Richa Singhal, Vibha Kalra

Efficient, low cost, non-precious metal based, and stable bifunctional electrocatalysts are key to various energy storage and conversion devices such as regenerative fuel cells and metal-air batteries. In this work, we report cobalt nanoparticle-embedded porous carbon nanofibers with inherent N- and F- doping as binder-free bifunctional electrocatalysts with excellent activity for both oxygen reduction and evolution reactions (ORR/OER) in alkaline medium. Single-step electrospinning of a solution of selected polymer mixture (carbon precursor) and the cobalt precursor followed by controlled pyrolysis with an intermediate reduction step in H2 (to reduce cobalt oxides to cobalt) was utilized to synthesize an integrated freestanding catalyst. The fabricated catalyst with effective structural and electronic interaction between the cobalt metal nanoparticles and the N- and F-doped carbon defect sites showed enhanced catalytic properties compared to the benchmark catalysts for ORR and OER (Pt, Ir, and Ru). The ORR potential at the current density of -3 mA cm-2 was 0.81 VRHE and the OER potential at a current density of 10 mA cm-2 was 1.595 VRHE, resulting in a ∆E of only 0.785V.