Bulk CoCrFeNiAlMo high entropy alloy as high-efficient electrocatalyst in alkaline environment

Abstract

Developing cost-efficient catalysts with high efficiency for water splitting has been considered as large challenge. Herein, the bulk high entropy alloys (HEAs) are fabricated through the vacuum induction melting, which could be beneficial to solving the above issues. At the same time, it also enhances the electrocatalysts activity and stability. The alloy composition is discovered to be crucial in the both hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) activity enhancements with the CoCrFeNiAlMo bulk HEA catalyst combination providing the exceptional catalytic activities. Forming the CoCrFeNiAlMo bulk HEA catalyst also significantly promotes the electrocatalytic cycling stabilities. Hence, the CoCrFeNiAlMo bulk HEA catalyst displays a small overpotential (261 mV @ 50 mA cm-2) and a corresponding Tafel slope (48.66 mV dec-1) for the OER in a 1.0 M KOH electrolyte. For HER, CoCrFeNiAlMo bulk HEA catalyst also possess a relatively small overpotential. Furthermore, it exhibits a relatively small cell voltage of 1.83 V at 50 mA cm-2 and superior durable for 14 h. This study presents a universal pathway for preparing sustainable high efficiency electrocatalysts, it demonstrates that the bulk HEAs have the potential to be effective catalysts in alkaline environments.