Surface chemistry of combustion-synthesized iron oxide nanoparticles determined by electron energy-loss spectroscopy

V. J. Leppert, Kent E Pinkerton, J. Jasinski

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Particulate matter (PM) that is composed of a complex mixture of organic compounds, soot, transition metals, sulfates, nitrates, and other trace elements has been associated with a range of adverse health effects. The effect of the separate components of PM and their interaction with each other is important in order to understand the origins of toxicity in these materials. Iron and soot are common environmental contaminants occurring in ultrafine particulate matter in the air, and have been experimentally generated, in a manner simulating high-temperature, industrial processes, through the combustion of iron pentacarbonyl in a mixture of acetylene and ethylene. Nanoprobe electron energy-loss spectroscopy (EELS) in the transmission electron microscope was used to collect Fe L 3:L 2 white line-intensity ratios from the interiors and surfaces of iron oxide nanoparticles present in samples generated under low and high soot conditions. This ratio is sensitive to any change in the iron oxidation state, and indicated that iron oxide nanoparticles co-generated with large quantities of soot during combustion processes show a subsurface layer (of thickness 2-3 nm) of decreased iron oxidation state. A quantitative analysis of the iron L 32 EELS ionization edge measured in nanoprobe mode indicated that in these particles, the oxidation state of iron at the surface is decreased from Fe 3+ to Fe 2+, possibly explaining the toxicity of these materials in the respiratory tract. The application of EELS to understanding the nanoscale distribution of the various components and their chemical interactions in these samples, and correlation of these results with acute respiratory toxicity studies of the laboratory-generated particulate matter, are discussed.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium Proceedings
EditorsD.C. Martin, D.A. Muller, P.A. Midgley, E.A. Stach
Pages17-21
Number of pages5
Volume839
StatePublished - 2005
Event2004 MRS Fall Meeting - Boston, MA, United States
Duration: Nov 29 2004Dec 1 2004

Other

Other2004 MRS Fall Meeting
CountryUnited States
CityBoston, MA
Period11/29/0412/1/04

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

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    Leppert, V. J., Pinkerton, K. E., & Jasinski, J. (2005). Surface chemistry of combustion-synthesized iron oxide nanoparticles determined by electron energy-loss spectroscopy. In D. C. Martin, D. A. Muller, P. A. Midgley, & E. A. Stach (Eds.), Materials Research Society Symposium Proceedings (Vol. 839, pp. 17-21). [P2.7]