title: Co-Adsorption of O2and CO on Au2-: Infrared Photodissociation Spectroscopy and Theoretical Study of [Au2O2(CO)n]-(n=2-6).
abstract: The co-adsorption of O2and 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 [Au2O2(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 [Au2O2(CO)n]-(n=2-6) complexes were characterized to have a core structure involving one CO and one O2molecule co-adsorbed on Au2-with the other CO molecules physically tagged around. The CO stretching frequency of the [Au2O2(CO)]-core ion is observed around ν˜ =2032-2042 cm-1, which is about 200 cm-1higher than that in [Au2(CO)2]-. This frequency difference and the analyses based on density functional calculations provide direct evidence for the synergy effect of the chemically adsorbed O2and 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 O2and CO on Au2-may have relevance to the elementary reaction steps on real gold catalysts.
authors.affiliation: Shanghai Key Lab of Chemical Assessment and Sustainability, Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai, 200092, P.R. China.
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
authors.affiliation: Shanghai Key Lab of Chemical Assessment and Sustainability, Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai, 200092, P.R. China. xingxp@tongji.edu.cn.
authors.forename: Xiaopeng
authors.identifier: http://orcid.org/0000-0001-7323-1705
authors.initials: X
authors.lastname: Xing
authors.affiliation: Shanghai Key Lab of Chemical Assessment and Sustainability, Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai, 200092, P.R. China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, P.R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Qu
authors.affiliation: Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, P.R. China.
authors.forename: Guan-Jun
authors.initials: GJ
authors.lastname: Wang
authors.affiliation: Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, P.R. China. mfzhou@fudan.edu.cn.
authors.forename: Ming-Fei
authors.initials: MF
authors.lastname: Zhou
keywords: IR spectroscopy; adsorption; density functional calculations; gold; oxidation