Carbon nanostructure characterization by XPS

ANYL 341

Randall L. Vander Wal, randy@rvander.grc.nasa.gov, The National Center for Space Exploration Research (NCSER), NASA-Glenn Research Center, M.S. 110-3, 21000 Brookpark Rd., Cleveland, OH 44135 and Michael D. Hays, hays.michael@epamail.epa.gov, National Risk Management Research Laboratory, U. S. Environmental Protection Agency, Mail Drop E343-02, Research Triangle Park, NC 27711.
Results will be presented of X-ray photoelectron spectroscopy (XPS) analysis applied to soot collected from various sources (sample classes) including jet engine exhaust, an oil fired boilers (industrial and residential), diesel engine exhausts using different fuels and wildfire emissions. Spectra reveal a variety of surface oxygen species in addition to carbon fine structure. Components of the C 1s peak include C-C sp2, C-C sp3 and fullerenic structure. Small but consistent differences in peak positions exist between different classes of samples. These differences are larger than those between samples within the same class of source, thereby permitting identification on the basis of peak positions. As significant spectral peak intensity differences exist between samples from different classes, peak intensity provides an additional independent measure of comparison and identification. Finally, selected XPS results will be compared to corresponding HRTEM images to illustrate these complimentary methods for characterizing the carbon nanostructure.