Hydrotreatment Catalysts Research Articles

MoS2-based materials as alternative cathode catalyst for PEM electrolysis

Pt and Ir are the most popular catalysts for electrochemical water splitting, but their low abundance on Earth's crust and high price render them unsustainable for future use. In the quest for alternative catalyst materials, a popular hydro-treating catalyst, molybdenum disulphide (MoS2), has been found to be promising for hydrogen evolution reaction (HER). Two types of MoS2-carbon composites, (i) physical mixture of MoS2 and carbon black (Vulcan®) and (ii) MoS2 supported on reduced graphene oxide (RGO), were examined. Among the MoS2-based materials tested, 47 wt% MoS2/Vulcan® gave the best performance in terms of current density at an encouraging level for practical application. The poor performance of bare MoS2 was attributed to its poor electrical conductivity. No indication of performance deterioration was observed for 18 h of continuous operation at 2.0 V cell voltage with 47 wt% MoS2/Vulcan®. MoS2/RGO hybrids showed HER activity, which was considerably higher than that of bare MoS2.

Self-complexation: the nature for high hydrodesulfurization activity of NiWO4 nanoparticles

NiWO4 nanoparticles and two kinds of the precursors were synthesized by a hydrothermal approach and tested for the hydrodesulfurization of sulfur containing organics. Results show that the hydrodesulfurization activity of sulfided NiWO4 nanoparticles is highest among them. The investigation about the nature for different hydrodesulfurization activities of the catalysts reveals that a simultaneous sulfidation i.e. self-complexation of nickel and tungsten can be observed on NiWO4 nanoparticles. Furthermore, both temperature-programmed sulfidation and TEM images demonstrated that the self-complexation is originated from the special structure and size of NiWO4 nanoparticles. These results show a promising potential to develop efficient hydrotreatment catalyst.

Hydrogen production from ethanol with low carbon monoxide generation in a one-pot reaction with iron oxides as catalysts

Bulk γ-Fe2O3 (maghemite) and Fe3O4 (magnetite) were synthesized with Fe(III) hydroxyacetate as an intermediate during the preparation step. The fresh and used catalysts were characterized by X-ray diffraction, N2 adsorption at 77 K, Mössbauer spectroscopy at 298 K, diffuse-reflectance spectroscopy, and thermogravimetric analysis. The solids were used as catalysts in the ethanol hydrotreatment within the range of 673–758 K. The catalysts showed a satisfactory selectivity for H2 and an especially low CO production. These activities and selectivities were analyzed in conjunction with the structural properties of the oxides. Magnetite seemed to be a more appropriate catalyst than maghemite since the latter was converted into magnetite at reaction temperatures higher than 713 K because of the reducing atmosphere.

Towards silicon speciation in light petroleum products using gas chromatography coupled to inductively coupled plasma mass spectrometry equipped with a dynamic reaction cell

Silicon speciation has recently gained interest in the oil and gas industry due to the significant poisoning problems caused by silicon on hydrotreatment catalysts. The poisoning effect clearly depends on the structure of the silicon species which must be determined and quantified. The hyphenation of gas chromatography (GC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) allows a specific detection to determine the retention times of all silicon species. The aim of this work is to determine the retention indices of unknown silicon species to allow their characterization by a multi-technical approach in order to access to their chemical structure. The optimization of the dynamic reaction cell (DRC) of the ICP-MS using hydrogen as reactant gas successfully demonstrated the resolution of the interferences (14N14N+ and 12C16O+) initially present on 28Si. The linearity was excellent for silicon compounds and instrumental detection limits ranged from 20 to 140μg of Si/kg depending on the response of the silicon compounds. A continuous release of silicon in the torch was observed most likely due to the use of a torch and an injector which was made of quartz. A non-universal response for silicon was observed and it was clearly necessary to use response coefficients to quantify silicon compounds. Known silicon compounds such as cyclic siloxanes (D3–D16) coming from PDMS degradation were confirmed. Furthermore, more than 10 new silicon species never characterized before in petroleum products were highlighted in polydimethylsiloxane (PDMS) degradation samples produced under thermal cracking of hydrocarbons. These silicon species mainly consisted of linear and cyclic structures containing reactive functions such as ethoxy, peroxide and hydroxy groups which can be able to react with the alumina surface and hence, poison the catalyst. This characterization will further allow the development of innovative solutions such as trapping silicon compounds or strengthening the resistivity of the hydrotreatment catalyst against silicon.

Hydrodeoxygenation, decarboxylation and decarbonylation reactions while co-processing vegetable oils over a NiMo hydrotreatment catalyst. Part I: Thermal effects – Theoretical considerations

The presented work covers theoretical considerations regarding the total heat effects associated with vegetable oil hydroconversion to form n-paraffinic diesel fuel biocomponents relative to the process conditions. The hydroconversion of fatty acid triglycerides is a highly exothermic process. The hydrodeoxygenation, decarboxylation and decarbonylation of fatty acids are the basic reactions occurring during this process. The hydrodeoxygenation and decarboxylation reactions are exothermic, while decarbonylation exhibits a relatively modest endothermic effect. A similar situation applies to the secondary reactions: rWGSR – reverse water gas shift reaction (endothermic) and CO methanation (strongly exothermic). The contribution of each reaction depends on the process conditions, particularly the hydrogen pressure. Theoretical considerations suggest that the total heat effect in the reactor should be similar under different pressure conditions. The heat effects connected to a particular hydroconversion reaction (main and secondary) may compensate one another.

Hydrodeoxygenation of Phenol Over Hydrotreatment Catalysts in their Reduced and Sulfided States

The influence of the composition of reduced CoMo, NiMo and NiW catalysts on the catalytic performance in hydrodeoxygenation (HDO) of phenol has been investigated. γ-Al 2 O 3 and TiO 2 were used as supports. Different activity orders were obtained over γ-Al 2 O 3 and TiO 2 supported catalysts reflecting the critical role of the support. NiMo catalyst supported on γ-alumina proved to be the most active followed by the CoMo catalyst supported on titania. CoMo and NiMo lab made catalysts were proved to be more active compared to a reduced industrial CoMo catalyst supported on γ- alumina. An increase of phenol conversion in the range 52-230% was obtained at 350°C. A series of CoMo, NiMo and NiW catalysts supported on TiO 2 was also prepared using the Equilibrium - Deposition - Filtration (EDF) method. The application of this technique, instead of the classical impregnation, increased considerably the activity of the CoMo catalyst supported on titania (48% increase of phenol conversion at 350°C). The most active lab catalysts (wet impregnated NiMo catalyst supported on alumina, EDF CoMo catalyst supported on titania) and the industrial CoMo catalyst were evaluated after sulfidation for simultaneous HDO of phenol and HDS of dibenzothiophene. These catalysts exhibited comparable HDO activities while the first one proved to be superior in HDS. Overall, taking into account the significantly higher loading of the industrial catalyst in the supported elements compared to the lab made catalysts, the latter seems to be quite promising, even in the frame of a co-processing strategy.

Genesis of HDT catalysts prepared with the use of Co2Mo10HPA and cobalt citrate: Study of their gas and liquid phase sulfidation

Genesis of alumina supported hydrotreating (HDT) catalysts prepared with the use of decamolybdodicobaltate heteropolyanion (Co2Mo10HPA) and cobalt citrate during their sulfidation processes and deactivation in diesel HDT has been investigated. The sulfidation stage was studied for two procedures: gas phase sulfidation by H2S/H2 and liquid phase treatment by a mixture of dimethyldisulfide in diesel at various temperatures and durations. The catalysts have been studied by N2 adsorption, thermogravimetric analysis, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy methods. The catalysts were tested in HDT of mixture of 70wt.% straight run gas oil with 16wt.% light cycle oil and 14wt.% light coker gas oil. Mechanisms of the active phase formation in the course of gas and liquid phase sulfidation processes have been established. It was found that gas phase sulfidation led to formation of the CoMoS active phase with higher cobalt content comparing to liquid sulfidation of the catalyst and initial activity of the gas phase treated catalysts in diesel HDT was also higher than catalysts subjected to liquid sulfidation. Catalytic examination after accelerated deactivation conditions showed that the liquid phase sulfided sample was more resistant to the deactivation. Probably it is due to stabilization of active phase particles by coke formed intensively during liquid phase sulfidation. The results were discussed using the recently developed concept of interlayer dynamics of the active sites of the CoMoS phase.

Hydrodeoxygenation, decarboxylation and decarbonylation reactions while co-processing vegetable oils over NiMo hydrotreatment catalyst. Part II: Thermal effects – Experimental results

Two paraffinic feedstocks containing 20 vol.% of significantly different vegetable oils (olive or corn oil) were subjected to hydroconversion over a commercial NiMo catalyst under two different pressures (3.0 or 6.0MPa), at 320°C, with liquid hourly space velocity (LHSV) of 1.0h−1 and hydrogen/feedstock ratio equal to 300Nm3/m3.Changes in the hydroconversion pressure significantly affect the contribution of the major (hydrodeoxygenation, decarboxylation and decarbonylation) and secondary reactions (strongly exothermic methanation and endothermic reverse water gas shift reaction (rWGSR)). Nevertheless, the total heat effect in the reactor did not differ significantly.The heat effects changed noticeably when different vegetable oils were used as feedstocks. It was found that the differences in the total heat effects noted during hydroconversion for the two vegetable oils depend on the unsaturated fatty acid contents.

Combined Effects of EDTA and Heteroatoms (Ti, Zr, and Al) on Catalytic Activity of SBA-15 Supported NiMo Catalyst for Hydrotreating of Heavy Gas Oil

M-SBA-15 (M = Ti, Al, and Zr) materials with a Si/M ratio of 20 were synthesized using a direct synthesis method. M-SBA-15 supported NiMo hydrotreating catalysts with and without EDTA was prepared by an incipient wetness impregnation method. A EDTA/Ni molar ratio of 2 was used for catalysts with EDTA. The hydrotreating activities of these catalysts were measured using Athabasca bitumen derived heavy gas oil, and comparison was done with the performance of NiMo/SBA-15 and NiMo/γ-Al2O3 catalysts. All catalysts were thoroughly characterized by BET, TPR, TPD, CO-chemisorption, XRD, XANES, HRTEM, ICP-MS, and 13C NMR. Incorporation of Ti, Al, and Zr in SBA-15 framework results in an increase in the surface acidity and metal support interactions in otherwise neutral SBA-15 material. This increases the dispersion, and HDS, HDN and HDA activity of a NiMo/SBA-15 catalyst increases by 12%, 70%, and 22%, respectively, as in the case of a NiMo/Ti-SBA-15 (Cat-Ti) catalyst. EDTA addition helps in better redispersion of ...

Towards the Improvement of Hydrotreatment Catalysts through the Encapsulation of Heteropolyoxometalates inside the Framework of SBA‐15 Silica

AbstractIn the context of the search for higher performance hydrodesulfurization catalysts, materials made by a novel method of immobilizing heteropolyoxometalates on mesoporous oxides were compared to those derived by incipient wetness impregnation for the hydrogenation of toluene. The catalysts prepared by the one‐pot encapsulation of HPMo into the walls of SBA‐15 silica were found to be significantly more active for the reaction.

Relationship between active phase morphology and catalytic properties of the carbon–alumina-supported Co(Ni)Mo catalysts in HDS and HYD reactions

Effects of activated carbon of a carbon-coated alumina support and active phase morphology of transition metal sulfide (TMS) catalysts in hydrotreatment (HDT) of S-containing compounds were studied. The catalysts were synthesized from Anderson-type heteropoly compounds and characterized with multiple methods: X-ray powder diffraction, N2 physisorption, temperature-programmed desorption of ammonia, pyridine-adsorbed Fourier transform infrared spectroscopy, H2 temperature-programmed reduction, and high-resolution transmission electron microscopy. The catalysts were tested in hydrodesulfurization (HDS) of thiophene, dibenzothiophene and HDT of diesel. The results suggest that the catalytic activity in HDS and hydrogenation reactions depends on the shape of crystallites of the active phase. The results are interpreted using recently proposed concept of interlayer dynamics. This concept is helpful in establishing structure–activity relations for TMS.

Maya crude oil hydrotreating reaction in a batch reactor using alumina-supported NiMo carbide and nitride as catalysts

The hydrotreating (HT) of Maya crude oil was carried out in a Parr batch reactor, using alumina-supported catalysts based on NiMo sulfides, carbides and nitrides, which were synthesized by temperature programmed reaction of the oxidic precursors. The catalysts were characterized by X-ray diffraction, N2 physisorption, scanning- and high resolution transmission-electron microscopy. Next, catalysts with the best performance in thiophene hydrodesulfurization (HDS) were selected to be used in the HT of Maya crude oil. HT reactions were carried out at 320°C and 70–80kg/cm2. All catalysts were sulfided ex situ with a mixture of CS2/H2, prior to reaction. Products of reaction were analyzed by simulated distillation, sulfur and metal contents. Specific weight was also obtained, which was further used to calculate specific gravity and API gravity. Here, it was shown a synergistic effect by using Ni as promoter to Mo carbides and nitrides which is in contrast to previous reports. Moreover, during Maya crude oil HT, it was accomplished the enhancement of API gravity by using NiMo sulfide. Sulfur and metal removal was also successful using these materials, confirming that active phases based on NiMo nitrides and/or carbides could be considered as new HT catalysts for real feedstocks processing.

Stabilized Ni-based catalysts for bio-oil hydrotreatment: Reactivity studies using guaiacol

The development of catalysts possessing high activity and high stability in the catalytic hydrotreatment of pyrolysis oils (bio-oil) is of great interest. NiCu bimetallic catalytic systems are very attractive for use in hydrotreatment process due to their low price and high activity in hydrogenation, hydrodeoxygenation and hydrocracking reactions. In the present work P-/Mo-containing agents were used to modify bimetallic catalytic system NiCu/SiO2–ZrO2 to improve its mechanical strength and stability in acidic medium. The modified catalysts were tested in hydrodeoxygenation (HDO) of guaiacol—a well-known model compound of bio-oil. HDO process has been carried out in an autoclave at 320°С, 17MPa initial hydrogen pressure, reaction time 1h. It was shown that phosphorus and molybdenum addition to the catalysts composition results in the decrease of guaiacol conversion and deoxygenation degree. The yield of undesirable gaseous reaction products (mainly methane) and coking of the catalyst were lower for the modified catalysts in contrast to the initial NiCu/SiO2–ZrO2 system. The catalysts treatment in glacial acetic acid at 118°C showed that modification by P and Mo gives a significant improvement of catalysts stability in acidic medium (mass loss decreases from 53 wt.% to 1 wt.%). Also a significant improvement of bulk crushing strength has been observed for PMo-modified samples (from 0.5MPa to 1.2MPa).

Optimal pretreatment conditions for Co–Mo hydrotreatment catalysts prepared using ethylenediamine as a chelating agent

Co–Mo/Al2O3 catalysts were prepared using bimetallic complexes consisting of ethylenediamine and polybasic carboxylic acid ligands coordinated to cobalt and molybdenum, respectively. The structures of the complex compounds remained unchanged upon initial adsorption to alumina. However, the chemical composition, morphology of the Co–Mo–S phase and thiophene hydrogenolysis activity of the catalysts were dependent on the pretreatment temperature before sulphidation. Nitrogen, a product of ligand decomposition, significantly inhibited catalytic activity. To attain the maximum thiophene hydrogenolysis activity, a 400°C pretreatment was necessary. At this temperature, most of the nitrogen was removed, but the formation of Co and Mo compounds, which transform into low activity compounds during sulphidation, was not observed.

Characterization of silicon species issued from PDMS degradation under thermal cracking of hydrocarbons: Part 2 – Liquid samples analysis by a multi-technical approach based on gas chromatography and mass spectrometry

Silicon speciation has recently gained interest in the oil and gas industry due to the impact of silicon species on hydrotreatment (HDT) catalysts. The determination of the chemical structure of silicon compounds appears as essential to limit silicon poisoning as to improve the lifetime of catalysts. To achieve a representative speciation of silicon in petroleum products, fresh samples of PDMS degradation under thermal cracking of hydrocarbons were produced using a pilot plant. The samples were carefully stored in a dewar containing liquid nitrogen (−195°C) to minimize the possible evolution of silicon species and to allow their analysis in representative conditions. A complete analytical approach based on gas chromatography (GC) and mass spectrometry techniques (MS) was developed and applied to the samples produced at 500°C. Moreover, to resolve coelutions observed by GC/TOFMS, GC–GC/TOFMS was successfully applied to obtain the mass spectrum of only one silicon compound. Combining the GC/MS mass spectrum giving access to the fragmentation of the compound and the raw formula and double bond equivalent (DBE) obtained by ESI-FT-ICR/MS, chemical structures were proposed. Almost molecules were strengthened by MSn.Cyclic siloxanes (Dn) were confirmed as the major compounds of PDMS thermal degradation even in the presence of hydrocarbons with a relative amount generally around 95% or above. No significant difference on the formation of Dn were observed according to the different operating conditions under thermal cracking of hydrocarbons. For the first time, several other silicon compounds present at trace levels (<5% of the total area) were characterized. α,ω-dihydroxy polydimethylsiloxanes, methylhydroxy cyclic siloxanes, (n+1)oxasilabicyclo alcanes or bis(cyclosiloxanyl) siloxane, α-hydroxy, ω-methyl polysiloxanes and (n)oxasilabicyclo alcanes were preferentially formed in the presence of steam. Under evaluated coking or visbreaking conditions (long residence time without steam), other compounds were mainly characterized such as dimethoxy polysiloxanes, methyl(hydroperoxy) cyclic siloxanes, or ethoxy methyl cyclic siloxanes, linear polysiloxanes and methylpropyl cyclic siloxanes. Around one hundred silicon compounds were highlighted belonging to 12 different chemical families. The same repetition pattern (C2H6OSi), initially in PDMS, was present in all silicon compounds characterized in this study. Molecules with a number of silicon atoms ranging from 1 to 40 silicon atoms clearly demonstrated the occurrence of silicon in all petroleum cuts through very different chemical structures. This study shows that silicon species can distillate from gas fractions to the heavy petroleum cuts depending on their boiling points and chemical properties. These silicon species contain reactive groups (hydroxy, hydroperoxy, methoxy and ethoxy) which are able to react at the surface of HDT catalysts and cause a severe deactivation. Thus, these results appear as a crucial advance in progressing in the understanding of silicon poisoning.

Characterization of silicon species issued from PDMS degradation under thermal cracking of hydrocarbons: Part 1 – Gas samples analysis by gas chromatography-time of flight mass spectrometry

Silicon species are becoming emergent contaminants in the oil and gas industry due to their severe poisoning effect on the hydrotreatment (HDT) catalysts. Using an experimental pilot plant, fresh and representative samples of PDMS degradation under thermal cracking of hydrocarbons were produced. To follow the evolution of silicon species, the gas fraction was immediately analyzed by GC/TOFMS after the production and also after 4months of storage at 4°C. Cyclic siloxanes (Dn) as the major products of PDMS thermal degradation were characterized in the gas phase but these compounds are mainly present in the liquid fraction. Five volatile silicon compounds belonging to the families of silanes, siloxanes and silanols were characterized and quantified in the thermal cracking samples depending on the operating conditions applied in degradation tests. Under coking or visbreaking conditions (long residence time, absence of steam), silanes and siloxanes were preferentially formed. Under evaluated steam cracking conditions (short residence time and presence of steam), trimethylsilanol (TMSOH) was mainly produced by the hydrolysis of PDMS. The formation of the linear siloxane (L2) after several month of storage at 4°C by the self-condensation of TMSOH was also observed. The suspected poisoning effects of these molecules were discussed and could explain the deactivation of catalysts taking place in the refining of the light petroleum cuts. The new identified volatile silicon compounds could affect the performance of the catalyst by the reaction of hydroxyl groups potentially present at the surface of the support with reactive silicon molecules, more specifically silanols.

Selectivity of Bio-oils Catalytic Hydrotreatment Assessed by Petroleomic and GC*GC/MS-FID Analysis

We propose to assess the selectivity of hydrotreatment catalysts by two complementary analytical methods: (1) high-resolution mass spectrometry (MS), called “petroleomic” analysis, by Fourier transform ion cyclotron resonance (FT ICR, 9.4T) MS for species heavier than m/z of about 200 Da and (2) quantitative GC*GC (heart-cutting)/MS-flame ionization detector (FID) analysis of lighter species. The methodology is illustrated on methanol-soluble bio-oils produced by lignin pyrolysis and hydrotreated by iron-based catalysts. GC*GC analysis is calibrated by a combination of internal standard and prediction of response factors on the FID. Laser desorption ionization (LDI) and electro spray ionization (ESI) in negative-ion mode are combined for the petroleomic analysis. The selectivity of hydrotreatment (catalytic fixed bed, 1 atm, 400 °C) is assessed as a function of catalyst loads and iron support (silica and activated carbon). Hundreds of species are analyzed by GC*GC and petroleomic and mapped in Van Krevelen diagrams. The high selectivity of reduced iron for the hydrodeoxygenation of lignin pyrolysis vapors is demonstrated. The effect of the catalytic treatment on oxygen content and unsaturation is studied for a broad range of species: from C2 to C14 by GC analysis and from C8 to C37 by petroleomic. Many heavy lignin oligomers produced by the pyrolysis are trapped by the catalytic bed, highlighting the need of new catalytic systems to convert them into valuable fuels or chemicals.

Textural characteristics of sulphided hydrotreatment catalysts prepared using Co–Mo complex compounds

Sulphided Co–Mo catalysts prepared by supporting (CoL)2[Mo4(C6H5O7)2O11]·xH2O on γ-Al2O3 were studied. Pores with diameters less than 40 A in the catalysts preliminary dried at 120 °C were observed. The volume of these pores is proportional to the amount of carbon-containing decomposition products of the citrate ligands. No narrow pores in preliminary calcined catalysts were observed, whereas a sulphided active component was uniformly distributed in pores with diameters greater than 50 A, independent of the active-metal concentration. The morphology of the active component particles depends on the conditions of the heat pretreatment. Catalysts that contain particles with an average of 2.1 ± 0.2 layers in a stack and pores with diameters of 60–120 A are the most active in the hydrotreatment of diesel fuels.

Impregnation of Decamolybdocobaltate Heteropolyanions over γ-Alumina: Detailed Description of the Physico-Chemical Phenomena

In this work, the physicochemical phenomena occurring during equilibrium impregnation of Anderson-like decamolybdocobaltate H(4)Co(2)Mo(10)O(38)(6-) heteropolyanion aqueous solutions over γ-Al(2)O(3) were described in detail comprising chemical analysis, pH measurements, Raman, and UV-vis spectra. For a surface density lower than 2.5 Mo atoms nm(-2), the buffering effect of the support leads to decomposition of H(4)Co(2)Mo(10)O(38)(6-) into monomolybdates MoO(4)(2-) and Co(2+) cobalt cations that are then adsorbed by electrostatic and covalent interactions with γ-alumina. Between 2.5 and 3.8 Mo atoms nm(-2), MoO(4)(2-) monomers condense into heptamolybdates Mo(7)O(24)(6-) that are then adsorbed by electrostatic interactions and H(4)Co(2)Mo(10)O(38)(6-) becomes stable because of the lowering of the pH. Above 3.8 Mo atoms nm(-2), the quantities of adsorbed MoO(4)(2-) and Mo(7)O(24)(6-) become much smaller than that of electrostatically adsorbed H(4)Co(2)Mo(10)O(38)(6-). Adsorption of preserved H(4)Co(2)Mo(10)O(38)(6-) could be consecutive to the decomposition of the first molecules leading to prior adsorption of MoO(4)(2-) and Co(2+), and decrease in the buffering effect of γ-Al(2)O(3) and in the pH value. For dry impregnation, the same physicochemical phenomena occur considering a given Mo surface density. The methodology used in this work to rationalize the preparation of hydrotreatment catalysts from H(4)Co(2)Mo(10)O(38)(6-) heteropolyanions can be transposed to any supported catalyst.

Synthesis and Structuring of Ni MoS2 by using an Ionic Liquid

AbstractTo minimize air pollution resulting from exhaust gas emission, a decrease in the concentrations of the sulfur compounds in fuels has become a major issue in the last 10 years. The development of catalysts for the hydrodesulfurization process is a challenge for the oil industry. In the present work, a new and easy way to synthesize Ni‐Mo‐S hydrotreatment catalysts and in particular the effect of ionic liquids on the final structure was studied. It was shown that the addition of the ionic liquid [BMIM][NTf2] to the main reactants [Ni(NO3)2·6H2O and (NH4)2MoS4] had a great impact on the final product morphology. Indeed, formation of nanoparticles instead of gel was observed, and the amount of ionic liquid introduced helped to control the shape and size of the particles. Moreover, it was also highlighted that the presence of an ionic liquid favored the promotion of MoS2 with Ni with an optimal Ni/(Ni+Mo) atomic ratio of 0.3, and it also impacted the nanostructure, leading to thinner and shorter MoS2 slabs, which are two attractive points for catalytic applications.