Preparation And Structure Properties Of Metal-doped Ordered Uniform Porous Carbon Molecular Sieves

Carbon molecular sieves (CMS) as a kind of novel porous absorbent material are obtained by high-carbon content organics through carbonization. Compare with conventional molecular sieves, CMS have several advantages, such as uniform pore size distribution, developed pore structure, excellent gas permeability and selectivity, thermal and chemical stability. For these reason, CMS have been widely applied in the flied of air adsorption/separation, catalyst supports, and energy storage.In this thesis, it is reported that the metal-doped polymer-derived carbon molecular sieve particles were prepared by inverse suspension polymerization. And the different addition processes of template are explored to study the effects on metal-doped situation and pore structure developing of CMS. The two addition processes as follows:a) External template method:Monomer and metal-salt are introduced into the skeleton pores of silica directly by dipping process. Through polymerization, carbonization and co-reduction, the metal-doped ordered uniform porous carbon molecular sieves can be obtained. Research and analysis results show that the external template method has better structural controllability for CMS.b) Internal template method:The metal ion-containing copolymer of acrylonitrile (AN)/y-methacryloxypropyltrimethoxysilane (KH-570) as precursor after hydrolysis under acidic condition (HCL/H2SO4), through carbonization and post-treatment process, the metal-doped carbon-silica composite carbon molecular sieves are obtained. In the process of hydrolysis, KH-570plays two roles, one can controls the pore structure of CMS as template by partial hydrolysis to SiO2, the other is introduced into carbon chain as a silicon source;-CN hydrolyze to-COOH groups, complexation with Ag+, make for metal catalyst disperse evenly. Employ this novel method, the template can avoid covered with part of precursor.Effect of synthetic method, KH-570content, carbon temperature, holding time and heating rate on CMS properties were investigated, optimizing the preparing procedure. The thermal stability, chemical structure of precursor and microstructure, pore structure of CMS were studied by TGA, FTIR, XRD and Nitrogen adsorption at77K, respectively. Result showed that:during the high-heat treatment, precursor displayed similar thermal decomposition behavior, such as dehydrogenation, deoxidization, cyclization and transform into agraphitic carbon structure gradually. The metal-doped highly dispersible CMS particles can be prepared, and keep the pore structure under control can be realized. But some significant difference can be observed between two synthetic methods, including microstructure and pore structure of CMS. The inorganic phase Si could be introduced into CMS effectively by internal template method, and the excellent permeability and selectivity will be observed in the field of air-separation. The higher specific surface area (reached1056m2/g) and developed pore structure (reached0.45cm3/g, account for ca.70%) are quite obvious that it is better than external template method.