Influence of Preparation Modes on Pt-Ni/CNTs Catalysts Used in the Selective Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

Pt-Ni/CNTs catalysts are prepared by different impregnation techniques and different reduction methods (H-2, HCHO, and KBH4) for the selective hydrogenation of cinnamaldehyde (CMA) to hydrocinnamaldehyde (HCMA) and investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (H-2-TPR) techniques. The results show that the catalytic selectivity and activity of the Pt-Ni/CNTs catalysts would significantly be improved by using KBH4 as a reducing agent, due to the electronic synergetic effect of Pt-Ni-B, and 96% for conversion of CMA and 88% for selectivity of HCMA are obtained over Pt-Ni/CNTs catalyst reduced by KBH4. Furthermore, the hydrogenation rate of CMA and selectivity of CMA to HCMA over Pt-Ni/CNTs catalyst are significantly improved in the presence of trace base or acid promoters again. The best result (92% for conversion of CMA and 96% for selectivity of HCMA) is obtained when NaOAc is used as base promoter.