Abstract
Ceria nanoparticles with well defined facets are prepared in argon–hydrogen thermal plasma followed by controlled oxidation. With increasing hydrogen fraction in the plasma, a clear sphere-to-polyhedron shape transition is observed. The heat released during the hydrogenation of cerium, which significantly enhances the species mobility on the surface, favors the growth of well defined facets. The polyhedron ceria nanoparticles, though lower in specific surface area, exhibit superior catalytic performance for CO oxidation over the round particles, which is attributed to the higher density of the reactive {200} and {220} facets on the surface. The hydrogen mediated shape control mechanism provides new insights into the shape control of nanoparticles during thermal plasma processing.
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Acknowledgments
The authors acknowledge MOST of China (Nos. 2010CB631301 and 2009CB939902) and NSFC (Nos. 307 20971009, 20821091 and 51071003) for financial support.
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Jie Zheng and Yaohua Zhang have contributed equally to the study.
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Zheng, J., Zhang, Y., Song, X. et al. Formation of polyhedral ceria nanoparticles with enhanced catalytic CO oxidation activity in thermal plasma via a hydrogen mediated shape control mechanism. J Nanopart Res 13, 4445–4450 (2011). https://doi.org/10.1007/s11051-011-0527-4
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DOI: https://doi.org/10.1007/s11051-011-0527-4