Thermal desorption spectra of the PdHxsystem in a powder form

Publisher Website
Google Scholar
Abstract
Thermal desorption spectroscopy (TDS) of hydrogen from metal hydrides is a technique where the rate of hydrogen desorption is measured as a function of temperature while the temperature is increased linearly with time. The authors present the TDS of a powdered PdHx (particle size approximately 2 mu m) for various initial concentrations and for various heating rates. The spectra develop from a single peak (A) and a small shoulder curve at low initial H concentrations to two peaks (A,B) and a shoulder at high initial concentration (x equivalent to 0.9). The peaks are correlated to the phase diagram-the peak A to the alpha + beta region, the peak B to the beta region and the shoulder to the alpha region. Activation energies for desorption and preexponential factors are derived from the Arrhenius-like parts that the spectra exhibit in their onset regions and in the region alpha + beta . The results are discussed in terms of a model in which the desorption rate is determined by the rate of the recombination process H+H to 2 at the surface.