title: [Analysis of surface composition of three-way catalysts of in-use vehicles].
abstract: The kinds and contents of surface elements in three-way catalysts of six light-duty in-use taxi cabs, which were mainly operated in Beijing and whose driving mileages were in the range of 34 x 10(4)-59 x 10(4) km, were determined by X-ray fluorescence spectrometry (XRF), and the effect of driving mileage on element content was investigated. Results showed that nearly 30 kinds of elements were present on the catalyst surface. The main elements of different samples were similar. The common elements of the pollutant on the front and rear catalysts were P, Ca, Zn and Mn etc., most of which are from engine oil and gasoline. S was only observed on the rear catalysts, indicating that S tends to deposit on the rear catalysts. After 34 x 10(4) km run, the P content increased very slowly and 40 x 10(4) km run S content reached a saturated value. While the contents of Ca, Zn and Mn still exhibit an increase tendency after 56 x 10(4) km. That means after 40 x 10(4) km driving mileage, the effects of P and S on the catalyst activity are minor, and the continuous deposit of Ca, Zn and Mn will lead to further decrease of the activity.
authors.affiliation: Chinese Research Academy of Environmental Sciences, Beijing 100012, China. sxxie2003@yahoo.com.cn
authors.forename: Shu-xia
authors.initials: SX
authors.lastname: Xie
authors.forename: Jing-nan
authors.initials: JN
authors.lastname: Hu
authors.forename: Xiao-feng
authors.initials: XF
authors.lastname: Bao
authors.forename: Ke-song
authors.initials: KS
authors.lastname: Zhang
authors.forename: Zhen-hua
authors.initials: ZH
authors.lastname: Li
authors.forename: Hai-tao
authors.initials: HT
authors.lastname: Wang
mesh_terms: D000393:Air Pollutants / Q000737:chemistry / Q000302:isolation & purification*; D000397:Air Pollution / Q000517:prevention & control*; D002118:Calcium / Q000032:analysis; D002384:Catalysis; D010758:Phosphorus / Q000032:analysis; D013052:Spectrometry, X-Ray Emission; D001335:Vehicle Emissions / Q000032:analysis* / Q000517:prevention & control; D015032:Zinc / Q000032:analysis
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D010758:Phosphorus; D015032:Zinc; D002118:Calcium