Sökning: "proton-conduction"

Visar resultat 1 - 5 av 17 avhandlingar innehållade ordet proton-conduction.

  1. 1. Thin-Film Electrocatalysts for Polymer Electrolyte Fuel Cells - Activity, Durability and Proton Conduction

    Författare :Björn Wickman; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nafion; thin film evaporation; PEMFC; platinum; titanium oxide; cathode; fuel cell; oxygen reduction reaction; electrocatalyst; proton conduction; model systems;

    Sammanfattning : The polymer electrolyte membrane fuel cell (PEMFC) is a potential technology for future energy conversion in sustainable energy systems. By using hydrogen from renewable energy sources and oxygen from the air, the fuel cell produces electricity with water as the only exhaust. LÄS MER

  3. 2. Proton Conducting Ceramics; Synthesis, Characterization and Sample Cell Environments

    Författare :FRANCIS GACHAO KINYANJUI; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; perovskites; neutron diffraction; Rietveld refinements; BaSnO3; in-situ cell; deuteron position; proton conduction; BaZrO3;

    Sammanfattning : Acceptor doped Perovskite ceramics have been shown to exhibit high levels of protonic conduction in humid atmospheres. However significant grain boundary resistance and long sintering times required to achieve sufficient grain size growth has hindered their widespread application as electrolyzers, fuel cells and gas separation membranes. LÄS MER

  4. 3. Significance of grain boundaries for transport phenomena in graphene and proton-conducting barium zirconate

    Författare :Edit Ahlberg Helgee; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; graphene; density functional theory; phonons; proton conduction; grain boundaries; BaZrO3; interatomic model potentials;

    Sammanfattning : Grain boundaries can have a significant influence on the properties of polycrystalline materials. When determining the type and extent of this influence it is frequently useful to employ computational methods such as density functional theory and molecular dynamics, which can provide models of the grain boundary structure at the atomistic level. LÄS MER

  5. 4. Structure and Dynamics in Transition Metal Perovskites — An Optical Spectroscopy Study

    Författare :Johan Bielecki; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; multiferroics; colossal magnetoresistance; magnetism; proton-conduction; spin-state transition; structure; Ultrafast spectroscopy; high temperature superconductivity; dynamics; Raman;

    Sammanfattning : Transition metal oxides with the perovskite structure exhibit a vast number of exotic properties due to the large number of competing degrees of freedom at the Fermi surface. Together with couplings between and correlations within these degrees of freedom, this class of materials is of high interest from both a practical and theoretical point of view. LÄS MER

  7. 5. Hydrogen in oxides: a density-functional study of thermodynamic and kinetic aspects

    Författare :Mårten Björketun; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; proton conduction; La$_2$Zr$_2$O$_7$; protonation; kinetic Monte Carlo; density functional theory.; BaZrO$_3$; hydrogen oxide systems; electronic structure;

    Sammanfattning : Many solid oxides, especially those possessing a perovskite structure, exhibit significant proton conductivity when being acceptor doped and placed in hydrogen-containing atmospheres. Consequently, they have attracted attention foruse as solid membranes in electrochemical devices such as gas sensors, steam electrolyzers and fuel cells. LÄS MER