[The Application of X-Ray Photoelectron Spectroscopy on Refining Catalyst].

Abstract XPS analysis provides qualitative, quantitative and chemical state information for surface elements of solid materials. Therefore, XPS is widely applied in the characterization of refining catalyst. In the present paper, the applications of XPS in the field of typical refining catalysts, including hydrogenation catalyst, S Zorb sorbent and rare-earth modified Y zeolite, are illustrated and exemplified. For sulfided Co (Ni)-Mo (W)/Al2O3(-SiO2) hydrodesulfurization catalysts, the anhydrous oxygen-free transfer process from the reactor to XPS chamber was illustrated. The identification and peak fitting of S(2p) , Mo(3d), W (4f), Co(2p) and Ni(2p) XPS spectra were summarized. The typical chemical states of the active elements were described. Based on these results, the sulfidation extents of the active metals and the cause for the sulfidation inadequency of the catalysts were deduced. As for the application of XPS in S Zorb sorbent, the existence form of zinc was obtained from ZnLMM Auger spectra, and the fracture mechanism and deactivation reason of the sorbent were derived. The distribution of sulfur along the vertical direction was investigated using XPS and argon ion sputtering XPS. Besides, in situ XPS was applied to study the conversion of sulfur- and nickel-containing species for spent sorbent under hydrogen condition. Finally, for cerium modified Y zeolite, the location of cerium ion inside and outside Y zeolite cage was investigated. The results indicate that the liquid phase method is more suitable for the migration of cerium ion toward zeolite as compared with the solid phase method.

[Laser Raman spectra study on Co-Mo/Al2O3 hydrodesulphurization catalysts].

Due to the implementation of more stringent specifications in sulfur content for gasoline , a deep understanding of the active phase of Co-Mo/Al2O3 catalysts is necessary to the development of hydrodesulphurization (HDS) catalysts. A series of Co-Mo/Al2O3 HDS catalysts with different metal loading were studied by laser Raman spectra. The existence form and the content of the active component of the catalyst were obtained by Raman spectra. The result shows that the percentage of characteristic Raman bands 940 cm(-1) correlates linearly with the HDS selectivity, which can be used as an experimental evidence for developing industrial selective HDS catalysts. Raman spectra of sulfided catalysts show that the bands of oxidic catalysts at 839 and 940 cm(-1) disappeared, and simultaneously, the bands of Mo-S at 372 and 408 cm(-1) emerged, which indicate that the oxidic sample is sulfided completely.

[In situ FTIR and XPS study on selective hydrodesulfurization catalyst of FCC gasoline].

Improvement of the selectivity of hydrodesulfurization (HDS) for hydrogenation (HYD) of olefins is crucial to produce sulfur-free (S < 0.001%) gasoline from fluid catalytic-cracked (FCC) gasoline. A series of sulfided CoMo/Al2O3 catalysts with different metal loading were prepared by pore-filling impregnation. MoS2 and COMoS active phases on the surface of sulfided COMo/Al2O3 catalyst were identified and analyzed quantitatively by XPS and in-situ FTIR of adsorbed CO. The results reveal that the increase in COMoS phase on the catalyst surface improves the HDS activity and selectivity. And the HDS selectivity correlates linearly with the ratio of active site number of CoMoS and MoS2, the higher the ratio of active site number of CoMoS and MoS2, the better the HDS selectivity. In situ variable temperature FTIR analysis shows that CoMoS phase has stronger electron accepting ability than MoS2. The strong electron deficient property of CoMoS active sites is the main reason for its excellent HDS activity and selectivity.

[In-situ FTIR study of CO adsorption on Co-Mo/Al2O3 hydrodesulphurization catalysts].

Due to the implementation of more stringent specifications in sulfur content for diesel oil, a deep understanding of the active phase of Co-Mo/Al2O3 catalysts is necessary to the development of ultra-deep hydrodesulphurization (HYD) catalysts. A series of reductive Co-Mo/Al2O3 catalysts prepared in the lab and the high-active industrial catalyst (G) were studied by in-situ FTIR using CO as probe molecule. The showed a good relationship with the desulphurization activities of the catalysts. With the increase in MoO3 and CoO loading, the desulphurization activity of catalyst increases, and the infrared spectrum changes with the amount of CO adsorbed on the catalyst. There is a new band at 2179 cm(-1) when the MoO3 loading is up to 20% and CoO up to 4. 16%. According to the activities of the catalysts, the appearance of this new band suggests that the catalyst has higher hydrodesulphurization (HYD) activity. Compared with the infrared spectrum of CO on the catalyst of the same MoO3 and CoO loading by the common preparation method, the catalyst prepared with chelating agents has higher HYD activity and its band at 2 179 cm(-1) is stronger. The infrared spectrum of CO adsorbed on optimum Co-Mo/Al2O3 catalyst prepared in the lab is similar to the highly active industrial catalyst (G). Their bands at 2179 cm(-1) are both very strong and their HYD activities are both higher than the others. Thus, the appearance and the increase of the band at 2179 cm(-1) indicate the increase in the HYD activity of Co-Mo/Al2O3 catalysts to some extent, which could be an effective tool for developing ultra-deep HYD catalysts.