posted on 2021-02-18, 17:33authored byBaran Sarac, Tolga Karazehir, Eray Yüce, Marlene Mühlbacher, A. Sezai Sarac, Jürgen Eckert
Increasing
the efficiency of hydrogen storage and release using
recent generation metallic glass nanofilms (MGNFs) offers green solutions
for nanoscale energy applications. Contrary to flat nanofilms, enhanced
electrochemical performance of Pd–Cu–Si MGNF assemblies
for hydrogen interaction is obtained on different sizes and configurations
of a nanoporous alumina support. In particular, 10 nm thick samples
with pore diameters of 25 nm reach a high specific pseudocapacitance
per unit mass of 637 F g–1, which is more than an
order of magnitude larger than for flat samples, surpassing the precious
metal-based systems in the literature. The same electrode exhibits
the highest double-layer capacitance calculated from the equivalent
circuit model of the electrochemical impedance spectra, featuring
its eligibility for hydrogen nanosensors. A rough and fully coated
surface is attained for samples of 250 μm thickness and above,
while smoother and open-pore structures are observed for lower thicknesses,
inducing a capillary pressure and turbulent flow effect for the latter
case. The comparison of cyclic voltammetry (CV) profiles recorded
in the region where hydrogen–metal interactions occur confirms
a remarkable desorption charge difference, reaching 2.5 times higher
values for the 50 nm thick 25 nm pore diameter than the 40 nm pore
diameter and flat electrodes, and lower absolute impedance values
near-DC range revealing their highly conductive behavior.