Affiliation:
1. Department of Electronic Materials Engineering Research School of Physics The Australian National University Canberra ACT 2601 Australia
2. School of Engineering The Australian National University Canberra ACT 2601 Australia
3. Centre for Advanced Microscopy The Australian National University Canberra ACT 2601 Australia
4. ARC Centre of Excellence for Transformative Meta‐Optical Systems Research School of Physics The Australian National University Canberra ACT 2601 Australia
Abstract
AbstractCrucial advancements in versatile catalyst systems capable of achieving high current densities under industrial conditions, bridging the gap between fundamental understanding and practical applications, are pivotal to propel the hydrogen economy forward. In this study, vertically oriented hierarchically multiscale nanoflakes of NiFeCo electrocatalysts are presented, developed by surface modification of a porous substrate with nano‐structured nickel. The resulting electrodes achieve remarkably low overpotentials of 139 mV at 10 mAcm−2 and 248 mV at 500 mAcm−2. Further, scaled‐up electrodes are implemented in a water‐splitting electrolyser device exhibiting a stable voltage of 1.82 V to deliver a constant current density of 500 mA cm−2 for over 17 days. Moreover, the role of the unique structures on electrochemical activity is systematically investigated by fractal analysis, involving computation of structure factors such as Minkowski connectivity, fractal dimension, and porosity using scanning electron microscope images. It is found that such structures offer higher surface area than typical layered double hydroxide structures due to morphological coherence that results in a superhydrophilic surface, while the base Ni layer boosts the charge transfer. This study demonstrates a Ni/NiFeCo(OH)x heterostructure with highly porous morphology, a key to unlocking extremely efficient oxygen evolution reaction activity with exceptional stability. Moreover, fractal analysis is presented as a valuable tool to evaluate the electrochemical performance of catalysts for their structured morphology.
Funder
Australian Renewable Energy Agency
Australian Research Council
Subject
General Materials Science,Renewable Energy, Sustainability and the Environment
Cited by
4 articles.
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