Oxide (CeO 2, NiO, Co 3O 4 and Mn 3O 4)-promoted Pd/C electrocatalysts for alcohol electrooxidation in alkaline media

This study investigated Pt/C, Pd/C and oxide (CeO 2, NiO, Co 3O 4 and Mn 3O 4)-promoted Pd/C for electrooxidation reactions of methanol, ethanol, ethylene glycol and glycerol in alkaline media. The results show that Pd/C electrocatalysts alone have low activity and very poor stability for the alcohol electrooxidation. However, addition of oxides like CeO 2, NiO, Co 3O 4 and Mn 3O 4 significantly promotes catalytic activity and stability of the Pd/C electrocatalysts for the alcohol electrooxidation. The Pd-Co 3O 4 (2:1, w:w)/C shows the highest activity for the electrooxidation of methanol, EG and glycerol while the most active catalyst for the ethanol electrooxidation is Pd-NiO (6:1, w:w)/C. On the other hand, Pd-Mn 3O 4/C shows significantly better performance stability than other oxide-promoted Pd/C for the alcohol electrooxidation. The poor stability of the Pd-Co 3O 4/C electrocatalysts is most likely related to the limited solubility of cobalt oxides in alkaline solutions.