Kinetically controlling surface atom arrangements in thermally robust, amorphous high-entropy alloy nanoparticles by solvent selection

TL;DR

This study demonstrates how solvent choice during pulsed laser synthesis can kinetically control surface atom arrangements in amorphous high-entropy alloy nanoparticles, enabling tailored surface compositions and enhanced thermal stability.

Contribution

It introduces a novel solvent-driven synthesis method to control surface atom arrangements in amorphous high-entropy nanoalloys via carbon incorporation.

Findings

Carbon shells form on nanoparticles, stable up to 350°C.

Solvent selection influences nanoparticle morphology and composition.

Kinetic control of formation processes determines surface structure.

Abstract

The ability to tailor nanoscale surface atom arrangements through multi-elemental compositional control provides high-entropy nanoalloys with promising functional properties. Developing a fundamental understanding of nanoalloy formation mechanisms during synthesis is therefore essential for effectively engineering the surface composition and resulting functional properties. Using the Cantor alloy (CrMnFeCoNi) as a model system, we investigate how solvent selection during reactive, nanosecond-pulsed laser synthesis influences carbon doping and the resulting changes in nanoparticle morphology, structure, and composition. Supersaturated carbon incorporation, partitioned from the organic solvent molecules, produces amorphous nanoparticles with distinctive carbon shells, thermally stable up to 350 {\deg}C. We propose kinetically controlled particle formation mechanisms and rationalize the criticality of the time scales between the competing reactions of carbon doping, carbon shell formation, and coalescence of metallic fragments, ruling compositional and morphological characteristics. This work demonstrates effective solvent-driven surface-compositional control in amorphous high-entropy nanoalloys. It introduces a novel synthesis approach for tailoring surface atom arrangements through carbon incorporation via reactive, pulsed laser synthesis.