(617ha) Fast Prediction of CO Oxidation Activity on Rare-Earth Metal Doped CeO2

Fast
Prediction of CO Oxidation Activity on Rare-Earth Metal Doped CeO₂

Kyeounghak
Kim¹, JeongDo Yoo², Siwon Lee²,
WooChul Jung², and Jeong Woo Han^1,*

¹Department of Chemical Engineering,
University of Seoul, Seoul 130-743, Republic of Korea

²Department of Materials Science and Engineering, Korea
Advanced Institute of Technology, Daejeon 305-701, Republic of Korea

*E-mail: jwhan@uos.ac.kr

Owing to high oxygen storage capacity and high stability over the wide range of temperatures, CeO₂ has
been widely applied to support materials for the electrode of solid oxide fuel
cells or diverse oxidation catalysts. While there have
been several studies for understanding the catalytic activity according to the
rare-earth (RE) metal dopants on CeO₂ nanoparticles, it is hard to find
the detailed reaction mechanism and a simple descriptor which enables to
rapidly estimate the activity. In this study, our combinatorial study of experiments
and theories shows the catalytic activities of CO oxidation are in order of CeO₂
> Ce_0.8Pr_0.2O₂ (PDC) > Ce_0.8Nd_0.2O₂
(NDC) > Ce_0.8Sm_0.2O₂ (SDC). Our density
functional theory calculations demonstrated that CO oxidation reaction on
RE-doped CeO₂(111) is well described via the Mars-Van Krevelen (MvK)
mechanism (Fig. 1). We found that the ionic radius of dopants can be used as a simple
descriptor to predict the whole reaction activity (Fig. 2). Based on our
results, we suggest that La might be a promising dopant to enhance the
catalytic activity of CO oxidation. Our results will provide useful insight to
unravel and predict the CO oxidation activity of ceria based catalysts.

Figure 1 Relative
energy diagram of CO oxidation on RE-doped CeO₂(111).

Figure 2 Linear
relationship between maximum reaction energy for CO oxidation and ionic radius
of dopants on RE-doped CeO₂(111).