Alloying/dealloying mechanisms, microstructural modulation and mechanical properties of nanoporous silver via a liquid metal-assisted alloying/dealloying strategy

Nanoporous metals show great potentials in various applications including catalysis, sensing, actuation and supercapacitors. The liquid Ga-assisted alloying/dealloying strategy is a feasible and scalable way to fabricate substrate-supported nanoporous metals. However, the influence of intrinsic alloying mode and mechanism on the formation and modulation of nanoporous structure has not been thoroughly explored before. In this work, after painting liquid Ga on Ag foil, both the bulk-like Ag3Ga (in the Ag-rich zone) and wire-like Ag3Ga (in the liquid Ga-rich zone) form owing to the interdiffusion of Ag and Ga atoms. Correspondingly, the bimodal wire-like and unimodal bulk-like nanoporous Ag is obtained because of the structure inheritance during dealloying. In addition, the thickness of alloy layer (nanoporous layer) versus mass loading of liquid Ga follows a good linear relationship. The in-situ X-ray diffraction of dealloying from Ag3Ga to nanoporous Ag illustrates no other intermetallic phase appears and the dealloying process can be described by the dissolution-surface diffusion model. More importantly, the substrate-supported nanoporous Ag exhibits excellent mechanical properties which are of great importance to the future applications of nanoporous metals. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Nanoporous metals have shown great potential in various applications, and the liquid Ga-assisted alloying/dealloying strategy is a feasible and scalable method for fabricating substrate-supported nanoporous metals. The study found that the formation of wire-like and bulk-like nanoporous Ag is influenced by the interdiffusion of Ag and Ga atoms, and the thickness of the alloy layer shows a linear relationship with the mass loading of liquid Ga. The mechanical properties of the substrate-supported nanoporous Ag are excellent, which is crucial for future applications of nanoporous metals.