Mitigating Had 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 ZrO₂/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 ZrO₂ 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 ZrO₂/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.