It is of significant implication to fabricate high-performance,
durable and low-cost catalysts toward to oxygen reduction reaction
(ORR) to drive commercial application of fuel cells. In our work,
we synthesize the Fe/N-CNT catalyst via one-pot grinding combined
with calcination using a mixture of carbamide, CNTs and iron salts
as precursors, the as-synthesized catalysts show the structure that
Fe nanoparticles are encapsulated in the tube of intertwined CNTs
with abundant active sites. The catalyst is synthesized at 800 °C
(Fe/N-CNT-800–20) obtain high graphitization degree and high
N doped content, especially the high content and proportion of Fe–N
and pyridinic-N, exhibiting outstanding ORR activity. Moreover, too
high calcination temperature (850 °C) and high Fe content (25%)
lead to the agglomeration of Fe during the calcination, which blocked
some catalytic sites, leading to poor ORR activity. This facile synergy
route will provide new thoughts for the fabrication and optimization
of catalysts.