Atomic-scale insight into adsorption of sterically hindered dibenzothiophenes on MoS2 and Co–Mo–S hydrotreating catalysts

Adsorption of nitrogen‐ and sulfur‐containing compounds on NiMoS for hydrotreating reactions: A DFT and vdW‐corrected study

“…The square planar geometry of the nickel edge allows for direct adsorption. The brim of the catalyst does not offer the most stable adsorption sites on NiMoS, in contrast to scanning tunneling microscopy (STM) and DFT studies on the adsorption of organonitrogen and organosulfur compounds on unpromoted and Co-promoted edges 25,[62][63][64] that show adsorption to be favored on the brim sites of CoMoS.…”

“…Further, it has been recently shown through STM that dibenzothiophene can adsorb at the corners of unpromoted molybdenum sulfide catalyst particles. 64 Such sites are, therefore, likely sites for inhibition by nitrogen compounds as well. In addition, Lercher and coworkers 35 showed that the IR spectra of CO adsorption on NiMoS/Al 2 O 3 shows several bands corresponding to multiple types of sites, including Ni sites, Mo sites, and Mo sites that are in the vicinity of nickel atoms.…”

Synthesis of a Co–Mo sulfide catalyst with a hollow structure for highly efficient hydrodesulfurization of dibenzothiophene

“…The results show that the (Co)MoS 2 slabs on the reference catalyst particles look like several long and straight lines, while those on the sub-microtube catalyst particles are much shorter and more curved, which by contrast supply more corner sites that are responsible for improving the direct desulfurization capabilities of DBT. 15 As a result, the sub-microtube catalyst reveals a much higher HDS activity than the reference catalyst, although the proportion of the Co-Mo-S phase for the sub-microtube catalyst is 1.5 times higher compared to that of the reference catalyst. Generally, the HDS process of DBT undergoes two parallel routes: direct desulfurization (DDS) and hydrodesulfurization (HYD).…”

Morphology, Dispersion and Catalytic Functions of Supported Molybdenum Sulfide Catalysts for Hydrotreating Petroleum Fractions

“…As discussed earlier in this paper, HYD requires two different adsorp- . In a recent study using STM and MoS2 nanoclusters on gold, 4,6-DMDBT could adsorb on the "brim sites" of MoS2 sheets in a flat configuration, so two sites, one for HYD and the other for sulfur extrusion, were needed for the HDS of S-containing molecules that required preceding HYD of aromatic rings 32) . These discussions concur with our conclusion that single-layer MoS2 catalysts were HYDoriented.…”

“…DBT is adsorbed on the edge sites of CoMoS or MoS2 sheet, but only the corner sites of the sheets (Fig. 16(d)) could catalyze the HDS of DBT due to steric hindrance 32) . For the HDS of large molecules including DBT even without substituents, steric hindrance may be a more important factor that limits HDS reaction than suggested in Fig.…”