The Synthesis Of Hybrid Mesoporous Carbons And Their Applications

Ordered mesoporous carbons possess good conductivity, strong framework and high surface areas, showing great advantages in electrical chemistry, adsorption, separation and catalysis. Hybrid ordered mesoporous carbons are therefore of great interest owing to the high surface areas, high stability, uniform and large pore sizes and confined mesochannels of inorganic solids, as well as functionalities which are generated from the hybrid component. Ordered hybrid mesoporous carbons prepared by the direct amphiphilic surfactant templating approach are chosen for this thesis. The reactivity of the organic precursors is the key factors for one-step synthesis of hybrid mesoporous carbons. The hybrid mesoporous carbons have potential applications in catalysis, adsorption and electronic devices.Firstly, N-doped highly ordered mesoporous polymers and carbons are synthesized via a one-step organic-organic evaporation induced self-assembly method. The frameworks are constituted by polymer and carbon upon calcination at 350°C and 900°C, respectively, and N incorporates into the frameworks (0.2– 1.6% in molar ratio). N-doped mesoporous carbons have high surface areas (~ 1200 m2/g) and large pore volumes (~ 0.65 cm3/g). With the increase of the initial amount of m-aminophenol, the graphitizing degree of mesoporous carbon increases.In Chapter 3, mesoporous C/SiO2-Al2O3 nanocomposites are synthesized via an organic-organic self-assembly method by using resols as a polymer precursor, tetraethyl orthosilicate (TEOS) and aluminum isopropoxide or aluminum chloride as inorganic precursors, and triblock copolymer F127 as a template. The surface areas, pore sizes and pore volumes of mesoporous C/SiO2-Al2O3 nanocomposites are ~ 1200 m2/g, ~ 6.4 nm and ~ 0.65 cm3/g, respectively. The nanocomposites possess acidic sites which are originated from SiO2-Al2O3 and the acidic sites uniformly dispersed in the carbonaceous frameworks. In Chapter 4, the effects of acid in the synthesis of mesoporous carbons from the organic-organic assembly are investigated. Boric and phosphoric acids exhibit significant influence on the assembly. They can react with phenol/formaldehyde resins to form hybrid resins with B or P atoms. After high-temperature carbonization at 900oC, the highly ordered mesoporous carbon products contain hybrid atoms. A phase transformation simultaneously occurs, which is related to the variation in the hydrophilic/hydrophobic ratio. The addition of non-reactive acids, e.g. HCl and H2SO4, shows negligible effects on the mesostructure within a certain concentration, but accelerates the polymerization.In Chapter 5, we report, for the first time, the adsorption ability for dyes on highly ordered mesoporous carbons prepared from the direct surfactant self-assembly route. Both the pore size and the surface areas show influence on the adsorption properties. The mesoporous carbon with extremely high surface area and large pore size exhibits the highest adsorption amount for all involved dyes. For example, the adsorption amount for rhodamine B is 876 mg/g, while this value is only 128 mg/g on activated carbon.