Advances in Chemical Engineering and Science, 2013, 3, 1-3
http://dx.doi.org/10.4236/aces.2013.33A3001 Published Online August 2013 (http://www.scirp.org/journal/aces)
Room Temperature Storage of Hydr ogen by Carbons
Mitsunori Furuya, Ayaka Yanagitsuru, Yuuya Matsuo, Kenji Ichimura
Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan
Received May 9, 2013; revised June 9, 2013; accepted July 9, 2013
Copyright © 2013 Mitsunori Furuya et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
The adsorption states of hydrogen at around 300 K are found on carbons by means of thermal desorption measurements.
This sorption ability has utility for energy technologies such as fuel cells.
Keywords: Hydrogen; Storage; Carbon; Absorption States
1. Introduction
We have reported the chemical interactions of hydrogen
in the solids C60, Na-C60-H ternary systems (super-con-
ducting (SC) and non-super-conducting non-SC Phases)
and carbon nanotube [1-7], as shown in Figure 1.
This paper presents results in the thermal desorption of
hydrogen from carbon blacks and carbon nanohorn.
0200 400 600 800
0.0
5.0x10-7
1.0x10-6
1.5x10-6
1000 1200
OSWCNT
CSWCNT
0.0
2.0x10-7
4.0x10-7
6.0x10-7
8.0x10-7
Temperature/K
OMWCNT
CMWCNT
0.0
5.0x10-7
1.0x10-6
1.5x10-6
Na-H-C60
non-SC phase
0.0
4.0x10-6
8.0x10-6
1.2x10-5
Na-H-C60
SC phase
0.0
4.0x10-7
8.0x10-7
0200 400 600 80010001200
pressure/mbar
C60
Figure 1. The thermal desorption of hydrogen from C60,
Na-H-C60 and carbon nanotubes.
2. Experimental
C60 (Hoechst, 99.98% purity) was used without further
purification.
The synthesis of NaxHyC60 was done as follows: The
mixture of stoichiometric amounts of NaH and C60 pow-
ders was loaded in a quartz tube in a dry box filled with
Ar gas. Then the sample in the tube sealed under the
pressure of ~10−4 Pa was heated at 553 K for 1 h in a
muffle furnace.
Capped and open (no endcaps) single wall carbon
nanotubes (CSWCNT and OSWCNT, Bucky USA BU-
202 (endcaps) and BU-203 (no endcaps), respectively,
with 1.4 - 3 nm diameter and 10 - 50 μm length) were
used without further purification for the adsorption stu-
dies. The only difference between BU-202 and BU-203
is the endcap structure at both ends, and other- wise the
two structures are the same.
Carbon black (Seast 3HAF) and graphitized carbon
blacks (#3855, #3845 and #3800) were supplied from
Tokai Carbon Co. Table 1 shows the characterizaion of
samples.
Carbon nanohorn was synthesized by means of the
arcing method and supplied by Yamaguchi and Iijima
[8,9].
Table 1. Caracteristics of carbon blacks.
sample weight/mgParticle radii/nm
N2 specific surface
area/m2/g
Seast 3HAF
(S3) 32 28 79
#3855 32.2 25 90
#3845 33.1 40 57
#3800 32.1 70 27
C
opyright © 2013 SciRes. ACES

M. FURUYA ET AL. 2
After vacuum heating at 653 K or 1073 K, the samples
were exposed to hydrogen (Nippon Sanso, >99.9999%
purity) 1 to 1.4 atm, at 473 K for 3 - 5 days. After the
sample was cooled to liquid nitrogen temperature, the
sample tube was evacuated to ultra-high vacuum. De-
sorbed gas was analyzed by using two mass-spectro-
meters when the sample was heated at a temperature-rise
rate of 5 K/min.
3. Results and Discussion
As shown in Figure 1, for C60 and carbon nanotubes, the
desorption of hydrogen was observed below 300 K. The
temperature region of desorption below 300 K suggests
the interaction by van der Waals and/or weak chemical
bonding. The further desorption peaks were observed at
around 820 K for C60 and 650 K for carbon nanotubes.
The temperature region of desorption above 300 K sug-
gests the interaction by strong chemical bonding. In the
KC8H0.6 ternary system, the hydrogen desorption peak
appears at 512 K. The desorption peaks of hydrogen in
Na-H-C60 appear at around 650 K and 900 K, in which
hydrogen species at around 650 K has a strong correla-
tion with super-conductivity. In these systems, hydrogen
exists as H− or Hδ−. The hydrogen desorption peaks for
carbon nanotubes are lower than C60, indicating that the
interaction of carbon nanotubes with hydrogen is weaker
than that of C60. The temperature region of desorption
suggests that the charge transfer occurs hydrogen from
C60 and carbon nanotubes.
For OMNT and CMNT, the absorbed amount of hy-
drogen for CMNT is larger than that for OMNT. As for
the both, the basic structure is the same, and the diffe-
rence of the both is only the presence of end caps. There-
fore, this result that CMNT with end caps shows a larger
amount of absorption indicates that sites which are com-
posed of end caps are more active for the adsorption and
absorp- tion of hydrogen on and in the used OMNT and
CMNT in the temperature region above 77 K. C60 shows
the de- sorption of hydrogen at around 300 K.
Figure 2 shows the thermal desorption of hydrogen
from carbon blacks. An amorphous type carbon black S3
has sorption states for hydrogen at around 300 K. The
sorption state of S3 appeared at 374 K changed to the
higher temperature side by graphitization. However, gra-
phitization causes the creation of the sorption states at
around 230 K by appearance of new electronic states of
micro-graphite. Among these carbon blacks, amorphous
type carbon black shows the sorption characteristic for
hydrogen sorption at around room temperature.
Figure 3 shows the hydrogen desorption from carbon
nanohorn. The desorption feature is similar to the graph-
itized carbon blacks: The sorption states appear at around
130 K and 500 K. However, the sorption states appeared
in the lower temperature side are stronger the than
Figure 2. The thermal desorption of hydrogen from carbon
blacks.
0200 400 600 80010001200
5 1 0 K
1 3 0 K
Pressure / arbitrary unit
Termperature / K
Figure 3. The thermal desorption of hydrogen from carbon
nanohorn.
those of graphitized carbon blacks.
4. Conclusions
The sorption state at around 300 K is found in H2 desorp-
tion from C60, carbon blacks and carbon nanohorn. These
sorption abilities have utility for energy technologies
such as fuel cells. By changing the structure and aggre-
gation states of carbons as shown in C60, carbon blacks
and carbon nanohorn, it is possible to create the new
electronic state and their sorption characteristics for hy-

M. FURUYA ET AL. 3
drogen sorption at around room temperature.
5. Acknowledgements
Authors thank Tokai Carbon Co. for the sample supply
of carbon blacks. Authors also thank Dr. T. Yamaguchi
of Nagoya University and Professor S. Iijima of Meijo
University for the sample supply of carbon nanohorn.
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