A One-Pot Hydrothermal Preparation of High Loading Ni/La 2 O 3 Catalyst for Efficient Hydrogenation of Cinnamaldehyde.

It is a challenging task for selective hydrogenation of cinnamaldehyde (CAL) to hydrocinnamaldehyde (HCAL) without additional by-product formation. In this work, a La2O3 supported high Ni content nanoparticle catalyst was prepared for CAL selective hydrogenation. Meanwhile, Co-La2O3 catalysts were used as a reference catalyst. XRD, TEM, STEM-HAADF, XPS, and H2-TPR measurements were used to investigate the physicochemical properties of Ni-La2O3 catalysts. The experimental results confirmed that the CAL conversion and HCAL selectivity were effectively promoted with the increase of Ni loading amounts. At a Ni/La molar ratio of four, a high HCAL selectivity of 87.4% was obtained at a CAL conversion of 88.1% under mild reaction conditions. The catalyst was recycled five times without activity loss. Combined with various characterizations, it could be inferred that the good hydrogen adsorption and dissociation capacity of Ni and the presence of a certain amount of oxygen vacancies on the La2O3 support have a positive effect on the improvement of HCAL selectivity. This work provided an effective path to design transition-metal-based supported oxide catalyst for the cinnamaldehyde hydrogenation to hydrocinnamaldehyde. [ABSTRACT FROM AUTHOR]