N-doped graphitic carbon shell-encapsulated FeCo alloy derived from metal-polyphenol network and melamine sponge for oxygen reduction, oxygen evolution, and hydrogen evolution reactions in alkaline media.

ABSTRACT

Exploiting low cost and durable electrocatalysts with high efficiency for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) is of great significance for energy conversion and storage applications. Herein, a hybrid electrocatalyst of FeCo alloy nanoparticles embedded in a porous N-doped carbon was prepared via a pyrolysis process of low-cost melamine sponge and mass-produced metal-polyphenol network. Benefting from the metal coordination of metal-polyphenol network and abundant N source of melamine sponge, the metal-N moiety and FeCo alloy nanoparticles (wtih a diameter around 50 nm) encapsulated in a N-doped graphene-like carbon layer were formed in-situ. Such intimate integration of graphene-like carbon-encapsulated FeCo alloys, metal-N active species, and porous structure is conducive to improve the catalytic activity and increase the catalytic durability in alkaline media. As a consequence, the as-prepared electrocatalyst exhibits the pronounced activity toward ORR, OER, and HER simultaneously under alkaline condition, particularly on the performances of potential, stability, and methanol tolerance.