Metallic Glass Films with Nanostructured Periodic Density Fluctuations Supported on Si/SiO₂as an Efficient Hydrogen Sorber

Abstract

Nanostructured metallic glass films (NMGF) can exhibit surface and intrinsic effects that give rise to unique physical and chemical properties. Here we report a facile synthesis and electrochemical, structural, and morphologic characterization of Pd-Au-Si based MGs of ~50 nm thickness supported on Si/SiO2. Impressively, the maximum total hydrogen charge stored in Pd-Au-Si nanofilm is equal to that in polycrystalline Pd films with 1 µm thickness in 0.1 M H2SO4 electrolyte. The same NMGF has a volumetric desorption charge that is more than eight times and 25% higher than that of polycrystalline PdNF and Pd-Cu-Si NMGF with the same thickness supported on Si/SiO2, respectively. A significant number of nanovoids originated from PdHx crystals, and an increase in average interatomic spacing is detected in Pd-Au-Si NMGF by highresolution TEM. Such a high amount of hydrogen sorption is linked to the unique density fluctuations without any chemical segregation exclusively observed for this NMGF.

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

“…Table S1 explains the substrate abbreviations (P: porous), including interpore distances, pore diameter, porosity, and pore number. The MG composition is selected based on its tendency to deposit a fully amorphous nanofilm (see ref ) and our previous electrochemical hydrogenation experiments …”

“…New-generation Pd-based nanomaterials are promising candidates to enhance the efficiency of hydrogen interactions, thus providing green alternatives for nanoscale energy applications. Among these, Pd-metallic glasses (MGs) have recently garnered significant recognition in a variety of energy applications, including hydrogen storage and release, − hydrogen evolution reaction (HER), − hydrogen oxidation reaction in fuel cells, methanol/ethanol electrooxidation, − glucose sensors, MEMS hydrogen sensor, − and hydrogen permeation membranes. − The grain-free structure of metallic glasses, along with the presence of free volume between atomic clusters, are advantages of Pd-MGs over polycrystalline Pd (alloys) in terms of hydrogen storage and release as well as electrochemical stability in long-term use. ,,,, …”

“…Au in Pd–Au–Si metallic glasses breaks down the strong metal–metalloid bonds, forming new short- to medium-range order clusters (as in Pd–Cu–Si and Pd–Ni–P systems). , These clusters are disordered Pd atoms and/or nanocrystals, and the space between these structures is occupied by absorbed hydrogen, either in ionic or molecular form, which is subsequently attached to the metallic glass . Previous observations have revealed that compared to Pd, larger Au atoms can enhance the number of PdH x crystals ensuring their homogeneous distribution within the MG matrix . In that study, the formation of large numbers of tiny nanocrystalline regions with size of several nanometers was linked to the amount of charged hydrogen upon cyclic voltammetry (CV) cycles.…”

“…Although Pd systems have been extensively studied in terms of gas–solid reactions, hydrogen permeation systems, or pressure-composition-isotherm measurements, − the diffusion and electron-transfer kinetics, as well as the stability during hydrogen sorption and evolution determine their practical applications. , In this respect, electrochemical impedance spectroscopy (EIS) provides remarkable insight into kinetic and diffusion-related parameters, including the influence of pores and composition, by frequency-dependent measurements. , Different parameters, i.e., charge-transfer resistance, solution and Warburg resistance, double-layer capacitance, inductance, and resistance and capacitance of interfaces and porous surfaces, are determined by means of fitting the experimental data with an equivalent circuit model (ECM). − In this work, we compare an optimized Pd–Au–Si glassy alloy based on our previous study and Pd nanocrystals sputtered on two different pore architectures and flat substrates. The hydrogen interactions with Pd in terms of porosity are assessed by EIS-ECM complemented by DC-type cyclic voltammetry (DC) and chronoamperometry (CA).…”

Hydrogen storage performance of the multi-principal-component CoFeMnTiVZr alloy in electrochemical and gas–solid reactions

“…35 CV is also used to analyze the sorption and desorption behavior of hydrogen and electrocatalytic behavior in various materials and applications. [36][37][38][39][40][41][42][43][44][45][46][47][48][49] Hydrogen absorption and evolution reactions have attracted growing interest in the past years due to their insufficient kinetics, i.e. low conductivity of OH À ions in alkaline electrolytes.…”