| Recently, great interest has been devoted to spherical carbon aerogels due to their particular properties and promising applications such as electrode materials for supercapacitors and hydrogen storage. In this paper, spherical carbon aerogels were prepared through the sol-gel polymerization of formaldehyde with the potassium salt of 2,4-dihydroxybenzoic acid using an inverse emulsion polymerization, under the catalyst of potassium carbonate. Spherical carbon aerogels were characterized by N2 adsorption,IR,TG-DSC,SEM,TEM and dynamic light scattering. It was found that the preparation condition had little effect on the sphericity of carbon aerogels. We investigated the influence of stirring speed,the amounts of surfactant and catalyst and carbonization temperature on the particle size distribution. The results indicated that they all influenced the particle size distribution. The surface area of the sample prepared under supercritical drying was higher than that synthesized under ambient drying. The surface area increased with the augment of catalyst addition. We had prepared Fe-,Co-and Ni-doped carbon aerogels through sol-gel polymerization of formaldehyde with the potassium salt of 2,4-dihydroxybenzoic acid, followed by ion exchange with Fe(NO3)3,Co(NO3)2 and Ni(NO3)2. When the samples were pyrolyzed at 1000℃, the Fe-,Co- and Ni-doped carbon aerogels were spherical particles, and the growth of metal nanoparticles and graphitic nanoribbons were observed within the framework of the aerogels; The distance of graphite layers in the nanoribbons was -0.34nm. These metal-doped carbon aerogels had lower surface areas and wider pore size. The Nickel content (13.84%) in the Ni-doped carbon aerogels was highest.We investigated the influence of activation methods on the structure and performance of carbon aerogels. The samples activated by KOH or steam remained spherical shape after activation treatment. When the samples were activated by KOH, with the increase of activation temperature, the yield decreased but the value of adsorption to Iodine of products decreased; Carbon aerogels activated at 800℃exhibited high surface area of 2000m2/g and multimodal pore size distribution. The yield of carbon aerogels activated by steam was higher than that chemical activation, and the value of adsorption to Iodine was 491m2/g for the sample.Spherical carbon aerogels were studied as electrode materials in supercapacitor by galvanostatic charge/discharge and cyclic voltammetry. The results showed that electrode reaction exhibited nearly ideal double-layer capacitance characteristics, high efficiency and stability. The capacitance of supercapacitor increased with the augment of catalyst addition. Spherical carbon aerogels synthesized under nD/nC of 100 and with supercritical drying method had the largest capacitance of 142F/g. For the activated samples, they all exhibited higher capacitances than that without activation. When the mass ratio of KOH between carbon aerogels was 4:1, the activation product delivered the highest capacitance of 195F/g. The metal-doped carbon aerogels had much lower capacitance than metal-free carbon aerogels. The result of impedance spectroscopy showed that the sample activated by KOH had higher resistance.The Electrochemical hydrogen storage properties of carbon aerogels electrodes were also investigated. The result showed that the amount of catalyst addition influenced the hydrogen storage capacity. The sample synthesized under nD/nC of 500 exhibited highest capacity and its first discharge capacitance was 57.4mAh/g. The first discharge capacities of Fe-,Co- and Ni-doped carbon aerogels were much higher than metal-free samples, but the capacities decreased by more than 55% under several circles.
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