ePrints

Robust Metallic Actuators Based on Nanoporous Gold Rapidly Dealloyed from Gold–Nickel Precursors

Lookup NU author(s): Dr Chuan ChengORCiD

Downloads

• Published version [.pdf]

Licence

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).

Abstract

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.

Publication metadata

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

Altmetrics

Funding

Share