Platinum-based heterogeneous catalysts are critical to many important commercial chemical processes, but their efficiency is extremely low on a per metal atom basis, because only the surface active-site atoms are used. Catalysts with single-atom dispersions are thus highly desirable to maximize atom efficiency, but making them is challenging. Here we report the synthesis of a single-atom catalyst that consists of only isolated single Pt atoms anchored to the surfaces of iron oxide nanocrystallites. This single-atom catalyst has extremely high atom efficiency and shows excellent stability and high activity for both CO oxidation and preferential oxidation of CO in H2. Density functional theory calculations show that the high catalytic activity correlates with the partially vacant 5d orbitals of the positively charged, high-valent Pt atoms, which help to reduce both the CO adsorption energy and the activation barriers for CO oxidation.
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We thank Y. Huang, S. Zhang, T. Hu, J. Zhang, Y. Xie and L. Zheng for their help in the EXAFS measurements and data analysis, and L. Li for infrared measurements and discussion. We also acknowledge E. Okunishi for assistance on operating the JEM ARM-200F TEM/STEM. Particularly, we thank Jeffrey T. Miller for his suggestions and comments on EXAFS analysis during the manuscript revision process. Financial support for this research work from the National Science Foundation of China (20325620, 20773124) and the Ministry of Science and Technology of China (NKBRSF 2007CB815200, 2011CB932400) is also acknowledged. Part of the electron microscopy work was conducted at the Oak Ridge National Laboratory's High Temperature Materials Laboratory, sponsored by the US Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program. The calculations were performed at the Shanghai Supercomputing Center and the Computer Network Information Center, Chinese Academy of Sciences.
The authors declare no competing financial interests.
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Qiao, B., Wang, A., Yang, X. et al. Single-atom catalysis of CO oxidation using Pt1/FeOx. Nature Chem 3, 634–641 (2011). https://doi.org/10.1038/nchem.1095
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