| Recently, the great increases in gas and oil prices reminder people to develop cleaner, more reliable and renewable fuels to satisfy our society’need. In all of the aletermative fuel sources, H2is the most promising one. The biggest problem of applying H2is the storage. Several materials have shown varying degrees of promise for H2storage. Amoung these, porous carbons are the leading candidate for investigation as potential H2storage media, due to the low cost, high surface area and controllable pore structures. It is thought that microporous carbon materials have the pore diameters best suited for H2storage. However, it has proven non-trivial to achieve both the large surface area and the micropore diameters necessary for high H2storage. Many methods such as activation and inorganic or organic templating have been utilized to achieve such porous materials; however, no material has mastered both a large surface area and small pore diameter. Additionally, most of the templating procedures suffer from dangerous template removal conditions and very narrow production conditions, making large scale production impractical. Initial results indicated that CO2treatments of poly (etheretherketone)(PEEK), may be very interesting to investigate for the production of porous carbonsHere, we describe two methods by employing CO2and steam to activate PEEK. Large surface area (524-3275m2/g) microporous carbons (MPCs) have been synthesized and categorized for their roles as H2storage materials. It was found that the hydrogen uptake was essentially related to the surface area, pore volume and pore size. These two activation methods had different mechanism. CO2activation was more likely to expand the micropores to mesopores, while the steam activation was intend to increase the pore volume, but preserve the micropores. The well balanced surface area, pore volume and pore size were significant to the hydrogen uptake. Because of the very high surface area (≥3000m2/g), large cumulative pore volume (～1.7cm3/g) and small pore size (≤3nm), these materials displayed impressive H2sorption properties, including gravimetric and volumetric H2storage capacities of approximately5wt%and35g/L respectively at-196℃,2MPa. Furthermore, the impressive binding energies up to～8kJ/mol were also observed.It’s thought that boron-doping in carbon could improve the H2uptake. To dope boron in PEEK derived high surface area microporous carbon, two kinds of boron-containg precursors (phenylboronic acid and o-carborane) were used to post-treat microporous carbon, and up to6.6wt%B was achieved in the final samples. The bonding states of boron were analysized by X-ray photoelectron spectroscopy (XPS) and found that boron could exist as two chemical structures, identified as B-O and B-C species. The boron-doped samples were also used for H2storage.In some applications, porous graphitic carbon, which has high conductivity, well-aligned crystallization, is nessesery. In chapter5, ordered mesoporous carbon materials with partially graphitized structure were synthesized by the one-pot, co-assembly of tri-block copolymer with phenolic resin in the presence of ammonium ferric citrate. The structure was characterized by XRD, TEM, N2sorption and TG/DTA. The mesoporous structure of the polymer conserved after the addition of ammonium ferric citrate. The graph itization of carbon material was achieved at700℃by utilizing iron as catalyst. The final graphitic porous carbon materials performed well in the selective oxidation of benzyl alcohol.The excellent properties of porous carbon protruded their commercial application in the electrochemical energy. Electrochemical energy resources are essential to the world. The energy resources storage devices, including batteries, fuel cells and supercapacitors, are important components for the application of renewable energy related technology. Supercapacitors have higher power density and longer cyclic life. Among all the materials investigated as electrode in supercapacitors, porous carbon is the most widely used electrode materials in energy storage devices. It is generally accepted that in such electrodes, mesoporosity is better for supercapacitor than microporosity. To improve the capacity of mesoporous carbon based electrode, we have designed a composite film composed of mesoporous carbon, multiwalled carbon nanotubes (MWNTs) and conducting polymer, Poly-3,4-ethylenedioxythiophene/poly (styrenesulfonate)(PEDOT-PSS). Each component in the composed film contributes differently to the improved electrochemical properties. The electrochemical performance of the film is evaluated by cyclic voltammetry and constant current charge/discharge method. With the assistance of MWNTs and conducting polymer, the capacitance of the mesoporous carbon based electrode is amplified six times. The electrode also presented excellent charge/discharge rate and good cycling stability, retaining about94%of its initial capacitance after1000cycles. The results demonstrated that the mesoporous carbon is more effectively utilized with assistance of MWNTs and conducting polymer in the electrode. Such method is very promising for the future applications of the porous carbon in electrode materials of high performance electrochemical supercapacitors. |
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