Monodisperse and Tiny Co2N0.67 Nanocrystals Uniformly Embedded over Two Curving Surfaces of Hollow Carbon Microfibers as Efficient Electrocatalyst for Oxygen Evolution Reaction

Rational design of highly efficient electrocatalysts for oxygen evolution reaction (OER) is critical for both water splitting and rechargeable metal–air batteries. Especially, developing excellent earth-abundant catalysts for OER is an ongoing challenge. We report a series of cobalt nitride (Co2N0.67)–carbon composites with different textural properties as high-activity OER materials herein. Experimental results demonstrate that the specific morphologies of different carbon matrices (such as carbon nanotubes (CNTs), graphene (GN), macroporous carbons (MPCs), and hollow carbon microfibers (CMFs)) play crucial roles in determining the overall OER catalytic efficacies of corresponding composites. Both SEM and TEM characterization results revealed that monodisperse and tiny Co2N0.67 nanoparticles (NPs) indeed grew uniformly over both the inner and outer walls of CMFs because of the widespread edges and defect sites. This is beneficial to fully expose and utilize active sites on each Co2N0.67 NP. In addition, ...