An in situ exploration of how Fe/N/C oxygen reduction catalysts evolve during synthesis under pyrolytic conditions

Abstract In pursuing cheap and effective oxygen reduction catalysts, the Fe/N/C system emerges as a promising candidate. Nevertheless, the structural transformations of starting materials into Fe- and N-doped carbon catalysts remains poorly characterized under pyrolytic conditions. Here, we explore the evolution of Fe species and track the formation of Fe–N 4 site development by employing diverse in-situ diagnostic techniques. In-situ heating microscopy reveals the initial formation of FeO x nanoparticles and subsequent internal migration within the carbon matrix, which stops once FeO x is fully reduced. The migration and decomposition of nanoparticles then leads to carbon layer reconstruction. Experimental…

• NN
  National Natural Science Foundation of China

  Awards: U1932201, 22172134, U22A20396, U2032202, 22288102, 22279011
• XU
  Xiamen University
• BS
  Beijing Synchrotron Radiation Facility