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arXiv · 2511.09711

Controlling Metastability through Annealing of High-Entropy Nanoalloy Electrocatalysts to Boost Performance towards the Oxygen Evolution Reaction

Varatharaja Nallathambi·Aneeta Jose Puthussery·Andrea M. Mingers·Robert Stuckert·André Olean-Oliveira·Sven Reichenberger·Dierk Raabe·Viktor Čolić·Baptiste Gault·Stephan Barcikowski
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Abstract

Low-cost transition metal high-entropy nanoalloys are emerging as sustainable alternatives to platinum group electrocatalysts. Synthesis conditions of single-phase solid solutions can alter phase stability, causing surface composition changes that affect electrocatalytic performance. Here, we propose to exploit the metastability of carbon-doped Cantor alloy-based amorphous high-entropy alloy nanoparticles produced by nanosecond-pulsed laser synthesis in organic solvents. In situ electron microscopy reveals crystallization and partitioning of elements upon heating to 600 {\deg}C, forming heterostructured nanoparticles with reinforced carbon shells that exhibit a 5- to 7-fold enhancement of the electrocatalytic activity compared to the as-synthesized counterparts for the oxygen evolution reaction. We demonstrate the strategic utilization of phase metastability in high-entropy nanoalloys through post-synthesis annealing to enhance the electrochemical activity of laser-generated nanoparticles.

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Varatharaja Nallathambi, Aneeta Jose Puthussery, Andrea M. Mingers, Robert Stuckert, André Olean-Oliveira, Sven Reichenberger, Dierk Raabe, Viktor Čolić, Baptiste Gault, Stephan Barcikowski. 2025-11-12. Controlling Metastability through Annealing of High-Entropy Nanoalloy Electrocatalysts to Boost Performance towards the Oxygen Evolution Reaction. https://arxiv.org/abs/2511.09711

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