title: Impact of Soot on NOxAdsorption over Cu-Modified Hydrotalcite-Derived Lean NOxTrap Catalyst.
abstract: The impact of soot on NOxadsorption was studied over a Cu-modified hydrotalcite-derived lean NOxtrap catalyst in a NO + O2atmosphere. Powder X-ray diffraction, scanning electron microscopy, Raman scattering spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the surface properties of the pure catalyst and the soot/catalyst mixture. The adsorbed NOxspecies on the samples were evaluated by in situ diffuse reflectance Fourier transform spectroscopy. The soot coverage decreases the available adsorption sites on the surface of the catalyst, and a portion of active oxygen species are consumed by the soot oxidation during He pretreatment process. The NOxadsorption on two catalyst samples simultaneously undergoes two routes: the "nitrite route" and the "nitrate route". The "nitrite route" is more dominant than the "nitrate route". During NOxadsorption, the soot oxidation weakens the NO oxidation to NO2, and the released CO2competes with NOxon the adsorption sites. Moreover, the temperature-programmed desorption tests indicate that the presence of soot reduces the NOxstorage capacity of the catalyst and shifts the NO desorption peak to the lower temperature range by 50 °C.
authors.affiliation: State Key Laboratory of Engines, Tianjin University , Tianjin 300072, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.affiliation: State Key Laboratory of Engines, Tianjin University , Tianjin 300072, People's Republic of China.
authors.forename: Chonglin
authors.identifier: 0000-0003-1256-7269
authors.initials: C
authors.lastname: Song
authors.affiliation: State Key Laboratory of Engines, Tianjin University , Tianjin 300072, People's Republic of China.
authors.forename: Gang
authors.initials: G
authors.lastname: Lv
authors.affiliation: State Key Laboratory of Engines, Tianjin University , Tianjin 300072, People's Republic of China.
authors.forename: Ke
authors.initials: K
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Engines, Tianjin University , Tianjin 300072, People's Republic of China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Cao