Facile Solvothermal Synthesis of Pt–Ir–Pd–Rh–Ru–Cu–Ni–Co High-Entropy Alloy Nanoparticles

Abstract

High-entropy alloys (HEAs) present a promising class of materials due to extraordinary properties and vast possibilities for tailoring product characteristics through changes in stoichiometry. Nanosized HEAs are especially interesting with respect to catalysis of multistep reactions and replacement of scarce, expensive, and/or toxic elements. Finding suitable methods for the synthesis of nano-HEAs remains a severe challenge, and typical methods are limited in productivity, compatibility of different elements, substrate types, and/or specialized laboratory equipment. Here, we report a simple solvothermal method for the synthesis of eight-component Pt−Ir−Pd−Rh−Ru−Cu−Ni−Co HEA nanoparticles with a high potential production capacity. The method relies on simple autoclaves heated to a moderate temperature. In situ X-ray scattering experiments show that the individual metal components form from one-element precursors at higher reaction temperatures, suggesting that the formation is auto-catalyzed, that is, the particles catalyze their own growth, in correspondence with previous findings for a five element (Pt−Ir−Rh−Pd−Ru) noble-metal HEA. This paper extends the method to cheaper and more abundant 3d metals (Co, Ni, and Cu) despite the differences in atomic radii and chemical reactivity and thereby adds significantly to the synthetic chemistry and understanding of HEA nanomaterials.

High-entropy alloys in electrocatalysis: from fundamentals to applications

“…Researchers have extensively explored suitable metal combinations and optimal compositions to develop low-cost, high-performance electrocatalysts. 180,181 However, most studies on HEAs are empirical and lack a rational basis for the selection of specific metal elements, which hampers further progress in the field. To overcome this limitation, it is imperative to This journal is © The Royal Society of Chemistry 2023 establish a deeper understanding of the relationship between the composition of HEAs and their catalytic activity.…”

Unveiling the formation mechanism of PbxPdy intermetallic phases in solvothermal synthesis using in situ X-ray total scattering

“…With the PbPt intermetallic phase forming by a co-reduction, the effect of swapping Pt with Pd is examined. Pd has been shown to nucleate at lower temperatures than Pt, 30,31 and with the Pb x Pt y system only containing three intermetallic compounds 32 compared with the five intermetallic compounds of the Pb x Pd y system, 12–14 differences are expected.…”

Programmable Synthesis of High-Entropy Nanoalloys for Efficient Ethanol Oxidation Reaction

“…Unfortunately, this route generally needs to be carried out at a very high temperature, − which makes it very difficult to realize the synthesis of HEA with controllable morphologies. An alternative approach based on the solution-phase syntheses has recently shown promise for the synthesis of HEA nanostructures with different morphologies, ,− with a few notable examples including HEA nanowires, , nanoribbons, and nanoplates. , Nevertheless, these solution-phase syntheses, either one-pot synthesis ,− ,, or galvanic-reaction-induced synthesis, suffer from insufficient generality of the synthetic method and/or the narrow elemental distributions. In this context, it is of great significance to develop a general route to synthesize HEA nanostructures with controllable morphologies and diverse elemental compositions, which, however, has not yet been reported to the best of our knowledge.…”

“…Very recently, two types of synthetic approaches have been explored for the synthesis of HEA nanostructures. − One involves shock-type syntheses, e.g., the carbothermal shock, , fast moving bed pyrolysis, vapor phase spark discharge, and a laser-assisted strategy, which enables the general synthesis of HEA nanoparticles with a wide compositional range and broad elemental combinations by the strong kinetics-driven process. Unfortunately, this route generally needs to be carried out at a very high temperature, − which makes it very difficult to realize the synthesis of HEA with controllable morphologies.…”