| Single-atomic catalysts,due to their unique structure,electronic properties and uniform active sites dispersed by atoms,exhibit excellent catalytic performance in a variety of chemical reactions.This thesis aims to develop a novel catalyst by doping V atoms into the mesoporous silica KIT-6 to cooperate with Pt metal for the selective hydrogenation of 1-acetylpiperidine;and to develop a Ni single-atomic catalyst through a core-shell strategy,which can selectively hydrogenate nitrobenzene to aniline.The main research contents are as follows:1.Through the one-step co-assembly method,V atoms were introduced into mesoporous silica KIT-6,and then Pt metal nanoparticles were loaded to the surface of KIT-6 to obtain the catalyst Pt/x V-KIT-6,which was used for the hydrodeoxygenation of 1-acetylpiperidine.This work proved that V atoms were successfully incorporated into the KIT-6,activating the silica surface to strength the interactions with the Pt nanoparticles.As a result,more Pt~0 species were formed.In addition,the effect of V content on the structure and performance of the catalyst was further examined.It was found that increasing V content was beneficial for the dispersion of Pt nanoparticles on the surface of KIT-6 and the increase of the surface Pt~0 species ratio,thereby improving the conversion and selectivity of1-acetylpiperidine hydrodeoxygenation.The conversion rate of 1-acetylpiperidine at150°C for 10 h is 99%,the selectivity is close to 100%,and the catalyst has excellent stability.2.In this part,a core-shell strategy is used to coat the metal hydroxide with polymer,and then high-temperature pyrolysis and pickling were conducted to synthesize an hollow nitrogen-doped carbon(CN)material anchored with single-atomic Ni.This work proves that the Ni in the as-synthesized SA-Ni/CN is mainly distributed uniformly on CN in the form of quasi-single atoms.In addition,the Ni atoms as the active sites could catalyze the hydrogenation of nitrobenzene to aniline.This thesis introduces two different atoms(V,Ni)into the catalyst through two different strategies.The V atom in the former acts as an auxiliary agent by activating the surface of silica,and interacts with the main active components Pt to synergistically catalyze the hydrogenation of amide.The Ni atom in the latter is used as an activity to catalyze the hydrogenation of nitrobenzene.This work will provide ideas for the preparation of single-atomic catalysts and the development of high-efficiency hydrogenation catalysts. |
