Active phase genesis of NiW hydrocracking catalysts based on nickel salt heteropolytungstate: Comparison with reference catalyst

• Published in: Applied catalysis. B, Environmental Vol. 126; pp. 55 - 63
• Main Authors: Tayeb, Karima Ben, Lamonier, Carole, Lancelot, Christine, Fournier, Michel, Bonduelle-Skrzypczak, Audrey, Bertoncini, Fabrice
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 25.09.2012; Elsevier
• Subjects: Catalysis; Chemistry; EPR; Exact sciences and technology; General and physical chemistry; Heteropolyanion; HRTEM; NiW catalysts; Raman; Sulfidation; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; WS2; XPS; Heteropolyanion; Sulfidation; EPR; WS2; NiW catalysts; XPS; Raman; HRTEM; High resolution; EPR spectrometry; Nickel nitrate; X ray; Sulfurization; Precursor; Supported catalyst; Tungsten; Photoelectron spectrometry; WS; Hydrotreating; Reference; Transition metal; Heterogeneous catalysis; Impregnation; Transmission electron microscopy; Hydrocracking; Nickel; Electron paramagnetic resonance; Catalyst; Environmental protection
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2012.06.025

. [Display omitted] ▸ Study of HCK catalysts sulfidation by Raman, XPS, HRTEM and EPR. ▸ Higher quantity of NiWS for HPA based catalyst than for conventional NiW catalysts. ▸ Evidence of sulfidation intermediates WS3 and WOxSy. ▸ Ni-WOxSy species proposed as NiWS phase precursors. The sulfidation of supported NiW hydrotreating catalysts is followed by a combination of X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM), Raman and electron paramagnetic resonance (EPR) spectroscopy. In this work, we compared two catalysts prepared by incipient wetness impregnation from different precursors. The first one is an innovating catalyst prepared with the nickel salt of the derived lacunary Keggin heteropolyanion (HPA) Ni4SiW11O39 and the second one is a conventional catalyst synthesized from ammonium metatungstate and nickel nitrate. The results show for both catalysts that the sulfidation of nickel and tungsten elements does not occur at the same temperature. However, a better sulfidation of tungsten and nickel atoms respectively to WS2 and NiWS phases is observed at 400°C for HPA precursor compared to conventional catalyst, highlighting the benefit of HPA starting material.