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Co‐Adsorption of O 2 and CO on Au 2 − : Infrared Photodissociation Spectroscopy and Theoretical Study of [Au 2 O 2 (CO) n ] − ( n =2–6)
Author(s) -
Liu Hao,
Xing Xiaopeng,
Wang Xuefeng,
Qu Hui,
Wang Guanjun,
Zhou Mingfei
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201504384
Subject(s) - photodissociation , adsorption , chemistry , carbon monoxide , infrared spectroscopy , catalysis , infrared , spectroscopy , desorption , molecule , ion , analytical chemistry (journal) , inorganic chemistry , photochemistry , physics , biochemistry , organic chemistry , quantum mechanics , chromatography , optics
The co‐adsorption of O 2 and CO on anionic sites of gold species is considered as a crucial step in the catalytic CO oxidation on gold catalysts. In this regard, the [Au 2 O 2 (CO) n ] − ( n =2–6) complexes were prepared by using a laser vaporization supersonic ion source and were studied by using infrared photodissociation spectroscopy in the gas phase. All the [Au 2 O 2 (CO) n ] − ( n =2–6) complexes were characterized to have a core structure involving one CO and one O 2 molecule co‐adsorbed on Au 2 − with the other CO molecules physically tagged around. The CO stretching frequency of the [Au 2 O 2 (CO)] − core ion is observed around ν ˜ =2032–2042 cm −1 , which is about 200 cm −1 higher than that in [Au 2 (CO) 2 ] − . This frequency difference and the analyses based on density functional calculations provide direct evidence for the synergy effect of the chemically adsorbed O 2 and CO. The low lying structures with carbonate group were not observed experimentally because of high formation barriers. The structures and the stability (i.e., the inertness in a sense) of the co‐adsorbed O 2 and CO on Au 2 − may have relevance to the elementary reaction steps on real gold catalysts.