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

Abstract

Contrary to the electrochemical energy storage in Pd nanofilms challenged by diffusion limitations, extensive metal–hydrogen 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 gold-containing 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 energy-dispersive X-ray analysis after hydrogenation corroborate the existence of several nanometer-sized crystals homogeneously dispersed throughout the matrix. These nanocrystals are induced by PdH x 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 (∼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.

Magnetron Sputtered Non‐Toxic and Precious Element‐Free TiZrGe Metallic Glass Nanofilms with Enhanced Biocorrosion Resistance

“…is relatively faster. [7,52] This behavior reached at different frequencies was also shown for ZnCl 2 activated carbons carbonized at different temperatures. [53] The reason for the frequencyindependent impedance is that at high frequencies, the Warburg impedance is quite small since the diffusing ions move only very little, where the resistance becomes independent of the applied frequency.…”

“…Their exclusive combination of the high elasticity, mechanical strength, corrosion stability, and good resistance against hydrogen embrittlement renders metallic glasses for use as alternative materials for hydrogen storage, electrocatalytic converters, and lithium-ion rechargeable batteries. [1][2][3][4][5][6][7] Besides, due to their minimal stress shielding and anti-biocorrosion, biocompatibility with the promotion of cell adhesion, and in some cases, biodegradability, these advanced amorphous alloys have started to be used in daily healthcare applications such as orthopedics and dental implants, screws for bone fracture fixation, and stents for cardiovascular repair. [8][9][10][11][12][13][14][15] Promising antimicrobial properties of thin film metallic glass (TFMG) coatings have been shown in the literature.…”

Pd-based Metallic Glasses as Promising Materials for Hydrogen Energy Applications

“…15b), Si2p at ∼99 eV and Au4f 7/2 at ∼83 eV signals. 118 The inner layer does not contain C or S, and negligible oxidation is observed on the material's surface, implying pronounced passivation stability. On the surface, the PdO reduction into Pd (i.e., the drop in Pd 2+ ) is possibly the reason for the rise in the H/Pd ratio.…”

Synergistic enhancement of hydrogen interactions in palladium–silicon–gold metallic glass with multilayered graphene

“…11,12 Hence, these materials have been suggested as green energy materials for hydrogen storage and production. 13–33…”