SOFT X-RAY ABSORPTION SPECTRA IN THE 0 K REGION OF MICROPOROUS CARBON AND SOME REFERENCE AROMATIC COMPOUNDS

Abstract

To analyze the oxidation states of the graphitic surface of microporous carbon, soft X-ray absorption spectra in the 0 K region have been obtained for microporous carbon and various aromatic compounds. The aromatic molecules studied are substituted with one or more of the following oxygenated functional groups: hydroxy (–OH), carboxy (–COOH), carbonyl (>C=O), formyl (–CH=O), and ether (–O–). From comparison of the soft X-ray absorption spectra of microporous carbon and of reference aromatic compounds, the most probable chemical bonding states of oxygen in microporous carbon are found to be –COOH and >C(H)=O. Spectral features in the soft X-ray absorption spectra of microporous carbon are well explained by the O2p density of states in these oxygenated functional groups from discrete variational (DV)-Xα molecular orbital calculations.