title: Fundamental properties of high-quality carbon nanofoam: from low to high density.
abstract: Highly uniform samples of carbon nanofoam from hydrothermal sucrose carbonization were studied by helium ion microscopy (HIM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Foams with different densities were produced by changing the process temperature in the autoclave reactor. This work illustrates how the geometrical structure, electron core levels, and the vibrational signatures change when the density of the foams is varied. We find that the low-density foams have very uniform structure consisting of micropearls with ≈2-3 μm average diameter. Higher density foams contain larger-sized micropearls (≈6-9 μm diameter) which often coalesced to form nonspherical μm-sized units. Both, low- and high-density foams are comprised of predominantly sp2-type carbon. The higher density foams, however, show an advanced graphitization degree and a stronger sp3-type electronic contribution, related to the inclusion of sp3connections in their surface network.
authors.affiliation: Department of Physics and Astronomy, University of Hawaii, 2505 Correa Road, Honolulu, HI 96822, USA; Physics of Supramolecular Systems and Surfaces, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany.
authors.forename: Natalie
authors.initials: N
authors.lastname: Frese
authors.affiliation: Department of Physics and Astronomy, University of Hawaii, 2505 Correa Road, Honolulu, HI 96822, USA.
authors.forename: Shelby
authors.initials: S
authors.lastname: Taylor Mitchell
authors.affiliation: Physics of Supramolecular Systems and Surfaces, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Neumann
authors.affiliation: Department of Physics and Astronomy, University of Hawaii, 2505 Correa Road, Honolulu, HI 96822, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Bowers
authors.affiliation: Physics of Supramolecular Systems and Surfaces, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany.
authors.forename: Armin
authors.initials: A
authors.lastname: Gölzhäuser
authors.affiliation: Department of Physics and Astronomy, University of Hawaii, 2505 Correa Road, Honolulu, HI 96822, USA.
authors.forename: Klaus
authors.initials: K
authors.lastname: Sattler
keywords: carbon nanofoam; helium ion microscopy; hydrothermal carbonization; nanocarbons