An Extremely Active Pt/Carbon Nano-Tube Catalyst for Selective Oxidation of CO in H 2 at Room Temperature
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An Extremely Active Pt/Carbon Nano-Tube Catalyst for Selective Oxidation of CO in H2 at Room Temperature Ken-ichi Tanaka Æ Masashi Shou Æ Hongbin Zhang Æ Youzhu Yuan Æ Tokio Hagiwara Æ Atsushi Fukuoka Æ Junji Nakamura Æ Daling Lu
Received: 5 June 2008 / Accepted: 3 July 2008 / Published online: 13 August 2008 Ó Springer Science+Business Media, LLC 2008
Abstract Pt catalyst supported on carbon nano-tube (CNT) was extremely active for the selective oxidation of CO in H2 at room temperature, which was remarked contrast to the Pt supported on an active carbon (Vulcan carbon) and a graphite powder. Complete oxidation of CO was attained on a 5 wt.% Pt/CNT catalyst (0.8 g) at ca. 40 °C when the O2/CO ratio in a flow of H2 (20 mL/ min) + CO (3.0 mL/min) + O2 + N2 was adjusted to be larger than 0.75 at the total flow rate of 100 mL/min. Specific activity of the Pt/CNT catalyst was explained by efficient provision of reactant molecules diffusing on CNT surface to Pt particles.
K.-i. Tanaka (&) M. Shou T. Hagiwara Advanced Science Research Laboratory, Saitama Institute of Technology, 1690 Fusaiji, Fukaya, Saitama 369-0293, Japan e-mail: [email protected] H. Zhang Y. Yuan State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, Xiamen University, Xiamen 361005, China A. Fukuoka Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan J. Nakamura Graduate School of Pure and Applied Science, Tsukuba University, Tennoudai 1-1-1, sukuba, Tsukuba, Ibaraki 304-8573, Japan D. Lu Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
Keywords Selective oxidation of CO Pt/nano-tube carbon Pt/Graphite Pt/Vulcan carbon CO tolerant hydrogen fuel cell
1 Introduction Hydrogen fuel cell generates the power by the shift reaction gas is impossible at the present time, because the anode of hydrogen fuel cell is poisoned by several 10th ppm CO. Fore example, 50 ppm CO for a Pt–Ni/C anode [1] and 100 ppm CO for Pt–Ru on defect free carbon nanotube (CNT) [2]. Therefore, CO in hydrogen fuel is lowered to ca. 10 ppm by preferential oxidation (PROX) reaction using Ru catalyst at 150–170 °C. So far, several low temperature catalysts for the selective oxidation of CO in H2 have been reported [3–9]. The mechanism of selective oxidation of CO in H2, however, has never been clarified. Very recently, it was proved that the selective oxidation of CO on a FeOx/Pt/TiO2 catalyst is not caused by the oxidation of HCOO intermediate with OH instead of a competitive oxidation of adsorbed CO with oxygen [10, 11]. In this paper, we developed an extremely active catalyst for the selective oxidation of CO in H2 at room temperature, which was Pt catalyst supported on carbon nano-tube (CNT). Developed Pt/CNT catalyst has a lot of advantage in the activity, selectivity, and feasibility for preparation compared to the other low temperature catalysts so far developed. It is possible to remove the CO in fuel H2 by inserting Pt/CNT catalyst in front of hyd
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