Near-Unity Reaction Probability in Olefin Hydrogenation Promoted by Heterogeneous Metal Catalysts Maryam Ebrahimi Juan Pablo Simonovis Francisco Zaera 10.1021/jz500954g.s001 https://acs.figshare.com/articles/journal_contribution/Near_Unity_Reaction_Probability_in_Olefin_Hydrogenation_Promoted_by_Heterogeneous_Metal_Catalysts/2034825 The kinetics of the hydrogenation of ethylene on platinum surfaces was studied by using high-flux effusive molecular beams and reflection–absorption infrared spectroscopy (RAIRS). It was determined that steady-state ethylene conversion with probabilities close to unity could be achieved by using beams with ethylene fluxes equivalent to pressures in the mTorr range and high (≥100) H<sub>2</sub>:C<sub>2</sub>H<sub>4</sub> ratios. The RAIRS data suggest that the high reaction probability is possible because such conditions lead to the removal of most of the ethylidyne layer known to form during catalysis. The observations from this study are contrasted with those under vacuum, where catalytic behavior is not sustainable, and with catalysis under more realistic atmospheric pressures, where reaction probabilities are estimated to be much lower (≤1 × 10<sup>–5</sup>). 2015-12-17 02:43:28 reaction probability platinum surfaces mTorr range ethylene fluxes equivalent RAIRS data Heterogeneous Metal Catalysts ethylidyne layer ethylene conversion catalysi Olefin Hydrogenation Promoted reaction probabilities