PdAg Alloy Nanoparticles Immobilized on Functionalized MIL-101-NH2: Effect of Organic Amines for Hydrogenation of Carbon Dioxide into Formic Acid

Exploration of excellent performance catalysts for carbon dioxide (CO2) hydrogenation is essential for CO2 utilization. In this work, a series of PdAg nanoparticles (NPs) immobilized on various organic amine functionalized MIL-101-NH2 catalysts were synthesized and investigated for the hydrogenation of CO2 to formic acid (FA). This showed that PdAg NPs immobilized on the triethylenediamine (TEDA) functionalized MIL-101-NH2 catalyst with an average size of 1.6 nm, denoted PdAg/TEDA-MIL-101-NH2, possessed the highest TON of 1500 at 70 °C after 10 h. Decorated amine groups in MOFs not only played a key role in the formation of ultra-small metal clusters, but also had a strong metal–support interaction with PdAg nanoparticles, where the electron-rich states of Pd could promote H2 dissociation, thereby enhancing the catalytic activity.