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Synthesis of N-doped Co@C/CNT materials based on ZIF-67 and their electrocatalytic performance for oxygen reduction.
- Source :
- Ionics; Jun2021, Vol. 27 Issue 6, p2561-2569, 9p
- Publication Year :
- 2021
-
Abstract
- ZIF-67/CNT materials are prepared by using in situ growth method with cobalt nitrate and 2-methylimidazole (2-MI) as raw materials, polyvinyl pyrrolidone (PVP) as complexing agents. A series of N-Co@C/CNT catalysts are prepared through heating ZIF-67/CNT in N<subscript>2</subscript> atmosphere. The effects of additional proportion of CNT on the catalytic performance of N-Co@C/CNT catalysts for oxygen reduction reaction (ORR) are studied. The chemical states of the materials, micro-morphology, elemental composition, and crystalline structure are analyzed by X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). The results show that polyhedral ZIF-67 has grown on the surfaces of CNTs. After heat treatment, ZIF-67/CNT transforms to N-Co@C/CNT. The particle size of Co is 10–20 nm. N-Co@C/CNT-2.6 shows the best catalytic performance for ORR in alkaline solution with the onset potential of 0.94 V, half-wave-potential of 0.83 V, and limiting diffusion current density of 5.6 mA cm<superscript>−2</superscript>. The ORR on N-Co@C/CNT proceeds through a four-electron path and the yield of H<subscript>2</subscript>O<subscript>2</subscript> is 12%, which is close to Pt/C. N-Co@C/CNT shows higher methanol-tolerant ability than Pt/C. The addition of CNT makes N-Co@C expose more active sites. CNT plays an important role in connecting different N-Co@C particles and enhancing the electron conductivity. The contents of graphitic nitrogen and pyridine nitrogen in N-Co@C/CNT-2.6 catalysts are 15.8% and 38.6%, respectively, which are higher than those in N-Co@C (7% and 34%). [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09477047
- Volume :
- 27
- Issue :
- 6
- Database :
- Complementary Index
- Journal :
- Ionics
- Publication Type :
- Academic Journal
- Accession number :
- 150452604
- Full Text :
- https://doi.org/10.1007/s11581-021-04031-y