1. Understanding the Structural Evolution of IrFeCoNiCu High-Entropy Alloy Nanoparticles under the Acidic Oxygen Evolution Reaction
- Author
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Maulana, Arifin Luthfi, Chen, Peng-Cheng, Shi, Zixiao, Yang, Yao, Lizandara-Pueyo, Carlos, Seeler, Fabian, Abruña, Héctor D, Muller, David, Schierle-Arndt, Kerstin, and Yang, Peidong
- Subjects
Nanotechnology ,Bioengineering ,high-entropy alloy ,acidic OER ,structuralevolution ,dissolution ,structural evolution ,Nanoscience & Nanotechnology - Abstract
High-entropy alloy (HEA) nanoparticles are promising catalyst candidates for the acidic oxygen evolution reaction (OER). Herein, we report the synthesis of IrFeCoNiCu-HEA nanoparticles on a carbon paper substrate via a microwave-assisted shock synthesis method. Under OER conditions in 0.1 M HClO4, the HEA nanoparticles exhibit excellent activity with an overpotential of ∼302 mV measured at 10 mA cm-2 and improved stability over 12 h of operation compared to the monometallic Ir counterpart. Importantly, an active Ir-rich shell layer with nanodomain features was observed to form on the surface of IrFeCoNiCu-HEA nanoparticles immediately after undergoing electrochemical activation, mainly due to the dissolution of the constituent 3d metals. The core of the particles was able to preserve the characteristic homogeneous single-phase HEA structure without significant phase separation or elemental segregation. This work illustrates that under acidic operating conditions, the near-surface structure of HEA nanoparticles is susceptible to a certain degree of structural dynamics.
- Published
- 2023