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Lookup NU author(s): Dr Chuan ChengORCiD
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).
Dealloyed nanoporous gold (np-Au) has applications as oxygen reduction catalysis in Li-air batteries and fuel cells, or as actuators to convert electricity into mechanical energy. However, it faces the challenges of coarsening-induced structure instability, mechanical weakness due to low relative densities, and slow dealloying rates. Here, monolithic np-Au is dealloyed from a single-phase Au25Ni75 solid-solution at a one-order faster dealloying rate, ultra-low residual Ni content, and importantly, one-third more relative density than np-Au dealloyed from conventional Au25Ag75. The small atomic radius and low dealloying potential of the sacrificing element Ni are intrinsically beneficial to fast produce high relative density np-Au, as predicted by a general model for dealloying of binary alloys and validated by experiments. Stable, durable, and reversible actuation of np-Au takes place under cyclic potential triggering in alkaline and acidic electrolytes with negligible coarsening-induced strain-shift. The thermal and mechanical robustness of bulk np-Au is confirmed by two-order slower ligament coarsening rates during annealing at 300 °C and 45 MPa macroscopic yielding strength distinctive from the typical early onset of plastic yielding. This article opens a rich direction to achieve high relative density np-Au which is essential for porous network connectivity, mechanical strength, and nanostructure robustness for electrochemical functionality.
Author(s): Cheng C, Lührs L
Publication type: Article
Publication status: Published
Journal: Advanced Functional Materials
Year: 2021
Volume: 31
Issue: 48
Print publication date: 25/11/2021
Online publication date: 31/08/2021
Acceptance date: 28/08/2021
Date deposited: 02/02/2023
ISSN (print): 1616-301X
ISSN (electronic): 1616-3028
Publisher: John Wiley & Sons, Ltd
URL: https://doi.org/10.1002/adfm.202107241
DOI: 10.1002/adfm.202107241
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