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

由sp2碳原子组成的活性炭常被用作催化反应的载体材料。然而，迄今为止，由sp3碳原子组成的金刚石还没有被用作催化反应的载体材料。本工作着重研究了载于氧化金刚石催化剂上的各种金属或金属氧化物对几种反应的催化活性，并在国际上首次阐明了氧化金刚石粉末具有优异的催化活性1。研究了几种金属氧化物负载氧化金刚石催化乙烷脱氢反应，发现氧化铬负载氧化金刚石在乙烷脱氢制乙烯反应中表现出较高的活性。在此反应中，以二氧化碳为乙烷的稀释剂，在650℃下得到23%的乙烯收率。这个值比在氩气环境下运行时观察到的值高3倍。在负载镍的氧化金刚石催化剂上进行了甲烷的部分氧化。在650℃条件下，得到了高收率的合成气体。将反应温度提高到700℃，催化剂上的积碳量大大减少，表明氧化金刚石即使在氧化条件下也可以使用。载钴氧化金刚石表现出与载镍催化剂相似的催化活性。在60Q℃的低温下也不发生积碳现象。在负载镍的氧化金刚石催化剂上进行了甲醇分解。在250℃时催化活性显著提高，在300℃时催化活性显著提高。然而，在较高的温度下，甲烷的生成增加，使氢的产率降低。甲醇加水减少甲烷的生成，使CO / H_2比为1。通过对催化剂和非稳态反应的光谱分析，对这些反应进行了详细的研究，以阐明反应路径的机理。氧化金刚石载体的高性能似乎是弱的，但负载金属或金属氧化物与金刚石表面的相互作用较少

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