Non-precious Melamine/Chitosan Composites for the Oxygen Reduction Reaction: Effect of the Transition Metal

Aghabarari, Behzad; Martı́nez-Huerta, M.V.; Capel-Sanchez, M. Carmen; Lázaro, M.J.

doi:10.3389/fmats.2020.578518

Cited by 9 publications

(7 citation statements)

References 49 publications

(60 reference statements)

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“…Consequently, we need to gradually increase the size of polymelamines to capture the metal ions by several reaction steps [ 1 , 2 , 3 , 4 ]. Melamine needs to combine with other conducting polymers [ 5 ] or matrix [ 6 , 7 , 8 , 9 ] before calcining to become M–Nx–C catalysts.…”

Section: Introductionmentioning

confidence: 99%

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2,6-Diaminopyridine-Based Polyurea as an ORR Electrocatalyst of an Anion Exchange Membrane Fuel Cell

Wang

Hsieh²,

Huang³

et al. 2023

Polymers

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In order to yield more Co(II), 2,6-diaminopyridine (DAP) was polymerized with 4,4-methylene diphenyl diisocyanates (MDI) in the presence of Co(II) to obtain a Co-complexed polyurea (Co-PUr). The obtained Co-PUr was calcined to become Co, N-doped carbon (Co–N–C) as the cathode catalyst of an anion exchange membrane fuel cell (AEMFC). High-resolution transmission electron microscopy (HR-TEM) of Co–N–C indicated many Co-Nx (Co covalent bonding with several nitrogen) units in the Co–N–C matrix. X-ray diffraction patterns showed that carbon and cobalt crystallized in the Co–N–C catalysts. The Raman spectra showed that the carbon matrix of Co–N–C became ordered with increased calcination temperature. The surface area (dominated by micropores) of Co–N–Cs also increased with the calcination temperature. The non-precious Co–N–C demonstrated comparable electrochemical properties (oxygen reduction reaction: ORR) to commercial precious Pt/C, such as high on-set and half-wave voltages, high limited reduction current density, and lower Tafel slope. The number of electrons transferred in the cathode was close to four, indicating complete ORR. The max. power density (Pmax) of the single cell with the Co–N–C cathode catalyst demonstrated a high value of 227.7 mWcm−2.

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Section: Introductionmentioning

confidence: 99%

“…Furthermore, they will release the captured metal during calcination if decomposition occurs. Therefore, an additional carbon matrix [ 6 , 7 , 8 , 9 ] is needed to adhere to the MOF unit to prevent the collapse of the cyclic structures.…”

Section: Introductionmentioning

confidence: 99%

2,6-Diaminopyridine-Based Polyurea as an ORR Electrocatalyst of an Anion Exchange Membrane Fuel Cell

Wang

Hsieh²,

Huang³

et al. 2023

Polymers

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“…The oxygen reduction reaction (ORR) is critically important in sustainable and green energy technologies, such as metal-air batteries and fuel cells. [1][2][3] Due to its sluggish kinetic process, how to improve the performance of the ORR is still a critical issue. [4][5][6] Currently, Fe single-atom catalysts (Fe SACs) exhibit better catalytic activities in the ORR, [7][8][9] because of denite active centers and extremely high atom utilization.…”

Section: Introductionmentioning

confidence: 99%

Bimetallic diatomic nanoclusters with longitudinal Fe–O–Fe units and latitudinal Cu–S–Fe–S–Cu units as efficient ORR active sites

Shu

et al. 2022

J. Mater. Chem. A

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“…In the last years, the conversion of biomasses [25,[43][44][45][46][47][48][49][50] or waste polymers [42] into activated carbon has become a promising approach for the synthesis of self-templating M-N-C catalysts. In this paper, we present the synthesis and characterization of Fe-N x doped MCs by thermochemical conversion of a preconditioned hydrogel, prepared from a refined biomass, i.e., chitosan, without the use of any additional template or carbon black support.…”

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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Non-precious Melamine/Chitosan Composites for the Oxygen Reduction Reaction: Effect of the Transition Metal

Cited by 9 publications

References 49 publications

2,6-Diaminopyridine-Based Polyurea as an ORR Electrocatalyst of an Anion Exchange Membrane Fuel Cell

2,6-Diaminopyridine-Based Polyurea as an ORR Electrocatalyst of an Anion Exchange Membrane Fuel Cell

Bimetallic diatomic nanoclusters with longitudinal Fe–O–Fe units and latitudinal Cu–S–Fe–S–Cu units as efficient ORR active sites

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

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