Key Words:GRAPHENE NANOSHEETS; QUANTUM DOTS; DOPED CARBON; EVOLUTION; PERFORMANCE; CATALYST; NI; NANOSTRUCTURES; COMPOSITES; ABSORPTION

Abstract:Owing to sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), it is still challenging to rationally design and construct bifunctional electrocatalysts with high performance, low-cost and good stability to substitute precious-metal catalysts. Herein, we introduce Ni ions to obtain spherical Prussian blue analog (PBA) doped with Co/Fe/Ni and further to synthesize nitrogen and Co/Fe/Ni co-doped carbon nanotubes (denoted as CoFeNi-CNTs) with small diameters (20-30 nm) by pyrolyzing the mixture of melamine and PBA. The optimized CoFeNi-CNTs have abundant metal-nitrogen-carbon (M-N-C) structures and CoFeNi nanoparticles respectively as effective ORR and OER active sites, which lead to outstanding electrocatalytic activities and durability with a half-wave potential of 0.85 V for ORR and an overpotential of 440 mV for OER. Especially, the rechargeable Zn-air battery based on CoFeNi-CNTs catalyst delivers a high peak power density of 138.7 mW cm(-2), specific capacity of 793 mAh g(Zn)(-1) and stable charge-discharge cycling over 500 h, outperforming the Pt/C-RuO2 based devices. And all-solid-state Zn-air battery also displays excellent discharge-charge performance and stability. This work explores the optimization of oxygen catalytic activity for carbon nanotubes by reducing diameters and constructing dual-active-sites strategy. (C) 2022 Elsevier B.V. All rights reserved.

Volume:910

Issue:无

Translation or Not:no