Comparison of preparation routes of spinel catalyst for alkaline fuel cells

MnCo₂O₄ has been used as a catalyst for oxygen reduction reaction (ORR) in alkaline fuel cells due to easier production and lower costs compared to noble metals. A novel method using a microwave-assisted route of synthesis in the presence of amorphous carbon was developed resulting in MnCo₂O₄ with particle sizes <30 nm. For comparison, spinel prepared in a conventional oven with or without carbon was also studied. The surface area, carbon content, and chemical and morphological properties of the catalyst materials were analyzed. The catalytic activity towards oxygen reduction reaction was measured in a half-cell in 6 M KOH and by microagglomerate method. Compared to the catalysts prepared in a conventional oven, microwave-assisted route resulted in higher specific surface areas, higher current densities and stability, as well as lower apparent activation energies and Tafel slopes.