Au–MnO2/MWNT and Au–ZnO/MWNT as oxygen reduction reaction electrocatalyst for polymer electrolyte membrane fuel cell

Bi-functional catalysts based on Au supported on oxide based nanomaterials for use in fuel cells were evaluated by electrochemical methods for oxygen reduction reaction (ORR) in Polymer Electrolyte Membrane Fuel Cell (PEMFC). Metal oxide coated multi walled carbon nanotubes (MWNTs) (MnO2/MWNT and ZnO/MWNT) were prepared by reduction of potassium permanganate and oxidation of Zn powder on MWNT surface respectively. Au–MnO2/MWNT and Au–ZnO/MWNT were prepared by chemical reduction of chloroauric acid on MnO2/MWNT and ZnO/MWNT. The samples were characterized and linear sweep voltammetric studies were performed in N2 saturated, O2 saturated and methanol containing 1 M KOH solution and the results have been discussed. A single fuel cell was also constructed using Au–MnO2/MWNT and Au–ZnO/MWNT as ORR electrocatalysts. A maximum power density of 45 mW/cm2 and 56 mW/cm2 was obtained with Au–MnO2/MWNT and Au–ZnO/MWNT respectively. Additionally, the methanol tolerance of these electrocatalysts has been investigated and results have been discussed.