Multiscale porous Fe–N–C networks as highly efficient catalysts for the oxygen reduction reaction

Li, Ying; Liu, Tong; Yang, Wenxiu; Zhu, Zhijun; Zhai, Yanling; Gu, Wenling; Zhu, Chengzhou

doi:10.1039/c9nr05726a

Cited by 41 publications

(33 citation statements)

References 46 publications

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“…Superb electrocatalytic performance and satisfactory stability toward ORR could be exhibited in these synthesized M–N–C catalytic materials. , Li and group reported that metallic iron species existing in the electrocatalysts could promote the ORR reactive activity of the obtained Fe-N x sites by systematic experiments and theoretical analysis, revealing the reason for the source of activity of the as-synthesized Fe-N-C catalysts together with their prospects about for energy conversion system . In addition, the electroactivity of the M–N–C electrocatalysts could be significantly strengthened by the following strategies . One is designing appropriate active sites to increase the contact between active species and reactive substances and improve the utilization of active sites.…”

Section: Introductionmentioning

confidence: 99%

Dual-Template Construction of Iron–Nitrogen-Codoped Hierarchically Porous Carbon Electrocatalyst for Oxygen Reduction Reaction

et al. 2020

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The oxygen reduction reaction (ORR) is identified as a core issue in the technologies for convert energy, especially in proton-exchange membrane fuel cell (PEMFC). Highly reactive, low-cost, and durable electrocatalysts are ideal for the sluggish ORR. Herein, iron–nitrogen codoped hierarchically porous carbon (Fe-N-HPC-0.05) electrocatalytic material was prepared by a dual-template-assisted strategy. Upon accurate control of metal–organic framework (MOF) composition, Fe/Fe3C nanocrystals, FeN x , and N-doped carbon were produced. Fe-N-HPC-0.05 shows enhanced ORR performance in both alkaline and acidic conditions by taking advantage of the hierarchically porous structure and numerous active sites. In alkaline conditions, Fe-N-HPC-0.05 exhibited similar onset and half-wave potentials compared with 1.02 and 0.85 V for commercial Pt/C, respectively. In acidic conditions, Fe-N-HPC-0.05 possessed half-wave potential of 0.78 V, only 60 mV lower than that of Pt/C (0.84 V), indicating that the Fe-N-HPC-0.05 catalyst has application prospects in PEMFCs. This work also provides the design principle for increasing the ORR catalytic activity of hierarchically porous structure with exposed active sites.

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Section: Introductionmentioning

confidence: 99%

Dual-Template Construction of Iron–Nitrogen-Codoped Hierarchically Porous Carbon Electrocatalyst for Oxygen Reduction Reaction

et al. 2020

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“…Chitosan is a polysaccharide obtained from the deacetylation of chitin which is easily extracted from shrimp's shell [51]. Chitosan is biocompatible and was proved to be a useful material in a wide range of fields, such as food industry, water treatment [52], tissue engineering, medical area [53], supercapacitor [54], CO 2 hydrogenation [55], reduction of nitro compounds [56], batteries [57,58] and fuel cell devices [30,59,60]. Furthermore, chitosan is a suitable N-containing biopolymeric material with a high N content (7.1%) and jellifies by producing a self-template hydrogel precursor.…”

Section: Introductionmentioning

confidence: 99%

Highly Graphitized Fe-N-C Electrocatalysts Prepared from Chitosan Hydrogel Frameworks

et al. 2021

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The development of platinum group metal-free (PGM-free) electrocatalysts derived from cheap and environmentally friendly biomasses for oxygen reduction reaction (ORR) is a topic of relevant interest, particularly from the point of view of sustainability. Fe-nitrogen-doped carbon materials (Fe-N-C) have attracted particular interest as alternative to Pt-based materials, due to the high activity and selectivity of Fe-Nx active sites, the high availability and good tolerance to poisoning. Recently, many studies focused on developing synthetic strategies, which could transform N-containing biomasses into N-doped carbons. In this paper, chitosan was employed as a suitable N-containing biomass for preparing Fe-N-C catalyst in virtue of its high N content (7.1%) and unique chemical structure. Moreover, the major application of chitosan is based on its ability to strongly coordinate metal ions, a precondition for the formation of Fe-Nx active sites. The synthesis of Fe-N-C consists in a double step thermochemical conversion of a dried chitosan hydrogel. In acidic aqueous solution, the preparation of physical cross-linked hydrogel allows to obtain sophisticated organization, which assure an optimal mesoporosity before and after the pyrolysis. After the second thermal treatment at 900 °C, a highly graphitized material was obtained, which has been fully characterized in terms of textural, morphological and chemical properties. RRDE technique was used for understanding the activity and the selectivity of the material versus the ORR in 0.5 M H2SO4 electrolyte. Special attention was put in the determination of the active site density according to nitrite electrochemical reduction measurements. It was clearly established that the catalytic activity expressed as half wave potential linearly scales with the number of Fe-Nx sites. It was also established that the addition of the iron precursor after the first pyrolysis step leads to an increased activity due to both an increased number of active sites and of a hierarchical structure, which improves the access to active sites. At the same time, the increased graphitization degree, and a reduced density of pyrrolic nitrogen groups are helpful to increase the selectivity toward the 4e- ORR pathway.

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“…Chitosan is a polysaccharide obtained from the deacetylation of chitin which is easily extracted from shrimp's shell [53]. Chitosan is biocompatible and was proved to be a useful materials in a wide range of fields, such as food industry, water treatment [54], tissue engineering, medical area [55], supercapacitor [56] ,CO2 hydrogenation [57], reduction of nitro compounds [58], batteries [59,60] and fuel cell devices [32,61,62]. Furthermore, chitosan is a suitable N-containing biopolymeric material with a high N content (7.1%) and jellify producing a self-template hydrogel precursor.…”

Section: Introductionmentioning

confidence: 99%

Highly Graphitized Fe-N-C Electrocatalysts Prepared from Chitosan Hydrogel Frameworks

Daniel¹,

Kosmala²,

Brombin³

et al. 2021

Preprint

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The development of platinum group metal-free (PGM-free) electrocatalysts derived from cheap and environmentally friendly biomasses for oxygen reduction reaction (ORR) is a topic of relevant interest, particularly from the point of view of sustainability. Fe-nitrogen-doped carbon materials (Fe-N-C) have attracted particular interest as alternative to Pt-based materials, due to the high activity and selectivity of Fe-Nx active sites, the high availability and good tolerance to poisoning. Recently, many studies focused on developing synthetic strategies, which could transform N-containing biomasses into N-doped carbons. In this paper chitosan was employed as a suitable N-containing biomass for preparing Fe-N-C catalyst in virtue of its high N content (7.1%) and unique chemical structure. Moreover, the major application of chitosan is based on its ability to strongly coordinate metal ions, a precondition for the formation of Fe-Nx active sites. The synthesis of Fe-N-C consists in a double step thermochemical conversion of a dried chitosan hydrogel. In acidic aqueous solution, the preparation of physical cross-linked hydrogel allows to obtain sophisticated organization, which assure an optimal mesoporosity before and after the pyrolysis. After the second thermal treatment at 900 °C, a highly graphitized material was obtained, which has been fully characterized in term of textural, morphological and chemical properties. RRDE technique was used for understanding the activity and the selectivity of the material versus the ORR in 0.5 M H2SO4 electrolyte. Special attention was put in the determination of the active site density according to nitrite electrochemical reduction measurements. It was clearly established that the catalytic activity expressed as half wave potential linearly scales with the number of Fe-Nx sites. It was also established that the addition of the iron precursor after the first pyrolysis step leads to an increased activity because of both an increased number of active sites and of a hierarchical structure, which improves the access to active sites. At the same time, the increased graphitization degree, and a reduced density of pyrrolic nitrogen groups are helpful to increase the selectivity toward the 4e- ORR pathway.

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Multiscale porous Fe–N–C networks as highly efficient catalysts for the oxygen reduction reaction

Abstract: Dual-template method was proposed to synthesize multiscale porous Fe–N–C catalysts, which exhibited a superior ORR performance in comparison with that of commercial Pt/C.

Cited by 41 publications

References 46 publications

Dual-Template Construction of Iron–Nitrogen-Codoped Hierarchically Porous Carbon Electrocatalyst for Oxygen Reduction Reaction

Dual-Template Construction of Iron–Nitrogen-Codoped Hierarchically Porous Carbon Electrocatalyst for Oxygen Reduction Reaction

Highly Graphitized Fe-N-C Electrocatalysts Prepared from Chitosan Hydrogel Frameworks

Highly Graphitized Fe-N-C Electrocatalysts Prepared from Chitosan Hydrogel Frameworks

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