Proton Dynamics in Palladium-Silver: An Inelastic Neutron Scattering Investigation

• Published in: Molecules (Basel, Switzerland) Switzerland), 2020-11, Vol.25 (23), p.5587
• Main Authors: Colognesi, Daniele, Demmel, Franz, Filabozzi, Alessandra, Pietropaolo, Antonino, Pozio, Alfonso, Romanelli, Giovanni, Santucci, Alessia, Tosti, Silvano
• Format: Article
• Language: English
• Subjects: Alloys; Atomic properties; Data analysis; Elastic scattering; Energy; Hydrogen; hydrogen diffusion; Hydrogenation; inelastic neutron scattering; Inelastic scattering; Membrane separation; Membranes; Neutron Diffraction; Neutron scattering; Neutrons; Palladium; Palladium - chemistry; palladium/silver membranes; Permeability; Phase transitions; Protons; Silver; Silver - chemistry; Spallation; Spectrometers; Temperature
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules25235587

Proton dynamics in Pd Ag membranes is investigated by means of various neutron spectroscopic techniques, namely Quasi Elastic Neutron Scattering, Incoherent Inelastic Neutron Scattering, Neutron Transmission, and Deep Inelastic Neutron Scattering. Measurements carried out at the ISIS spallation neutron source using OSIRIS, MARI and VESUVIO spectrometers were performed at pressures of 1, 2, and 4 bar, and temperatures in the 330-673 K range. The energy interval spanned by the different instruments provides information on the proton dynamics in a time scale ranging from about 10 to 10 ps. The main finding is that the macroscopic diffusion process is determined by microscopic jump diffusion. In addition, the vibrational density of states of the H atoms in the metal lattice has been determined for a number of H concentrations and temperatures. These measurements follow a series of neutron diffraction experiments performed on the same sample and thus provide a complementary information for a thorough description of structural and dynamical properties of H-loaded Pd-Ag membranes.