Toward New Fuel Cell Support Materials: A Theoretical and Experimental Study of Nitrogen‐Doped Graphene

Seo, Min Ho; Choi, Sung Mook; Lim, Eun Ja; Kwon, In Hye; Seo, Joon Kyo; Noh, Seung Hyo; Kim, Won; Han, Byungchan

doi:10.1002/cssc.201402258

Cited by 52 publications

(49 citation statements)

References 109 publications

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“…The following techniques were used to characterize the bulk and surface structures of different catalysts: high-angle annular dark-field scanning transmission electron microscopy (JEOL JEM-2100 LaB 6 , JEOL, Tokyo, Japan) at 200 kV, energy-dispersive X-ray spectroscopy (JEOL JED-2300, JEOL), X-ray diffraction (with an Ultima IV X-ray diffractometer, Rigaku, Tokyo, Japan) using Cu-Kα radiation (λ = 1.5418 Å) at 40 kV and 40 mA, and X-ray photoelectron spectroscopy (with a JEOL JPS-9010MC (JEOL) and a Mg-Kα (1253.6 eV) source).…”

Section: Characterizationmentioning

confidence: 99%

“…Over the past few decades, studies have sought to achieve this goal, but the alternatives investigated have not been commercialized yet, owing to either their electrochemical instability or their low ORR activity in acidic media. 2, [4][5][6] Recent progress in the use of non-precious carbon-based catalysts for ORR is notable because these materials not only are much cheaper than Pt-based alloys but also are stable for prolonged periods. Furthermore, the catalytic properties of carbon-based materials can be well tuned by simple thermo-chemical treatments.…”

Section: Introductionmentioning

confidence: 99%

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Towards a comprehensive understanding of FeCo coated with N-doped carbon as a stable bi-functional catalyst in acidic media

et al. 2016

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The identification and development of efficient catalysts made of non-precious materials for oxygen reduction reaction (ORR) are essential for the successful operation of a wide range of energy devices. This study provides evidence that earth-abundant nanoparticles of transition metals encapsulated in a nitrogen-doped carbon shell (M@N-C, M = Fe, Co, Ni, Cu or Fe alloys) are promising catalysts in acidic solutions. By density functional theory calculations and experimental validations, we quantitatively propose a method of tuning the ORR activity of M@N-C by controlling the nitrogen-doping level, the thickness of the N-C shells and binary alloying. FeCo@N-C/KB was chosen as the best ORR catalyst because of its onset and half-wave potentials of 0.92 and 0.74 V vs a reversible hydrogen electrode (RHE), respectively, and its excellent durability. Furthermore, FeCo@N-C/KB possesses a high activity for the hydrogen evolution reaction (HER; − 0.24 V vs RHE at − 10 mA cm − 2 ), thus demonstrating that it is a good bi-functional ORR and HER catalyst in acidic media.

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Section: Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Towards a comprehensive understanding of FeCo coated with N-doped carbon as a stable bi-functional catalyst in acidic media

et al. 2016

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“…O-dopants were found to work best in this respect, with Ir/Au performing better than Pt. Seo et al 183 also investigated durability of Pt clusters on N-doped graphene substrates, with a 5.5% N-dopant concentration. Their PW-DFT PBE calculations agreed with previous work in that Pt atoms adsorbed more strongly to the N-doped surface compared with undoped graphene.…”

Section: Fuel Cellsmentioning

confidence: 99%

“…For the previously-mentioned N-doped graphene and pristine graphene systems reported by Seo et al 183 , these authors also used DFT calculations to evaluate the range of ε dc for the surface-adsorbed Pt 55 NP. These authors correlated these ε dc values with the adsorption energy of an oxygen atom on the supported PtNP; oxygen binding was weakest for the N-doped graphene support, thus supporting the prediction that PtNPs supported by N-doped graphene could improve ORR kinetics.…”

Section: Fuel Cellsmentioning

confidence: 99%

“…Their PW-DFT PBE calculations demonstrated the possibility for tuning the bandgap of these doped graphene materials, based on symmetry considerations. As an example of a systematic process to identify doping structures, the use of cluster expansion theory 205,206 was reported by Seo et al 183 to propose and screen, via PW-DFT PBE calculations, 117 different dopant site structures ranging from 0% to 100% doping levels of nitrogen in graphene. As an alternative to nitrogen and boron doping, Zhang et al 207 explored the electronic effects of sulfur doping, using finite hydrogen-terminated graphene flakes (100 carbon atoms).…”

Section: Fuel Cellsmentioning

confidence: 99%

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Computational chemistry for graphene-based energy applications: progress and challenges

Hughes

Walsh

2015

Nanoscale

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Citation: Hughes ZE and Walsh TR (2015) Computational chemistry for graphene-based energy applications: progress and challenges. Nanoscale. 7: 6883-6908. Research in graphene-based energy materials is a rapidly growing area. Many graphene-based energy applications involve interfacial processes. To enable advances in the design of these energy materials, such that their operation, economy, efficiency and durability is at least comparable with fossil-fuel based alternatives, connections between the molecular-scale structure and function of these interfaces are needed. While it is experimentally challenging to resolve this interfacial structure, molecular simulation and computational chemistry can help bridge these gaps. In this Review, we summarise recent progress in the application of computational chemistry to graphene-based materials for fuel cells, batteries and photovoltaics. We also outline both the bright prospects and emerging challenges these techniques face for application to graphene-based energy materials in future.

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Sulfur Atoms Bridging Few‐Layered MoS₂ with S‐Doped Graphene Enable Highly Robust Anode for Lithium‐Ion Batteries

Wang

Seo

et al. 2015

Advanced Energy Materials

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109

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anodes mainly involve in two strategies: (1) reducing the characteristic dimensions of MoS 2 and controlling the morphologies such as nanofl owers, [ 23 ] nanofl akes, [ 24 ] nanospheres, [ 25,26 ] and nanosheets; [ 27 ] and (2) building conductive and robust scaffold to improve both the kinetics and integrity, [28][29][30][31][32][33] such as embedding the single-layered MoS 2 in carbon nanofi bers, [ 34 ] confi ning few-layered MoS 2 within 3D carbon nanosheets, [ 35 ] and coupling MoS 2 nanocrystals on N-enriched graphene [ 36 ] or N-doped carbon nanoboxes. [ 37 ] Although improved performance can be achieved, the development of novel highly stable MoS 2based materials with fast kinetics remains challenging, owing to the lack of a ration design from molecular level. Moreover, it is also critical to correlate the performance with materials structure, and to understand the chemistry behind before its future practical applications.Herein, we demonstrate a facile solvothermal synthesis of nanocomposites consisting few-layered MoS 2 and covalently sulfur-doped graphene (MoS 2 /SG) with excellent electrochemical performance. We focus on not only the development of MoS 2 -based electrode materials but also the materials design based on both structure and chemistry considerations. As shown in Scheme 1 , the sulfur atoms covalently bonded to graphene sheets and effectively bridging 2D few-layered MoS 2 and graphene enable high robustness of the composite materials. Moreover, the intimate contact of MoS 2 and highly conductive graphene provides effi cient electron transfer pathways, while the high surface of assembled 2D structured materials allows fast access to active materials. Such a unique composite architecture derived from the "bridging effect" ensures the electrode with an exceptional cycling stability and superior rate capability, which is also interpreted by the density functional theory (DFT) calculations. A capacity retention of 92.3% can be achieved after 2000 cycles at a current density of 10 A g −1 ; even at a high current density of 20 A g −1 , the electrode still possesses a specifi c capacity of 766 mA h g −1 . This composite material with excellent electrochemical properties synthesized via a facile solvothermal approach holds great promise in the practical application of high-performance LIBs.The MoS 2 /SG composites were synthesized through a facile solvothermal approach with element sulfur as the precursor for both MoS 2 and S dopants of graphene, followed by annealing. X-ray diffraction (XRD) pattern of as-synthesized composites aligns well with literatures (JCPDS No. 77-1716) [ 38 ] with no obvious S peaks that can be found ( Figure S1, Supporting Information), which can be indexed to a hexagonal crystal structure of MoS 2 . [ 39 ] Figure 1 A shows the representative Tremendous research interest from both academy and industry has been dedicated to the rechargeable lithium-ion batteries (LIBs) in the last decades for the upcoming era of portable electronics, electric vehicles (EVs), and hybrid ele...

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Toward New Fuel Cell Support Materials: A Theoretical and Experimental Study of Nitrogen‐Doped Graphene

Cited by 52 publications

References 109 publications

Towards a comprehensive understanding of FeCo coated with N-doped carbon as a stable bi-functional catalyst in acidic media

Towards a comprehensive understanding of FeCo coated with N-doped carbon as a stable bi-functional catalyst in acidic media

Computational chemistry for graphene-based energy applications: progress and challenges

Sulfur Atoms Bridging Few‐Layered MoS₂ with S‐Doped Graphene Enable Highly Robust Anode for Lithium‐Ion Batteries

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Toward New Fuel Cell Support Materials: A Theoretical and Experimental Study of Nitrogen‐Doped Graphene

Cited by 52 publications

References 109 publications

Towards a comprehensive understanding of FeCo coated with N-doped carbon as a stable bi-functional catalyst in acidic media

Towards a comprehensive understanding of FeCo coated with N-doped carbon as a stable bi-functional catalyst in acidic media

Computational chemistry for graphene-based energy applications: progress and challenges

Sulfur Atoms Bridging Few‐Layered MoS2 with S‐Doped Graphene Enable Highly Robust Anode for Lithium‐Ion Batteries

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Resources

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Sulfur Atoms Bridging Few‐Layered MoS₂ with S‐Doped Graphene Enable Highly Robust Anode for Lithium‐Ion Batteries