Electrocatalytic conversion of oxygen holds great potential for clean energy technologies, including water electrolysis, regenerative fuel cells, and rechargeable metal-air batteries. The development of highly efficient and inexpensive oxygen electrocatalysts as replacements for precious metal-based catalysts is vitally important for large-scale practical application in the future. A bifunctional oxygen electrocatalyst based on FeCo nanoparticles/N-doped carbon core-shell spheres supported on N-doped graphene sheets was prepared via one-step pyrolysis of graphitic carbon nitride and acetylacetonates. The optimized product exhibited an oxygen electrode activity of 0.87 V and excellent durability. The remarkable performance is mainly attributed to the synergetic effect arising from the FeCo nanoparticles and N-doped carbon shell. This study introduces an inexpensive and simple way to develop highly active bifunctional oxygen electrocatalysts.
Nan WuYongpeng LeiQichen WangBing WangCheng HanYingde Wang
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.
