CoNi/MoC nanoparticles entrapped into N, P-codoped carbon nanotubes-on-nanosheets: A synergy of 1D@2D heterostructures with multiple active sites for rechargeable Zn-air battery

Abstract

Researches of bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are crucial in development of liquid metal-air batteries. Herein, a simple one-step method is developed for carbonizing the metal precursors and dicyandiamide to prepare CoNi/MoC nanoparticles incorporated into N, P-codoped carbon nanotubes-on-nanosheets (CoNi/MoC-NP-CTS). Benefiting from the unique sheet-like architectures with regular nanotubes and the synergistic effect of multi-components, the resultant CoNi/MoC-NP-CTS shows the positive half-wave potential of 0.89 V (vs. RHE) and small Tafel slope of 51.1 mV dec−1 for ORR, coupled by the enhanced OER performance with an overpotential of 335 mV at 10 mA cm−2. More notably, the CoNi/MoC-NP-CTS-based Zn-air battery exhibits largely higher power density (132 mW cm−2) than commercial Pt/C + RuO2-based battery (80 mW cm−2), together with the outstanding cycling durability (480 cycles, 160 h). This work opens a new avenue to design and construct advanced non-precious-metal electrocatalysts in metal-air batteries.