Showing papers on "Ammonium tetrathiomolybdate published in 2011"

HDS of DBT with Molybdenum Disulfide Catalysts Prepared by In Situ Decomposition of Alkyltrimethylammonium Thiomolybdates

Abstract: Three alkyltrimethylammonium thiomolybdates, [R–N(CH3)3]2MoS4 (where R = lauryl, myristyl or cetyl) were synthesized in aqueous solution, and characterized by 1H-NMR spectroscopy. These alkyltrimethylammonium thiomolybdates were used (the lauryl and myristyl thiomolybdates for the first time) as precursors for in situ prepared MoS2 catalysts, activated during the hydrodesulfurization of dibenzothiophene. The catalysts were analyzed by EDX, showing large voids and a S/Mo ratio around 2. High surface areas up to 443 m2/g and type IV adsorption–desorption nitrogen isotherms were obtained. X-ray diffraction showed that the catalysts are poorly crystalline, with a very weak (002) peak intensity for all samples except the MoS2 catalyst prepared from pure ammonium tetrathiomolybdate precursor. A high dibenzothiophene conversion (74%) was observed with the catalyst obtained from the lauryltrimethylammonium thiomolybdate precursor, attributed mainly to its high specific surface area. Selectivity results showed that all the prepared catalysts strongly favored the hydrogenation pathway.

Sulfur-tolerant catalyst prepared through high pressure decomposition

Abstract: A method of producing a MoS2 catalyst. The method begins by the decomposition of ammonium tetrathiomolybdate in an organic solvent. This decomposition is done in the presence of a solution comprising: a solvent and a promoter, and done under gaseous pressure.

Direct synthesis of porous molybdenum disulfide materials using silica sol as the template

Abstract: A simple, convenient, and effective synthetic approach has been proposed to prepare the porous molybdenum disulfide materials by utilizing ammonium tetrathiomolybdate as the precursor and silica sol as the template. The as-synthesized products were characterized by X-ray powder diffraction, low-temperature N2 adsorption, Scanning Electron Microscopy, and Transmission Electron Microscopy. The characterization results reveal that the as-synthesized molybdenum disulfide material has the “worm-shaped” pores, high specific surface area (170.2 m2/g), and large pore volume (0.64 cm3/g).

Adhesion Layer for Solution-Processed Transition Metal Oxides on Inert Metal Contacts

Abstract: An ammonium thio-transition metal complex is used as an adhesion promoter for immobilizing temperature-stable transition metal oxide layers on an inert metal surface. The ammonium thio-transition metal complex comprises a transition metal selected from molybdenum, tungsten and vanadium, and is preferably ammonium tetrathiomolybdate. A precursor of the transition metal oxide is deposited on the inert metal surface by a solution-based process. The precursor is a dispersion or a dissolution of the transition metal oxide, a transition metal oxide hydrate, an ammonium salt of an acidic transition metal oxide hydrate or phosphoric acid-transition metal oxide complex in water or a phosphoric acid-transition metal oxide complex dissolved in a polar organic solvent.

Synthesis and Characterization of Rodlike Ammonium Tetrathiomolybdate and its Thermal Decomposition Mechanism

Abstract: Rodlike ammonium tetrathiomolybdate has been synthesized via ultrasonic assistance using monocrystal ammonium dimolybdate and ammonium sulfide as raw materials. The phase compositions, purity of as-synthesized products were characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), laser Raman spectroscopy(LRS). The thermal decomposition mechanism of ammonium tetrathiomolybdate was deduced by thermoanalysis. It is shown that brownish-red rhombic ammonium tetrathiomolybdate crystal with high purity could be obtained at 60°C for 1h under relatively mild conditions.

Synthesis of Porous Molybdenum Disulfide Materials with High Specific Surface Area Using Sodium Chloride as the Template

Abstract: One novel, simple and convenient synthetic approach has been proposed to prepare the porous molybdenum disulfide materials by utilizing ammonium tetrathiomolybdate as the precursor and sodium chloride as the template. The as-synthesized products were characterized by X-ray powder Diffraction (XRD), Low-temperature N2 Adsorption (BET method), and Scanning Electron Microscopy (SEM). The characterization results reveal that the as-synthesized molybdenum disulfide material has high specific surface area (253.5 m2/g).

Adhesion layer for solution-processed transition metal oxides on inert metal contacts

Abstract: An ammonium thio-transition metal complex is used as an adhesion promoter for immobilising temperature-stable transition metal oxide layers on an inert metal surface. The ammonium thio-transition metal complex comprises a transition metal selected from molybdenum, tungsten and vanadium, and is preferably ammonium tetrathiomolybdate. A precursor of the transition metal oxide is deposited on the inert metal surface by a solution-based process. The precursor is a dispersion or a dissolution of the transition metal oxide, transition metal oxide hydrate, ammonium salt of an acidic transition metal oxide hydrate or phosphoric acid-transition metal oxide complex in water or a phosphoric acid-transition metal oxide complex dissolved in a polar organic solvent.