Preparation of Bi-functional hydrogen production/storage catalyst with Constructing Pd nanoparticles and amino functionalities on layered double hydroxide

The utilization of formic acid (FA) as efficient H₂ medium through the conversion between FA and CO₂ has received the great attention recently. In this research, the mesoporous material layered double hydroxide grafted with different types of amine groups (primary, secondary, and tertiary amine) have been synthesized via traditional impregnation method. The primary amine becomes the significant parameter to synthesis of ultrafine Pd nano-particles with high initial TOF of 1250 h⁻¹ at room temperature in FA dehydrogenation. Meanwhile, the density functional theory (DFT) calculations verify that controlling the Pd sites at 2 nm can effectively accelerate the formation of hydrogen and avoid the occurrence of dehydration reaction. The subsequent hydrogenation of CO₂ into formic acid/formate on Pd-based layered double hydroxide catalyst achieves the TOF over 100 h⁻¹ in finishing H₂ interconversion cycle. These findings will have considerable implications in the fields of H₂ generation/storage chemistry and CO₂ utilization economic.