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<p>Nanoporous high-entropy alloys (HEAs) represent promising electrocatalytic platforms combining compositional complexity, corrosion resistance, and mechanically robust, self-supported architectures. A Ti31V26Zr12Nb26Co5-based HEA electrode was fabricated via selective chemical dealloying and evaluated for oxygen evolution reaction (OER) in alkaline media. Dealloying generates a bicontinuous nanoporous network while preserving metallic backbone integrity, yielding a monolithic, binder-free electrode. Microstructural and surface analyses reveal preferential iron dissolution, Cobalt and vanadium surface-enrichment, and formation of a stable Ti-Zr-Nb oxide framework. <i>Ex situ</i> X-ray photoelectron spectroscopy after electrochemical cycling confirms the emergence of cobalt (oxy)hydroxide and vanadium oxide, consistent with surface reconstruction in Co-based OER electrodes under anodic polarisation. Electrochemical testing demonstrates an overpotential of ~ 370 mV at 10&#xa0;mA cm⁻² and a Tafel slope of ~ 135 mV dec⁻¹, characteristic of charge-transfer-limited OER kinetics on dynamically reconstructed oxide surfaces. Electrochemically active surface area and turnover frequency were estimated from cobalt redox charge; however, these metrics remain model-dependent and represent apparent quantities for internal comparison. Rather than targeting record intrinsic activity, this work demonstrates metallurgically engineered HEAs as robust, self-supported electrocatalyst platforms, where activity arises from controlled surface reconstruction integrated with a stable nanoporous architecture.</p> Graphical Abstract <p></p>

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Nanoporous High-Entropy Alloy Electrodes Produced by Selective Dealloying: Microstructure, Surface Chemistry, and Proof-of-Concept OER Performance

  • 期刊论文

  • 发表日期：

    2026年3月16日

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  • Alberto Moreira Jorge Junior,
  • Yannick Champion,
  • Virginie Roche,
  • Remi Daudin,
  • Gregory Berthomé,
  • Marian Chatenet

摘要

Nanoporous high-entropy alloys (HEAs) represent promising electrocatalytic platforms combining compositional complexity, corrosion resistance, and mechanically robust, self-supported architectures. A Ti31V26Zr12Nb26Co5-based HEA electrode was fabricated via selective chemical dealloying and evaluated for oxygen evolution reaction (OER) in alkaline media. Dealloying generates a bicontinuous nanoporous network while preserving metallic backbone integrity, yielding a monolithic, binder-free electrode. Microstructural and surface analyses reveal preferential iron dissolution, Cobalt and vanadium surface-enrichment, and formation of a stable Ti-Zr-Nb oxide framework. Ex situ X-ray photoelectron spectroscopy after electrochemical cycling confirms the emergence of cobalt (oxy)hydroxide and vanadium oxide, consistent with surface reconstruction in Co-based OER electrodes under anodic polarisation. Electrochemical testing demonstrates an overpotential of ~ 370 mV at 10 mA cm⁻² and a Tafel slope of ~ 135 mV dec⁻¹, characteristic of charge-transfer-limited OER kinetics on dynamically reconstructed oxide surfaces. Electrochemically active surface area and turnover frequency were estimated from cobalt redox charge; however, these metrics remain model-dependent and represent apparent quantities for internal comparison. Rather than targeting record intrinsic activity, this work demonstrates metallurgically engineered HEAs as robust, self-supported electrocatalyst platforms, where activity arises from controlled surface reconstruction integrated with a stable nanoporous architecture.

Graphical Abstract