[1Ip01-08] Low-dimensional Material/Nanostructure/Nanomaterial (LD/NS/NM)

[1Ip01] In situ XAFS and DRIFT studies on reaction during carbon nanotube growth by alcohol catalytic chemical vapor deposition

*Takahiro Maruyama^1,2, Yukiya Koyama¹, Shinya Mizuno¹, Mao Yotsumoto¹, Shusaku Karasawa¹, Kamal Prasad Sharma², Yuichi Haruyama³, Shigeya Naritsuka⁴, Takahiro Saida^1,2 (1. Department of Applied Chemisty, Meijo Universiy, 2. Nanomaterial Research Center, Meijo University, 3. Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 4. Department of Materials Science and Engineering, Meijo University)

We investigated growth process of CNTs by ACCVD from Ir catalysts on SiO₂ and Co catalysts on Al₂O₃ by using in situ DRIFT and XAFS analyses. In the case of Ir catalysts, ethoxy was formed by decomposition of ethanol, forming CH_x on the catalyst surface, and SWCNTs were grown from metallic Ir catalyst particles. On the other hand, acetate was formed on Co catalysts, which was decomposed into CH_x. During SWCNT growth, Co catalysts were partially carbonized. UPS results showed that the d band center of the 3d band of Co catalyst particles was ~0.8 eV lower than that of the 5d band of Ir catalyst particles. Such a low energy position of the d band center of Co catalysts would lead to high efficiency of decomposition rate of ethanol molecules and the wide range in the optimal growth temperature.