Carbon-based metal-free catalysts are a promising substitute for the rare and expensive platinum （Pt） used in the oxygen reduction reaction. We herein report N-doped graphene （NG） that is exquisitely integrated in...Carbon-based metal-free catalysts are a promising substitute for the rare and expensive platinum （Pt） used in the oxygen reduction reaction. We herein report N-doped graphene （NG） that is exquisitely integrated into highly conductive frameworks, simultaneously providing more active sites and higher conductivity. The NG was in situ grown on carbon fibers derived from silk cocoon （SCCf） using a simple one-step thermal treatment. The resulting product （NG-SCCf）, possessing a meso-/macroporous structure with three-dimensional （3D） interconnected networks, exhibits an onset potential that is only 0.1 V less negative than that of Pt/C and shows stability and methanol tolerance superior to those of Pt/C in alkaline media. Moreover, in the absence of Pt as co-catalyst, NG-SCCf shows a photocatalytic H2 production rate of 66.0 ~tmol-h l.g 1, 4.4-fold higher than that of SCCf. This outstanding activity is intimately related to the in situ grown NG, hierarchically porous structure, and 3D interconnected networks, which not only introduce more active sites but also enable smooth electron transfer, mass transport, and effective separation of electron-hole pairs. Considering the abundance of the green raw material in combination with easy and low-cost preparation, this work contributes to the development of advanced sustainable catalysts in energy storage/conversion fields, such as electro- and photocatalysis.展开更多
The strategy of combining highly conductive frameworks with abundant active sites is desirable in the preparation of alternative catalysts to commercial Pt/C for the oxygen reduction reaction （ORR）. In this study, N...The strategy of combining highly conductive frameworks with abundant active sites is desirable in the preparation of alternative catalysts to commercial Pt/C for the oxygen reduction reaction （ORR）. In this study, N-doped graphene （NG） and carbon nanotubes （CNT） were grown in-situ on Co-containing carbon nanofibers （CNF） to form three-dimensional （3D） interconnected networks. The NG and CNT bound the interlaced CNF together, facilitating electron transfer and providing additional active sites. The 3D interconnected fiber networks exhibited excellent ORR catalytic behavior with an onset potential of 0.924 V （vs. reversible hydrogen electrode） and a higher current density than Pt/C beyond 0.720 V. In addition, the hybrid system exhibited superior stability and methanol tolerance to Pt/C in alkaline media. This method can be extended to the design of other 3D interconnected network architectures for energy storage and conversion applications.展开更多
基金The work was financially supported by National Natural Science Foundation of China （Nos. 51203182 and 51173202）, Foundation for the Author of Excellent Doctoral Dissertation of Hunan Province （No. YB2014B004）, Aeronautical Science Foundation of China （No. 20143188004）, Key Laboratory of Advanced Textile Materials and Manufacturing Technology （Zhejiang Sci-Tech University）, Ministry of Education （No. 2015001）, Key Laboratory of Lightweight and Reliability Technology for Engineering Vehicle, College of Hunan Province （No. 2016kfjj01）, Research Project of NUDT. We thank Tengyuan Wang for help in ORR experiment and helpful discussions.
文摘Carbon-based metal-free catalysts are a promising substitute for the rare and expensive platinum （Pt） used in the oxygen reduction reaction. We herein report N-doped graphene （NG） that is exquisitely integrated into highly conductive frameworks, simultaneously providing more active sites and higher conductivity. The NG was in situ grown on carbon fibers derived from silk cocoon （SCCf） using a simple one-step thermal treatment. The resulting product （NG-SCCf）, possessing a meso-/macroporous structure with three-dimensional （3D） interconnected networks, exhibits an onset potential that is only 0.1 V less negative than that of Pt/C and shows stability and methanol tolerance superior to those of Pt/C in alkaline media. Moreover, in the absence of Pt as co-catalyst, NG-SCCf shows a photocatalytic H2 production rate of 66.0 ~tmol-h l.g 1, 4.4-fold higher than that of SCCf. This outstanding activity is intimately related to the in situ grown NG, hierarchically porous structure, and 3D interconnected networks, which not only introduce more active sites but also enable smooth electron transfer, mass transport, and effective separation of electron-hole pairs. Considering the abundance of the green raw material in combination with easy and low-cost preparation, this work contributes to the development of advanced sustainable catalysts in energy storage/conversion fields, such as electro- and photocatalysis.
基金The work was financially supported by the National Natural Science Foundation of China （Nos. 51203182 and 51173202）, Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics （No. KF201312）, Key Laboratory of High Performance Fibers ＆ Products, Ministry of Education, Donghua University, Guangxi Key Laboratory of Information Materials （Guilin University of Electronic Technology） （No. 1210908-01-K）, Research Project of NUDT （No. JC13-01-05）, Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province, and Aid Program for Innovative Group of National University of Defense Technology.
文摘The strategy of combining highly conductive frameworks with abundant active sites is desirable in the preparation of alternative catalysts to commercial Pt/C for the oxygen reduction reaction （ORR）. In this study, N-doped graphene （NG） and carbon nanotubes （CNT） were grown in-situ on Co-containing carbon nanofibers （CNF） to form three-dimensional （3D） interconnected networks. The NG and CNT bound the interlaced CNF together, facilitating electron transfer and providing additional active sites. The 3D interconnected fiber networks exhibited excellent ORR catalytic behavior with an onset potential of 0.924 V （vs. reversible hydrogen electrode） and a higher current density than Pt/C beyond 0.720 V. In addition, the hybrid system exhibited superior stability and methanol tolerance to Pt/C in alkaline media. This method can be extended to the design of other 3D interconnected network architectures for energy storage and conversion applications.
基金This work was supported by the National Natural Science Foundation of China (21176221, 21273224)the National Basic Research Program of China (973 Program, 2011CB201402, 2013CB933100)~~
