Mesoporous waffle-like N-doped carbon with embedded Co nanoparticles for efficiently electrocatalytic oxygen reduction and evolution

Rational design and facile preparation of high-performance carbon-based eletrocatalysts for both oxygen reduction and evolution reactions (ORR and OER) is crucial for practical applications of rechargeable zinc -air batteries. Inspired by the fact that the metallic Co catalysis on the formation of carbon nanotubes (CNTs), this work develops a facial compression-pyrolysis route to synthesize a mesoporous waffle-like N-doped carbon framework with embedded Co nanoparticles (Co@pNC) using a Co metal-organic frame-work and melamine as precursors. The unique porous waffle-like carbon framework is built up of inter-woven N-doped CNTs and graphene nanosheets, which offers abundant catalytic-active sites and rapid diffusion channels for intermediates and electrolyte. The optimized Co@pNC shows excellent bifunctional ORR/OER electrocatalytic activity in alkaline media with a half-wave potential (E1/2) of 0.85 V for ORR and a small potential gap of 0.70 V between ORR E1/2 and OER potential at 10 mA cm-2. Its assembled battery exhibits a peak power density up to 150.3 mW cm-2, an energy density of 928 Wh kgZn-1and superb rate capability. It highlights a facile component and architecture strategy to design high-performance carbon -based eletrocatalysts. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

Rational design and facile preparation of Co@pNC, a mesoporous waffle-like N-doped carbon framework with embedded Co nanoparticles, exhibit excellent bifunctional ORR/OER electrocatalytic activity. The Co@pNC shows a half-wave potential of 0.85 V for ORR and a small potential gap of 0.70 V between ORR E1/2 and OER potential at 10 mA cm-2. The assembled battery using Co@pNC demonstrates high peak power density, energy density, and superb rate capability, highlighting the importance of a facile component and architecture strategy for high-performance carbon-based electrocatalysts.