Preparation And Characterization Of Corn Starch-based Porous Carbon Materials

In this paper, we put forward a method that can transform starch powder into monolithic materials and two methods that can retain the original shape of porous starch while carbonizing based on the properties of gelatinization and enzymolysis of corn starch. The products were characterized by SEM, XRD, FTIR, N2adsorption and ultimate analysis.Monolithic carbon materials with three dimensional network structures were successfully prepared by combining so-gel technology, vacuum freezing drying with high temperature carbonization technology using corn starch as carbon source, realizing the target of transforming powder materials into porous monolithic materials with three dimensional network structures. The effect of gelatinization process on three dimensional network structures of monolithic carbon materials was investigated. It was found that the concentration of starch suspension and nickel acetate simultaneously has an important influence on three dimensional network structures of monolithic carbon materials.Magnetic carbon spheres with hierarchical pore structure included micropores, mesopores, and macropores were designed and controllably synthesized using corn starch as carbon source and nanoclusters of iron species made by glycol reduction method as metal source by a combined procedure of enzymolysis, pre-oxidation and catalytic carbonization. The effect of pre-oxidation was discussed and found that the decisive factor of retaining the original shape of porous starch while carbonizing was the destruction of crystallite structure at low temperature, in order to prevent melting while carbonizing.Nitrogen doping porous carbon spheres were synthesized using corn porous starch as carbon source and NH4Cl as protectants and nitrogen source. The dual role of NH4CI was discussed while carbonizing. It was found that the HC1from the decomposition of NH4C1facilitated the dehydration of porous starch during carbonizing, which led to the destruction of the crystallite structure at low temperature and benefited the synthesis of carbon spheres that retaining the original shape of porous starch. In addition, the NH3from the decomposition of NH4C1can react with the hydroxyl groups on porous starch and form C-N bonds in order to achieve the target of nitrogen doping during carbonizing.