Controllable synthesis of CoN3 catalysts derived from Co/Zn-ZIF-67 for electrocatalytic oxygen reduction in acidic electrolytes
Author(s)
Lai, Shoujuan
Xu, Li
Liu, Hongli
Chen, Shuai
Cai, Rongsheng
Zhang, Lijie
Theis, Wolfgang
Sun, Jin
Yang, Dongjiang
Zhao, Xiaoliang
Griffith University Author(s)
Year published
2019
Metadata
Show full item recordAbstract
Metal nitrides have attracted significant attention due to their noble metal-like electron features; however, their applications are still limited by numerous predicaments in their synthesis owing to their large bond enthalpy and high ionization potential, which is generally implemented under extra-high pressure and temperature. Herein, the controllable synthesis of CoN3 nanoparticles embedded in graphite carbon was successfully achieved through the in situ pyrolysis of a Co/Zn-ZIF-67 (ZIF, zeolitic imidazolate framework) precursor (Co/Zn molar ratio ranging from 5/95 to 9/91 in Zn-ZIF-67 crystals). During the pyrolysis, the ...
View more >Metal nitrides have attracted significant attention due to their noble metal-like electron features; however, their applications are still limited by numerous predicaments in their synthesis owing to their large bond enthalpy and high ionization potential, which is generally implemented under extra-high pressure and temperature. Herein, the controllable synthesis of CoN3 nanoparticles embedded in graphite carbon was successfully achieved through the in situ pyrolysis of a Co/Zn-ZIF-67 (ZIF, zeolitic imidazolate framework) precursor (Co/Zn molar ratio ranging from 5/95 to 9/91 in Zn-ZIF-67 crystals). During the pyrolysis, the Co/Zn-ZIF-67 precursor was first converted into Co nanoparticles (NPs) embedded in N-doped porous carbon (Co@NC), accompanied by the release of NH3 from the decomposition of the ZIF structure. The abundant micropores formed by the evaporation of Zn and large surface area of Co@NC facilitate the contact between NH3 molecules and Co, generating CoN3 species. Importantly, when the CoN3@NC-7-1000 sample was evaluated as an electrocatalyst for the oxygen reduction reaction (ORR), it exhibited high performance with a positive half-wave potential (0.72 V vs. RHE) and a high current density (5.40 mA cm-2) in the 0.5 M H2SO4 electrolyte. According to the density functional theory (DFT) calculation, the exposed (220) facet of CoN3 with a low energy barrier can benefit the adsorption of O2 molecules.
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View more >Metal nitrides have attracted significant attention due to their noble metal-like electron features; however, their applications are still limited by numerous predicaments in their synthesis owing to their large bond enthalpy and high ionization potential, which is generally implemented under extra-high pressure and temperature. Herein, the controllable synthesis of CoN3 nanoparticles embedded in graphite carbon was successfully achieved through the in situ pyrolysis of a Co/Zn-ZIF-67 (ZIF, zeolitic imidazolate framework) precursor (Co/Zn molar ratio ranging from 5/95 to 9/91 in Zn-ZIF-67 crystals). During the pyrolysis, the Co/Zn-ZIF-67 precursor was first converted into Co nanoparticles (NPs) embedded in N-doped porous carbon (Co@NC), accompanied by the release of NH3 from the decomposition of the ZIF structure. The abundant micropores formed by the evaporation of Zn and large surface area of Co@NC facilitate the contact between NH3 molecules and Co, generating CoN3 species. Importantly, when the CoN3@NC-7-1000 sample was evaluated as an electrocatalyst for the oxygen reduction reaction (ORR), it exhibited high performance with a positive half-wave potential (0.72 V vs. RHE) and a high current density (5.40 mA cm-2) in the 0.5 M H2SO4 electrolyte. According to the density functional theory (DFT) calculation, the exposed (220) facet of CoN3 with a low energy barrier can benefit the adsorption of O2 molecules.
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Journal Title
Journal of Materials Chemistry A
Volume
7
Issue
38
Subject
Macromolecular and Materials Chemistry
Materials Engineering
Interdisciplinary Engineering
Science & Technology
Physical Sciences
Chemistry, Physical
Energy & Fuels