title: A unified intermediate and mechanism for soot combustion on potassium-supported oxides.
abstract: The soot combustion mechanism over potassium-supported oxides (MgO, CeO2 and ZrO2) was studied to clarify the active sites and discover unified reaction intermediates in this typical gas-solid-solid catalytic reaction. The catalytically active sites were identified as free K(+) rather than K2CO3, which can activate gaseous oxygen. The active oxygen spills over to soot and forms a common intermediate, ketene, before it was further oxidized into the end product CO2. The existence of ketene species was confirmed by density functional theory (DFT) calculations. The oxygen spillover mechanism is proposed, which is explained as an electron transfer from soot to gaseous oxygen through the active K(+) sites. The latter mechanism is confirmed for the first time since it was put forward in 1950, not only by ultraviolet photoelectron spectroscopy (UPS) results but also by semi-empirical theoretical calculations.
authors.affiliation: School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.affiliation: School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xin
authors.affiliation: School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Zhaoliang
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Science, Ningbo 315201, China.
authors.forename: Yexin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Faculty of Chemical, Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024, China.
authors.forename: Ce
authors.initials: C
authors.lastname: Hao
authors.affiliation: Tianjin Key Laboratory of Applied Catalysis Science & Engineering, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Meng
authors.affiliation: Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Lirong
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zheng
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