The synergistic effects of alloying on the performance and stability of Co3Mo and Co7Mo6 for the electrocatalytic hydrogen evolution reaction

Sun, Y. and Ganin, A. Y. (2020) The synergistic effects of alloying on the performance and stability of Co3Mo and Co7Mo6 for the electrocatalytic hydrogen evolution reaction. Hydrogen, 1(1), pp. 11-21. (doi: 10.3390/hydrogen1010002)

Abstract

Metal alloys have become a ubiquitous choice as catalysts for electrochemical hydrogen evolution in alkaline media. However, scarce and expensive Pt remains the key electrocatalyst in acidic electrolytes, making the search for earth-abundant and cheaper alternatives important. Herein, we present a facile and efficient synthetic route towards polycrystalline Co3Mo and Co7Mo6 alloys. The single-phased nature of the alloys is confirmed by X-ray diffraction and electron microscopy. When electrochemically tested, they achieve competitively low overpotentials of 115 mV (Co3Mo) and 160 mV (Co7Mo6) at 10 mA cm−2 in 0.5 M H2SO4, and 120 mV (Co3Mo) and 160 mV (Co7Mo6) at 10 mA cm−2 in 1 M KOH. Both alloys outperform Co and Mo metals, which showed significantly higher overpotentials and lower current densities when tested under identical conditions, confirming the synergistic effect of the alloying. However, the low overpotential in Co3Mo comes at the price of stability. It rapidly becomes inactive when tested under applied potential bias. On the other hand, Co7Mo6 retains the current density over time without evidence of current decay. The findings demonstrate that even in free-standing form and without nanostructuring, polycrystalline bimetallic electrocatalysts could challenge the dominance of Pt in acidic media if ways for improving their stability were found.

• Item Type: Articles
• Additional Information: Parts of this research was funded by The Carnegie Trust for a Research Incentive Grant (RIG007428). China Scholarship Council (CSC) funded the CSC scholarship to Y.S.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Ganin, Dr Alexey and Sun, Youyi
• Authors: Sun, Y., and Ganin, A. Y.
• College/School: College of Science and Engineering > School of Chemistry; College of Science and Engineering > School of Engineering
• Journal Name: Hydrogen
• Publisher: MDPI
• ISSN: 2673-4141
• ISSN (Online): 2673-4141
• Copyright Holders: Copyright © 2020 The Authors
• First Published: First published in Hydrogen 1(1):11-21
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
302151		Development of basal-plane active layered transition metal dichalcogenides for electrocatalytic hydrogen evolution reactions	Alexey Ganin	The Carnegie Trust for the Universities of Scotland (CARNEGTR)	RIG007428	Chemistry