Abstract
Platinum-based heterogeneous catalysts are critical to energy production, pollution control, and many other important chemical processes. The efficiency of such catalysts as used in industry is, however, 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 the atom efficiency. Practical manufacture of such a single-atom catalyst remains a grand challenge. Here we report synthesis of a practical single-atom catalyst consisting of only isolated single Pt atoms anchored onto the surfaces of iron oxide (FeOx) nanocrystallites. This single-atom catalyst has extremely high atom efficiency and excellent stability for
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both CO oxidation and preferential oxidation of CO in H2. Our catalyst is 2-3 times more active than the best-known CO oxidation catalyst. DFT calculations show that the remarkable catalytic activity of single Pt atoms is correlated with the partially vacant 5d-orbitals of positively charged, high-valent Pt atoms, which help to reduce both the CO adsorption energy and the activation barriers for CO oxidation.
