K K Bando et al 2009 J. Phys.: Conf. Ser. 190 012158 doi:10.1088/1742-6596/190/1/012158
K K Bando1,6, T Wada2, T Miyamoto2, K Miyazaki2, S Takakusagi2, T Gott3, A Yamaguchi4, M Nomura5, S T Oyama3,6 and K Asakura2,6
Show affiliationsSupported Ni2P catalysts are efficient for the hydrodesulfurization (HDS) of liquid fuels. In situ extended x-ray absorption fine-structure (EXAFS) analysis of the Ni2P catalyst under realistic HDS conditions revealed the formation of Ni-S bonds in the catalyst system. In order to identify the origin of these bonds, a quick x-ray absorption fine structure (QXAFS) system was set up, which enabled measurement of one Ni K-edge EXAFS spectrum in 10 sec. In addition, a Fourier transform infrared (FTIR) unit was incorporated to the QXAFS system, which allowed simultaneous measurements of XAFS and IR spectra on the same sample. The catalyst (12.2 wt% Ni2P/MCM-41) was activated under H2 at 723 K to regenerate an active phosphide phase. After activation, a reaction gas mixture (thiophene/He/H2 = 0.1/1.9/98, at a total flow rate of 102 ml/min) was introduced. Under the reaction conditions, there was a change in the pre-edge area of XANES, which corresponded to the evolution of Ni-S bonds in EXAFS. The simultaneous measurements of XANES and IR revealed that this Ni-S could be attributed to the formation of a Ni phosphosulfide species rather than bonding between Ni and S of adsorbed thiophene. The combined in situ techniques proved to be an effective tool for the characterization of working catalysts.
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
78.70.Dm X-ray absorption spectra
82.80.Ej X-ray, Mössbauer, and other gamma-ray spectroscopic analysis methods
Condensed matter: electrical, magnetic and optical
Issue 1 (2009)
K K Bando et al 2009 J. Phys.: Conf. Ser. 190 012158
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