Nanoporous Quasi-High-Entropy Alloy Microspheres

Abstract

High-entropy alloys (HEAs) present excellent mechanical properties. However, the exploitation of chemical properties of HEAs is far less than that of mechanical properties, which is mainly limited by the low specific surface area of HEAs synthesized by traditional methods. Thus, it is vital to develop new routes to fabricate HEAs with novel three-dimensional structures and a high specific surface area. Herein, we develop a facile approach to fabricate nanoporous noble metal quasi-HEA microspheres by melt-spinning and dealloying. The as-obtained nanoporous Cu30Au23Pt22Pd25 quasi-HEA microspheres present a hierarchical porous structure with a high specific surface area of 69.5 m2/g and a multiphase approximatively componential solid solution characteristic with a broad single-group face-centered cubic XRD pattern, which is different from the traditional single-phase or two-phase solid solution HEAs. To differentiate, these are named quasi-HEAs. The synthetic strategy proposed in this paper opens the door for the synthesis of porous quasi-HEAs related materials, and is expected to promote further applications of quasi-HEAs in various chemical fields.

Recent Progress in High‐Entropy Alloy Electrocatalysts for Hydrogen Evolution Reaction

“…Subsequently, the metal ingots were transformed into metal Reproduced with permission. [30] Copyright 2004, Elsevier Ltd. b) The synthesis method consists of the following stages: following ultrashort-pulse laser irradiation of bulk HEAs, bulk atomization/ionization to form a plume, followed by nucleation and condensation of the ablative substance in the liquid vapor phase, and electrostatic stabilization of colloidal high entropy alloy nanoparticles in ethanol. c) The progressive synthesis of nanoscale particles from a single metal.…”

“…Similarly, in the work by Zhang et al (Figure 3b), AlCoCr-FeNi HEA powders were successfully synthesized through highenergy ball milling. [30] Employing additional wet ball milling further optimized the powder size and shape for Electromagnetic Interference (EMI) applications. The HEAs sample exhibited a maximum total shielding (SET) of 20 dB, surpassing the 8.44 dB of the HEAL sample.…”

“…Copyright 2020, Elsevier Ltd. b) Schematic diagram of the synthetic mechanism of the planetary ball mill to form HEA powders. Reproduced with permission [30]. Copyright 2019, MDPI Ltd. c) Schematic diagram of key steps of FeCoNiCuPd film preparation.…”

Diversity of Nanoporous Metals

“…This alloy system was a good precursor candidate for the preparation of nanoporous copper because of the easy dissolution of Mg and Ca. Yang et al [6] developed a new route to fabricate nanoporous high-entropy alloy (HEA) with a high specific surface area. The as-obtained nanoporous Cu 30 Au 23 Pt 22 Pd 25 quasi-HEA microspheres displayed a hierarchical porous structure with a high specific surface area of 69.5 m 2 /g.…”

Development of porous high-entropy alloys by mechanical alloying and chemical de-alloying

“…Okulov et al [14] developed a nanoporous TaMoNbVNi HEA with open porosity by liquid metal de-alloying. Nanoporous quasi-HEA microspheres were developed by melt-spinning and de-alloying [15]. Despite these HEA studies, to the best of our knowledge, there are no reports on the fabrication of HEA foams using powder metallurgical routes involving mechanical alloying and chemical de-alloying, wherein the nanoporous structure can be readily produced and controlled.…”