The Synthesis And Properties Of Inorganic Hierarchically Porous Masterials

The hierarchically porous materials hierarchical porous materials possessing well defined macropores and interconnected meso-and micropores, have attracted much attention. Hierarchically porous materials can combine in one system:improved mass transport facilitated by the macropores and high surface area and pore volume from micro-/mesopores. As a result, they show a highly potential application value as adsorbent, catalyst carrier, energy storage and conversion, sensors, etc. This thesis is mainly launched the synthesis and application of multi-sized porous structure, hierarchically porous materials have new chemical properties through the adjustment of surface properties, the main research results are as follows:(1) Simulating the polymerization of polyphenol on the solid surface in nature, hybrid adsorbents were prepared by coating the hierarchically porous silica (HPS) with poly pyrogallol (PG) layer. Such material has a macroporous skeleton and well-defined mesopores. During a facile and mild reaction, poly PG membrane is strongly bindedd to the pore surface of HPS through covalent and noncovalent interactions. A high-performance adsorbent, HPS/PG, was got. It exhibits a large capability to adsorb various pollutants in wastewater, such as heavy metal ions (Hg2+, Pb2+, Cu2+, Ni2+ and CrO42-), organic dyes and pesticides. Especially, HPS/PG showed good purifying capacity to Hg2+ ion and neutral red, which could reach 157.2 mg g-1 and 671.1 mg g-1, respectively. More than that, HPS/PG showed good recovering ability to simulate wastewater with complex components. The removal rate for any of the pollutants was more than 98%. The high adsorption capability of HPS/PG should be due to the hierarchically porous structure and ideal surface coating, which combine the benefits of both physical and chemical adsorptions.(2) Porous carbon monoliths with hierarchical macro-mesoporous structure have been synthesized via a spontaneous sol-gel process and a carbonization process. Phenolic resin is used as structure-directing agent, polyphenol and formaldehyde can be used as carbon source, keeping in a closed condition at a constant temperature, these trimodal pore systems are formed spontaneously. A detailed investigation reveals that the features of pores are strongly associated with the catalyst concentration, the amount of phenolic resin and polyphenol. Appropriate choice of the starting composition, by which the phase separation and gelation concur, allows the production of bicontinuous macroporous carbon monoliths in large dimensions, the specific surface area can reach 602.14 m2 g-1. The PCM reveals a high specific capacitance value and electrochemical stability as the electrode materials of super capacitor. The specific capacitance value of PCM can reach up to 385 F g-1. Furthermore, such PCM materials also show considerable electrochemical stability, which remain at least 90% of the capacitance after 1000 cycles.