Self- supported high-entropy alloy electrocatalyst for highly efficient H2 evolution in acid condition

• Main Authors: Peiyan Ma, Mingming Zhao, Long Zhang, Heng Wang, Junfeng Gu, Yuchen Sun, Wei Ji, Zhengyi Fu
• Format: Article
• Language: English
• Published: Elsevier 2020-12-01
• Series: Journal of Materiomics
• Subjects: High-entropy alloy; Hydrogen evolution reaction; Electrocatalysts; Acidic electrolyte; Stability
• Online Access: http://www.sciencedirect.com/science/article/pii/S2352847820301544

Developing non-precious catalysts as Pt substitutes for electrochemical hydrogen evolution reaction (HER) with superior stability in acidic electrolyte is of critical importance for large-scale, low-cost hydrogen production from water. Herein, we report a CoCrFeNiAl high-entropy alloy (HEA) electrocatalyst with self-supported structure synthesized by mechanical alloying and spark plasma sintering (SPS) consolidation. The HEA after HF treatment and in situ electrochemical activation for 4000 cycles of cyclic voltammetry (HF-HEAa2) presents favourable activity with overpotential of 73 mV to reach a current density of 10 mA cm−2 and a Tafel slope of 39.7 mV dec−1. The alloy effect of Al/Cr with Co/Fe/Ni at atomic level, high-temperature crystallization, as well as consolidation by SPS endow CoCrFeNiAl HEA with high stability in 0.5 M H2SO4 solution. The superior performance of HF-HEAa2 is related with the presence of metal hydroxides/oxides groups on HEA.