Modulating the d-Band Center of Palladium via Ethylene Glycol Modification: Accelerating Had Desorption for Enhanced Formate Electrooxidation

This study addresses the critical challenge in alkaline direct formate fuel cells (DFFCs) of slow formate oxidation reaction (FOR) kinetics as a result of strong hydrogen intermediate (Had) adsorption on Pd catalysts. We developed WO3-supported Pd nanoparticles (EG–Pd/WO3) via an organic reduction method using ethylene glycol (EG), aiming to modulate the d-band center of Pd and alter Had adsorption dynamics. Cyclic voltammetry demonstrated significantly improved Had desorption kinetics in EG–Pd/WO3 catalysts. Density functional theory (DFT) calculations revealed that the presence of EG reduces the d-band center of Pd, leading to weaker Pd–H bonds and enhanced Had desorption during the FOR. This research provides a new approach to optimize catalyst efficiency in DFFCs, highlighting the potential for more effective and sustainable energy solutions through advanced material engineering.