Unsupported Ni/Mo(W)S₂ Catalysts from Hexamethylenediammonium Thiometallates Precursors: In Situ Activation During the HDS of DBT

• Published in: Catalysis letters Vol. 134; no. 1-2; pp. 138 - 146
• Main Authors: Lumbreras, J. A, Huirache-Acuña, R, Rivera-Muñoz, E. M, Berhault, G, Alonso-Núñez, G
• Format: Journal Article
• Language: English
• Published: Boston Boston : Springer US 2010; Springer US; Springer; Springer Nature B.V
• Subjects: Ammonium molybdate; Aqueous solutions; Carbon; Catalysis; Catalysts; Catalytic activity; Chemistry; Chemistry and Materials Science; Crystallization; Dibenzothiophene; Electron microscopes; Exact sciences and technology; General and physical chemistry; Hydrodesulfurization; Industrial Chemistry/Chemical Engineering; Microscopy; Molybdenum disulfide; Nickel; Organometallic Chemistry; Physical Chemistry; Precursors; Scanning electron microscopy; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Transmission electron microscopy; Tungsten disulfide; X-ray diffraction; Ni-promotion; Hexamethylenediammonium thiometallates; In situ activation; Hydrodesulfurization; In situ; Adsorption isotherm; Activation; Decomposition; Precursor; Solid; Desorption isotherm; Scanning electron microscopy; BET method; Catalytic reaction; Crystallization; Transition metal; Carbon; X ray diffraction; Heterogeneous catalysis; Transmission electron microscopy; Nickel; Accommodation; Aqueous solution; Surface area; Catalyst; Thiomolybdates
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-009-0209-3

Unsupported Ni/MoS₂ and Ni/WS₂ HDS catalysts were prepared by in situ activation of hexamethylenediammonium thiometallates promoted with Ni. The method involved an aqueous solution reaction of ammonium thiomolybdate (ATM) or ammonium thiotungstate (ATT) with Ni(NO₃)₂·6H₂O and hexamethylenediamine. Ni-promoted precursors were then in situ activated during the hydrodesulfurization (HDS) of dibenzothiophene (DBT) producing Ni/MoS₂ and Ni/WS₂ catalysts. Solids were analyzed after the in situ activation by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and for textural properties by using the BET and BJH methods. Catalysts with relatively high surface area and type IV N₂ adsorption-desorption isotherms were obtained. The use of the hexamethylenediammonium precursor led to a significant nickel promotion of MoS₂ and WS₂ catalysts. For Ni/MoS₂, the use of this carbon-containing precursor was found to be more beneficial for the final HDS catalytic activity than using the classical ammonium tetrathiomolybdate (ATM) without carbon. For Ni/WS₂, compared to tetraalkylammonium thiosalts, the lower amount of carbon in excess formed during the decomposition of the hexamethylenediammonium precursor coupled with a lower crystallization rate of WS₂ favors a correct nickel accommodation on the WS₂ edges.