Development of new dehydrogenation catalyst using powdered or thin film diamond as support

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Activated carbon composed of sp2 carbon atoms were often used as support material for catalytic reactions. However, up to now diamond composed of sp3 carbon atoms have never been used as support material for catalytic reactions. This work focused on the catalyiic activities of various metal or metal oxides loaded on oxidized diamond catalyst for several reactions, and have first elucidated in the world that oxidized powdered diamond exhibited excellent behavior1. Several metal oxides loaded oxidized diamond catalyzed dehydrogenation of ethane was carried out, and found that chromium oxide loaded oxidized diamond exhibited high activity in the dehydrogenation of ethane to ethene. In this reaction, when carbon dioxide was used as a diluent for ethane, at 650 ℃ 23 % ethene yield was obtained. This value is three times higher than that observed in the run under Ar atmosphere2. Partial oxidation of methane was carried out over nickel loaded oxidized diamond catalyst. At 650 ℃ synthesis gas … More was obtained in a high yield. Increasing a reaction temperature to 700 ℃, carbon deposition over catalyst was greatly decreased, indicating that oxidized diamond can be used even in oxidizing conditions. Cobalt loaded oxidized diamond exhibited similar catalytic activity as that of nickel loaded catalyst. Carbon deposition did not occur even lowertemperature of 60Q ℃3. Methanol decomposition over nickel loaded oxidized diamond catalyst was carried out. Catalyiic activity was observed at 250 ℃ and increased greatly at 300 ℃. However, at a higher temperature methane formation increased to give lower yield of hydrogen. Addition of water to methanol decreased methane formation to give CO to H_2 ratio of 1. Detailed studies on these reactions by spectroscopic analyses of the catalysts and non steady state reactions to elucidate mechanisms of the reaction path ways were carried out. High performance of oxidized diamond support seemed to be weak but significant interaction of loaded metal or metal oxide to diamond surface Less