Hydrophilic Engineering of MOF-Derived Pd Nanocatalysts Enables Efficient Formic Acid Dehydrogenation: Intermolecular Protons/Hydrides Shuttling Mediated by FA–H 2 O Hydrogen-Bonding Network

The ambient-temperature catalytic dehydrogenation of formic acid (FA) relies on the mediation of sufficient water (H₂O) molecules, but its specific mechanism remains insufficiently studied. To deeply explore the FA dehydrogenation behavior in the H₂O solution system and synergistically regulate metallic sites with the hydrophilic microenvironments on the catalyst surface for constructing high-efficiency catalytic interfaces, we developed a surface hydrophilic engineering strategy for MOF-derived carbon. The results demonstrate that the introduction of surfactants can regulate the morphology and surface chemical composition to improve the hydrophilicity of catalysts and promote the dispersion of metal centers. The prepared hollow nanorod-like Pd/NC_ZIF-8-25 with notable hydrophilicity and ultrafine Pd nanoparticles (NPs) exhibits excellent catalytic performance (TOF = 1925 h^-1) under ambient conditions. The results of the mechanistic research reveal that H₂O molecules directly participate in the reaction process beyond serving as the solvent. Theoretical calculations demonstrate that the formed intermolecular FA-H₂O hydrogen-bonding network can facilitate the shuttling of hydrogen species (protons and hydrides) and suppress the excessive adsorption of intermediates. This work not only proposes a novel mechanism of FA decomposition in the solution system but also provides theoretical guidance for the development of transition metal catalysts suitable for high-concentration FA environments.