Approaches towards Improving the Dispersion of Electrodeposited Palladium on Carbon Supports

Palladium (Pd) was electrochemical deposition on activated carbon from chloride precursor in acid media. The effect of precursor concentration was studied in relation to the dispersion of Pd at a particular deposition potential, and the influence of support material such as conventional Vulcan XC-72R (VXC) and activated carbon prepared from Wood Apple Shell (WAS) on the dispersion of Pd is investigated. Scanning electron microscope images showed, changing the support from VXC to WAS carbon improved the dispersion of Pd, and CO stripping and hydrogen adsorption/desorption experiments displayed an increase in electrochemical surface area for Pd on WAS carbon support. Comparison of electrochemical data for oxygen reduction reaction and formic acid oxidation suggests that Pd deposited on wood apple shell (WAS) carbon showed higher activities relative to Pd deposition on Vulcan. Cyclic and linear sweep voltammetry results showed a positive shift in onset potential up to 80 mV towards oxidation and reduction reactions on changing the support to WAS carbon. The effectiveness of improving the utilization of Pd by changing the support from VXC to WAS activated carbon is discussed in detail.