Sequestration of carbon dioxide in coal: Energetics and bonding from first-principles calculations

Abstract Sequestration of CO 2 in unmineable coalbeds is one of the attractive ways being investigated to reduce the CO 2 concentration in the atmosphere. Extensive experimental studies have demonstrated that storage of CO 2 molecules in coal seam involves both chemisorption and physisorption, but the underlying mechanism at the atomic scale has remained elusive. We report results of first-principles density-functional-theory calculations for the interaction between molecular CO 2 and coal. The calculations show that chemisorption of CO 2 in defective coal is possible, and CO 2 can form chemical bonding with defective coal, particularly at the defects involving carbon and hydrogen vacancies and epoxy functional groups. On the other hand, formation of chemical bonding of CO 2 with defect-free coal network is unlikely.