The Nanomorphology-Controlled Palladium-Support Interaction and the Catalytic Performance of Pd/CeO 2 Catalysts
- PDF / 594,647 Bytes
- 6 Pages / 595.276 x 790.866 pts Page_size
- 41 Downloads / 176 Views
The Nanomorphology-Controlled Palladium-Support Interaction and the Catalytic Performance of Pd/CeO2 Catalysts Jin-Yong Luo • Ming Meng • Hui Xian • Yun-Bao Tu Xin-Gang Li • Tong Ding
•
Received: 24 August 2009 / Accepted: 13 October 2009 / Published online: 24 October 2009 Ó Springer Science+Business Media, LLC 2009
Abstract Nanorods and nanoparticles of CeO2 were successfully synthesized and used as support of Pd/CeO2 catalysts. It is found that the nanorods show obvious advantages as the support, compared with the nanoparticles. Low efficiency in the formation of reduced Pd, and partial encapsulation of Pd species account for the poor activity of Pd supported on CeO2 nanoparticles. On the contrary, a favorable interaction between Pd and the crystal planes [1 1 0] and [1 0 0] of CeO2 nanorods effectively promotes the reducibility of Pd species, resulting in much better catalytic performance of Pd/CeO2 catalyst for CO oxidation. Keywords Nanorod Nanoparticle Metal-support interaction Reducibility Crystal plane CO oxidation
1 Introduction Pd is often used in three-way catalyst due to its low price and high catalytic performance. Meanwhile, CeO2 is a unique promoter because of its capability for oxygen storage [1, 2]. Therefore, Pd/CeO2 catalysts are often studied as model catalysts for exhaust purification [3–7]. Their catalytic performance is influenced by the chemical
J.-Y. Luo M. Meng (&) H. Xian Y.-B. Tu X.-G. Li T. Ding Tianjin Key Laboratory of Catalysis Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, 300072 Tianjin, People’s Republic of China e-mail: [email protected]
123
nature of CeO2, the dispersion of Pd and the interaction strength of Pd–CeO2 [8]. Recently, much attention has been focused on the nature of pure CeO2 with different nanomorphology, including nanoparticles, nanorods and nanocubs. It is found that the preferentially exposed crystal planes [0 0 1] and [1 1 0] of ceria nanorods are more reactive for CO oxidation than the crystal plane [1 1 1] of ceria nanoparticles [9], and the nanorods of ceria possess much better property for oxygen storage and CO oxidation [10]. For ceria supported Au, Cu or Rh catalysts, the morphology of CeO2 also has a great influence on their catalytic performance [11–13]. It is revealed that the interaction strength between these metals and CeO2 is controlled by the different exposed crystal planes of CeO2. However, very little is known with respect to the effect of ceria nanomorphology on the catalytic performance of Pd/CeO2. Moreover, there are still some debates about the effect of interaction strength between Pd and CeO2 on the catalytic performance of Pd/CeO2. For example, Priolkar et al. [8] reported that a maximum Pd– CeO2 interaction, with the formation of a solid solution having Pd–O–Ce linkage, is favorable to its oxidation activity, while Carvalho [14] found that ceria decreases the performance of Pd/Al2O3 catalyst for CO oxidation, meaning that Pd–CeO2 interaction should be avoided. Obvious
Data Loading...
