High-entropy alloy (HEA) nanoparticles (NPs) are an emerging group of nanomaterials, gaining considerable attention in recent years due to their tunable compositions, stability towards oxidation and corrosion, high hardness and strength, high-temperature resistance, and remarkable ductility. The synthesis of HEAs as monodisperse NPs is of high interest to understand how their structure and composition contribute to their function. However, downsizing HEAs to the nanoscale has been synthetically challenging as most colloidal routes to metal NPs rely on the reduction of metal salts, which will occur at different rates depending on the metal precursor. Past work has shown that colloidally prepared monodisperse core@shell NPs can be converted to monodisperse HEA NPs by annealing them at high temperature. The initial system considered core@shell PdCu@PtNiM NPs as precursor NPs to HEA NPs, where M = Co, Ir, Rh, Ru, or Fe. These core@shell NPs were prepared by seed-mediated co-reduction (SMCR), and while quite versatile, some metals (e.g., Au and Sn) could not be used in the SMCR process with PdCu seeds. As will be presented, now these metals are being added into the seeds, followed by core@shell NP formation by SMCR and their conversion to HEA NPs. Specifically, AuCu@PdPtNi and Pd<sub>3</sub>Sn@PtNiCu NPs are synthesized via SMCR and converted to AuCuPdPtNi and PdSnPtNiCu HEA NPs by annealing. Control experiments provide guidelines for the design of precursor NPs by considering the relative rates of metal precursor reduction and metal deposition as well as the feasibility for galvanic replacement. The ability to use different seeds will pave the pathway for generalization of this NP conversion strategy towards HEA NPs. More broadly, gaining control over the composition of monodisperse HEA NPs can open a new door to durable catalysts for a range of processes.

Search for a generalizable route to high-entropy alloy nanoparticles from core@shell nanoparticles

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.