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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) CVs of Fe-N/C NNs and Fe-N/C NMs in O2- and N2-saturated 0.5 M H2SO4 solution. (b) ORR polarization curves of different Fe-N/C catalysts and 20% Pt/C in O2-saturated 0.5 M H2SO4 at 1600 rpm. ORR polarization curves of (c) Fe-N/C NNs and (d) Fe-N/C NMs in O2-saturated 0.5 M H2SO4 at different rotation rates. Inset is the corresponding K-L plots at a potential range from 0.35 to 0.55 V. (e) Nyquist plots of Fe-N/C NNs and Fe-N/C NMs. (f) Scheme of interconnected Fe-N/C NNs facilitating mass and electron transport.
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f5: (a) CVs of Fe-N/C NNs and Fe-N/C NMs in O2- and N2-saturated 0.5 M H2SO4 solution. (b) ORR polarization curves of different Fe-N/C catalysts and 20% Pt/C in O2-saturated 0.5 M H2SO4 at 1600 rpm. ORR polarization curves of (c) Fe-N/C NNs and (d) Fe-N/C NMs in O2-saturated 0.5 M H2SO4 at different rotation rates. Inset is the corresponding K-L plots at a potential range from 0.35 to 0.55 V. (e) Nyquist plots of Fe-N/C NNs and Fe-N/C NMs. (f) Scheme of interconnected Fe-N/C NNs facilitating mass and electron transport.

Mentions: To evaluate the electrochemical activity of Fe-N/C NNs and Fe-N/C NMs, a series of CVs were carried out in N2- and O2-saturated 0.5 M H2SO4 solution at a scan rate of 10 mV s−1 (Fig. 5a). One can see that the two samples exhibit a well-defined cathodic peak at around 0.7 V in O2-saturated H2SO4 solution. To correct the background current, the featureless voltammogram recorded in N2-saturated 0.5 M H2SO4 solution is subtracted from the voltammogram recorded in O2-saturated electrolyte. It is well known that a higher peak current density (JP) is beneficial to a better ORR performance. The JP of Fe-N/C NNs (1.02 mA cm−2) is significantly 34% higher than that of Fe-N/C NMs (0.76 mA cm−2). The higher JP of Fe-N/C NNs correlates well with the interconnected nanofiber networks, which provide continuous pathways for electron transport37.


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) CVs of Fe-N/C NNs and Fe-N/C NMs in O2- and N2-saturated 0.5 M H2SO4 solution. (b) ORR polarization curves of different Fe-N/C catalysts and 20% Pt/C in O2-saturated 0.5 M H2SO4 at 1600 rpm. ORR polarization curves of (c) Fe-N/C NNs and (d) Fe-N/C NMs in O2-saturated 0.5 M H2SO4 at different rotation rates. Inset is the corresponding K-L plots at a potential range from 0.35 to 0.55 V. (e) Nyquist plots of Fe-N/C NNs and Fe-N/C NMs. (f) Scheme of interconnected Fe-N/C NNs facilitating mass and electron transport.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: (a) CVs of Fe-N/C NNs and Fe-N/C NMs in O2- and N2-saturated 0.5 M H2SO4 solution. (b) ORR polarization curves of different Fe-N/C catalysts and 20% Pt/C in O2-saturated 0.5 M H2SO4 at 1600 rpm. ORR polarization curves of (c) Fe-N/C NNs and (d) Fe-N/C NMs in O2-saturated 0.5 M H2SO4 at different rotation rates. Inset is the corresponding K-L plots at a potential range from 0.35 to 0.55 V. (e) Nyquist plots of Fe-N/C NNs and Fe-N/C NMs. (f) Scheme of interconnected Fe-N/C NNs facilitating mass and electron transport.
Mentions: To evaluate the electrochemical activity of Fe-N/C NNs and Fe-N/C NMs, a series of CVs were carried out in N2- and O2-saturated 0.5 M H2SO4 solution at a scan rate of 10 mV s−1 (Fig. 5a). One can see that the two samples exhibit a well-defined cathodic peak at around 0.7 V in O2-saturated H2SO4 solution. To correct the background current, the featureless voltammogram recorded in N2-saturated 0.5 M H2SO4 solution is subtracted from the voltammogram recorded in O2-saturated electrolyte. It is well known that a higher peak current density (JP) is beneficial to a better ORR performance. The JP of Fe-N/C NNs (1.02 mA cm−2) is significantly 34% higher than that of Fe-N/C NMs (0.76 mA cm−2). The higher JP of Fe-N/C NNs correlates well with the interconnected nanofiber networks, which provide continuous pathways for electron transport37.

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