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The role of metal/oxide interfaces for long-range metal particle activation during CO oxidation

Y. Suchorski, S. M. Kozlov, I. Bespalov, M. Datler, D. Vogel, Z. Budinska, K. M. Neyman, G. Rupprechter.
Nature Materials 17 (2018) 519.

A tiny contact line between Pd grain and support strongly affects CO oxidation on the entire grain that is hundred thousand times larger.

For catalytic particles of thousands of atoms, the support should not affect chemical reactions occurring far away from it. However, an astonishing long-range effect of supports has been visualized, which can make car catalytic converters more efficient for decreasing toxic CO exhaust. Chemical processes on micro-crystallites of palladium catalysts changed significantly, when such particles were supported on inert metal oxides. Namely, the particles remained active for oxidizing CO at higher CO pressure. A very narrow contact line between grains and support influenced CO oxidation over the entire micrometre-size palladium grains. Experiments revealed that catalyst deactivation starts at a grain contacts with the support and from there deactivation spreads like a tsunami wave over the whole grain. These observations are rationalized by calculated stronger binding of oxygen on palladium atoms in direct contact with the support.