Sulfidation Degree Research Articles

PEG400-assisted synthesis of oxygen-incorporated MoS2 ultrathin nanosheets supported on reduced graphene oxide for sodium ion batteries

Oxygen-incorporated MoS2 (OI-MoS2) ultrathin nanosheets have been successfully fabricated using a PEG400-assisted one-pot hydrothermal method. The role of polyethylene-glycol 400 (PEG400) in promoting the formation of long-range ordered single-phase OI-MoS2 has not been investigated previously. In our study, we demonstrate that polyethylene-glycol 400 (PEG400) can act as a surfactant to reduce nanosheet aggregation. Furthermore, it can function as a structural modifier to regulate the degree of sulfidation and stabilize the oxygen-incorporated structure with larger interlayer spacing and higher intrinsic electronic conductivity for facilitating sodiation/de-sodiation reactions. A very low content of reduced graphene oxide (rGO) is enough to provide a highway for electron transport between adjacent OI-MoS2 layers, and prevent OI-MoS2 layers from stacking in the [002] direction. Enhanced electrochemical performance is observed in the OI-MoS2/L-rGO nanosheets with carbonate-based electrolyte, delivering a discharge capacity of 462 mAh g−1 during the 2nd cycle with 89.1% capacity retention after 50 cycles.

Morphological and Structural Properties of MoS2and MoS2-Amorphous Silica-Alumina Dispersed Catalysts for Slurry-Phase Hydroconversion

Unsupported MoS2 and bifunctional MoS2-amorphous silica-alumina (ASA) catalysts, active for hydrogenation and hydrocracking reactions, were obtained by in situ thermal decomposition of molybdenum octoate in the presence of a sulfur source at temperatures between 300 and 400 °C. Unsupported MoS2 was formed at temperatures as low as 300 °C with yields higher than 76%. Increasing temperature increased the degree of sulfidation but also increased particle dimensions and, consequently, decreased the MoS2 dispersion. The presence of ASA reduced MoS2 particle dimensions compared to the unsupported MoS2, while the effect on sulfidation degree was dependent on temperature. High temperature (400 °C) was required to achieve high MoS2 yield due to interactions with the support at lower temperatures. The catalytic activity of the unsupported MoS2 showed that, as a result of the opposing effects of temperature on the MoS2 dispersion and MoS2 sulfidation degree, the activity toward hydrogenation of phenanthrene, reporte...

Enhanced Oxidative and Adsorptive Removal of Diclofenac in Heterogeneous Fenton-like Reaction with Sulfide Modified Nanoscale Zerovalent Iron.

Sulfidation of nanoscale zerovalent iron (nZVI) has shown some fundamental improvements on reactivity and selectivity toward pollutants in dissolved-oxygen (DO)-stimulated Fenton-like reaction systems (DO/S-nZVI system). However, the pristine microstructure of sulfide-modified nanoscale zerovalent iron (S-nZVI) remains uncovered. In addition, the relationship between pollutant removal and the oxidation of the S-nZVI is largely unknown. The present study confirms that sulfidation not only imparts sulfide and sulfate groups onto the surface of the nanoparticle (both on the oxide shell and on flake-like structures) but also introduces sulfur into the Fe(0) core region. Sulfidation greatly inhibits the four-electron transfer pathway between Fe(0) and oxygen but facilitates the electron transfer from Fe(0) to surface-bound Fe(III) and consecutive single-electron transfer for the generation of H2O2 and hydroxyl radical. In the DO/S-nZVI system, slight sulfidation (S/Fe molar ratio = 0.1) is able to nearly double the oxidative removal efficacy of diclofenac (DCF) (from 17.8 to 34.2%), whereas moderate degree of sulfidation (S/Fe molar ratio = 0.3) significantly enhances both oxidation and adsorption of DCF. Furthermore, on the basis of the oxidation model of S-nZVI, the DCF removal process can be divided into two steps, which are well modeled by parabolic and logarithmic law separately. This study bridges the knowledge gap between pollutant removal and the oxidation process of chemically modified iron-based nanomaterials.

Effects of gallium addition to mesoporous alumina by impregnation on dibenzothiophene hydrodesulfurization performances of the corresponding NiMo supported catalysts

The effects of gallium (Ga) modification on mesoporous Al2O3 (MA) were studied, focusing on the morphology changes of the active phases and the application as catalyst support for catalytic performances for dibenzothiophene (DBT) hydrodesulfurization (HDS). MA samples with wide mesopore size distribution (MA-W), double mesopore size distribution (MA-D) and single mesopore size distribution (MA-S) were synthesized from the boehmite sol–gel via a hydrothermal synthesis method. The synthesized MA-S sample was modified with Ga2O3, and the corresponding sulfide NiMo supported catalysts were prepared. The as-synthesized samples were characterized by XRD, N2 physisorption, NH3-TPD, H2-TPR, HRTEM and XPS. Superior catalytic performance was observed over the NiMo/MA-S-2Ga catalyst due to the moderate interaction between the active metals and the supports; the superior morphology for Ni promoted MoS2 crystals, the highest sulfidation degree, the largest proportion of the NiMoS phase and the enhanced hydrogenation activity caused by the introduction of Ga species.

Optimal Synthesis of Hierarchical Porous Composite ZSM-5/SBA-16 for Ultradeep Hydrodesulfurization of Dibenzothiophene and 4,6-Dimethyldibenzothiophene. Part 1: The Influence of Inorganic Salt on the Properties of NiMo Catalysts

Series ZSM-5/SBA-16 (ZS) composites were prepared using various inorganic cations as additives, and the associated catalysts were tested for dibenzothiophene and 4,6-dimethyldibenzothiophene hydrodesulfurization (HDS). The structure–function relationship was investigated through various characterization methods. The NiMo/ZS–Mg catalyst using MgCl2 as an additive displayed higher HDS reaction rate constant and turnover frequency values, which could be attributed to its major acidity, higher metal–support interaction (MSI), higher sulfidation degree, higher dispersion degree, moderate stacking number, and shorter stacking length of sulfide Mo species, of which the higher acidity and higher MSI contributed more to the improvement of its HDS performance. Besides, the possible HDS pathways on the NiMo/ZS–Mg catalyst were provided.

From cheap natural bauxite to high-efficient slurry-phase hydrocracking catalyst for high temperature coal tar: A simple hydrothermal modification

Slurry-phase hydrocracking (SPHC) of unconventional heavy feedstocks is considered as a promising process to fill the gap between the ever-increasing demand for vehicle fuels and the fast-depleting supply of conventional crude oil. The one-through nature of SPHC processes requires low-cost yet high-performance catalyst. This article reports a simple but effective hydrothermal modification strategy to treat a cheap natural bauxite mineral as a support (HMB) to prepare SPHC catalyst (HMBC) with outstanding catalytic performance. For comparison, an acid-modified bauxite (AMB) derived catalyst (AMBC) was also prepared. The physicochemical properties of HMB, HMBC, AMB and AMBC were systematically characterized, and the catalytic performance of HMBC and AMBC was assessed in the SPHC of a high temperature coal tar (HTCT). The results showed that HMBC exhibited HTCT hydrocracking activity superior to AMBC, attributed to the more suitable acidity of the support HMB and the weaker interaction between MoO3 and HMB that results in the higher sulfidation degree of molybdenum oxide species and thereby provides more active MoS2 phases for hydrocracking. Furthermore, compared with the acid treatment previously reported, the hydrothermal modification is simpler, more energy-saving, and more environment-friendly and therefore is feasible for industrial application.

Effects of Doping Rare Earth Elements (Y, La, and Ce) on Catalytic Performances of CoMo/MgAlM for Water Gas Shift Reaction

Rare earth element (La, Y, and Ce) modified MgAl-hydrotalcites of MgAlM were synthesized from coprecipitation and calcination, and further loaded with CoMo active species to give CoMo/MgAlM catalysts. X-ray powder diffraction, inductively coupled plasma, and N2 adsorption isotherms indicate that MgAlM possess large BET surface areas (58–91 m2/g), and rare earth elements were successfully introduced into samples. CO2-TPD (temperature-programmed desorption), NH3-TPD, H2-TPR (temperature-programmed reduction), H2S-TPS (temperature-programmed sulfidation), and Raman spectra indicate the presence of unique interactions between rare earth elements and Mo active species, which strongly affect the reduction and sulfidation behaviors of these catalysts. High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis suggest that the addition of rare earth elements decreases the slab length and stacking numbers of MoS2 and promotes the sulfidation degree of Mo oxides. Th...

Liquid-Phase Ion Gun for Local Acidification of Na2S Aqueous Solution and Local Sulfidation of Fe-Cr Alloy Surface

Local sulfidation of Fe-Cr alloy surfaces was attempted by using a liquid-phase ion gun (LPIG), in which a platinum microelectrode was anodically polarized in the vicinity of the alloy surface in 0.1 M Na2S aqueous solution. An increase in H+-concentration, namely local acidification, of the solution in the narrow space between the microelectrode and alloy surface successfully induced the formation of an H2S-concentrated environment and resulted in local sulfidation of the Fe-Cr alloy surface. The degree of sulfidation was dependent on acidification conditions such as the microelectrode current, specimen electrode potential and Cr concentration of the alloy. The use of an LPIG enables a sulfidation test not only to restrict the amount of H2S generated but also to evaluate sulfidation of a material surface quantitatively.

Hydrocracking of Vacuum Gasoil on NiMoW/AAS-Al2O3 Trimetallic Catalysts: Effect of the W : Mo Ratio

The effect of the W: (W + Mo) atomic ratio in NiMoW trimetallic catalysts on their catalytic and physicochemical properties is studied. The catalysts are prepared by impregnating a carrier containing amorphous aluminosilicate (AAS) and aluminium oxide with an aqueous solution containing Ni, Mo, W compounds, and citric acid. They are studied via XRF, TEM, NH3 TPD, and low-temperature nitrogen adsorption and are tested in the hydrocracking of vacuum gasoil (VGO). The average length of a sulfide active component layer shrinks as the amount of Mo increases and the amount of W in the catalyst is reduced. XPS data indicate that the degree of sulfidation of tungsten in NiMoW trimetallic catalysts is lower than in NiW catalyst. Testing of the catalysts in hydrocracking of a straight-line VGO at 390–420°C, 16 MPa, a feedstock hourly space velocity (FHSV) of 0.71 h−1, and a H2: VGO ratio of 1200 L/L shows the activities of hydrodesulfurization, hydrodenitrogenation, hydrogenation, and hydrocracking grow along with the W: (W + Mo) ratio. When the process pressure is high and the amount of sulfur in the NiW feedstock is low, the catalysts have higher activity in the target reactions of VGO hydrocracking than NiMo catalyst.

MoW synergetic effect supported by HAADF for alumina based catalysts prepared from mixed SiMonW12-n heteropolyacids

MoW catalysts supported on Al2O3 with equal surface content of metals (Mo+W=3.9 at/nm2) were synthesized by using mixed Keggin type heteropolyacids (HPAs) H4[SiMo1W11O40] and H4[SiMo3W9O40] and corresponding mixture of monometallic H4[SiMo12O40] and H4[SiW12O40] HPAs. After liquid phase sulfidation, catalysts were characterized by high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). For the first time, High Angle Annular Dark Field microscopy (HAADF) was used to evidence the morphology and composition of the active sulfide phase. The catalysts were tested in hydrotreating of model feed that contained dibenzothiophene (DBT) and naphthalene. Using mixed SiMonW12-nHPAs as starting precursors had a beneficial effect on the catalytic activity. Incorporation of molybdenum in the structure of SiW Keggin-type HPA led to a decrease of the size of active phase crystallites, to an increase of the metal sulfidation degree and of the number of active sites. Substitution of a quarter of tungsten atoms by molybdenum allowed to achieve DBT conversion comparable to value obtained on pure SiMo12HPA based catalyst and higher conversion of naphthalene. Both SiMonW12-nHPAs based catalysts had higher rate constants in studied reactions compared to their corresponding references prepared from two separate monometallic HPAs. Moreover, MonW12-n/Al2O3 catalysts had the highest selectivity in respect of hydrogenation (HYD) pathway of DBT hydrodesulfurization (HDS). The presence of mixed MoxW1-xS2 slabs was evidenced by HAADF analysis. On Mo3W9/Al2O3, small randomly distributed islands of Mo were present in the WS2 slabs, while on Mo3+W9/Al2O3, Mo islands appeared larger and in the core of the WS2 slabs. Moreover, on this last sample, some monometallic slabs were also present. It was concluded that using mixed HPA precursors resulted in the formation of mixed MoxW1-xS2 active phase possessing higher synergetic effect between the two metals and consequently higher catalytic activity.

Application of Heteropolyacid H4SiMo3W9O40 for the Preparation of Bimetallic MoWS2/Al2O3 Hydrotreatment Catalysts

The bimetallic MoWS2/Al2O3 catalyst was synthesized using the Keggin-type mixed heteropolyacid H4SiMo3W9O40. The monometallic catalysts SiMo12/Al2O3 and SiW12/Al2O3 based on the H4SiMo12O40 and H4SiW12O40 acids are prepared as reference samples. The sulfidized catalysts are analyzed by temperature-programmed reduction with hydrogen, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. Their catalytic properties are studied in the cohydrotreatment of dibenzothiophene (DBT) and naphthalene on a flow-type setup. The introduction of three molybdenum atoms into the structure of an oxide precursor is shown to increase the degree of sulfidation of the tungsten particles by 20% in comparison with SiW12/Al2O3. The DBT turnover frequency in the hydrodesulfurization (HDS) on the sites on the edges of the active phase of the SiMo3W9/Al2O3 catalyst is shown to be 5.5 times higher than in the presence of SiW12/Al2O3. The bimetallic sample demonstrated the highest selectivity in the preliminary DBT hydrogenation route and activity in the prehydrogenation of naphthalene. The high level of activity of the SiMo3W9/Al2O3 catalyst was due to the formation of a mixed Mo x W(1–x)S2 active phase with a MoW oxide precursor, whose structure contained both metals bonded at the molecular level.

Preparation of hydrodesulfurization catalysts using MoS3 nanoparticles as a precursor

γ-Alumina-supported MoS3 nanoparticles (NPS) denoted as MoS3/Al2O3 were firstly synthesized by chemical deposition method, and then used as the “second support” for promoter Ni atoms to prepare a pre-sulfided bimetallic HDS catalyst denoted as CAT-MoS3 by the conventional impregnation method. Meanwhile, for comparison purpose, two bimetallic catalysts denoted as CAT-MoS2 and CAT-MoO3 with the same metal loadings were prepared using MoS2/Al2O3 and MoO3/Al2O3 as the starting material, respectively. Characterization and activity assessment show that, using MoS3 as the precursor not only promotes the resulting bimetallic catalyst with a much higher sulfidation degree of Mo species, but also realizes a better decoration of Ni atoms onto the edges of MoS2 nanoslabs. The dual effect guarantees the plentiful formation of Type II Ni-Mo-S active sites and thus remarkably enhances the hydrodesulfurization (HDS) activity. Compared with CAT-MoS2, CAT-MoS3 possesses very similar physical properties, microstructure and sulfidation degree of Mo species, however, due to its much higher decoration degree of Ni atoms, it holds a significantly enhanced HDS activity. Moreover, in comparison with CAT-MoS2, CAT-MoO3 exhibits a worse microstructure (more MoS2 nanoslabs with larger length and lower stacking) and a much lower sulfidation degree of Mo species, but it still holds much higher HDS activity, further implying that the decoration degree (i.e. promoting effect) imposes the most important impact on the HDS activity. It is rational and effective to modify the starting state of Mo species to enhance the promoting effect and thereof improve the catalytic performance.

The effect of alkali metals on the synthesis of methanethiol from CO/H2/H2S mixtures on the SBA-15 supported Mo-based catalysts

The effects of alkali promoters on catalytic behaviors for synthesizing CH3SH over Mo-based catalysts were investigated. The selectivity of CH3SH for Na, K, Cs and non-alkali promoted catalysts are following in the order of Cs-Mo/SBA–15> K-Mo/SBA–15> Na-Mo/SBA–15> Mo/SBA-15. The addition of alkali metals dramatically improved the CH3SH selectivity and CO conversion. The highest selectivity of CH3SH was 66% obtained by incorporating Cs into Mo/SBA-15 which was superior to those reported in the current literature. Based on N2 adsorption-desorption, XRD, Raman, XPS and NO-TPD characterizations, active MoS2 species on oxidized Mo O-S species, obtained from the sulfidation temperature as low as 553K, was considered as active sites for synthesizing CH3SH. And it deemed that the different alkali metals (Na, K, Cs) could give rise to the difference in the sulfidation degree of Mo oxidized species and modify the chemical and electronic environment of the active sites, which resulted in the generation of distinguished concentration of Mo containing coordinatively unsaturated sites (Mo-CUS). Those concentrations of Mo-CUS were detected by NO-TPD to be 161, 210 and 222μmol/g, respectively, which had a positive relationship with the selectivity of CH3SH.

Pore confinement effect of MoO3/Al2O3 catalyst for deep hydrodesulfurization

To investigate the pore confinement effect of MoO3/Al2O3 catalyst for deep hydrodesulfurization, a series of MoO3/γ-Al2O3 catalysts were prepared via impregnation method. All catalysts had almost the same physicochemical properties, such as the specific surface area, apparent morphology, microstructure, coordination of Al atom and acidity, and differed in the pore size. The control experiments results showed that enlarging the pore size from 3.6 to 8.8nm increased the desulfurization efficiency of 4,6-dimethyldibenzothiophene (4,6-DMDBT) from 62.6% to 95.0%, then decreased to 71.3%. The catalyst with a pore size of 5.9nm displayed the optimum hydrodesulfurization performance. The larger pores weaken the effect of polarization of Al3+ on the van der Waals interactions between the layers of active phase and result in more stacking of MoS2. The more stacked MoS2 contribute to more edge and corner active sites for the catalysts with the pore size of 5.9nm, which resulted that this catalyst exhibited the highest reaction rate and sulfidation degree of Mo species, lowest reduction temperature and largest amount of chemisorbed CO. The reaction and characterization results revealed that the smaller mesopores favored the accessibility of 4,6-DMDBT to the edge sites of MoS2 active phase, whereas the larger ones promoted the reactant molecules to the corner sites. Compared to the catalyst with mono-pore size, the catalyst with hierarchical mesopore structure had a higher hydrodesulfurization activity through the synergism of small and large pores. The larger pores enable 4,6-DMDBT to reach the active sites located in the small pores and promote the accessibility of the reactants to the corner sites of hexagonal shaped MoS2. This catalyst possessed a lower ratio of hydrodesulfurization products to direct desulfurization ones.

Effect of thermal treatment on morphology and catalytic performance of NiW/Al2O3 catalysts prepared using citric acid as chelating agent

In the present work, NiW/Al2O3 catalyst was prepared with the use of citric acid and thermally treated at temperatures of 120, 220, 300 and 450°C. It was shown that the thermal treatment at temperatures of 220–300°C leads to decomposition of citrate ligands, 450°C – to the almost complete removal of organic carbon. HRTEM of the sulfided catalysts showed that stacking number of WS2 increases with the increase of the thermal treatment temperature while the WS2 slab length has minimum at 220°C. The results of XPS indicated that the sulfidation degree of tungsten and nickel decreases with the increase of the thermal treatment temperature.The catalyst thermally treated at 300°C resulted to be most active in DBT HDS, quinoline HDN and naphthalene hydrogenation reactions. The higher activity of this catalyst in comparison with the samples thermally treated at 120°C and 220°C can be explained by an increased stacking degree of the sulfide WS2 slabs while maintaining a small length of sulfide slabs and by a smaller carbon content that can impede access to the active sites. The calcination at 450°C leads to low activity due to the low dispersion of the active component and a decrease in the degree of sulfidation of tungsten and nickel.

Effects of Ga- and P-modified USY-based NiMoS catalysts on ultra-deep hydrodesulfurization for FCC diesels

USY zeolites have been modified by incorporation of gallium, phosphorus and a combination of gallium and phosphorus by wetness impregnation method using gallium nitrate and ammounium phosphate diabasic, and the corresponding NiMo supported hydrodesulfurization (HDS) catalysts have been prepared for HDS of an inferior FCC diesel. The individual physical-chemical properties of the modified USY zeolites and the series NiMo supported catalysts were characterized using XRD, N2-adsorption-desorption(BET), NH3-TPD, Py-FTIR, H2-TPR, HRTEM and XPS methods, and their catalytic performances for an inferior FCC diesel HDS were assessed. The results show that both gallium and phosphorus modification can modulate the acid property of USY zeolite and weaken the interaction between the active metal and the supports, thus enhancing the degree of sulfidation and the dispersion of Mo species that are beneficial for the HDS of highly refractory organosulfur compounds. The highest HDS and HDN efficiencies of 99.7% and 99.6%, respectively, were observed over the catalyst containing the PGaUSY zeolite. More importantly, gallium modification of the USY zeolite promotes the hydrodesulfurization of all organosulfur compounds, and especially 4,6-DMDBT, in the FCC diesel and phosphorus modification of the USY zeolite promotes the hydrodesulfurization of most organosulfur compounds except for 4,6-DMDBT in the FCC diesel.

Trimetallic NiMoW/Al2O3 hydrotreating catalyst based on H4SiMo3W9O40 mixed heteropoly acid

Trimetallic NiMoW/Al2O3 catalyst was prepared using mixed H4SiMo3W9O40 heteropoly acid of Keggin structure and nickel citrate. Bimetallic NiMo/Al2O3 and NiW/Al2O3 catalysts based on H4SiMo12O40 and H4SiW12O40, respectively, were synthesized as reference samples. The use of mixed H4SiMo3W9O40 heteropoly acid as an oxide precursor allows the tungsten sulfidation degree and the degree of promotion of active phase particles to be increased. The hydrodesulfurization activity is enhanced as compared to NiW/Al2O3 catalyst. The synergistic enhancement of the activity of the NiMo3W9/Al2O3 catalyst relative to the bimetallic analogs is probably caused by formation of new mixed promoted active sites for direct desulfurization.

4,6-Dimethyldibenzothiophene Hydrodesulfurization on Nickel-Modified USY-Supported NiMoS Catalysts: Effects of Modification Method

The effects of the method of modifying USY zeolite with nickel on the hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) have been investigated. USY zeolites were modified with a small amount of Ni by three different methods, namely, the in situ synthesis method, the ion-exchange method, and the impregnation method, and the resulting Ni-modified USY zeolites were used as supports for NiMo sulfide catalysts. We found that the Ni modification method affects the textural properties, the acidity of the Ni-modified USY zeolites, the Ni–Mo–S active-phase morphology, the dispersion of the active metals, the structure of the Ni–Mo–S active phase, the sulfidation degree of the active metals, the 4,6-DMDBT HDS reaction rate constant, the turnover frequency, and the selectivity of the 4,6-DMDBT HDS pathways. Although the impregnation modification method was found to promote the dispersion of active metals most strongly and the ion-exchange modification method was found to enhance the sulfidation ...

Hydro-upgrading Performance of Fluid Catalytic Cracking Diesel over Different Crystal Forms of Alumina-Supported CoMo Catalysts

A series of CoMo/Al2O3 catalysts was prepared using different crystal forms of alumina (including γ-Al2O3, δ-Al2O3, θ-Al2O3, and α-Al2O3) as supports for the hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) of fluid catalytic cracking diesel. The physicochemical properties of the supports and the corresponding catalyst were analyzed by various characterization methods. The results showed that δ-Al2O3 possessed a moderate surface area, a concentrated pore size distribution, and less surface hydroxyl groups. The CoMo/δ-Al2O3 catalyst exhibited the highest HDS and HDN efficiencies, 98.4 and 96.1%, respectively. This could be attributed to its reduced metal–support interaction, moderate stacking morphology, and highest sulfidation degree of active phases. The HDS and HDN efficiencies of the catalysts followed the order of CoMo/α-Al2O3 (87.3 and 72.2%) < CoMo/γ-Al2O3 (94.8 and 87.9%) < CoMo/θ-Al2O3 (96.2 and 90.1%) < CoMo/δ-Al2O3 (98.4 and 96.1%).

A real support effect on the hydrodeoxygenation of methyl oleate by sulfided NiMo catalysts

The effect of the support on the catalytic performance of sulfided NiMo in the hydrodeoxygenation of methyl oleate as a model compound for triglyceride upgrading to green diesel was investigated. NiMo sulfides were prepared by impregnation and sulfidation on activated carbon, silica, γ-alumina and amorphous silica-alumina (ASA). High sulfidation degrees were obtained in all cases. Despite the use of a chelating agent to minimize metal-support interactions, the support had a significant influence on the morphology of the active phase (MoS2 dispersion and stacking). All catalysts convert methyl oleate to C17 and C18 olefins and paraffins. Initially, NiMo/Al2O3 and NiMo/ASA displayed the highest overall HDO activity, but these catalysts deactivated slowly during the week on stream. Finally, they exhibited similar activity as NiMo/SiO2. NiMo/C and NiMo/SiO2 did not deactivate. The NiMo/C catalyst was appreciably more active than the others after prolonged reaction. The high initial and then deactivating performance of NiMo/Al2O3 and NiMo/ASA is due to the Lewis acidity of surface Al species active in methyl oleate hydrolysis. It has earlier been demonstrated that deposition of heavy products on the alumina surface deactivates these sites. SiO2 lacks such sites, resulting in lower catalytic performance. The NiMo/C support is more active in methyl oleate hydrolysis. This can be either due to intrinsically higher activity of the metal sulfide on carbon or to acidic surface groups. Besides, the reaction data show that the C18 hydrocarbons selectivity for NiMo/SiO2 and NiMo/C was substantially higher than for the other two catalysts. Clearly, the support has a significant influence on the performance of NiMo sulfide in methyl oleate HDO. The use of activated carbon as the support presents high and stable HDO activity of methyl oleate with good C18 hydrocarbons selectivity.