Enhancement of Interfacial Hydrogen Interactions with Nanoporous Gold-Containing Metallic Glass

Sarac B., Ivanov Y. P., Micusik M., Karazehir T., Putz B., Dancette S., ...More

ACS APPLIED MATERIALS & INTERFACES, vol.13, no.36, pp.42613-42623, 2021 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 13 Issue: 36
  • Publication Date: 2021
  • Doi Number: 10.1021/acsami.1c08560
  • Journal Name: ACS APPLIED MATERIALS & INTERFACES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Compendex, EMBASE, INSPEC, MEDLINE
  • Page Numbers: pp.42613-42623
  • Keywords: thin films, metallic glass, palladium, gold, electrochemical hydrogen, transmission electron microscopy, X-ray photoelectron spectroscopy, equivalent circuit model, EVOLUTION REACTION, HIGHLY EFFICIENT, THIN-FILMS, PALLADIUM, ALLOY, ABSORPTION, ADSORPTION, OXIDATION, METHANOL, PERFORMANCE
  • Istanbul Technical University Affiliated: Yes

Abstract

Contrary to the electrochemical energy storage in Pd nanofilms challenged by diffusion limitations, extensive metalhydrogen interactions in Pd-based metallic glasses result from their grain-free structure and presence of free volume. This contribution investigates the kinetics of hydrogen-metal interactions in goldcontaining Pd-based metallic glass (MG) and crystalline Pd nanofilms for two different pore architectures and nonporous substrates. Fully amorphous MGs obtained by physical vapor deposition (PVD) co-sputtering are electrochemically hydrogenated by chronoamperometry. High-resolution (scanning) transmission electron microscopy and corresponding energydispersive X-ray analysis after hydrogenation corroborate the existence of several nanometer-sized crystals homogeneously dispersed throughout the matrix. These nanocrystals are induced by PdHx formation, which was confirmed by depth-resolved X-ray photoelectron spectroscopy, indicating an oxide-free inner layer of the nanofilm. With a larger pore diameter and spacing in the substrate (Pore40), the MG attains a frequency-independent impedance at low frequencies (similar to 500 Hz) with very high Bode magnitude stability accounting for enhanced ionic diffusion. On the contrary, on a substrate with a smaller pore diameter and spacing (Pore25), the MG shows a larger low-frequency (0.1 Hz) capacitance, linked to enhanced ionic transfer in the near-DC region. Hence, the nanoporosity of amorphous and crystalline metallic materials can be systematically adjusted depending on AC- and DC-type applications.