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Abstract:
The rational control of the active site of metal-organic frameworks (MOFs) derived nanomaterials is essential to build efficient bifunctional oxygen reduction/evolution reaction (ORR/OER) catalysts. Accordingly, through designing and constructing a Co3O4-Co heterostructure embedded in Co, N co-doped carbon polyhedra derived (Co3O4-Co@NC) from the in-situ compositions of ZIF-67 and cobalt nanocrystals synthesized by the strategy of in-situ NaBH4 reduction, the dual-active site (Co3O4-Co and Co-N-x) is synchronously realized in a MOFs derived nanomaterials. The formed Co3O4-Co@NC shows excellent bifunctional electrocatalytic activity with ultra-small potential gap (Delta E = E-j=10 (OER) - E-1/2 (ORR)) of 0.72 V, which surpasses the commercial Pt/C and RuO2 catalysts. The theory calculation results reveal that the excellent bifunctional electrocatalytic activity can be attributed to the charge redistribution of Co of Co-N-x induced by the synergistic effects of well-tuned active sites of Co3O4-Co nanoparticle and Co-N-x, thus optimizing the rate-determining step of the desorption of O-2* intermediate in ORR and OH* intermediate in OER. The rechargeable Zn-air batteries with our bifunctional catalysts exhibit superior performance as well as high cycling stability. This simple-effective optimization strategy offers prospects for tuning the active site of MOF derived bifunctional catalyst in electrochemical energy devices.
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NANO RESEARCH
ISSN: 1998-0124
Year: 2020
Issue: 7
Volume: 14
Page: 2353-2362
8 . 8 9 7
JCR@2020
9 . 6 0 0
JCR@2023
ESI Discipline: PHYSICS;
ESI HC Threshold:115
JCR Journal Grade:1
CAS Journal Grade:1
Affiliated Colleges: