Dibenzothiophene hydrodesulfurization with NiMo and CoMo catalysts supported on niobium-modified MCM-41

• Published in: Applied catalysis. B, Environmental Vol. 219; pp. 479 - 491
• Main Authors: Méndez, Franklin J., Franco-López, Oscar E., Bokhimi, Xim, Solís-Casados, Dora A., Escobar-Alarcón, Luis, Klimova, Tatiana E.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.12.2017; Elsevier BV
• Subjects: Aqueous solutions; Catalysis; Catalysts; Catalytic activity; CoMo catalysts; Dibenzothiophene; Diffuse reflectance spectroscopy; Effects; Electron microscopy; Hydrodesulfurization; MCM-41; Metals; Nickel; NiMo catalysts; Niobium; Photoelectron spectroscopy; Raman spectroscopy; Salts; Scanning electron microscopy; Selectivity; Spectroscopy; Sulfur; Temperature; Transmission electron microscopy; X ray photoelectron spectroscopy; X-ray diffraction; NiMo catalysts; MCM-41; CoMo catalysts; Niobium; Hydrodesulfurization
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2017.07.079

[Display omitted] •MCM-41 materials modified with Nb were used as supports for CoMo and NiMo catalysts.•Effect of Nb on characteristics and activity of the prepared catalysts was studied.•Hydrodesulfurization of dibenzothiophene was used as a test reaction.•Addition of Nb (3–5wt.%) to MCM-41 improved activity of CoMo and NiMo catalysts.•Nb-containing catalysts showed different selectivity than the MCM-41-supported ones. In the present work, we studied the effect of the addition of niobium to CoMo/MCM-41 and NiMo/MCM-41 catalysts on their characteristics and performance in the hydrodesulfurization of dibenzothiophene. The MCM-41 support was synthesized at room temperature according to a well-known procedure. The metal species (Nb, Mo, Ni or Co) were deposited by successive impregnation using aqueous solutions of the corresponding metal salts. MCM-41 and Nb-containing MCM-41 supports were characterized by X-ray diffraction, N2 physisorption, FT-Raman spectroscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy and scanning electron microscopy. The CoMo and NiMo catalysts in oxide state, in addition to the above techniques, were characterized by temperature-programmed reduction and the sulfided catalysts were characterized by high resolution transmission electron microscopy. The results show that the incorporation of small amounts of Nb (3–5wt.%) increased the catalytic activity of both NiMo and CoMo catalysts in dibenzothiophene hydrodesulfurization and affected their selectivity. The effect of Nb on the selectivities of the NiMo and CoMo catalysts was different: for the NiMo catalysts, Nb increased selectivity towards the HYD route, whereas for the CoMo catalysts, it increased selectivity towards the DDS route. The analysis of the effect of Nb on the catalysts’ selectivity was performed based on the kinetic constants calculated for the different steps of the DBT HDS network.