| 초록 |
Among the fuel-cell reactions, oxygen reduction reaction (ORR) is responsible for reducing the overall efficiency due to its high overpotential. Non-Pt ORR electrocatalysts have been studied for a long time, however, there is still a debate over active site because the heterogeneity of catalysts increases during pyrolysis. For example, in the case of Fe-N/C synthesis, not only Fe-Nx sites but metallic Fe or Fe carbide particle can be also generated by atomic agglomeration of Fe during pyrolysis. From now, Fe-Nx sites have been considered as active sites of the ORR in many reports but recently other species such as Fe@C or Fe-Fe3C@C has been also insisted as active sites. Here, we synthesized model catalysts that have selective species by experimental control and measured their electrochemical properties. Through this research, we identify each role of active species in Fe based ORR electrocatalysts and suggest the direction of prospective research for non-Pt ORR catalysts. |
