The Role of Chemisorbed Oxygen on Diamond Surfaces for the Dehydrogenation of Ethane in the Presence of Carbon Dioxide

Abstract

Oxidized diamond played a significant role as an efficient support for a Cr 2 O 3 -loaded catalyst during the dehydrogenation of C 2 H 6 to C 2 H 4 in the presence of carbon dioxide at 923 K, giving a 22.5% C 2 H 4 yield with a 87.7% C 2 H 4 selectivity. The activity of the oxidized diamond-supported Cr 2 O 3 catalyst in the presence of CO 2 was about 3 times higher than that in the absence of CO 2 . The activity of the oxidized diamond-supported Cr 2 O 3 catalyst increased with increasing CO 2 partial pressures. XPS analyses of the fresh and the reacted catalysts in the presence and absence of CO 2 revealed that CO 2 maintained the surface Cr 2 O 3 at a higher-oxidation state than the reaction in the absence of CO 2 . On the other hand, bulk of Cr 2 O 3 was not reduced in either atmosphere.