Porous Carbon Materials For Energy Storage And CO₂ Adsorption

In this thesis, we focus on the synthesis of novel porous carbons and their applications in the energy storage and CO₂ adsorption and separation have been investigated. We have designed and prepared a series of porous carbon materials with well-developed porosity and excellent chemical properties. These carbon materials exhibit excellent performance in the energy storage and CO₂ adsorption and separation.Highly porous carbons have been successfully prepared using Fe-doped activated carbons as precursors and KOH as activated agent. The obtained porous carbons possess well-developed porosity with ultra-high surface area ?up to 3474 m2/g? and large pore volume ?up to 1.91 cm3/g?. The results indicate that the carbon matrix can be etched to generate more pores due to the reaction between iron oxide and carbons during the activation processes. Due to the excellent textual properties, the porous carbons show a high hydrogen uptake capacity of 2.76-2.96 wt%at 77 K and 1 bar. Furthermore, the porous carbons exhibit a high CO₂ capture capacity of 26.2 wt% and 16.4 wt% at 273 and 298 K and 1 bar. Additonally, the MnO₂-loaded porous carbons also have been synthesized. The electrochemical tests indicated that the sample possesses a high specific capacitance of 456 F/g at the current density of 1 A/g in the 6 M KOH aqueous electrolyte.Nitrogen-doped porous carbons have been successfully synthesized via chemical activation using hydrothermally carbonized chitosan as precursors and KOH as the chemical agent. The carbons possess a well-developed porosity and high nitrogen content. These properties can be tuned by the modification of chemical conditions ?KOH/HC ratio and chemical activation?. Due to their excellent porous structure and surface property, the N-doped porous carbons exhibit high performance for CO₂ capture and supercapacitors. The CH-2-600 shows a large CO₂ adsorption capacity up to 19.5 wt%and the CH-2-800 preserves a high specific capacitance of 366 F/g at the current density of 0.2 A/g in the 6 M KOH aqueous electrolyte.Poly?o-phenylenediamine? ?PoPD? is used as a precursor to synthesize nitrogen-doped carbons with high surface area through chemical activation. The obtained carbons possess high nitrogen content ?4.6-11.2 wt%? and well-developed porosity with large surface areas ?2116-3515 m2/g? and narrow pore size distribution ?0.6-1.4 nm?. The nitrogen-doped carbons are examined as absorbents for gas adsorption and as electrode materials for supercapacitors. Due to the high nitrogen content and large surface area, the carbons show high CO₂ uptakes of 14.1-17.2 wt% at 298 K and 1 bar and large hydrogen adsorption capacities of 2.0-2.5 wt% at 77 K and 1 bar. Furthermore, we observe that the carbons exhibit excellent performance as supercapacitor electrodes with a high specific capacitance of 303 F/g at a current density of 0.2 A/g. In addition, well-dispersed RuCo nanoparticles ?NPs? supported on N-doped porous carbons have been in situ synthesized via the co-reduction of aqueous solution of ruthenium ??? chloride, cupric ??? chloride and N-doped porous carbons with ammonia borane. The results show that the as-synthesized NPs exhibit high catalytic activity for hydrolytic dehydrogenation of AB. The activity of RU2CO3/NPC catalyst in terms of turnover frequency is 495 mol H2/min/?mol Ru?, which is higher than that of most reported Ru-based or other noble metal-based NPs for the catalytic hydrolysis of ammonia borane. Furthermore, the as-prepared NPs exhibit satisfied durable stability for the hydrolytic dehydrogenation of AB.Hydrothermally carbonized organic materials have been used as precursors to synthesize N-doped porous carbon. The synthesis methodology comprises two steps:?i? hydrothermal carbonization of L-arginine and glucose, and ??? chemical activation using KOH as activating agent. The obtained N-doped porous carbon possesses high surface area ?1372-1899 m2/g?, narrow micropore size distribution in the 0.6-1.3 nm range and high nitrogen content ?up to 5.89 wt%?. Ascribed to the large surface area and high nitrogen contents, the carbon shows mediate hydrogen uptakes of 2.01 wt%, high CO₂ uptakes ?17.7 wt%, at 298 K and 1 bar? and a good performance as the supercapacitor electrode with specific capacitance of 281 F/g in 6 M KOH at a current density of 0.1 A/g.