Multi-active sites of iron carbide nanoparticles on nitrogen@cobalt-doped carbon for a highly efficient oxygen reduction reaction

The design of a low-cost, stable, and highly efficient electrocatalyst using a non-precious material and carbon composites for oxygen reduction reaction (ORR) activity to replace platinum-based electrocatalyst is essential for future energy conversion devices, such as fuel cells and metal air batteries. However, previous efforts to acquire the high ORR activity by non-precious material and carbon composites faced substantial challenges due to a few active sites during electrochemical reactions. Herein, we synthesize an advanced composite of iron carbide nanoparticles on nitrogen and cobalt-doped carbon nanofiber (Fe₃C/N@Co-doped CNF) by electrospinning, a precures coating process and carbonization. Fe₃C/N@Co-doped CNF offers a high onset potential of 0.9 V, high half-wave potential (E_1/2) potential of 0.8 V, and a nearly four-electron pathway (n = 3.9). Therefore, this unique composite provides multi-active sites using the doping system and metal carbide nanoparticles for the ORR activity, as well as an outstanding tolerance to methanol crossover.