Development of Diamond-Carbon Nanotube Hybrid Materials

金刚石具有独特的物理性质，CVD金刚石工艺的最新进展为制备半导体金刚石薄膜提供了条件。我们首次发现，负载在金刚石粉末表面的几种金属或金属氧化物在甲烷和低碳氢化合物的几种反应中表现出非常高的催化活性。本研究是在一定程度上利用金刚石催化碳氢化合物在负载金属的氧化金刚石上的反应，得到金刚石/碳纳米管杂化材料。金刚石由sp3碳组成，而碳纳米管由sp2碳组成。如果能合成出金刚石和碳纳米管杂化材料，就有望获得独特的物理性能。从这些角度出发，本研究计划并成功地合成了金刚石-碳纳米管杂化材料。几种铁族金属负载金刚石粉在400~800℃的高温下被氢气还原并与甲烷和乙烷反应。镍和钯负载的金刚石af…更多的是伪造了大量的碳纳米纤维。在负载镍的情况下，甲烷和乙烷的碳化速率分别在500℃和600℃时达到最大，而在650℃时，两种碳氢化合物都没有观察到纳米纤维的形成。无论反应温度如何，在负载钴和铁的金刚石上都可以得到非常少量的碳纳米纤维。结果表明，在1000℃的载铁金刚石表面，只有很少量的单壁碳纳米管直接结合在金刚石表面，而载Pd的金刚石则在500~800℃的高温下生成了碳纳米纤维，在800℃的高温下，甲烷和乙烷都能生成大量的碳纳米纤维。此外，在800℃的条件下，以乙烷为碳源，在负载Pd的金刚石催化剂上，由初始生成的细碳纤维组合而成的超厚碳纤维，阐明了金属催化碳氢化合物分解碳纳米纤维的生长机理，为催化剂的设计和生长条件的确定提供了依据。较少

Diamond has unique physical properties and recent progress in CVD diamond process provided semi-conductor diamond thin films. We have first discovered that several metals or metal oxide loaded on powdered diamonds surface exhibited very high catalytic activities in several reactions involving methane and lower hydrocarbons. This research is extent ion of diamond catalyzed reactions of hydrocarbons on metal loaded oxidized diamond to give diamond and carbon nanotube hybrid materials. Diamond is composed of sp3 carbons whereas carbon nanotube is composed of sp2 carbons. If diamond and carbon nanotube hybrid materials could be synthesized, unique physical properties would be expected. From these perspectives, this research was planned and synthesis of diamond-carbon nanotube hybrid material was successfully achieved.Several iron group metal loaded diamond powder was hydrogen reduced and reacted with methane and ethane at an elevated temperature of 400 to 800 ℃. Ni and Pd loaded diamond af … More forded a large amount of carbon nanofibers. On Ni-loaded case the maximum rate of carbon was obtained at 500 ℃ with methane and 600 ℃ with ethane, and from both hydrocarbons no nanofiber formation was observed at 650 ℃. Very small amount of carbon nanofibers were obtained on Co and Fe loaded diamond irrespective of the reaction temperature. On Fe-loaded diamond at 1000 ℃, very small amount of single wall carbon nanotube directly bonded to diamond surface was obtained by TEM observation.On the contrary, with Pd-loaded case carbon nanofibers were produced at higher temperature of 500 to 800 ℃, and even at 800 ℃ a large amount of carbon nanofibers were produced both from methane and ethane. In addition, at 800 ℃ with ethane as a carbon source over Pd-loaded diamond catalyst, very thick carbon fibers were produced by the combinations of initially produced thin carbon fibers.Metal catalyzed carbon nanofiber growth mechanism by the decomposition of hydrocarbon was clarified and this shed light to the design of the catalyst and growth conditions. Less