ceramics offer promising thermoelectric (TE) materials for recycling high-temperature waste heat, generated extensively from industrial sources. To further improve the functional performance of TE materials, their power factor should be increased. This can be achieved by nanostructuring and texturing the oxide-based ceramics creating multiple interphases and nanopores, which simultaneously increase the electrical conductivity and the Seebeck coefficient. The aim of this work is to achieve this goal by compacting electrospun nanofibers of calcium cobaltite Ca 3 Co 4−x O 9+δ , known to be a promising p-type TE material with good functional properties and thermal stability up to 1200 K in air. For this purpose, polycrystalline Ca 3 Co 4−x O 9+δ nanofibers and nanoribbons were fabricated by sol-gel electrospinning and calcination at intermediate temperatures to obtain small primary particle sizes. Bulk ceramics were formed by sintering pressed compacts of calcined nanofibers during TE measurements. The bulk nanofiber sample pre-calcined at 973 K exhibited an improved Seebeck coefficient of 176.5 S cm −1 and a power factor of 2.47 μW cm −1 K −2 similar to an electrospun nanofiber-derived ceramic compacted by spark plasma sintering.

A new heterogeneous catalyst for hydrogen oxidation reaction (HOR), metallic palladium within which nanoparticles of ceria are entrapped, CeO2@Pd, is described. Its preparation is based on a new materials methodology of molecular doping of metals. The metallic matrix, which encages the nanoparticles, is prepared in foam architecture, to ensure easy molecular diffusion. Characterization of the structural properties of the CeO2@Pd composite using SEM, STEM, TEM, XRD, EXAFS and nitrogen adsorption reveals its morphological architecture, which leads to improved catalytic activity. In-situ electrochemical and H2 temperature-programmed reduction (H2-TPR) spectra provide direct experimental evidence of the weakening of Pd‒H bond in the CeO2@Pd composites, relative to pure (undoped) Pd catalysts. Gas diffusion electrodes based on the entrapped CeO2@Pd catalysts demonstrated one order of magnitude higher activity than pure Pd analog in the HOR reaction in an alkaline medium.