Oxide (CeO2, NiO, Co3O4 and Mn3O4)-promoted Pd/C electrocatalysts for alcohol electrooxidation in alkaline media

This study investigated Pt/C, Pd/C and oxide (CeO2, NiO, Co3O4 and Mn3O4)-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 CeO2, NiO, Co3O4 and Mn3O4 significantly promotes catalytic activity and stability of the Pd/C electrocatalysts for the alcohol electrooxidation. The Pd-Co3O4 (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-Mn3O4/C shows significantly better performance stability than other oxide-promoted Pd/C for the alcohol electrooxidation. The poor stability of the Pd-Co3O4/C electrocatalysts is most likely related to the limited solubility of cobalt oxides in alkaline solutions.