Preparation and Characterization of SBA-15 Supported Cobalt–Molybdenum Sulfide Catalysts for HDS Reaction: An All Sulfide Route to Hydrodesulfurization Catalysts

Abstract

MoS 2 hydrodesulfurization (HDS) catalysts promoted with Co supported on SBA-15 were synthesized from sulfur-containing Mo sources [ammonium thiomolybdate (ATM), and tetramethylammonium thiomolybdate (TMATM)] and Co complexes cobalt dimethylthiocarbamate by using different synthesis strategies in order to achieve active catalysts. The (Co)-MoS 2 /SBA-15 catalysts were characterized with X-ray diffraction, N 2 -physisorption and High-Resolution Transmission Electron Microscopy. The catalytic performance in the HDS reaction of dibenzothiophene was examined at T = 623 K and P H2 = 3.4 MPa. The results of the experiments suggest that the sequence of impregnation steps has no significant influence on the HDS activity. On the other hand, the use of different thiomolybdate precursors significantly affects the catalytic activity. The catalysts derived from TMATM show lower HDS activities compared to the catalysts synthesized from ATM which is probably due to the presence of pronounced pore blocking as well as the generation of big needle-like aggregates of the Co-MoS 2 phase. It seems that the formation of intermediate MoS 3 is not a prerequisite for the generation of catalytic active CoMoS phases. The high activity and high selectivity for the direct desulfurization pathway of catalysts prepared with ATM despite the large MoS 2 stacking could be due to the generation of a large number of coordinately unsaturated sites.

SBA-15 as Support for Ni–MoS2 HDS Catalysts Derived from Sulfur-containing Molybdenum and Nickel Complexes in the Reaction of HDS of DBT: An All Sulfide Route

“…An increasing Mo loading yields an enhanced rate constant, for example, by increasing the Mo content from 10 to 18 wt%, the rate constant increases from 8.1 to 12.3 9 10 -7 mol/gs. This observation is similar to the results achieved for Co-MoS 2 /SBA-15 catalysts [8,9]. Comparison of the rate constants determined for Ni(1.5)Mo(10)/SBA-15(6A) (8.1 9 10 -7 mol/g.s) and…”

“…The presence of Ni 2 S 3 particles probably related to the fact that Ni 3 S 2 aggregates more rapidly under the synthesis conditions than Co 9 S 8 because of its lower Tamman temperature (532 K for Ni 3 S 2 versus 686 K for Co 9 S 8 ) [18,19]. The average MoS 2 particle size is found to be around 4 nm (Table 1) (corresponds to five to six stacking layers along the c-axis), which is a typical MoS 2 size observed for the catalysts supported on SBA-15 prepared with ATM [8,9]. Comparing the size of MoS 2 nanocrystals with the pore diameters of the SBA-15 material suggests that the MoS 2 crystallites might be located inside the channels of SBA-15.…”

“…2g). We want to note that for the Co-MoS 2 /SBA-15 catalysts prepared by the same methods [9], no crystalline Co sulfide phases could be detected. The presence of Ni 2 S 3 particles probably related to the fact that Ni 3 S 2 aggregates more rapidly under the synthesis conditions than Co 9 S 8 because of its lower Tamman temperature (532 K for Ni 3 S 2 versus 686 K for Co 9 S 8 ) [18,19].…”

“…Indeed, SBA-15 and hetero-atom containing (Al, Ti or Zr) SBA-15 were found to have excellent potential for deep hydrotreatment of petroleum feedstocks [2][3][4][5][6][7]. Very recently, CoMo sulfide catalysts supported on SBA-15 derived from ammonium thiomolybdate were reported by us [8,9]. The catalysts activated in a H 2 /N 2 (H 2 10%) gas flow showed a higher HDS activity compared to a commercial CoMo/c-Al 2 O 3 catalyst.…”

Catalytic study in the HDO HDT reaction of guaiacyl model compound for the direct valorization of biomasses pyrolysis oil

“…Therefore, as proof of the effectiveness of H 2 S sulfiding treatment, the Fig. 1B shows the XRD patterns of sulfided catalysts, in which besides the broad reflection peaks of tetragonal -alumina support, the convoluted diffraction lines of MoS 2 phase were recorded in the region of 26-44 degrees [1,17]. In Fig.…”