A high-efficiency noble metal-free electrocatalyst of cobalt-iron layer double hydroxides nanorods coupled with graphene oxides grown on a nickel foam towards methanol electrooxidation

The main challenges to the direct methanol fuel cell (DMFC) are the limited catalytic activity and durability of electrocatalysts. Developing active, cost-effective and stable electrocatalysts with earth-abundant metals (Fe, Co, Ni) is a prerequisite to boost the commercial application of DMFCs. Herein, cobalt-iron layer double hydroxides (CoFe-LDH) nanorods coupled with graphene oxides (GO) are directly synthesized on Nickel foam (NF), which are used directly as a noble metal-free electrocatalyst for methanol oxidation reaction (MOR). Among the as-synthesized noble metal-free CoFe-LDH/GO/NF electrocatalysts, Co2Fe1-LDH/GO/NF exhibits a high electrochemical activity of 490.88 mA cm(-2) in alkaline solution. The prolong Cyclic voltammograms (CVs) scanning (over 500 cycles) verifies that the Co2Fe1-LDH/GO/NF electrode achieves a better overall performance and stability with only 3% decay than that of Co1Fe1-LDH/GO/NF and Co3Fe1-LDH/GO/NF for MOR. The excellent electrocatalytic activity of Co2Fe1-LDH/GO/NF is attributed to high exposed surface active sites, abundant oxygen vacancies, and efficient electron transfer between the electrocatalyst and the electrode surface. This study about the noble metal-free electrocatalyst may provide a new idea to improve the electrocatalytic activity for MOR. (C) 2020 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.