Mitigating H_ad Binding Energy in Formate Oxidation through Electron Translocation between Pd and ZrO₂

Abstract

Palladium metal catalysts have emerged as the preferred choice for alkaline formate oxidation reaction (FOR) due to their high activity. However, their strong binding with adsorbed H (H ad ) allows H ad to occupy the active site, resulting in slow FOR kinetics. Herein, we developed a ZrO 2 /Pd/C catalyst to decrease the H ad binding strength on Pd active sites, thereby enhancing the FOR in alkaline media. Through experimental investigations and density functional theory (DFT) calculations, we elucidated the relationship between the d-band center of Pd and hydrogen binding energy (HBE). Our findings reveal that electron transfer from ZrO 2 to Pd, driven by the work function disparity, results in a downshift of the d-band center of Pd. This shift weakens the HBE at Pd active sites, facilitating the desorption of H ad intermediates and thereby improving catalytic efficiency. As a result, the ZrO 2 /Pd/C catalyst demonstrated a 2.8-fold increase in activity over commercial Pd/C, exhibiting a lower peak potential and a significantly higher peak current of 1787 mA mg −1 . This work advances our understanding of the interplay between electronic structure and catalytic performance, setting a benchmark for high-performance electrocatalysts in energy conversion technologies.