Mesoporous high-surface-area activated carbons were prepared from coconut shells by a simultaneous physical and chemical activation technique that employs carbon dioxide and zinc chloride as the physical and chemical agents, respectively. The resultant activated carbons possess an N_2-BET surface areas above 2000 m~2/g, a total pore volumes as high as 1.9 cm~3/g, and a mesopore content (ratio of mesopore volume to total pore volume) of over 70percent. The average pore size ranges from 2 nm to 3.5 nm. Both the surface area and the mesopore content could be tuned by controlling the experimental parameters, viz. ZnCl_2 to coconut shell (Zn-C) ratio, duration of exposure to the carbon dioxide atmosphere and temperature of activation. In particular, Zn-C ratios above 1 yielded high surface areas and ratios above 2 resulted in high mesopore content.
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