Effect of precursor nature on the performance of palladium-cobalt electrocatalysts for direct methanol fuel cells

The performance of platinum-free palladium-cobalt catalysts in oxygen reduction was investigated for a direct methanol fuel cell. The dependence of catalytic activity on precursor nature was determined for two classes of precursors; namely, palladium chloride and palladium nitrate. The nitrate precursor exhibits much higher catalytic performance than the chloride precursor. X-ray absorption fine structure (XAFS) spectra indicate that the structure of palladium catalyst prepared from nitrate is much closer to Pd₃Co structure that can explain high catalytic activity. The MEA prepared from the nitrate catalyst achieved the peak power density of 125 mW cm^-2, which is much higher than 19 mW cm^-2 measured on the cell prepared from the chloride catalyst.