Abstract: Microporous carbonaceous materials, useful in the storage of gaseous fuels such as methane and natural gas, are improved through modification of their microporous structure in a post-carbonization process. This modification is done by heat treatment in an oxidizing atmosphere containing carbon dioxide with or without other diluting gases such as nitrogen, argon or water-vapor. The post-carbonization process involved modifying a starting microporous carbon with heat treatment in which the carbon is contacted with a carbon dioxide-containing atmosphere. This new treatment can be favorably applied either to selected and commercially available activated microporous carbons which have been designed for applications other than fuel gas storage or to synthetic microporous carbons proposed for storage of light gases.

Abstract: A method of making a microporous carbon material which includes providing a precursor selected from the group consisting of crystalline salts of aromatic sulfonates and nonporous polymeric salts. Prior to carbonization, the precursor is treated by ion exchange or other conventional processes to introduce a metal such as iron, nickel and cobalt into the precursor. Heat treatment of such composite precursors in the temperature range of 350.degree. to 850.degree. C. in an inert oxygen free atmosphere for a sufficient time promotes thermally induced hydrogen abstraction and rearrangement of BSUs which result in the formation of a composite, carbonaceous microporous material which contains a metal component, and has a pore size distribution in the range of about 4-15 .ANG. A. The structural and storage characteristics of the microporous carbon materials are also disclosed.