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<p>One of the key challenges in alkaline direct ethanol fuel cells (ADEFCs) is the sluggish kinetics of the anodic ethanol oxidation reaction (EOR) process. While mono-, bi-, and trimetallic catalysts have been employed to address this issue, high-entropy materials (HEMs) have attracted much attention as EOR electrocatalysts. Due to their multi-elemental compositions and unique high-entropy mixing states, HEMs offer tunable electrocatalytic activity and enhanced stability. These attributes arise from their intriguing quadruple effects: high entropy, lattice distortion, cocktail effect, and sluggish diffusion. Herein, we demonstrate, for the first time, the use of a high-entropy spinel oxide (CuMnFeNiCo)<sub>3</sub>O<sub>4</sub>, denoted HESOx, uniquely synthesized using a modified Pechini method for the electrocatalytic EOR. The HESOx was decorated with palladium nanoparticles with Vulcan carbon as a support to form Pd-HESOx/C electrocatalyst. After spectroscopic and microscopic characterization, the material was tested for EOR and showcased excellent electroactivity with a mass activity of 3486.5 mAcm<sup>−1</sup><sub>Pd</sub>, outperforming the commercial counterpart Pd/C (2&#xa0;224.8 mAcm<sup>−1</sup><sub>Pd</sub>) at a lower onset potential. The material also demonstrated excellent durability, retaining mass activity above 90% after 500 cyclic voltammetry scans and higher residual mass activity after 4&#xa0;h of chronoamperometry. Density functional calculations revealed that Pd-HESOx/C reduces the energy barriers for both C–C bond cleavage and C–O coupling while facilitating easier removal of poisonous CO. Overall, the results indicate that Pd-HESOx/C holds promise to serve as a high-performing and durable anode material for alkaline direct ethanol fuel cells.</p> Graphical Abstract <p></p>

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Electronic modulation of palladium nanocatalysts supported on high-entropy spinel oxides for enhanced ethanol oxidation reaction

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年10月21日

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  • Colani T. Fakude,
  • Aderemi B. Haruna,
  • Patrick V. Mwonga,
  • Thapelo P. Mofokeng,
  • Kenneth I. Ozoemena

摘要

One of the key challenges in alkaline direct ethanol fuel cells (ADEFCs) is the sluggish kinetics of the anodic ethanol oxidation reaction (EOR) process. While mono-, bi-, and trimetallic catalysts have been employed to address this issue, high-entropy materials (HEMs) have attracted much attention as EOR electrocatalysts. Due to their multi-elemental compositions and unique high-entropy mixing states, HEMs offer tunable electrocatalytic activity and enhanced stability. These attributes arise from their intriguing quadruple effects: high entropy, lattice distortion, cocktail effect, and sluggish diffusion. Herein, we demonstrate, for the first time, the use of a high-entropy spinel oxide (CuMnFeNiCo)3O4, denoted HESOx, uniquely synthesized using a modified Pechini method for the electrocatalytic EOR. The HESOx was decorated with palladium nanoparticles with Vulcan carbon as a support to form Pd-HESOx/C electrocatalyst. After spectroscopic and microscopic characterization, the material was tested for EOR and showcased excellent electroactivity with a mass activity of 3486.5 mAcm−1Pd, outperforming the commercial counterpart Pd/C (2 224.8 mAcm−1Pd) at a lower onset potential. The material also demonstrated excellent durability, retaining mass activity above 90% after 500 cyclic voltammetry scans and higher residual mass activity after 4 h of chronoamperometry. Density functional calculations revealed that Pd-HESOx/C reduces the energy barriers for both C–C bond cleavage and C–O coupling while facilitating easier removal of poisonous CO. Overall, the results indicate that Pd-HESOx/C holds promise to serve as a high-performing and durable anode material for alkaline direct ethanol fuel cells.

Graphical Abstract