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Dynamics of O 2 Chemisorption on a Flat Platinum Surface Probed by an Alignment‐Controlled O 2 Beam
Author(s) -
Ueta Hirokazu,
Kurahashi Mitsunori
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201612281
Subject(s) - sticking probability , chemisorption , platinum , adsorption , sticking coefficient , chemistry , beam energy , beam (structure) , atomic physics , analytical chemistry (journal) , molecular physics , desorption , physics , catalysis , optics , biochemistry , chromatography
O 2 adsorption on Pt surfaces is of great technological importance owing to its relevance to reactions for the purification of car exhaust gas and the oxygen reduction on fuel‐cell electrodes. Although the O 2 /Pt(111) system has been investigated intensively, questions still remain concerning the origin of the low O 2 sticking probability and its unusual energy dependence. We herein clarify the alignment dependence of the initial sticking probability ( S 0 ) using the single spin‐rotational state‐selected [( J , M )=(2,2)] O 2 beam. The results indicate that, at low translational energy ( E 0 ) conditions, direct activated chemisorption occurs only when the O 2 axis is nearly parallel to the surface. At high energy conditions ( E 0 >0.5 eV), however, S 0 for the parallel O 2 decreases with increasing E 0 while that of the perpendicular O 2 increases, accounting for the nearly energy‐independent O 2 sticking probability determined previously by a non‐state‐resolved experiment.