II International Symposium on Carbon for Catalysis ABSTRACTS

PP-<strong>II</strong>-12
RESULTS AND DISCUSSION
Selected results of the catalytic tests are presented in Fig. 1 and Fig. 2. As follows from
the data in Fig. 1, the catalytic activity of carbon samples activated by KOH strongly depends
on the amount of the activating agent. The best results were obtained at the KOH/coal weight
ratio of 4:1. The degree of burn-off for this sample was about 80%, and its surface area was
very high (2802 m 2 /g). The other samples (of lower surface areas) had similar initial activity
which however quickly decreased with the time of the process. This is most probably due to a
faster filling up of the catalyst’s pores by carbon formed as a result of methane
decomposition.
Activity (mmol*g -1 *min -1 )
0.8
0.6
0.4
0.2
Reaction temp. 850 o C
KOH/coal ratio:
4 : 1
1 : 1
1 : 2
0.0
0 50 100 150 200 250
Time (min)
Fig. 1. Catalytic activity as a function of
KOH/coal ratio
Activity (mmol*g -1 *min -1 )
2.5
2.0
1.5
1.0
0.5
KOH/coal ratio = 4 : 1
750 o C
850 o C
950 o C
0.0
0 50 100 150 200
Time (min)
Fig. 2. Catalytic activity as a function of
reaction temperature
Fig. 2 presents the effect of temperature
on the catalytic activity of the sample
activated at the KOH/coal ratio of 4:1. The
activity increases with increasing
temperature of the reaction. For the process
carried out at 950 o C, the catalyst activity is
very high but quickly decreases to stabilise
after about 100 minutes of the reaction. The
processes conducted at lower temperatures
are characterised by lower degrees of
methane conversion to hydrogen, bur the
catalyst activity in them is more stable in
time.
References
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2 Radmacher W, Mohrahauer P.
Brennstoff-Chemie 1956; 37: 353.
3 Lillo-Ródenas MA, Lozano-Castelló
D, Cazorla-Amorós D, Linares-
Solano A. Carbon 2001; 39: 751.
4 Hu Z, Srinivasan MP, Ni Y. Carbon
2001; 39: 877.
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