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Near-Unity Reaction Probability in Olefin Hydrogenation Promoted by Heterogeneous Metal Catalysts
journal contribution
posted on 2015-12-17, 02:43 authored by Maryam Ebrahimi, Juan Pablo Simonovis, Francisco ZaeraThe
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) H2:C2H4 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 × 10–5).