Green and facile synthesis of carbon nanotube supported Pd nanoparticle catalysts and their application in the hydrogena
- PDF / 515,295 Bytes
- 8 Pages / 584.957 x 782.986 pts Page_size
- 103 Downloads / 195 Views
ng Chen,a) Lingjun Chou, and Xiaolai Wangb) State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, People’s Republic of China (Received 10 December 2012; accepted 4 April 2013)
Carbon nanotubes (CNTs) supported Pd nanoparticle (NP) catalysts (Pd/CNTs) were prepared by a green and facile synthesis method based on hydrogen-bonding self-assembly. The size and loading of Pd NPs on catalysts were easily controlled by tuning both the relative amount of citrate to Pd salt in the solution and the relative amount of Pd NPs to CNTs. The size of Pd NPs on as-prepared catalysts can be tuned in the range of 3–6 nm, and Pd loading can be controlled in the range of 0–19 wt%. The catalysts were characterized by Brunauer–Emmett–Teller measurement, x-ray diffraction spectroscopy, and x-ray photoelectron spectroscopy. The performance of Pd/CNTs catalysts was evaluated in the hydrogenation of nitrobenzene. Compared with the catalysts prepared by the impregnation method or supported on conventional supports, Pd/CNTs catalysts show relatively higher activity and selectivity. The recyclability tests indicate that the Pd/CNTs catalysts can be used at least five times without significant loss in activity and selectivity.
I. INTRODUCTION
Aniline is a basic raw material for the production of methylene diphenyl diisocyanate (MDI), rubber chemicals, dyes, and pharmaceuticals. The industrial production of aniline is mainly carried out by catalytic hydrogenation of nitrobenzene.1 The use of supported Raney Ni catalysts in the hydrogenation of nitrobenzene has attracted great interest due to their high activity and low price.2–4 However, the drawbacks of high temperature, high H2 pressure, and low reaction rate for Raney Ni catalysts limit their application to a large extent.3,4 Noble metals (Pt, Pd, Rh, etc.) are known for their high activity and selectivity in hydrogenation reactions, but their wide applications are restricted by their high cost and scarce source.5–7 Developing highly dispersed supported catalysts with high activity and selectivity has been suggested to be one of the alternatives in the utilization of noble metal catalysts.8,9 In the last decades, extensive efforts have been made toward the synthesis of cost-effective and highly active catalysts in the hydrogenation of nitrobenzene using noble metal catalysts.
Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2013.101 1326
J. Mater. Res., Vol. 28, No. 10, May 28, 2013
http://journals.cambridge.org
Downloaded: 19 Jun 2014
Activated carbon (AC) is a widely used support in heterogeneous reactions because of its low cost, high specific surface area, and resistance for acidic and basic media.5,10,11 The main problem of AC as catalyst support is the presence of abundant micropores, which lead to the steric hindrance for reactants to contact the active sites.10 As one of the advanced carbon materials, carbon nanotube
Data Loading...
