High-Loading Cobalt Oxide Coupled with Nitrogen-Doped Graphene for Oxygen Reduction in Anion-Exchange-Membrane Alkaline Fuel Cells

He, Qinggang; Li, Qing; Khene, Samson; Ren, Xiaoming; López-Suárez, F.E.; Lozano‐Castelló, Dolores; Bueno‐López, Agustín; Wu, Gang

doi:10.1021/jp401814f

Cited by 250 publications

(190 citation statements)

References 67 publications

Supporting

Mentioning

180

Contrasting

Unclassified

Order By: Relevance

“…47,51,52 In addition, the σ* absorption feature (~405 eV) of PtCo/C-PNIPAM broadened, and its intensity was reduced, which may be attributed to a geometrical change for the C-N bond from sp 2 to sp 3 configurations by the interaction between the surface Co on the PtCo nanoparticles and the amide N in the PNIPAM functionalized on the carbon surfaces. 47 In addition, as shown in Supplementary Figure S7, both PtCo/C-PNIPAM and PtCo/C showed similar patterns in the X-ray diffraction measurements related to their periodic bulk structures rather than their surface structures.…”

Section: Resultsmentioning

confidence: 99%

Organic-inorganic hybrid PtCo nanoparticle with high electrocatalytic activity and durability for oxygen reduction

et al. 2016

View full text Add to dashboard Cite

In Pt-transition metal (TM) alloy catalysts, the electron transfer from the TM to Pt is retarded owing to the inevitable oxidation of the TM surface by oxygen. In addition, acidic electrolytes such as those employed in fuel cells accelerate the dissolution of the surface TM oxide, which leads to catalyst degradation. Herein, we propose a novel synthesis strategy that selectively modifies the electronic structure of surface Co atoms with N-containing polymers, resulting in highly active and durable PtCo nanoparticle catalysts useful for the oxygen reduction reaction (ORR). The polymer, which is functionalized on carbon black, selectively interacts with the Co precursor, resulting in Co-N bond formation on the PtCo nanoparticle surface. Electron transfer from Co to Pt in the PtCo nanoparticles modified by the polymer is enhanced by the increase in the difference in electronegativity between Pt and Co compared with that in bare PtCo nanoparticles with the TM surface oxides. In addition, the dissolution of Co and Pt is prevented by the selective passivation of surface Co atoms and the decrease in the O-binding energy of surface Pt atoms. As a result, the catalytic activity and durability of PtCo nanoparticles for the ORR are significantly improved by the electronic ensemble effects. The proposed organic/inorganic hybrid concept will provide new insights into the tuning of nanomaterials consisting of heterogeneous metallic elements for various electrochemical and chemical applications.

show abstract

Section: Resultsmentioning

confidence: 99%

Organic-inorganic hybrid PtCo nanoparticle with high electrocatalytic activity and durability for oxygen reduction

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Peaks at 786 eV and 800 eV (typical for CoO) were found for the other two samples [26]. Finally, Co/L7 presented an additional peak at 778.8 eV representative of Co atoms in zero oxidation state [72]. In addition, carbon and oxygen XPS regions were studied (see Supporting Information).…”

Section: Maitlis' Hot Filtration Testmentioning

confidence: 99%

Co-based heterogeneous catalysts from well-defined α-diimine complexes: Discussing the role of nitrogen

Formenti

Ferretti

Topf

et al. 2017

Journal of Catalysis

View full text Add to dashboard Cite

‡ These authors contributed equally to this work.Abstract: Ar-BIANs and related α-diimine Co complexes were wet impregnated onto Vulcan® XC 72 R carbon black powder and used as precursors for the synthesis of heterogeneous supported nanoscale catalysts by pyrolysis under argon at 800 °C. The catalytic materials feature a core-shell structure composed of metallic Co and Co oxides decorated with nitrogen-doped graphitic layers (NGr). These catalysts display high activity in the liquid phase hydrogenation of aromatic nitro compounds (110 °C, 50 bar H2) to give chemoselectively substituted aryl amines. The catalytic activity is closely related to the amount and type of nitrogen atoms in the final catalytic material, which suggests a heterolytic activation of dihydrogen.Keywords: cobalt, hydrogenation, nitro compounds, kinetic, heterolytic activation IntroductionCatalysis is a key-technology for the manufacturing of all kinds of bulk and fine chemical products. It allows for producing chemicals avoiding the formation of undesired and useless stoichiometric side products which leads to additional cost and energy consumption [1][2][3]. Many of the industrially relevant catalytic processes in the fine chemical industry are still based on expensive and rare late transition metals such as Pd, Pt, Rh, Ru and Ir [4,[1][2][3][4][5]. Although these metals exhibit very good catalytic performance for advanced organic substrates, the decreasing availability of these elements requires the development of efficient alternative metal-based catalysts [6]. In this regard, the design of catalytic systems based on abundant and biocompatible metals is an important goal for the implementation and progress of green and sustainable chemistry. Hence, transition metals such as Fe, Co and Cu are ideal candidates, which meet these requirements [7][8][9][10]. As a matter of fact, these elements are among the most abundant metals in the Earth's upper crust, thus being readily accessible [11]. Recently, heteroatom-doped carbon materials attracted major interest in the field of metal supported heterogeneous catalysts for both chemical synthesis [12][13][14] and/or energy-relevant transformations [15,16]. Indeed, doping graphene with heteroatoms such as N, B, P, or S leads to a radical modification of the electronic properties of both the support and the supported metal [17][18][19]. Consequently, it is possible to modify the activity and adjust the selectivity of the final catalytic material towards the desired transformation. Among the various dopants, nitrogen attracted most interest [15,[20][21][22]. and applications of transition metal/N-doped graphene (NGr) based catalytic systems ranges from oxygen reduction reactions (ORR) [23][24][25][26], hydrogen evolving reactions (HER) [27,28], photocatalysis [29,30], oxidation [31][32][33][34][35][36][37][38], and reduction [39][40][41][42][43][44] reactions of organic

show abstract

“…This suggests that nitrogen atoms are doped both within the carbon planes (graphitic) and at the edges ( pyridinic). [38][39][40] Nitrogen atoms can be regarded as n-type dopants in carbon, and have been associated with high ORR activity.…”

Section: Nitrogen Dopingmentioning

confidence: 99%

Size-controlled large-diameter and few-walled carbon nanotube catalysts for oxygen reduction

et al. 2015

Self Cite

View full text Add to dashboard Cite

) surface areas and, more importantly, the highest concentration of nitrogen incorporated into the carbon planes.Thus, in addition to the intrinsic high activity of Fe-derived catalysts, the high surface area and nitrogen doping contribute to high ORR activity. This work, for the first time, demonstrates size-controlled synthesis of large-diameter N-doped carbon tube electrocatalysts by varying the metal used in N-CNT generation. Electrocatalytic activity of the Fe-derived catalyst is already the best among studied metals, due to the high intrinsic activity of possible Fe-N coordination. This work further provides a promising route to advanced Fe-N-C nonprecious metal catalysts by generating favorable morphology with more active sites and improved mass transfer.

show abstract

High-Loading Cobalt Oxide Coupled with Nitrogen-Doped Graphene for Oxygen Reduction in Anion-Exchange-Membrane Alkaline Fuel Cells

Cited by 250 publications

References 67 publications

Organic-inorganic hybrid PtCo nanoparticle with high electrocatalytic activity and durability for oxygen reduction

Organic-inorganic hybrid PtCo nanoparticle with high electrocatalytic activity and durability for oxygen reduction

Co-based heterogeneous catalysts from well-defined α-diimine complexes: Discussing the role of nitrogen

Size-controlled large-diameter and few-walled carbon nanotube catalysts for oxygen reduction

Contact Info

Product

Resources

About