Field-Flow Fractionation of Carbon Nanotubes and Related Materials
During the grant period, we carried out FFF studies of carbonaceous soot, single-walled and multi-walled carbon nanotubes, carbon nano-onions and polyoxometallates. FFF alone does not provide enough information to fully characterize samples, so our suite of characterization techniques grew to include light scattering (especially Photon Correlation Spectroscopy), scanning and transmission electron microscopy, thermogravimetric analysis and spectroscopic methods. We developed convenient techniques to deposit and examine minute FFF fractions by electron microscopy. In collaboration with Arthur Cammers (University of Kentucky), we used Flow Field-Flow Fractionation (Fl-FFF) to monitor the solution-phase growth of keplerates, a class of polyoxometallate (POM) nanoparticles. We monitored the evolution of Mo-POM nanostructures over the course of weeks by by using flow field-flow fractionation and corroborated the nanoparticle structures by using transmission electron microscopy (TEM). Total molybdenum in the solution and precipitate phases was monitored by using inductively coupled plasma analyses, and total Mo-POM concentration by following the UV-visible spectra of the solution phase. We observe crystallization-driven formation of (Mo132) keplerate and solution phase-driven evolution of structurally related nanoscopic species (3-60 nm). FFF analyses of other classes of materials were less successful. Attempts to analyze platelets of layered materials, including exfoliated graphite (graphene) and TaS2 and MoS2, were disappointing. We were not able to optimize flow conditions for the layered materials. The metal sulfides react with the aqueous carrier liquid and settle out of suspension quickly because of their high density.
- Research Organization:
- Univ. of Kentucky, Lexington, KY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- FG02-00ER45847
- OSTI ID:
- 1029463
- Report Number(s):
- DOE/FG02-00ER45847-4; TRN: US201201%%891
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mechanistic Details and Reactivity Descriptors in Oxidation and Acid Catalysis of Methanol
Principles of water oxidation and O2-based hydrocarbon transformation by multinuclear catalytic sites
Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
77 NANOSCIENCE AND NANOTECHNOLOGY
CARBON
ELECTRON MICROSCOPY
FRACTIONATION
GRAPHITE
LIGHT SCATTERING
MOLYBDENUM
MONITORS
NANOSTRUCTURES
NANOTUBES
PHOTONS
PLASMA
SOOT
SPECTRA
SPECTROSCOPY
SULFIDES
THERMAL GRAVIMETRIC ANALYSIS
TRANSMISSION ELECTRON MICROSCOPY
nanoparticles
Field-Flow Fractionation (FFF)
carbon nanotubes
soot
carbon nanotubes
carbon nano-onions
polyoxometallates
laminar materials
graphene