Preparation of palladium-based electrocatalysts for direct ethanol fuel cells

This research was to investigate the effect of palladium-based catalyst and supporting materials for direct ethanol fuel cell in alkaline media. The studied variables were the secondary metal (gold, ruthenium, and tungsten), types of support (carbon Vulcan, carbon nanotubes). Regarding the secondary metal incorporation, Pd99W1/C resulted in a significant enhancement in activity and stability for ethanol and methanol electrooxidation. In contrast with glycerol oxidation, Pd99Au1/C exhibited a better activity and stability than other catalysts.  With the surface functionalization of carbon nanotube support, it was clear that the acid oxidation of carbon nanotube gave a poor palladium catalytic performance for ethanol oxidation compared with functionalized polyethyleneimine (PEI-CNT). Moreover, the activity and stability of the catalysts were improved by self-assembly PEI-CNT with phosphotungstic acid. For self-assembled PEI-CNT, 30% Pd was the most suitable loading of ethanol oxidation. Furthermore, the utilization of the nickel single atom catalyst as a new type of supporting material was performed. The results demonstrated that the use of this support can enhance the catalytic performance of palladium for alcohol oxidation. Finally, the study of the ethanol oxidation mechanism revealed that the acetate ion was the final product and acetaldehyde was still the active intermediate. It can be concluded that the catalytic activity of palladium did not cause the carbon session in ethanol structure.