Production of micro- and mesoporous carbons by pyrolysis of the lithium salts of aromatic acids

As a new process for the production of micro- and mesoporous carbon materials, the thermal decomposition of the lithium salts of aromatic acids (terephthalic acid, 1,3,5-benzenetricarboxylic acid, and 1,2,4,5-benzenetetracarboxylic acid) was followed by TGA, MS, SEM, TEM, elemental analysis, and N-2 adsorption. The lithium salt of terephthalic acid was decomposed at temperatures above 550 degrees C and then converted into a composite of amorphous carbon and microcrystalline lithium carbonate (600-700 degrees C) or oxide (800-900 degrees C). The amorphous carbons produced by washing out the lithium compounds showed surface areas of 480-780 m(2) g(-1), and the micro- and mesopore volumes attained 0.27 and 0.93 cm(3) g(-1), respectively, at the pyrolytic temperature of 850 degrees C. The mesopores were distributed from ca. 20 to 100 nm in size, and the distribution was independent of the pyrolytic temperatures. The pore size was, however, increased when larger-size crystals of the lithium salt were employed as the starting material. Both porous carbons prepared from the lithium salts of 1,3,5-benzenetricarboxylic acid and 1,2,4,5-benzenetetracarboxylic acid showed similar surface areas and pore size distributions to those from terephthalic acid. (c) 2005 Elsevier Inc. All rights reserved.