Non-noble metal oxygen reduction electrocatalysts based on carbon nanotubes with controlled nitrogen contents

Geng, Dongsheng; Líu, Hao; Chen, Yougui; Li, Ruying; Sun, Xueliang; Ye, Siyu; Knights, Shanna

doi:10.1016/j.jpowsour.2010.09.084

Cited by 107 publications

(64 citation statements)

References 33 publications

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“…graphene [10,[23][24][25][26][27][28][29][30][31][32][33], carbon nanotubes [11,20,21,[34][35][36][37][38][39][40][41][42][43], carbon nanofibers [12,[44][45][46][47], mesoporous carbon [15,22], graphitic carbon [48,49], carbon spheres [19,[50][51][52][53], carbon nanocages 4 [54], flower-like carbon [55], carbon aerogel [56,57], vesicular carbon [58], nanodiamonds [59]) relatively few have been tested in actual fuel cell conditions [58,[60][61][62]…”

Section: Introductionmentioning

confidence: 99%

Highly efficient cathode catalyst layer based on nitrogen-doped carbon nanotubes for the alkaline direct methanol fuel cell

Kanninen

Borghei

Sorsa

et al. 2014

Applied Catalysis B: Environmental

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Section: Introductionmentioning

confidence: 99%

Highly efficient cathode catalyst layer based on nitrogen-doped carbon nanotubes for the alkaline direct methanol fuel cell

Kanninen

Borghei

Sorsa

et al. 2014

Applied Catalysis B: Environmental

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“…The unfavorable molecule (11) can further react with hydroxyl radical anion generated in the reaction mixture through the electrochemically driven homolytic cleavage and create structure (12). The latest may react with hydrogen peroxide (by-product of 2-electron ORR process [29][30][31]) and form N-oxide (13)(14)(15)(16). Furthermore, we speculate that the structure (5) instead of recovering to step (4), is modified under attack of a strong oxidizing agent, H 2 O 2 [29][30][31], generating products (8-9) in Scheme 1.…”

Section: Electrochemical Stabilitymentioning

confidence: 99%

“…organic compounds [11], such as polypyrrole (PPy) [12], polyaniline (PANI) [2] and polyacrylonitrile [13]. In summary, this method provides a high surface area product with homogenous morphology due to low conversion (polymer-to-carbon) temperature, allowing to control better the final properties, such as the surface concentration of nitrogen, and the way it is incorporated in the carbon structure (e.g., as pyrrolic, graphitic, pyridinic or quaternary N-C states) [14]. Although the effect of nitrogen doping level (i.e., an established optimum at 2-15 at.% of N) on the catalytic activity toward oxygen reduction has been well described, there are discrepancies with regards to the long-term electrochemical stability of these compounds [15,16].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical stability of the polymer-derived nitrogen-doped carbon: an elusive goal?

Cong

Radtke

Stumpf

et al. 2015

Mater Renew Sustain Energy

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Nitrogen-doped carbon is a promising metalfree catalyst for oxygen reduction reaction in fuel cells and metal-air batteries. However, its practical application necessitates a significant cost reduction, which can be achieved in part by using new synthetic methods and improvement of catalytic activity by increasing the density of redox active centers. This can be modulated by using polymer as the carbon and nitrogen sources. Although, superior catalytic activity of such N-doped C has been investigated in details, the electrochemical long-term stability of polymer-derived doped-carbon is still unclear. Herein, in this study we generated N-doped carbon from the most recommended polymer that is comparable to the state-of-the-art materials with porosity as high as 2,086 m 2 g -1 and a nitrogen doping level of 3-4 at.%, of which 56 % is pyrrolic N, 36.1 % pyridinic and *8 % graphitic. The electrochemical characterization shows that N-doped carbon is catalytic toward oxygen reduction in an alkaline electrolyte via a favorable four-electron process, however, not stable under long-term potential scanning. The irreversible electrochemical oxidation of this material is associated with the presence of a significant content or pyrrolic and pyridinic N close to the edge of the carbon network originating from the polypyrrole precursor. These structures are less stable under operating electrochemical potential. The role of polypyrrole as the precursor of N-doped carbons has to be carefully revised since it supplies sufficient number of catalytic sites, but also generates unstable functionalities on the carbon surface.

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“…Moreover, addition of nitrogen varies the charge distribution of the carbon network so that the C atoms adjacent to N become more positively charged, resulting in an enhanced interaction with the adsorbing molecule and thus lower activation barrier for its decomposition [96]. 41 Recently, a variety of metal-free nitrogen doped CNMs have been synthesized in the form of CNTs [97][98][99][100][101][102], CNFs [103,104], graphene [105,106], mesoporous carbon [107], carbon nanocages [108], carbon spheres, hollow carbon nanoparticles [109], etc. In this thesis the synthesis and electrocatalytic activity of N-FWCNTs and N-GNPs for the ORR have been investigated.…”

Section: Cnms As Pt-free Catalystsmentioning

confidence: 99%

“…synthesized N-CNTs by detonation-assisted CVD using melamine without any metal catalysts [102]. However, the resulted bamboo-like N-CNTs did not show good ORR activity, despite of very high nitrogen content (~20 at.%).…”

Section: Preparation Of N-cntsmentioning

confidence: 99%

Nitrogen-doped graphene with enhanced oxygen reduction activity produced by pyrolysis of graphene functionalized with imidazole derivatives

Borghei

Azcune

Carrasco

et al. 2014

International Journal of Hydrogen Energy

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Direct methanol fuel cells (DMFC) are great candidates for portable power source applications. However, the sluggish reaction kinetics are key challenges in DMFC technology. The state-of-the-art electrocatalysts are Pt-based catalysts supported on carbon black. However, the high price of Pt, corrosion of carbon support and Pt degradation are the main problems.In this thesis, carbon nanomaterials, namely few-walled carbon nanotubes (FWCNTs) and graphitized nanofibers (GNFs) were used as catalyst supports in the search for stable and durable catalysts. PtRu nanocatalysts with similar particle size and composition were synthesized and deposited on FWCNTs and GNFs. The electrochemical activities for methanol oxidation were compared with that of PtRu-carbon black in acidic conditions. The half-cell electrochemical measurements revealed higher activity with PtRu-GNFs and PtRu-FWCNTs. Later, the electrocatalysts were tested in macro-and micro-DMFC. The results revealed the significant influence of the catalyst support, inomer contect, electrode structure, preparation method, as well as the fuel cell architecture on the performance of a specific electrode material. The results also highlighted the necessity of electrode composition optimization when applying new materials at the electrodes, in order to achieve the best activity and durability for a certain electrocatalyst.A special effort was also done to achieve Pt-free electrocatalysts with high activity for the oxygen reduction reaction (ORR) by introducing nitrogen heteroatoms in carbon nanomaterials, namely FWCNTs and graphite nanoplatelets (GNPs). N-FWCNTs exhibited remarkable electrocatalytic activity for ORR in alkaline media, despite their very low nitrogen content (~0.5 at.%). N-FWCNTs performed on par or better than a commercial Pt-C at the cathode of an alkaline DMFC. The N-GNPs exhibited enhanced electrocatalytic activity for ORR compared to pristine GNPs in alkaline media. The results indicated that N-doped carbon nanomaterials could be promising alternatives to their Pt counterparts to reduce fuel cell costs. However, further investigations are necessary to ascertain the real active sites in order to design more efficient and durable ORR electrocatalysts.Keywords Carbon nanomaterials, PtRu catalysts, nitrogen-doping, direct methanol fuel cell ISBN (printed) 978-952-60-6140-5 ISBN (pdf) 978-952-60-6141-2

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Non-noble metal oxygen reduction electrocatalysts based on carbon nanotubes with controlled nitrogen contents

Cited by 107 publications

References 33 publications

Highly efficient cathode catalyst layer based on nitrogen-doped carbon nanotubes for the alkaline direct methanol fuel cell

Highly efficient cathode catalyst layer based on nitrogen-doped carbon nanotubes for the alkaline direct methanol fuel cell

Electrochemical stability of the polymer-derived nitrogen-doped carbon: an elusive goal?

Nitrogen-doped graphene with enhanced oxygen reduction activity produced by pyrolysis of graphene functionalized with imidazole derivatives

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