N-Doped Carbon Networks Containing Inserted FeN<sub><i>x</i></sub>@NC Nanospheroids and Bridged by Carbon Nanotubes as Enhanced Catalysts for the Oxygen Reduction Reaction
Qing Dong, Zaiyong Mo, Hui Wang, Shan Ji, Xuyun Wang, Vladimir Linkov, Rongfang Wang
Abstract
Carbon composite materials containing nitrogen-doped carbon nanotubes (NCNTs) possess higher catalytic activity for the oxygen reduction reaction (ORR) in alkaline electrolytes than Pt/C, which makes them promising metal–air battery catalysts. Herein, ternary nitrogen-doped carbon composites (TNCCs) containing N-doped carbon networks with inserted FeNx@NC nanospheroids and bridged by carbon nanotubes were prepared to be used as highly active ORR catalysts, and the mechanism of competitive growth of NCNTs and FeNx@NC was established. The optimized newly developed material (TNCC-10) demonstrated excellent ORR performance comparable to the commercial Pt/C catalyst in a three-electrode system. Its performance in a zinc–air battery as an air cathode catalyst surpassed that of Pt/C in both power density and voltage. The results show the great potential of TNCC-10 as an ORR catalyst in metal–air battery applications.