238 Chem. Educator 2001, 6, 238­246
 2001 Springer-Verlag New York, Inc., S1430-4171(01)04490-9, Published on Web 07/27/2001, 10.1007/s00897010490a, 640237tm.pdf
Nanostructures in Physical Materials Chemistry: An Exploratory
Laboratory
Thomas J. Manning,*,
Amy Feldman,
Michael Anderson,
Leri Atwater,
Brent Lesile,
Derek
Lovingood,
Anna Lee McRae,
Rob Stapleton,
Kim Riddle,
Jun Lui,
Thomas Vickers,§
Naresh Dalal,§
and Lambertus J. van de Burgt§
Department of Chemistry, Valdosta State University, Valdosta, GA 31698, tmanning@valdosta.peachnet.edu,
Electron Microscope Facility, Biology Department, Florida State University, Tallahassee, Florida, and
Department of Chemistry, Florida State University, Tallahassee, Florida
Received January 22, 2001 Accepted March 9, 2001
Abstract: The blend of nanotechnology and material science is often beyond the scope of undergraduate
laboratories. Through undergraduate research, graphite-intercalated compounds have been incorporated in the
production of carbon-based nanostructures. Based on this work a series of exploratory exercises were designed
for the undergraduate physical chemistry laboratory emphasizing nanostructure material science. This rapidly
expanding area of science and technology can be introduced at an undergraduate level using a high temperature
oven to produce nanostructure samples that are analyzed by Raman spectroscopy, scanning electron microscopy,
and transmission electron microscopy at research university laboratories, infrared spectroscopy, and a bomb
calorimeter. In these experiments we use samples of pure graphite, fluorinated graphite, and lanthanum oxide to
induce the formation of nanostructures. An overview of fullerenes, nanotubes, boron nitride and Si
nanostructures, other carbon forms, graphite-intercalated compounds, and the storage of hydrogen in nanotubes
are provided in an appendix. Several extensions of the laboratory are proposed.
Introduction
Fullerenes. In 1985 the existence of a third form of carbon
was revealed. Until that discovery, only two forms of carbon
were known, diamond and graphite. Smalley, Kroto and Curl
at Rice University refined the mass spectrometric analysis of
carbon plasma produced by the laser vaporization of graphite
disks in a helium atmosphere [1]. A strong peak determined by
a mass spectrometer at 720 amu coupled with vibrational and
nuclear spectroscopy indicated that a spherical C60 structure
had been synthesized. Known as Buckminsterfullerene,
fullerene, or buckyballs, the closed-caged C60 structure
exhibits perfectly symmetric geometry and is stable at very
high temperatures and pressures. The molecule's name,
Buckminsterfullerene, is derived from the architectural creator
of geodesic domes, R. Buckminster Fuller. This new carbon
compound has sparked intense research into the chemistry of
C60 [2­14].
In 1991, Japanese researchers discovered tubes of carbon
with diameters of 2­4 nm [15]. By passing an electric current
between graphite rods in a low-pressure helium atmosphere,
nanotubes are created in similar fashion to buckyballs.
Variations of these experiments have produced both single-
walled carbon nanotubes (SWNT) and multi-walled nanotubes
(MWNT). Graphite rods packed with cobalt, nickel,
lanthanum, or iron have been shown to catalyze the production
of nanostructures.
*
Address correspondence to this author.

Department of Chemistry, Valdosta State University

Biology Department, Florida State University
§
Department of Chemistry, Florida State University
The synthesis of nanometer-sized particles has extended
beyond carbon [2, 10, 16­20]. Other completed work includes
nanostructure synthesis with silicon, boron nitride, and various
types of metal carbide nanoparticles such as Fe3C, CaC2,
Mn3C7 , SrC2, and LaC2 [2, 6­8, 21­23]
Previous work with undergraduates has centered on using
graphite-intercalated compounds (GIC) as a starting and
intermediate material and 27.12-MHz inductively coupled
argon plasma as the heat source in GIC-fluorinated graphite to
facilitate conversion to pure carbon nanostructures.
Fluorinated graphite (C1F1) has carbons with sp3
hybridization
and irregular spacing between the graphite sheets making it
potentially more reactive than closely stacked graphite [19]. In
these past studies we were able to synthesize spherical and
tubular allotropes of carbon as well as a form of exfoliated
graphite of 5­12 nm that is stable under ambient conditions.
We chose to build upon our research to implement an
undergraduate nanotechnology laboratory.
Some areas of nanotechnology involve fairly sophisticated
synthesis and analytical techniques (i.e., nanoelectronic
components, etc.) considered beyond the realm of the
undergraduate laboratory; however, we demonstrate the
feasibility of bulk nanostructure production in an
undergraduate laboratory setting and analysis by using FT­IR,
TEM, SEM, and Raman instruments. While students do not
use the Raman, TEM, and SEM instruments (samples are
shipped for testing), students gain experience in interpreting
the visual and spectroscopic data from these instruments.
Many academic, government, and industrial research
laboratories analyze chemical samples in a similar fashion.
Nanostructures in Physical Materials Chemistry: An Exploratory Laboratory Chem. Educator, Vol. 6, No. 4, 2001 239
 2001 Springer-Verlag New York, Inc., S1430-4171(01)04490-9, Published on Web 07/27/2001, 10.1007/s00897010490a, 640237tm.pdf
Figure 1. SEM image (10,000 times) of fluorinated graphite dust used
as the starting material.
Figure 2. Two SEM images (10,000 times) of exfoliated graphite
(EG) produced by the thermal decomposition of fluorinated graphite.
The material has a large surface area and low density. The graphite
sheets are clearly ripped apart and the material is essentially
defluorinated. EG is a low-density, black dust that can be easily
temporality suspended in the air.
Experimental
Pure graphite dust (Aldrich Chemical, #28286-3) and fluorinated
graphite dust (Aldrich Chemical, #37245-5) were used. A Mattson
FT­IR spectrometer was utilized. Carbon-based compounds were put
in a methanol slurry and dropped on IR cards and allowed to dry.
Diffuse reflectance (DRIFT) and attenuated total reflectance (ATR)
accessories were both tested, but sensitivity was inadequate. The
Raman spectrometer is located in the laboratory of Professor Thomas
Vickers and the Scanning electron Microscope and Transmission
Electron Microscope are located in the Electron Microscope facility
under the direction of Professor Ken Taylor located within the biology
department at Florida State University.
The work described here is broken into three projects.
ˇ The synthesis of exfoliated graphite and its subsequent
transformation into nanotubular structures using Fe3+
ˇ Synthesis of nanospheres of C1F1 using a novel electrochemical
cell
ˇ Calorimetric studies of carbon-compounds combustion in the
presence of La2O3.
In this laboratory, six students were broken into groups of two and
rotated through each project.
It should be emphasized that the instructor should read many of the
references listed to familiarize themselves with various aspects of the
work. Details on previous experimental work or theoretical
explanations for topics are lengthy and left to the citations provided.
Throughout, the laboratory subtopics are presented to give the
students a clearer image of the chemical and experimental parameters
involved. For example, models of graphite and fluorinated graphite
were constructed and discussed. A copper grid and an aluminum stud
used for sample mounting in TEM and SEM, respectively, were
shown and the sample analysis procedure explained.
Synthesis
Exfoliated Graphite. Synthesis of exfoliated graphite that is stable
under ambient conditions can be accomplished using the following
procedures:
Measure approximately 0.5 to 1.0 g of C1F1and record the sample
mass. The density of the fluorinated graphite dust is calculated by
measuring the sample volume using a graduated cylinder. The sample
is then placed in a covered ceramic crucible. An IR is recorded on site
and a small sample of C1F1 is set aside for Raman and EM analysis.
Figure 1 shows fluorinated graphite dust particles observed using
SEM.
While heating the C1F1 sample, flow argon (10­50 mL/min) into
the covered crucible to minimized combustion. Heat the sample with a
Bunsen burner in a well-ventilated hood. Caution should be taken to
avoid inhalation of the fluorine-based thermal decomposition
products. Extinguish the Bunsen burner every 5­10 min and gently
stir with a metal rod to ensure uniform heating of the sample.
After 60­90 min of heating, the gray fluorinated graphite should be
converted to exfoliated graphite, a low-density carbon compound. The
ceramic dish should be continuously monitored. Underheating will
result in little or no thermal decomposition. Overheating will cause all
of the fluorinated graphite dust to decompose. Figure 2a and b
provides two images of the product. At this point, the compound
should be relatively free of fluorine in any form. The students weigh
the soot, measure its volume, and calculate the density of the product.
A small quantity of this is set aside for transport to the SEM
laboratory and the remainder will be used in Part C with a Fe3+
solution.
Production of Nanotubular Structures. Carbon nanotubes are
typically produced in either a carbon-arc or a chemical-vapor
deposition chamber. These specialized pieces of equipment are
relegated to research laboratories and rarely incorporated in teaching
laboratories; however, the following approach of synthesizing 5 to 12
nm diameter nanotubular structures (See Figure 3) can be conducted
in most undergraduate laboratories.
Produce exfoliated graphite by thermal decomposition of C1F1 in a
ceramic dish (See Part A). This step should be conducted under a
hood.
240 Chem. Educator, Vol. 6, No. 4, 2001 Manning et al.
 2001 Springer-Verlag New York, Inc., S1430-4171(01)04490-9, Published on Web 07/27/2001, 10.1007/s00897010490a, 640237tm.pdf
Figure 3. Exfoliated graphite treated with Fe+3
and heated to dryness
produces solid nanotubular structures that range in diameter from 5 to
10 nanometers.
Figure 4. Synthesis #1. (See Table 1.) Five layers (NaF, Na, C1F1, I2,
NaF) are pressed consecutively into a high temperature ceramic
crucible.
Treat the EG dust with a 0.1 M Fe(NO3)3 in 1% HNO3 so that the
moles of Fe are at a 1:3 (Fe:C) ratio with the moles of carbon.
In an argon environment, gently heat the slurry with a Bunsen
burner to complete dryness. Occasionally turn off the burner and stir
the slurry/solid with a metal spatula. Do not overheat the mixture to
avoid splattering. This simple synthesis will cause some of the
graphite sheets to roll up into tubular bundles that are 5 to 12 nm in
diameter (See Figure 3).
Production of C1F1 Nanospheres. In this laboratory we
investigate a novel electrochemical approach to the production of
fluorinated graphite nanospheres in a low temperature environment (<
200 °C). As in previous experiments, FT­IR, Raman, SEM, and TEM
are used to qualitatively and quantitatively identify the starting
material and the structures produced.
Seven crucibles were prepared and subjected to the conditions
outlined in Table 1. The graphite dust (1 m) and fluorinated graphite
dust (C1F1, 1­2 m diameter) are trapped between layers of Na(s) and
I2(s) in a ceramic crucible (See Figure 4). Students used 0.5 to 1.0
grams of C1F1 (mass recorded exactly) and calculated the required
mass of I2 and Na(s) if a 1:1:1 ratio of Na(s) to C to I is desired. In
addition, the upper and lower layers of sodium fluoride allow gases
formed by the reaction to escape and minimize air contamination of
the electrochemical reaction.
Two ovens were used to heat each crucible for seven days. Each
oven is set at a different temperature (165 °C, 135 °C). The
temperature is maintained above the melting points of Na(s) (98 °C)
and I2(s) (114 °C) but below the thermal decomposition temperature
of fluorinated graphite (450 °C). Periodically check the sample.
The solid remaining in the crucible must be carefully washed with
water to remove NaF and Na(s). Care must be taken to ensure no solid
Na(s) is present that could react violently with water. The samples are
then centrifuged and the water removed. The residual solid is heated at
110 °C to remove all trace amounts of water. The sample is then
washed/soaked with hexane to remove any remaining I2(s). The
sample is centrifuged and heated at 60 °C until completely dry.
Analyze the sample by infrared spectroscopy and ship/store for
imaging by SEM and TEM.
By using various controls, the students noted that it is only the
ceramic dish with an electrochemical reaction that produces
nanospheres of fluorinated graphite. At the prescribed temperatures
(165 °C, 135 °C), melted sodium and iodine will liquefy and permeate
the C1F1 layers allowing for the electrochemical reaction,
Na(s) +  I2(s)  NaI(s)
Our analysis of the control samples (See Table 1) by several
electron microscopy techniques revealed essentially no change in the
structure of the graphite or the fluorinated graphite. Through IR and
Raman spectroscopy, a strong C­F peak (1210 cm­1
) indicated no
thermal decomposition of the fluorinated graphite controls occurred
and that the nanospheres observed via TEM were C1F1 (See Figures 5
and 6).
Thermodynamics
As discussed in the introduction, lanthanum has been shown
to play a role in the production of fullerenes, nanotubes, and
lanthanum carbide nanoparticles. Lanthanum was one of the
first metals to be used in making of endohedral fullerene and
metal carbide nanostructures. These lanthanum compounds
have been found to be unusually stable due to the
delocalization of the La electrons about the carbon skeleton.
In this part of the laboratory we chose to investigate whether
or not we could detect any thermodynamic evidence of La2O3
affecting the combustion of graphite or fluorinated graphite.
Benzoic acid was used to determine the calorimeter constant.
The gas-phase combustion products of each trial were trapped
in a 10-cm quartz cell and qualitatively identified by FT­IR.
The following reactions are pertinent to the experiment:
C(graphite) + O2(g)  CO2(g) Hrxn = ­393.51 kJ mol­1
(1)
4C1F1(s) + 3O2(g)  3CO2(g) + CF4(g) Hrxn = ­102 kJ mol­1
(2)
From our discussion we felt the formation of nanospheres of
LaxCy was more likely (as opposed to fullerene or nanotube
formation) and the students were asked to make arguments,
based on bond energies, as to whether they would observe an
increased, decreased, or constant enthalpy of combustion.
Appendix A provides some discussion of nanoparticles and
contains references for additional reading.
Ten combustion reactions were measured over two
laboratory periods. These are listed in Table 2. The results
(time versus temperature) are illustrated in Figures 8 and 9.
The heat of combustion calculated from bond energies of
pure graphite (eq 1) was determined to be ­393.51 kJ mo1­1
.
Pure graphite dust's experimental H value was determined
experimentally to be ­378.370 kJ mol­1
and ­381.579 kJ mol­1
for trials 1 and trial 2, respectively, with an average H of ­
379.975 kJ mol­1
. The values of the graphite and La2O3-
graphite were statistically the same. A similar result was
Nanostructures in Physical Materials Chemistry: An Exploratory Laboratory Chem. Educator, Vol. 6, No. 4, 2001 241
 2001 Springer-Verlag New York, Inc., S1430-4171(01)04490-9, Published on Web 07/27/2001, 10.1007/s00897010490a, 640237tm.pdf
Table 1. Contents, Temperature, Duration, and Purpose for Seven Crucibles Set Up the First Week, Heated in the Oven for Seven Days, and
Disassembled and Analyzed by IR, Raman, SEM and TEM
Crucible Contents
(from top to bottom)
Temperature, Duration, Purpose
Control #1.
NaF(s), Graphite, NaF(s) 165 °C, 7 days, Control to test effects of temperature on graphite dust
Control #2
NaF(s), fluorinated graphite, NaF(s) 165 °C, 7 days, Control to test effects of temperature on fluorinated graphite dust
Control #3
NaF(s), I2(s), fluorinated graphite, NaF(s) 165 °C, 7 days, Control to test effects of temperature and I2 on fluorinated graphite dust
Control #4
NaF(s), fluorinated graphite, Na(s), NaF(s) 165 °C, 7 days, Control to test effects of temperature and Na(s) on fluorinated graphite dust
Control #5
NaF(s), I2(s), graphite, Na(s), NaF(s) 165 °C, 7 days, Control to test effects of temperature, I2, and Na(s) on graphite dust
Synthesis #1
NaF(s), I2(s), fluorinated graphite, Na(s), NaF(s) 165 °C, 7 days, Electrochemical synthesis to convert on fluorinated graphite
Synthesis #2
NaF(s), I2(s), fluorinated graphite, Na(s), NaF(s) 135 °C, 7 days, Synthesis to test effects of a lower temperature on the electrochemical synthesis
of fluorinated graphite
Table 2. Ten Combustion Reactions Measured over Two Laboratory Periods
Combustion material Comment
1.0 g benzoic acid Used to determine calorimeter constant (2 trials)
1.0 g graphite dust Produced only CO2(g) (2 trials)
1.0 g fluorinated graphite Produces CO2 and CxFy(g) compounds (2 trials)
0.5 g graphite dust and 0.5 g fluorinated graphite Produces CO2, CxFy(g) and CxHy(g) (2 trials)
0.9 g fluorinated graphite and 0.1 g La2O3(s) Produces CO2 and CxFy(g) compounds (1 trial)
0.9 g graphite and 0.1 g La2O3 (s) Produces CO2(g) determined by IR (1 trial)
a b
Figure 5. a. TEM image of a nanosphere (12 nm diameter) of fluorinated graphite produced in the simple synthesis #2 (Table 1). B.Two 8­10 nm
nanospheres bound together. IR and Raman spectroscopy were used to confirm that no appreciable thermal decomposition took place and the
nanospheres are fluorinated graphite
obtained when the fluorinated graphite and Lanthanum mix
was burned. Figure 8 illustrates FT­IR spectra for CO2(g)
recorded from the combustion products of pure graphite;
Figure 9 illustrates the IR spectra (CO2 and molecular species
containing C­F bonds) for the combustion of fluorinated
graphite. Figure 10 is experimental calorimetric data for the
graphite-dust combustion. Figure 11 is experimental
calorimetric data for the C1F1 combustion.
Schedule
Session 1. Each student gave a five-minute oral presentation
about a technical paper (for example, see references 1, 6, 9,
13­15) provided the previous week. The use of the bomb
calorimeter was reviewed and the sample preparation for the
electrochemical cell was outlined. Two students started
working with the bomb calorimeter, two students prepared the
exfoliated graphite, and two students set up the
electrochemical cells and placed them in the ovens. One of the
students prepared the EG ran the FT­IR of graphite dust,
242 Chem. Educator, Vol. 6, No. 4, 2001 Manning et al.
 2001 Springer-Verlag New York, Inc., S1430-4171(01)04490-9, Published on Web 07/27/2001, 10.1007/s00897010490a, 640237tm.pdf
1
2
4
3
Figure 6. Several 5­14-nm diameter fluorinated graphite nanospheres
(1, 3, and 4) are captured in this TEM image. The other globular
materials (2) are referred to as carbon aerogels.
Figure 7. Raman spectra of treated fluorinated-graphite-containing
nanospheres (top), spectra of fluorinated graphite dust that was the
starting material (middle) and pure graphite dust (bottom) that was
used in some of the controls outlined in Table 1. This data, along with
the IR, demonstrated that the fluorinated graphite did not thermally
decompose into graphite; however, wavenumber shifts indicate
changes did take place. The x axis is in wavenumbers and the y axis is
the intensity of the laser scatter.
fluorinated graphite dust, and EG. The density of graphite
dust, fluorinated graphite, and EG were also measured.
Session 2. Each student gave a 5 to 7 minute talk at the
beginning of the laboratory concerning an analysis technique
(Raman, SEM, TEM) or a material (GICs, fullerenes,
nanoencapsulates) as assigned the previous week. The groups
of two were rotated so that different students continued work
on the bomb calorimeter, treated the EG produced in session 1
with Fe+3
, and disassembled the electrochemical cells. At the
end of the laboratory, two packets of each of the nine samples
(EG, EG treated with Fe+3
, and the seven carbon samples
outlined in Table 1) were shipped to the Raman spectroscopy
laboratory and the EM laboratory. FT­IR of the nine samples
was taken and the spectra distributed to all students.
Session 3. When the Raman spectra and SEM and TEM
images were returned (approximately one month after session
2), session 3 was convened. Students gave five-minute
presentations using visual aids on papers and Websites
assigned the previous laboratory period. Topics included
hydrogen storage, H2/O2 combustion engines, H2/O2
electrochemical cells, LaC nanoencapsulates, BN
nanostructures, and nanotechnology involving DNA. Students
assembled all of the data (density, IR, Raman, SEM, TEM, and
Hcombustion) and spent the remainder of the laboratory period
discussing and correlating thermodynamic, vibrational, and
electron microscopy data with the instructor. The primary
focus was clearly the images of what was produced at the
nanometer level. In addition to interpreting and correlating
different data sets, students began to organize data for their
final laboratory report.
Questions included in the laboratory
Exfoliated graphite: 1) What is a van der Waals force and
what role does it play in holding graphite together?
2) Its been proposed that H2 can be stored in nanotubes and
used as a battery. Discuss how the EG you produced might
work in this application. Specifically, outline the
electrochemical reaction involving hydrogen and oxygen,
compare it with the combustion reaction of hydrogen and
oxygen, and propose a simple schematic for how a H2/O2
battery might work.
3) Briefly discuss how hydrogen (H2) would absorb on the
surface of a carbon nanotube (forces involved, potential
geometries, etc.).
4) Compare the IR, Raman, density, SEM, and TEM data of
the EG with that of graphite and fluorinated graphite.
Electrochemical cell: 1) What is Eo
cell for the sodium­
iodine reaction at 25 °C? Assume enthalpy and entropy for the
reaction are constant, what is the Gibbs free energy at 75 °C?
2) Will iodine replace fluorine in C1F1 and make C1I1? Will
Na (atom, ion) bind carbon? Will NaF or NaI be the preferred
product? Use thermodynamics to support your argument.
3) If a fluorinated graphite sphere (C1F1) has a 20-nm
diameter and a density of 2 g cm­3
, how many carbon and
fluorine atoms are contained in that volume. Compare the IR,
Raman, density, SEM, and TEM data.
Nanostructures in Physical Materials Chemistry: An Exploratory Laboratory Chem. Educator, Vol. 6, No. 4, 2001 243
 2001 Springer-Verlag New York, Inc., S1430-4171(01)04490-9, Published on Web 07/27/2001, 10.1007/s00897010490a, 640237tm.pdf
Table 3. Heats of combustion obtained with an oxygen-filled bomb
calorimeter
Compound Enthalpy (J g­1
)
Graphite (1 g, trial 1) ­31,501.99
Graphite (1 g, trial 2) ­31,769.13
Fluorinated graphite (1g, trial 1) ­11,842.12
Fluorinated graphite (1 g, trial 2) ­11,713.15
Graphite (0.9 grams), La2O3 (0.1 g) ­31,280.01
Fluorinated graphite (0.9 g), La2O3 (0.1 g) ­12,800.56
Figure 8. FT­IR spectra of the CO2(g) in a 10-cm quartz cell. CO2 is
the primary combustion products of graphite dust.
Figure 9. Infrared spectra of the gas-phase combustion products of
fluorinated graphite dust (i.e., CO2, CxFy(g), etc.). The intense peak at
1210 cm­1
is the result of a C­F bond.
Bomb Calorimeter: 1) What effect did the lanthanum have
on the combustion of graphite? fluorinated graphite?
2) Calculate the heat of combustion of graphite from bond
energies and compare this with the value you measured.
3) Why is the heat of combustion for fluorinated graphite
lower than graphite? Use bond energies to explain your
answer.
Figure 10. Calorimetric T data recorded for the combustion of pure
graphite dust in a bomb calorimeter.
Conclusion
While nanotechnology has been a rapidly growing area of
science, there are few published laboratories for the
undergraduate chemistry curriculum, and a majority of those
are concerned with C60 [51­58]. From our exploratory work, a
range of other experiments and computer simulations can be
developed or tested including
Exfoliated graphite and nanotubular structures. Using
the same procedure described above, try other metals than Fe+3
(e.g., La+3
, Co+2
, Ni+2
, Ca+2
, Sr+2
) that have shown influence on
nanostructure formation. Also, test other metals and metalloids
that might potentially produce interesting carbide chemistry
(W, Si, etc.) and search for nanostructures.
Calorimetry. Test different ratios of La2O3 (1:1 by mass
and by atom ratio) with graphite and fluorinated graphite.
Experiment with different metal salts containing nickel, iron,
cobalt, calcium, or strontium at different ratios. Show fullerene
production in the flames of hydrocarbons (i.e., benzene),
combustion with and without the metal salts previously
mentioned. Soak graphite and fluorinated graphite in solutions
of La3+
, Fe3+
, Ni2+
, Co2+
, Ca2+
, or Sr2+
to adsorb cations, gently
drying the mixture. Take graphite and fluorinated graphite
through the same procedure as the controls (soak in just a
matching acid solution). After compounds are completely
dried, use them for combustion reactions. Treat EG as
described with any of the metals (including the heating stage),
thoroughly dry and attempt combustion of the solid. any of
these have been shown to form nanostructures (i.e., CaC2,
Fe3C, etc.).
Electrochemical cell. Instead of using Na(s), try a metal (K,
Rb, Cs) with a lower ionization potential and a lower boiling
point. Try Br2(l) instead of I2. For example, Cs metal (bp = 29
°C) could be embedded with fluorinated graphite dust by
gentle heating and mixing in an inert gas environment. It
would solidify at room temperature (25 °C). React these
mixtures with Br2(l) under carefully controlled conditions.
Perhaps some of these reactions will take a shorter period of
time, run at lower temperatures, or produce more nanospheres
with a different electrochemical reaction (Eo
cell varies).
Computer Simulations. A range of molecular modeling
programs are available that can be used in an undergraduate
244 Chem. Educator, Vol. 6, No. 4, 2001 Manning et al.
 2001 Springer-Verlag New York, Inc., S1430-4171(01)04490-9, Published on Web 07/27/2001, 10.1007/s00897010490a, 640237tm.pdf
laboratory. When this laboratory is completed, students have a
deeper understanding of carbon structures and could be given
exercises to simulate hydrogen (H2) adsorption on graphite,
construct spherical and tubular structures based on carbon and
boron nitride, and simulate small metal­carbide structures.
Collaborations between four year undergraduate programs
and research I programs can be productive for all parties
involved. Exploratory laboratories are unique experiences that
straddle the line between pure research and teaching focusing
faculty and students, on current topics and techniques. Sutents
gain first hand experience working with faculty, staff and
equipment and have an increased interest in graduate school.
Appendix A: Review of Nanotubes, Graphite-Intercalated
Compounds, Boron Nitrides, Etc.
Boron Nitride and Silicon. The syntheses of nanometer-
sized components have extended beyond carbon [2, 10, 16­
20]. A drawback to the utilization of carbon nanotubes, based
on conductivity, is the inability to control the chirality. Boron
nitride (BN) nanotubes, however, have conductive properties
that are independent of chirality, diameter, and even the
number of walls in the tube. BN nanotubes have been doped to
optimize their conductivity for uses in molecular electronic
devices and can be synthesized by several methods, depending
on the desired properties and yields. Tubes as long as 40 m
can be constructed by continuous laser heating, or smaller
tubes can be created via carbon substitution. Overheating in
nanoelectronics is of major concern, and the nonreactive BN
tubes are better-suited for these environments. Boron nitride
tubes should also be more durable than their carbon
counterparts, allowing for increased utilization in a variety of
fields.
Reducing the size in silicon-based nanotechnology is also a
major endeavor of scientific and electronic research [16].
Actual contact between carbon nanotubes and silicon
substrates has been achieved via heat treatment. Heating forms
a solid-state reaction in the regions between the nanotubes in
contact with the silicon. This reaction forms rod-shaped SiC.
Leaders in computer technology innovation are investigating
the potential semiconducting properties of this structure.
Silicon nanowires may also alter the future operation of
electronic devices. To increase speed and reduce the energy
use associated with electrical conductivity, engineers are
pushing to synthesize electronic devices smaller and more
complex. Silicon nanowires, which are etched from bulk
silicon, are constructed of clusters containing 24 silicon atoms
and attached to aluminum leads. Because the clusters form
hollow cages, similar to the carbon nanotubes, they could be
constructed containing a dopant atom. This approach should
increase device consistency.
Nanoparticles. All areas of science have embraced
nanoparticles [2, 6­8, 21­23]. In chemistry synthesis,
characterization, and applications of derivative forms of
buckyballs and nanotubes have been explored extensively [11,
12]. Nanoencapsulates, nanoparticles, and nanospheres are
terms that are used to describe small particles that are metal
(i.e., Cu) or metal-carbides (i.e., Fe3C). For example, Takeda
[17] measured the optical properties, including nonlinear
susceptibility and response for insulators with embedded
nanoparticles fabricated by ion implantation. Oku [18]
synthesized gold nanoparticles and nanowires in carbon
nanocapsules and nanotubes that spontaneously formed from
one-dimensional self-organized gold nanoparticles on carbon
thin films by annealing at low temperatures of 200­400 °C.
The one-dimensional arrangement of gold nanoparticles was
found to be strongly dependent on the adhesive force at the
atomic step edges of amorphous carbon thin films. The gold
crystals inside the nanotubes are distorted by the crystal
growth of the nanowires. Poly(2-methoxy-5-ethylhexyloxy-
1,4-phenylene vinylene) (MEH-PPV)/rutile-TiO2 composite
films were made by Kim [19] with various sizes from 7 to 23
nm and their electroluminescent characteristics were
investigated. Barnes [20] investigated the perturbing influence
of nanosize filler particles on the dewetting of spun-cast
polymer films. Rotkin [21] developed a new heuristic model
for the calculation of the formation energy of the carbon
nanoclusters.
Saito [22] generated a rectangular parallelopiped (or cube)
form of graphitic cages in nanometer scale. They were
produced by evaporation of a carbon electrode containing
calcium or strontium. Both the empty and the filled rectangular
nanocapsules, averaging 20 to 100 nm in size, were formed;
however, empty rectangular nanocapsules were dominant. The
rectangular cages were made up of multiwalled (5­20 layers)
graphitic carbon. The encapsulated materials were -
CaC2(tetragonal), -CaC2(cubic) and -CaC2 (monoclinic) for
C/Ca evaporation, and -SrC2 (tetragonal) and metallic Sr for
C/S revaporation.
Liu and Crowely [23] produced structures of manganese-
filled carbon nanotubes and nanoparticles using an arc-
discharge method by using a composite anode. These were
examined with high-resolution transmission electron
microscopy (HRTEM), selected-area electron diffraction, and
electron nanodiffraction techniques. The HRTEM images and
corresponding diffraction patterns show that various
manganese carbides (Mn3C, Mn5C2, Mn7C3, and Mn23C6) were
formed within nanotubes and nanoparticles. Most encapsulated
Mn carbides appeared as perfect single nanocrystals.
Single-domain microcrystals of LaC2 encapsulated within
nanoscale polyhedral carbon particles have been synthesized in
a carbon arc by Liu and Crowely [23]. Typical particle sizes
are on the order of 20 to 40 nanometers. The stoichiometry and
phase of the La-containing crystals have been assigned from
characteristic lattice spacings observed by high-resolution
transmission electron microscopy and energy dispersive
spectroscopy (EDS). EDS spectra show that La and C are the
only elements present. Characteristic interatomic distances of
3.39 and 2.78  identify the compound inside the nanoparticle
cavities as -LaC2, the phase of LaC2 that is stable at room
temperature. Bulk -LaC2 is metallic and hydrolytic.
Observation of crystals of pure encapsulated -LaC2 that were
exposed to air for several days before analysis indicate that the
LaC2 is protected from degradation by the carbon polyhedral
shells of the nanoparticles. A high percentage of the carbon
nanoparticles have encapsulated LaC2 single crystals. These
carbon-coated metal crystals were described as a new class of
materials that can be protected in their pure or carbide forms
and may have interesting and useful properties.
Exfoliated Graphite and GICs. In a previous paper [50],
we showed that the covalently bonded graphite-intercalation
compound fluorinated graphite (C1F1) forms exfoliated
graphite (EG) when processed in an atmospheric pressure
Nanostructures in Physical Materials Chemistry: An Exploratory Laboratory Chem. Educator, Vol. 6, No. 4, 2001 245
 2001 Springer-Verlag New York, Inc., S1430-4171(01)04490-9, Published on Web 07/27/2001, 10.1007/s00897010490a, 640237tm.pdf
27.12 MHz inductively coupled argon plasma. This EG
differed from other EG produced [25­44] in that the ends of
the graphitic sheets were rolled or formed tubes. The micron-
sized carbon dust produced by this process has a low density
(0.013 g cm­3
), high surface area (150 m2
g­1
), minimum
impurities (99.5%  Carbon), honey-combed structure (SEM
pictures), and tubular endings (1345 cm-1
, 1590 cm-1
, 1620
cm-1
, Raman Spectroscopy) [24]. Subsequent work has
demonstrated that C1F1 easily decomposes to a collapsible
form of EG when heated in a covered ceramic disk with
flowing argon to minimize combustion.
The industrial production of fluorinated-graphite (CnFn; n =
1) compounds is carried out at high temperatures (600 °C) by
reacting graphite with F2 gas for several hours [27]. Fluorine­
graphite intercalation compounds, which are nonconductors,
have an experimental density of 0.64 g cm­3
, a surface area of
218 m2
g­1
, and thermally decomposes at 450 °C. Brominated
graphite is easily synthesized by reacting graphite with Br2
liquid or vapor at room temperature and pressure and it has a
reversible intercalation­deintercalation process. When the
brominated graphite compound is heated above a critical
temperature, it puffs up or becomes exfoliated. When the
process is reversed, there exists a residual bromine component
in the graphite complex. How much bromine is left is
dependent on the original particle size, temperatures, etc. For
this laboratory, we sought a final product free of most
impurities and preferably 100% carbon, minimizing the use of
brominated-graphite.
Scientists have conducted extensive work with the graphite-
intercalated compounds Br2, ICl, and HNO3 and demonstrated
that the exfoliation or puffing of the structure takes place
above 170 °C, 190 °C, and 130 °C, respectively [27. 28]. The
Br2 GIC and ICl GIC collapse when cooled below 100 o
C /210
°C and 190 °C, respectively. The Br2 GIC's collapse
temperature varies with the starting material (HOPG, single-
crystal graphite, respectively). Mazieres et al. [29, 30]
observed that Br2­graphite on pyrocarbons underwent first
exfoliation at 200 °C and collapsed at 100 °C when cooled.
Mazieres et al. [30] observed irreversible exfoliation after
heating brominated graphite on pyrocarbons to 1000 °C and
cooling the compound in an argon atmosphere. Exfoliated
graphite can be synthesized by mixing and decomposing
graphite-intercalation compounds with various acids. For
example EG can be produced from reactions involving
HNO3/H2SO4, FeCl3/NH3, and AlCl3 [31­33]. Other methods,
not using acids, such as the heating of potassium-graphite-
tetrahydrofuran ternary compounds (KC24(THF)1 and
KC24(THF)2), have also been used to produce EG [34]. These
methods can be time consuming in that they require an initial
synthesis of a specific graphite-intercalation compound, the
conversion of the GIC to the exfoliated graphite, and a residue
such a metal ion or an acid removed from the EG by additional
washing or heating. Exfoliated graphite (EG), which has
several industrial applications, has been used in numerous
chemical and nuclear plants as sealing materials under the
name of Grafoil [35, 36]. Flexibility and elasticity
characteristics, high thermal resistance, high chemical stability,
and light weight characterize Grafoil.
Another form of pure carbon that has an open pore structure
is reticulated vitreous carbon (RVC) [40. 44]. It has a large,
honeycomb structure with 10 to 100 pores per inch. The pores
in those structures are approximately 1000 times larger than
those reported here and they have a large (500 m2
g­1
) surface
area and a low density (0.048 g cm­3
). This material has the
appearance of fused carbon whiskers and has reported
impurities of N, H, Fe, Cu, Al, or Mg. A range of applications
have been found for this material including electrode material,
filtration, and high temperature insulation.
Hydrogen Storage in Nanotubes. Hydrogen and oxygen
can produce energy by combustion or via an electrochemical
reaction. While oxygen is plentiful in the atmosphere, an
economical and practical method of hydrogen storage has long
been sought. With the discovery of carbon nanotubes, there
have been theoretical and experimental investigations into
using carbon nanotubes to store hydrogen gas [45­47].
Jorissen et al. [45] investigated hydrogen adsorption on carbon
materials at 25 bar and 23 °C and achieved values of 1.5 wt %.
Bauschlicher [46] modeled the addition of H and F to the side
of a carbon nanotube. Zuttel et al. [47] showed that carbon
nanotubes can electrochemically store relatively large amounts
(110 mAh/g) of hydrogen and the reaction is highly reversible.
The nanotube storage device is used to produce electrodes for
rechargeable batteries.
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