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Nitrogen-doped Graphene-Supported Transition-metals Carbide Electrocatalysts for Oxygen Reduction Reaction.

Chen M, Liu J, Zhou W, Lin J, Shen Z - Sci Rep (2015)

Bottom Line: A novel and facile two-step strategy has been designed to prepare high performance bi-transition-metals (Fe- and Mo-) carbide supported on nitrogen-doped graphene (FeMo-NG) as electrocatalysts for oxygen reduction reactions (ORR).The as-synthesized FeMo carbide -NG catalysts exhibit excellent electrocatalytic activities for ORR in alkaline solution, with high onset potential (-0.09 V vs. saturated KCl Ag/AgCl), nearly four electron transfer number (nearly 4) and high kinetic-limiting current density (up to 3.5 mA cm(-2) at -0.8 V vs.Ag/AgCl).

View Article: PubMed Central - PubMed

Affiliation: 1] School of Applied Science, Harbin University of Science and Technology, Harbin 150080, P.R. China [2] Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore.

ABSTRACT
A novel and facile two-step strategy has been designed to prepare high performance bi-transition-metals (Fe- and Mo-) carbide supported on nitrogen-doped graphene (FeMo-NG) as electrocatalysts for oxygen reduction reactions (ORR). The as-synthesized FeMo carbide -NG catalysts exhibit excellent electrocatalytic activities for ORR in alkaline solution, with high onset potential (-0.09 V vs. saturated KCl Ag/AgCl), nearly four electron transfer number (nearly 4) and high kinetic-limiting current density (up to 3.5 mA cm(-2) at -0.8 V vs. Ag/AgCl). Furthermore, FeMo carbide -NG composites show good cycle stability and much better toxicity tolerance durability than the commercial Pt/C catalyst, paving their application in high-performance fuel cell and lithium-air batteries.

No MeSH data available.


Related in: MedlinePlus

XRD patterns of (a) FeMo Carbide/G-800, FeMo Carbide/NG-800 and a dried-down GO. (b) FeMo Carbide/NG samples prepared at various annealing temperatures (700, 800 and 900 oC).
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f3: XRD patterns of (a) FeMo Carbide/G-800, FeMo Carbide/NG-800 and a dried-down GO. (b) FeMo Carbide/NG samples prepared at various annealing temperatures (700, 800 and 900 oC).

Mentions: XRD patterns of samples GO, FeMo Carbide/G-800 and FeMo Carbide/NG-800 are shown in Fig. 3a. GO displays a dominate diffraction peak at 10.6o, corresponding to an interlayer distance of 0.83 nm due to the presence of oxygenated functional groups and the intercalated solvent molecules34. For the FeMo-composite materials after mild heat treatment, the GO peak disappeared completely, indicating the reduction of graphite oxide to graphene. The graphite peak disappeared upon high temperature pyrolysis. In Fig. 3a both FeMo Carbide/G-800 and FeMo Carbide/NG-800 show the presence of Mo2C (JCPDS card no. 35-0787) as the major species because of the appreance of strong peaks at 34.4 o (100), 38.0 o (002), 39.4o (101), 52.1o (102), 61.5o (110), 69.5o (103), 74.6o (112) and 75.5o (201). FeMo Carbide/NG-800 is different from FeMo Carbide/G-800 in N-doping, since urea was added as the N-source for the preparation of FeMo Carbide/NG-800. The Mo2C peaks are relatively broadened for FeMo Carbide/NG⊠indicating that Mo2C is better dispered on the N-doped graphene support with smaller particle size than that over FeMo Carbide/G, in good consistence to SEM, TEM results (shown in Fig. 2 & S2†) and XRD results (Table S1†). In addition to Mo2C, two peaks at 43.3o and 74.1o are observable for both FeMo carbide/NG and FeMo carbide/G, corresponding to CFe15.1 (JCPDS card no. 52-0512), indicating the formation of iron carbide from the partial dissolution of carbon atoms into Fe crystal lattices at elevated temperatures35. Without the addition of urea some metallic iron phase can be detected in FeMo Carbide/G.


Nitrogen-doped Graphene-Supported Transition-metals Carbide Electrocatalysts for Oxygen Reduction Reaction.

Chen M, Liu J, Zhou W, Lin J, Shen Z - Sci Rep (2015)

XRD patterns of (a) FeMo Carbide/G-800, FeMo Carbide/NG-800 and a dried-down GO. (b) FeMo Carbide/NG samples prepared at various annealing temperatures (700, 800 and 900 oC).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC4441168&req=5

f3: XRD patterns of (a) FeMo Carbide/G-800, FeMo Carbide/NG-800 and a dried-down GO. (b) FeMo Carbide/NG samples prepared at various annealing temperatures (700, 800 and 900 oC).
Mentions: XRD patterns of samples GO, FeMo Carbide/G-800 and FeMo Carbide/NG-800 are shown in Fig. 3a. GO displays a dominate diffraction peak at 10.6o, corresponding to an interlayer distance of 0.83 nm due to the presence of oxygenated functional groups and the intercalated solvent molecules34. For the FeMo-composite materials after mild heat treatment, the GO peak disappeared completely, indicating the reduction of graphite oxide to graphene. The graphite peak disappeared upon high temperature pyrolysis. In Fig. 3a both FeMo Carbide/G-800 and FeMo Carbide/NG-800 show the presence of Mo2C (JCPDS card no. 35-0787) as the major species because of the appreance of strong peaks at 34.4 o (100), 38.0 o (002), 39.4o (101), 52.1o (102), 61.5o (110), 69.5o (103), 74.6o (112) and 75.5o (201). FeMo Carbide/NG-800 is different from FeMo Carbide/G-800 in N-doping, since urea was added as the N-source for the preparation of FeMo Carbide/NG-800. The Mo2C peaks are relatively broadened for FeMo Carbide/NG⊠indicating that Mo2C is better dispered on the N-doped graphene support with smaller particle size than that over FeMo Carbide/G, in good consistence to SEM, TEM results (shown in Fig. 2 & S2†) and XRD results (Table S1†). In addition to Mo2C, two peaks at 43.3o and 74.1o are observable for both FeMo carbide/NG and FeMo carbide/G, corresponding to CFe15.1 (JCPDS card no. 52-0512), indicating the formation of iron carbide from the partial dissolution of carbon atoms into Fe crystal lattices at elevated temperatures35. Without the addition of urea some metallic iron phase can be detected in FeMo Carbide/G.

Bottom Line: A novel and facile two-step strategy has been designed to prepare high performance bi-transition-metals (Fe- and Mo-) carbide supported on nitrogen-doped graphene (FeMo-NG) as electrocatalysts for oxygen reduction reactions (ORR).The as-synthesized FeMo carbide -NG catalysts exhibit excellent electrocatalytic activities for ORR in alkaline solution, with high onset potential (-0.09 V vs. saturated KCl Ag/AgCl), nearly four electron transfer number (nearly 4) and high kinetic-limiting current density (up to 3.5 mA cm(-2) at -0.8 V vs.Ag/AgCl).

View Article: PubMed Central - PubMed

Affiliation: 1] School of Applied Science, Harbin University of Science and Technology, Harbin 150080, P.R. China [2] Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore.

ABSTRACT
A novel and facile two-step strategy has been designed to prepare high performance bi-transition-metals (Fe- and Mo-) carbide supported on nitrogen-doped graphene (FeMo-NG) as electrocatalysts for oxygen reduction reactions (ORR). The as-synthesized FeMo carbide -NG catalysts exhibit excellent electrocatalytic activities for ORR in alkaline solution, with high onset potential (-0.09 V vs. saturated KCl Ag/AgCl), nearly four electron transfer number (nearly 4) and high kinetic-limiting current density (up to 3.5 mA cm(-2) at -0.8 V vs. Ag/AgCl). Furthermore, FeMo carbide -NG composites show good cycle stability and much better toxicity tolerance durability than the commercial Pt/C catalyst, paving their application in high-performance fuel cell and lithium-air batteries.

No MeSH data available.


Related in: MedlinePlus