Photon Factory Activity Report 2004 #22 Part B (2005)
Chemistry

9A, 7C/2003G247

A New High Pressure and High Temperature Cell for an Operando EXAFS
Observation of Hydrodesulfurization Catalysts
Toshihide KAWAI1,2, Kyoko K. BANDO3, S.Ted OYAMA3.4, Wang-Jae CHUN1, Kiyotaka
ASAKURA*1
1
CRC Hokkaido University, Sapporo 001-0021, Japan
2
Spring-8, JASRI, Koto, Mikazuki, Hyogo 679-5198, Japan
3
AIST, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
4
Departments of Chemical Engineering and Chemistry, Virginia Polytechnic Institute and State
University, Blacksburg, Virginia 24061-0211, USAIntroduction
The hydrodesulfurization catalysts are important inorder to decrease sulfur compounds in fuels, which are
the source of SOX and the acid rain. In order to develop
high performance hydrodesulfurization catalysts,
operando structure analysis is indispensable. EXAFS is
the best tool for this purpose.
However, operando
EXAFS studies on the hydrodesulfurization catalysts arequite difficult because of the presence of high pressureand high temperature oils, which absorb X-ray strongly.
We have constructed a new cell which enables us to carryout the operando EXAFS of Ni2P catalysts (the mostactive hydrodesulfurization catalysts) in the presence of 3
MPa liquid hydrocarbons at 600 K.

conclusion, Ni2P structure was stable even under thehigh-pressure reaction conditions.
In this work we carried out operando XAFS studies on
Ni2P catalysts and the current system is supposed to beapplicable to the operando EXAFS studies for otherhydrotreating catalysts such as NiMoS, CoMoS and PtPd.
We acknowledge support from the NEDO International
Joint Research Grant Program and MEXT Grant-in-aidfor scientific research Category S No 16106010.
We
acknowledged Dr. Hitoshi Sumiya (Sumitomo ElectricIndustries, Ltd.) for providing us with cBN windows.

Experimental
A new cell design
Figure 1 shows a new cell for measurement of EXAFS
under high pressure and high temperature liquid phasereaction conditions. The window material we used inthis work is high purity binderless c-BN (SumitomoElectric Industries, Ltd) It is the hardest material second
to diamond. It is stable, non-toxic and does not give any
diffraction peaks unlike Be or diamond.

0.3a)

0.2b)

χ(k)

Reaction conditions
We used the model oil containing 20 wt% tetralin and
77 wt% tetradecane with 3 wt% DBT (Dibenzothiophene).
It was supplied to the catalyst with 3 MPa H2. The oil
feed speed was 2 g / hour. The cell was heated up to 613
K and we measured EXAFS spectra under these highpressure and high temperature conditions.

Figure 1 Diagram ofthenewhighpressure and hightemperature cell

0.1c)

Results and discussion
Figure 2 shows the EXAFS oscillations before thereaction and under the steady state operating conditions.
Three spectra were quite similar to one another. As far as
the authors know, this is the first operando EXAFS
spectra for hydrotreating catalysts under the real catalytic
conditions in the presence of oil at 3 MPa. We could findlittle difference between the two EXAFS spectra underhydrodesulfurization conditions. High-pressure operando
EXAFS demonstrated that the Ni2P structure on SiO2
was quite stable under the reaction conditions.
In0.0-0.1
2468k / 10nm

1012-1Figure 2 XAFS oscillations: (a)before reaction, (b) 9 hours afterthe reaction initiation, (c) 24hours after the reaction initiation* askr@cat.hokudai.ac.jp

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