Redox-Inert Fe3+ Ions in Octahedral Sites of Co-Fe Spinel Oxides with Enhanced Oxygen Catalytic Activity for Rechargeable Zinc-Air Batteries.
Xiao-Tong WangTing OuyangLing WangJia-Huan ZhongTianyi MaZhao-Qing LiuPublished in: Angewandte Chemie (International ed. in English) (2019)
Bimetallic cobalt-based spinel is sparking much interest, most notably for its excellent bifunctional performance. However, the effect of Fe3+ doping in Co3 O4 spinel remains poorly understood, mainly because the surface state of a catalyst is difficult to characterize. Herein, a bifunctional oxygen electrode composed of spinel Co2 FeO4 /(Co0.72 Fe0.28 )Td (Co1.28 Fe0.72 )Oct O4 nanoparticles grown on N-doped carbon nanotubes (NCNTs) is designed, which exhibits superior performance to state-of-the-art noble metal catalysts. Theoretical calculations and magnetic measurements reveal that the introduction of Fe3+ ions into the Co3 O4 network causes delocalization of the Co 3d electrons and spin-state transition. Fe3+ ions can effectively activate adjacent Co3+ ions under the action of both spin and charge effect, resulting in the enhanced intrinsic oxygen catalytic activity of the hybrid spinel Co2 FeO4 . This work provides not only a promising bifunctional electrode for zinc-air batteries, but also offers a new insight to understand the Co-Fe spinel oxides for oxygen electrocatalysis.
Keyphrases
- metal organic framework
- aqueous solution
- carbon nanotubes
- quantum dots
- highly efficient
- visible light
- density functional theory
- room temperature
- dna methylation
- gene expression
- mass spectrometry
- single molecule
- solid state
- optical coherence tomography
- molecular dynamics simulations
- molecularly imprinted
- liquid chromatography
- oxide nanoparticles
- electron transfer