X‐ray photoelectron spectroscopic and electron spin resonance studies of cobalt species in CoMo/γ‐Al2O3hydrodesulfurization catalysts after operation for eight hours under pressure
- 1 October 1981
- journal article
- research article
- Published by Wiley in Surface and Interface Analysis
- Vol. 3 (5) , 206-210
- https://doi.org/10.1002/sia.740030505
Abstract
We report X‐ray photoelectron spectroscopic and electron spin resonance data on Co/γ‐Al2O3and CoMo/γ‐Al2O3catalysts Co/(Co+Mo) = 0.35 after sulfidation and catalytic operation under 30 bars pressure at 305°C for eight hours. The catalysts were protected from air contamination. Data on catalytic activity (hydrogenolysis of thiophene and hydrogenation of cyclohexene), X‐ray diffraction and diffuse reflectance spectroscopy are also reported. A reduced cobalt species is associated with Co9S8on Co/γ‐Al2O3. This species is not detected on CoMo/γ‐Al2O3, where cobalt occurs as CoAl2O4and as cobalt in a fully sulfided form, quite probably as Co9S8. If the hypothesis of the synergy by contact is correct, the results indicate that unreduced Co9S8is the activating agent.Keywords
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