CoNi nanoalloys embedded in N-doped carbon nanofibers derived from layered bimetal-organic framework and as efficient oxygen electrocatalyst

Abstract

Developing efficient and low-cost bifunctional catalysts towards oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is a significant scientific issue in establishing renewable energy systems. Herein, we propose a bifunctional oxygen electrocatalyst derived from a bimetal-organic framework. Two-dimensional (2-D) CoNi-BDC (BDC = benzenedicarboxylic acid) was synthesized via an bottom-up approach (improved inter-diffusion route). Lamellar CoNi nanoalloys embedded in N-doped carbon nanofibers (CoNi-N-CNFs) were obtained by electrospinning CoNi-BDC and dicyandiamide (DCD) into a polyacrylonitrile (PAN) polymer and subsequent post-calcination treatment. By taking advantage of the synergetic interactions between CoNi nanoalloys and N-doped carbon, the as-synthesized CoNi-N-CNFs catalysts exhibited outstanding catalytic performance with respect to the OER and ORR. CoNi-N-CNFs-60 exhibited a low overpotential of 229 mV at 10 mA cm−2 and a half-wave potential of 0.823 V in 1 M KOH, making it a promising candidate as an efficient air electrode in Zn-air battery. The hierarchical 1-D/2-D composite structure and porous morphology play a key role in improving electrocatalytic performance by exposing a greater number of active CoNi-N sites.