Comparative Study of In situ/Ex situ Activated Trimetallic NiMoW Sulfide Catalysts Prepared from Ammonium Thiomolybdotungstates

Abstract

Unsupported trimetallic NiMoW sulfide catalysts with high hydro-desulphurization activities are prepared from Ni-containing ammonium thiomolybdo tungstates by in situ and ex situ activation. These precursors are prepared by adding an aqueous NiCl 2 solution to an aqueous (NH 4 ) 4 MoWS 8 solution in either a 1:1 or 0.5:1 Ni/Mo(W) molar ratio. The resulting precursors Ni 0.5 / (NH 4 ) 4 MoWS 8 and Ni/(NH 4 ) 4 MoWS 8 yield Ni 0.5 MoW-in situ, NiMoW-in situ, Ni 0.5 MoW-ex situ and NiMoW-ex situ sulphide catalysts, respectively. The activation method affects both physical and chemical properties, such as macro and microstructure, crystalline structure, specific surface area, N 2 adsorption-desorption isotherms. The in situ/ex situ activation of these ammonium thiotrimetallate precursors leads to a mesoporous structure with a pore size ranging from 20 to 60 Å and type IV N 2 adsorptiondesorption isotherms. X-ray diffraction patterns of unsupported NiMoW sulfide catalysts correspond to those of a microcrystalline material, with outstanding reflections attributed to MoS 2 , WS 2 , NiS, and Ni 9 S 8 phases.

Effect of Polyethylene Glygol on Preparation and Performance of Ni-Mo Hydrodesulfurization Catalysts

“…Besides pore dispersing action, it contributes to the wetting and plasticizing functions [16][17][18][19][20][21][22][23]. Research has shown that the introduction of additives during the preparation of the catalyst increases its activity in hydrodesulfurization and denitrification reactions [24].…”

Synthesis, characterization and catalytic activity during hydrodesulphurization of dibenzothiophene of NiMoW catalysts supported on AlTi mixed oxides modified with MgO

“…As consequence, Soled et al [9] synthesized and patented the first unsupported NiMoW trimetallic catalyst, called NEBULA, which may be more effective than the conventional one used in industry. Nowadays the potential of applying NiMoW catalysts for HDT has been explored [10][11][12][13] and it has been reported that when Mo is partially substituted by W, an amorphous phase is created, which after reduction and sulphidation produces catalytically active materials. Despite the high catalytic activity for the unsupported NiMoW catalysts, they have the disadvantage of high cost and low utilization of active components, therefore further research is still required [14].…”

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

“…Ammonium thiometallates have already been extensively studied as potential precursors for HDS catalysts [4][5][6][8][9][10] Electronic supplementary material The online version of this article (doi:10.1007/s10562-009-0209-3) contains supplementary material, which is available to authorized users.…”