One-pot synthesis of CoFe alloy supported on N-doped carbon as Pt-free oxygen reduction catalysts

An efficient and inexpensive oxygen reduction catalyst to substitute platinum-based catalyst materials is the key to future development in energy storage and conversion. In this work, bimetal CoFe alloy decorated N-doped carbon was successfully synthesized from commercial acetylene black, glycine, and transition metal salt precursors. Four different samples were prepared using directly pyrolyzing the precursors at a temperature of 700 °C for 2h in nitrogen atmosphere without any further treatments. The catalyst activity was characterized using cyclic voltammetry in an acid electrolyte (0.1 M HClO4), while structure analysis was done using X-ray diffraction (XRD) and Raman spectroscopy. The results show that the bimetal CoFe catalyst has the highest onset potential (0.90 V vs. RHE) than those for other samples. Samples with monometallic Fe or Co result onset potential at about 0.8 V (vs. RHE), while the lowest onset potential is obtained from N-doped carbon (0.52 V vs. RHE). Positively shift in the onset potential is likely due to the synergetic effect from CoFe particles and N-doped carbon substrate.