| Selective hydrogenation of cinnamaldehyde（CAL）is an important reaction because the main products,cinnamic alcohol（COL）and hydrocinnamaldehyde（HCAL）,are used in various fields,such as production of pharmaceutical intermediates,chemicals,perfumes,and fragrances.The efficient and selective hydrogenation of cinnamaldehyde requires the design and synthesis of excellent catalysts,as well as an in-depth understanding of the reaction mechanisms involved in the catalysts.In this paper,the design and optimization of catalysts and possible reaction mechanism are investigated under the guidance of p-band intermediate state（PBIS）theory.The main research contents are as follow:（1）A series of Zn-doped carbon and nitrogen support were obtained by roasting ZIF-8 as precursors under inert atmosphere at different temperatures,and Ptwas loaded to form PtZn bimetallic catalysts.Using the PtZn catalysts as a control,cobalt nitrate was doped into the synthesis of ZIF-8 and Co was introduced in the subsequent treatment to synthesize PtCo bimetallic catalysts,which were significantly more active than PtZn bimetallic catalysts in the selective hydrogenation reaction of cinnamaldehyde.This is attributed to the fact that the Co as a co-catalyst is significantly more capable than Zn in constructing the interfacial state in conjunction with Pt,and is further supported by the subsequent comparison of the reactivity of the cobalt-based and zinc-based support loaded with Ptin different forms.（2）Three Ti O2-（101）,Ti O2-（100）and Ti O2-（001）with different dominant crystalline facets were selected as support to investigate the influence of facet effect in Pd and Ptbased catalysts.We have uncovered through a series of characterization and experiments such as XPS characterization,high temperature roasting（300°C and500°C）experiments,IR spectroscopy characterization and introduction of OH-into the reaction conditions that the factors behind the facet effect and noble metal effect that really affect the conversion and selectivity of the cinnamaldehyde selective hydrogenation reaction are highly correlated with the oxygen species on the surface of the support. |
