Pulse electrodeposited FeCoNiMnW high entropy alloys as efficient and stable bifunctional electrocatalysts for acidic water splitting

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 446; p. 137452
• Main Authors: Chang, Shun-Qin, Cheng, Chih-Chieh, Cheng, Po-Yin, Huang, Chun-Lung, Lu, Shih-Yuan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.10.2022
• Subjects: Acidic electrolytic water splitting; Bifunctional catalyst; High Entropy Alloy; Hydrogen evolution reaction; Oxygen evolution reaction; High Entropy Alloy; Hydrogen evolution reaction; Bifunctional catalyst; Oxygen evolution reaction; Acidic electrolytic water splitting
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.137452

A non-precious high entropy alloy H-FeCoNiMnW, grown in-situ on carbon paper with a pulse current electrodeposition, is developed as an efficient and a stable bi-functional electrocatalyst for acidic electrolytic water splitting. [Display omitted] •A non-precious metal based electrocatalyst is developed for acidic water splitting.•FeCoNiMnW high entropy alloy is designed based on volcano plots for HER and OER.•FeCoNiMnW shows ultralow η10 of 15 mV for HER and reasonable η10 of 512 mV for OER.•Good overall water splitting stability is exhibited at 10 mA cm−2 for 6 days. High entropy alloys, possessing unique advantages of atomic scale synergy between multi-constituents, can be suitably designed to fulfill requirements of both activity and stability. Herein, a pulse current electrodeposition method is developed to grow a high entropy FeCoNiMnW alloy (H-FeCoNiMnW) in-situ on carbon papers to serve as an efficient robust bi-functional catalyst for acidic electrolytic water splitting. It exhibits an extraordinarily low overpotential of 15 mV and a serviceable overpotential of 512 mV for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, both at 10 mA cm−2. The H-FeCoNiMnW//H-FeCoNiMnW couple delivers a current density of 10 mA cm−1 at 1.76 V for overall water splitting, and exhibits outstanding stability, a less than 10% increase in cell voltages after a 6-day operation. Tungsten in H-FeCoNiMnW forms a surface protection oxide layer during the water splitting, rendering the outstanding catalytic stability of H-FeCoNiMnW in acidic media.