NICKEL BASED CATALYSTS FOR SELECTIVE HYDROGENATION OF CINNAMALDEHYDE- INFLUENCE OF SUPPORT PHASES

摘要

Ni (15% w/w) supported on alumina, silica and titania (P-25, anatase and rutile phases) have been investigated for the liquid phase hydrogenation of cinnamaldehyde. XRD, TPR and XPS data (binding energy shifts for Ni 2p ) indicate metal-support interactions in all supported catalysts. Weaker bonding of H 2 on Ni/TiO 2 (H 2 -TPD) improves activity. Ni/TiO 2 phases display higher cinnamaldehyde conversion and selectivity to cinnamyl alcohol compared to the catalysts supported on alumina and silica. Amongst the three polymorphs of titania, the maximum activity and selectivity displayed by Ni/ TiO 2 -P-25, is attributed to the active Ni crystallites located at the interface between anatase and rutile phases in titania P-25 matrix (HRTEM). Though Ni crystallites on alumina and silica are relatively smaller (compared to those on the three TiO2 phases) in size, their activity vis-à-vis for those supported on titania phases is less, implying that factors other than crystallite size influence the performance.