Durable Ni3N porous nanosheets array for non-noble metal methanol oxidation reaction

Abstract

Direct methanol fuel cells (DMFCs) are energy carriers with a significant high energy density, easy implementation, a low operating temperature, and a convenient methanol fuel storage, rendering them a reasonable alternative for portable applications. However, there are several substantial barriers to the widespread use of DMFCs that must be addressed. Noble metal-based catalysts have long been regarded as outstanding electrocatalysts for fuel cells, but their high cost and low durability have kept them from becoming widely used. Nickel-based electrocatalysts are possible replacements for expensive noble metal catalysts owing to their low price, high durability, and remarkable surface oxidation properties. Herein, we develop an incredibly active and remarkably stable electrocatalyst for the methanol oxidation reaction (MOR) via a simple hydrothermal method coupled with nitridation to prepare highly porous Ni3N nanosheets arrays supported by nickel foam (NF) substrate. The in situ growth of highly porous nanosheets on NF (NSAs/NF) exposes more active sites and allows fast charge/mass transfer, creating synergistic effects between Ni3N and NF. As a result, the strong interaction between Ni3N and NF prevents leaching and renders the catalyst highly stable for over 20 h with a 72.58% retention rate, making it among the best retention rates reported recently for comparable Ni-based catalysts. Based on these findings, nickel nitride appears to be an excellent electrocatalyst for fuel cell applications.