Gas Reactions of Carbon

This chapter reviews the majority of pertinent papers on gas–carbon reactions. The inherent chemical reactivity of the carbon and mass transport of the reactants and products can play an important role in affecting the kinetics of gas–carbon reactions. The chapter discusses the possibilities of using bulk-density and surface-area profile data on reacted carbons for better understanding of reaction mechanisms. One of the steps involved in a gas–carbon reaction is the chemisorption of the gas on the carbon surface. Some of the products of the gas–carbon reactions chemisorb on the carbon surface under certain conditions. Therefore, an understanding of the chemisorptions of gases on carbon is essential for the understanding of the gas–carbon reactions. In chemisorption, it is known that the surface atoms must have free valence electrons to form strong chemical bonds with gas molecules or atoms. Much recent work using electron paramagnetic resonance absorption techniques has confirmed the presence of unpaired electrons in various types of carbons. The number of unpaired electrons is a complex function of carbon heat-treatment temperature, apparently being affected primarily by the number and nature of imperfections in the carbon structure.