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Electrospun interconnected Fe-N/C nanofiber networks as efficient electrocatalysts for oxygen reduction reaction in acidic media.

Wu N, Wang Y, Lei Y, Wang B, Han C, Gou Y, Shi Q, Fang D - Sci Rep (2015)

Bottom Line: One-dimensional electrospun nanofibers have emerged as a potential candidate for high-performance oxygen reduction reaction (ORR) catalysts.Intriguingly, the resulting Fe-N/C NNs exhibit 34% higher peak current density and superior durability than generic Fe-N/C ones with similar microstructure and chemical compositions.The higher electroactivity is mainly due to the more effective electron transport between the interconnected nanofibers.

View Article: PubMed Central - PubMed

Affiliation: Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, National University of Defense Technology, Changsha 410073, P.R. China.

ABSTRACT
One-dimensional electrospun nanofibers have emerged as a potential candidate for high-performance oxygen reduction reaction (ORR) catalysts. However, contact resistance among the neighbouring nanofibers hinders the electron transport. Here, we report the preparation of interconnected Fe-N/C nanofiber networks (Fe-N/C NNs) with low electrical resistance via electrospinning followed by maturing and pyrolysis. The Fe-N/C NNs show excellent ORR activity with onset and half-wave potential of 55 and 108 mV less than those of Pt/C catalyst in 0.5 M H2SO4. Intriguingly, the resulting Fe-N/C NNs exhibit 34% higher peak current density and superior durability than generic Fe-N/C ones with similar microstructure and chemical compositions. Additionally, it also displays much better durability and methanol tolerance than Pt/C catalyst. The higher electroactivity is mainly due to the more effective electron transport between the interconnected nanofibers. Thus, our findings provide a novel insight into the design of functional electrospun nanofibers for the application in energy storage and conversion fields.

No MeSH data available.


Related in: MedlinePlus

(a) Chronoamperometric response of Fe-N/C NNs, Fe-N/C NMs and Pt/C in O2-saturated 0.5 M H2SO4 at 0.75 V. (b) Chronoamperometric response with 3 M methanol in O2-saturated 0.5 M H2SO4 at 0.75 V.
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f6: (a) Chronoamperometric response of Fe-N/C NNs, Fe-N/C NMs and Pt/C in O2-saturated 0.5 M H2SO4 at 0.75 V. (b) Chronoamperometric response with 3 M methanol in O2-saturated 0.5 M H2SO4 at 0.75 V.

Mentions: Along with the excellent ORR activity, durability and tolerance towards the methanol crossover effect of the catalysts are two important factors for practical applications as well. The current-time (i-t) chronoamperometric response in O2-saturated electrolyte at 0.75 V (Fig. 6a) indicates that Fe-N/C NNs suffer from a slight attenuation (8.6%) after 15000 s compared with Fe-N/C NMs (13.7%) and Pt/C catalyst (28.4%), suggesting an outstanding durability of Fe-N/C NNs. It is well known that the poor durability of Pt/C catalyst originates from the aggregation of platinum nanoparticles after the oxidation degradation of carbon supports. In our system, the composite structure of iron-containing hybrids embedded in carbon nanofiber will hinder the dissolution and aggregation of active sites, leading to a better stability. As shown in Fig. 6b, the original ORR current of Pt/C catalyst changes dramatically after the addition of 3 M methanol, suggesting the occurrence of the methanol oxidation reaction. In sharp contrast, the chronoamperometric response of Fe-N/C NNs recovers quickly upon the injection of methanol. Indeed, Fe-N/C NNs catalyst is also a promising candidate for the direct methanol fuel cells.


Electrospun interconnected Fe-N/C nanofiber networks as efficient electrocatalysts for oxygen reduction reaction in acidic media.

Wu N, Wang Y, Lei Y, Wang B, Han C, Gou Y, Shi Q, Fang D - Sci Rep (2015)

(a) Chronoamperometric response of Fe-N/C NNs, Fe-N/C NMs and Pt/C in O2-saturated 0.5 M H2SO4 at 0.75 V. (b) Chronoamperometric response with 3 M methanol in O2-saturated 0.5 M H2SO4 at 0.75 V.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663764&req=5

f6: (a) Chronoamperometric response of Fe-N/C NNs, Fe-N/C NMs and Pt/C in O2-saturated 0.5 M H2SO4 at 0.75 V. (b) Chronoamperometric response with 3 M methanol in O2-saturated 0.5 M H2SO4 at 0.75 V.
Mentions: Along with the excellent ORR activity, durability and tolerance towards the methanol crossover effect of the catalysts are two important factors for practical applications as well. The current-time (i-t) chronoamperometric response in O2-saturated electrolyte at 0.75 V (Fig. 6a) indicates that Fe-N/C NNs suffer from a slight attenuation (8.6%) after 15000 s compared with Fe-N/C NMs (13.7%) and Pt/C catalyst (28.4%), suggesting an outstanding durability of Fe-N/C NNs. It is well known that the poor durability of Pt/C catalyst originates from the aggregation of platinum nanoparticles after the oxidation degradation of carbon supports. In our system, the composite structure of iron-containing hybrids embedded in carbon nanofiber will hinder the dissolution and aggregation of active sites, leading to a better stability. As shown in Fig. 6b, the original ORR current of Pt/C catalyst changes dramatically after the addition of 3 M methanol, suggesting the occurrence of the methanol oxidation reaction. In sharp contrast, the chronoamperometric response of Fe-N/C NNs recovers quickly upon the injection of methanol. Indeed, Fe-N/C NNs catalyst is also a promising candidate for the direct methanol fuel cells.

Bottom Line: One-dimensional electrospun nanofibers have emerged as a potential candidate for high-performance oxygen reduction reaction (ORR) catalysts.Intriguingly, the resulting Fe-N/C NNs exhibit 34% higher peak current density and superior durability than generic Fe-N/C ones with similar microstructure and chemical compositions.The higher electroactivity is mainly due to the more effective electron transport between the interconnected nanofibers.

View Article: PubMed Central - PubMed

Affiliation: Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, National University of Defense Technology, Changsha 410073, P.R. China.

ABSTRACT
One-dimensional electrospun nanofibers have emerged as a potential candidate for high-performance oxygen reduction reaction (ORR) catalysts. However, contact resistance among the neighbouring nanofibers hinders the electron transport. Here, we report the preparation of interconnected Fe-N/C nanofiber networks (Fe-N/C NNs) with low electrical resistance via electrospinning followed by maturing and pyrolysis. The Fe-N/C NNs show excellent ORR activity with onset and half-wave potential of 55 and 108 mV less than those of Pt/C catalyst in 0.5 M H2SO4. Intriguingly, the resulting Fe-N/C NNs exhibit 34% higher peak current density and superior durability than generic Fe-N/C ones with similar microstructure and chemical compositions. Additionally, it also displays much better durability and methanol tolerance than Pt/C catalyst. The higher electroactivity is mainly due to the more effective electron transport between the interconnected nanofibers. Thus, our findings provide a novel insight into the design of functional electrospun nanofibers for the application in energy storage and conversion fields.

No MeSH data available.


Related in: MedlinePlus