The sensitivity, or insensitivity, of catalysed reactions to catalyst structure is a commonly employed fundamental concept. Here we report on the nature of nano-catalysed ethylene hydrogenation, investigated through experiments on size-selected Pt_n (n=8–15) clusters soft-landed on magnesia and first-principles simulations, yielding benchmark information about the validity of structure sensitivity/insensitivity at the bottom of the catalyst size range. Both ethylene-hydrogenation-to-ethane and the parallel hydrogenation–dehydrogenation ethylidyne-producing route are considered, uncovering that at the <1  nm size-scale the reaction exhibits characteristics consistent with structure sensitivity, in contrast to structure insensitivity found for larger particles. the onset of catalysed hydrogenation occurs for pt_n (n≥10) clusters at T>150 K, with maximum room temperature reactivity observed for Pt₁₃. Structure insensitivity, inherent for specific cluster sizes, is induced in the more active Pt₁₃ by a temperature increase up to 400 K leading to ethylidyne formation. Control of sub-nanometre particle size may be used for tuning catalysed hydrogenation activity and selectivity.

Nature Communications 7, Article number: 10389 doi:10.1038/ncomms10389
Received 21 August 2015 Accepted 07 December 2015 Published 28 January 2016

http://www.nature.com/ncomms/2016/160128/ncomms10389/full/ncomms10389.html