Self-Supported ZIF-Derived Co3O4 Nanoparticles-Decorated Porous N-Doped Carbon Fibers as Oxygen Reduction Catalyst

Oxygen reduction is a significant cathodic reaction in the state-of-art clean energy devices such as fuel cell and metal-oxygen battery. Here, ZIF-incorporated hybrid polymeric fibres have been fabricated by using a dual-phase electrospinning method. These are then transformed into Co3O4-nanoparticle-decorated porous N-doped carbon fibres (ZIF-Co3O4/NCF) through multi-step annealing treatment. The resultant ZIF-Co3O4/NCF is interweaved into a self-supported film and can be used as a bi-functional catalyst for catalysing oxygen reduction in both aqueous and non-aqueous electrolytes. Electrochemical tests demonstrate that ZIFCo(3)O(4)/NCF displays a high catalytic activity for oxygen re-duction with a half-wave potential (E1/2) of 0.813 V (vs. RHE) and an almost favourable four-electron reduction pathway in alkaline medium. ZIF-Co3O4/NCF catalyst only shows 4 mV negative shift of E(1/)2 after 5000 continuous CV cycles. In addition, the ZIF-Co3O4/NCF can be applied as the cathode catalyst of non-aqueous Li-O-2 battery, exhibiting a remarkable ORR activity in LiPF6 contained 1,2-dimethoxyethane electrolyte. The excellent electrocatalytic performance of ZIF-Co3O4/ NCF is probably due to the abundance of active sites of graphitic carbon-wrapped Co3O4 nanoparticles, as well as the cross-linked fibrous nitrogen-doped carbon texture.