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

Abstract

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 (H ad ) adsorption on Pd catalysts. We developed WO 3 -supported Pd nanoparticles (EG−Pd/WO 3 ) via an organic reduction method using ethylene glycol (EG), aiming to modulate the d-band center of Pd and alter H ad adsorption dynamics. Cyclic voltammetry demonstrated significantly improved H ad desorption kinetics in EG−Pd/WO 3 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 H ad 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.