Nitrogen-Doped Carbon Nanotube Arrays with High Electrocatalytic Activity for Oxygen Reduction

American Association for the Advancement of Science (AAAS) - Tập 323 Số 5915 - Trang 760-764 - 2009
Kuanping Gong1,2,3,4, Feng Du1,2,3,4, Zhenhai Xia1,2,3,4, Michael F. Durstock1,2,4, Liming Dai1,3,4
1Department of Chemistry and University of Dayton Research Institute and Institute for the Development and Commercialization of Advanced Sensor Technology and Wright Brothers Institute, Dayton, OH 45469, USA.
2Department of Mechanical Engineering, University of Akron, Akron, OH 44325, USA
3Departments of Chemical and Materials Engineering, University of Dayton, 300 College Park, Dayton, OH 45469, USA.
4Materials and Manufacturing Directorate, Air Force Research Laboratory, RXBP, Wright-Patterson Air Force Base, OH 45433, USA.

Tóm tắt

The large-scale practical application of fuel cells will be difficult to realize if the expensive platinum-based electrocatalysts for oxygen reduction reactions (ORRs) cannot be replaced by other efficient, low-cost, and stable electrodes. Here, we report that vertically aligned nitrogen-containing carbon nanotubes (VA-NCNTs) can act as a metal-free electrode with a much better electrocatalytic activity, long-term operation stability, and tolerance to crossover effect than platinum for oxygen reduction in alkaline fuel cells. In air-saturated 0.1 molar potassium hydroxide, we observed a steady-state output potential of –80 millivolts and a current density of 4.1 milliamps per square centimeter at –0.22 volts, compared with –85 millivolts and 1.1 milliamps per square centimeter at –0.20 volts for a platinum-carbon electrode. The incorporation of electron-accepting nitrogen atoms in the conjugated nanotube carbon plane appears to impart a relatively high positive charge density on adjacent carbon atoms. This effect, coupled with aligning the NCNTs, provides a four-electron pathway for the ORR on VA-NCNTs with a superb performance.

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We gratefully acknowledge financial support for this work from the Air Force Office of Scientific Research (grant FA9550-06-1-0384). K.G. thanks L. Qu and J. Zhu for help with some initial work.

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American Association for the Advancement of Science (AAAS)

Tập 323 Số 5915

760-764

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