Bimetallic Pt-Co catalysis on carbon nanotubes for the selective hydrogenation of cinnamaldehyde to cinnamyl alcohol: Preparation and characterization

Carbon nanotubes (CNTs)-based Pt-Co catalysts are prepared by different impregnation techniques and different reduction methods (H2, HCHO and KBH4) for the selective reduction of cinnamaldehyde (CMA) to the corresponding cinnamyl alcohol (CMO). The selectivity and activity of the Pt-Co/CNTs catalysts can be improved significantly by using ammonia as a ligand and KBH4 as a reducing agent because of the synergetic effect of Pt-Co-B. Furthermore, the hydrogenation rate of CMA increases ulteriorly in the presence of trace base and acid promoters.

H2-TPR profiles of the CNTs supported Pt-Co catalysts are shown in Fig. 2. The Pt-Co/CNTs (I) catalyst presents a large peak of H2 consumption appearing at a higher temperature, 250 °C. The high consumption of H2 (H2/Pt = 3.3) is in accordance with that already observed and can be interpreted by the following equation: ⌈Pt(OH)4(Cl)2⌋2− + 3H2 → Pt0 + 4H2O + 2HCl + 2e−.The other catalysts present a reduction maximum at about 20 °C, with a H2/Pt ratio basically equal to 2.Figure optionsDownload as PowerPoint slide