Effects of the Support on the Performance and Promotion of (Ni)MoS₂Catalysts for Simultaneous Hydrodenitrogenation and Hydrodesulfurization

Abstract

MoS 2 and Ni-promoted MoS 2 catalysts supported on γ-Al 2 O 3 , siliceous SBA-15, and Zr-and Ti-modified SBA-15 were explored for the simultaneous hydrodesulfurization (HDS) of dibenzothiophene (DBT) and hydrodenitrogenation (HDN) of o-propylaniline (OPA). In all cases, OPA reacted preferentially via initial hydrogenation, and DBT was converted through direct sulfur removal. HDN and HDS activities of MoS 2 catalysts are determined by the dispersion of the sulfide phase. Ni promotion increased its dispersion and activity for DBT HDS and also increased the rate of HDN via enhancing the rate of hydrogenation. On nonpromoted MoS 2 catalysts, HDS was strongly inhibited by NH 3 , and the addition of Ni dramatically reduced this inhibiting effect. The conclusion is that HDS is proportional to the concentration of Mo and Ni on the edges of sulfide particles. In contrast, the direct hydrodenitrogenation of OPA occurs only on accessible Mo cations and, hence, decreases with increasing Ni substitution. The nature of the support influences the dispersion of the nonpromoted catalysts as well as the decoration degree of Ni on the edges of the Ni−Mo−S phase. Furthermore, the acidity of the support influences the acidity of the supported sulfide phase, which may play an important role in HDN.

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

“…Further, organonitrogen compounds inhibit the hydrogenation pathway in HDS of dibenzothiophenes significantly. 35,42,65 This can be rationalized, again, on the basis of the calculated adsorption structure. The hydrogenation pathway requires the flat-parallel adsorption structure which is likely destabilized to a greater extent by the presence of these organonitrogen compounds, some of which themselves tend to adsorb in a flatparallel adsorption structure.…”

“…Transmission electron microscopy studies have shown that NiMoS particles can be synthesized on alumina supports such that they contain one or two layers of catalyst. 35,46 Further, catalyst particles expose two types of edges based on their termination. Ab initio studies have shown that the most preferred nickel promoted edge morphology is a metal edge with complete replacement of edge molybdenum atoms by nickel and no further decoration by sulfur leading to a square planar geometry around the nickel atoms 31,47 ; this edge has been proposed to be the location of active sites in NiMoS.…”

Transition Metal–MoS2 Reactions: Review and Thermodynamic Predictions

“…13,30,31 Catalysis researchers are also looking at two-dimensional (2D) versions of existing hydrodesulfurization materials (MoS 2 with metals such as Ni and Co). 14,32 In each of these applications, the interaction between MoS 2 and various metals is important because either that interaction alters the primary properties of the system (e.g., wear resistance, catalytic activity, etc.) or MoS 2 is in contact with a metal, and the properties of all phases at the interface are important (e.g., electrical contacts).…”

Study of NiMoS mixed phase from catalyst precursors in residue slurry-bed hydrocracking

“…The addition of Ni increased dispersion, concentration of adsorption sites, and intrinsic activity of the sulfide phase in all cases. The effects of Ni addition were attributed to the formation of the NiMoS phase [17]. In the NiMoS phase, the enlargement of the Mo-S distance and the distortion of the electronic density of the bond in a particular direction, increased in this way.…”