title: Morphology and chemical characteristics of micro- and Nano-particles in the haze in Beijing studied by XPS and TEM/EDX.
abstract: X-ray Photoelectron Spectroscopy (XPS) is a useful surface sensitive tool to explore the particulate matter with different particle sizes. In this work, we report the analysis of elemental species in particulate matter with size ranging from 100nm to 10μm during the autumn haze of 2014 in Beijing. The size dependence of element composition and chemical state distribution on the particle surface was investigated. It was found that the number of investigated element species decreased from 8 (at stage 2) to 4 (at stage 10) with the decrease of particle sizes down to 100nm, which is in accordance with the result from Transmission electron microscopy (TEM/EDX) observations. Three chemical states of nitrogen, the amide group (399.9eV), the ammonium group (401.6eV), and the nitrate group (407.2eV), were confirmed according to the different binding energies. Nitrate was the main composition on the coarse particles, while the percentage of amide and ammonium at stage 3 (13.9% and 10.8% respectively) increased on the fine particles at stage 9 (46.8% and 38.8% respectively). The relative ratio of sulfate and ammonium (calculated 1:1) in the fine particles suggests that there is no enough NH4(+) to neutralize the sulfuric acid and the surface of the PM is acidic. The result is useful to investigate the generation processes and the sources of collected particles.
authors.affiliation: Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, and Laboratory of Catalysis Chemistry and Nanoscience, Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, China; CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China.
authors.forename: Peng
authors.initials: P
authors.lastname: Xu
authors.affiliation: CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China.
authors.forename: Jianxun
authors.initials: J
authors.lastname: Xu
authors.affiliation: CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China.
authors.forename: Meng
authors.initials: M
authors.lastname: He
authors.affiliation: Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China.
authors.forename: Lexin
authors.initials: L
authors.lastname: Song
authors.affiliation: College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China. Electronic address: chendl@mail.buct.edu.cn.
authors.forename: Dongliang
authors.initials: D
authors.lastname: Chen
authors.affiliation: Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, and Laboratory of Catalysis Chemistry and Nanoscience, Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, China. Electronic address: guogs@bjut.edu.cn.
authors.forename: Guangsheng
authors.initials: G
authors.lastname: Guo
authors.affiliation: Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, and Laboratory of Catalysis Chemistry and Nanoscience, Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, China. Electronic address: hxdai@bjut.edu.cn.
authors.forename: Hongxing
authors.initials: H
authors.lastname: Dai
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000393:Air Pollutants / Q000032:analysis*; D000068476:Beijing; D004784:Environmental Monitoring; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000032:analysis* / Q000648:ultrastructure; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D056951:Photoelectron Spectroscopy
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D052638:Particulate Matter
keywords: TEM; XPS; chemical state; particulate matter; size dependent