Electrodeposited Pt-Pd dendrite on carbon support as anode for direct formic acid fuel cells

The activity of bimetallic catalyst is predominantly determined by its composition and its shape. In this work, Pt-Pd bimetallic catalysts were codeposited using cyclic voltammetry on a carbon black-coated carbon paper at two different potential ranges (0 to 1.3V and -0.2 to 1.3V vs. SHE) and with two different Pt precursors (H2PtCl6 and K2PtCl4). SEM analysis revealed that the deposit obtained from both K2PtCl4 and H2PtCl6 precursor resembled the shape of a flower-like dendrite when the deposition potential window was in the range of 0 to 1.3V. However, shifting the lower potential limit from 0 to -0.2V resulted in a leaf-like dendritic structure, irrespective of the Pt precursor used. Leaf-like dendritic structures showed enhanced formic acid oxidation activity with high mass activity and superior stability compared to flower-like structures. The superior performance of the leaf-like structure was clearly evident from fuel cell polarization studies carried out at 70 degrees C, which showed a maximum power density of 49mWcm(-2), whereas flower-like structures showed a power density of 20mWcm(-2).