Preparation of MgAl LDH with Various Morphologies and Catalytic Hydrogenation Performance of Pt/LDH Catalysts

How to design and fabricate highly efficient and stable Pt nano-catalyst is of important practical value and scientific significance for improving the C=O hydrogenation selectivity of cinnamaldehyde. In present study, a series of MgAl hydrotalcite (LDH) supports with various morphologies were synthesized by co-precipitation and hydrothermal methods. The supported Pt/LDH catalysts were prepared by incipient wet impregnation (IMP) method with LDH supports, and used for cinnamaldehyde selective hydrogenation reaction, and influences of LDH with different morphology for the catalyst activity were studied. The structure, morphology, surface physicochemical properties of these catalysts were characterized. The results show that the morphology of different supports exerts a significant influence on the structure and properties of Pt/LDH catalysts. Interaction between lamellae LDH nanosheet and active component Pt facilitates dispersing and stabilizing of Pt nanoparticles. Meanwhile, there are abundant alkaline sites and surface hydroxyl groups in the LDH support, which are beneficial to improve the catalytic hydrogenation activity and stability. Results of catalytic performance show that selectivity of cinnamon alcohol (CMO) and conversion of cinnamon aldehyde (CMA) at reaction temperature of 40 degrees C, reaction pressure of 1 MPa, and reaction time of 120 min were 82.1% and 79.8%, respectively. After 5 rounds of cycle tests, the Pt/LDH catalyst still has excellent stability.

Automated summary

This study focused on designing and fabricating highly efficient and stable Pt nano-catalysts for improving the C=O hydrogenation selectivity of cinnamaldehyde. The results demonstrated that the morphology of different LDH supports significantly influenced the structure and properties of Pt/LDH catalysts, with interaction between LDH nanosheets and Pt facilitating dispersion and stabilization of Pt nanoparticles, and the alkaline sites and surface hydroxyl groups in LDH support enhancing catalytic activity and stability. Selectivity of cinnamon alcohol and conversion of cinnamon aldehyde were high after reaction under specific conditions, and the Pt/LDH catalyst showed excellent stability after repeated cycle tests.