Preparation And Catalytic Performance Of Fe_xO_y,MoS₂/Nitrogen Doped Porous Carbon

Nitrogen doped porous carbon materials are the ideal catalyst supports, because they have high specific surface area, narrow pore size distribution, flourishing hole structure and abundant functional groups,good conductivity and stability. Due to the interactions between doped nitrogen atoms and catalysts, the electronic structure of catalysts supported on nitrogen doped porous carbon can be tuned, which will enhance its catalytic activity and stability. In this dissertation, catalysts of several transition metal compounds loading on nitrogen doped porous carbon have been synthesized by in-situ and post synthetic methods, and their catalytic activity and recyclability towards the organic reactions and electrocatalytic reactions have been investigated. The main contents of this dissertation are as follows:Firstly, nitrogen doped porous carbon materials were synthesized via hard template method by using SiO2 spheres as the template and melamine as the nitrogen source. The results show that the products have 3D interconnection porous structures, mesopores of 2.5-13 nm, and high content of nitrogen which mostly exists in the form of pyridine nitrogen.Secondly, catalysts of Fe₂O₃/nitrogen doped porous carbon and Fe2O4/nitrogen doped porous carbon were synthesized by in situ and impregnation respectively. Then, the catalytic performance of the former with different pore sizes towards Ullmann C-N coupling reaction has been evaluated. The result shows that Fe₂O₃/nitrogen doped porous carbon prepared by using Si02 spheres of 337 nm as the template exhibits the highest catalytic activity and is also stable for reuse. Meanwhile,Fe₃O₄/nitrogen doped porous carbon has a high catalytic activity to the reduction reaction of nitrobenzene.Thirdly, SBA-15 was synthesized by using hydrothermal method synthesis with a certain size. Then, CMK-3 and N-CMK-3 was obtained by using SBA-15 as the template and sucrose as the carbon source in presence of ammonia and in absence of ammonia, respectively. Then,MoS₂/CMK-3 and MoS₂/N-CMK-3 were prepared by impregnation.Subsequently, The preparation temperature and content of MoS₂ were optimized. The results show that MoS₂/CMK-3 prepared at 300? with 41.5wt% content of MoS₂ has the highest electrocatalytic activity toward HER. Meanwhile, MoS₂/N-CMK-3 exhibits higher stability for reuse,which proves that the doping nitrogen is an effective way to improve the stability of the catalysts.