3D CNTs-threaded N-doped hierarchical porous carbon hybrid with embedded Co/CoO x nanoparticles as efficient bifunctional catalysts for oxygen electrode reactions

摘要

Developing an efficient non-precious metal catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in regenerative energy conversion and storage devices is very imperative but still challenging. Herein, a three-dimensional (3D) hierarchical porous Co/CoOxnanoparticles embedded N-doped carbon hybrid threaded with carbon nanotubes (Co/CoOx@NC-CNTs) was prepared viain situthreading CNTs through ZIF-67 polyhedron and a succedent carbonation process. Compared to those of commercial electrocatalysts (Pt/C and RuO2), the as-prepared hybrid showed comparable electrocatalytic activity with positive ORR half-wave potential (E1/2) of 0.836?V, low OER potential (Ej=10?=?1.62?V), good methanol tolerance and excellent electrocatalytic stability. Moreover, the small overpotential difference value (ΔE?=?Ej=10-E1/2) of 0.784?V is competitive to those of recent reported outstanding bifunctional oxygen electrocatalysts. The high electrocatalytic properties of the Co/CoOx@NC-CNTs hybrid are attributed to the synergistic effect of high surface area, desirable pore structure and reasonable chemical composition.