NiMo Catalysts Research Articles

Insights into alloy/oxide or hydroxide interfaces in Ni-Mo-based electrocatalysts for hydrogen evolution under alkaline conditions.

Nickel-molybdenum (Ni-Mo) alloys are promising non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) in alkaline water; however, the kinetic origins of their catalytic activities still remain under debate. In this perspective, we systematically summarize the structural characteristics of Ni-Mo-based electrocatalysts recently reported and find that highly active catalysts generally have alloy-oxide or alloy-hydroxide interface structures. Based on the two-step reaction mechanism under alkaline conditions, water dissociation to form adsorbed hydrogen and combination of adsorbed hydrogen into molecular hydrogen, we discuss in detail the relationship between the two types of interface structures obtained by different synthesis methods and their HER performance in Ni-Mo based catalysts. For the alloy-oxide interfaces, the Ni4Mo/MoO x composites produced by electrodeposition or hydrothermal combined with thermal reduction exhibit activities close to that of platinum. For only the alloy or oxide, their activities are significantly lower than that of composite structures, indicating the synergistic catalytic effect of binary components. For the alloy-hydroxide interfaces, the activity of the Ni x Mo y alloy with different Ni/Mo ratios is greatly improved by constructing heterostructures with hydroxides such as Ni(OH)2 or Co(OH)2. In particular, pure alloys obtained by metallurgy must be activated to produce a layer of mixed Ni(OH)2 and MoO x on the surface to achieve high activity. Therefore, the activity of Ni-Mo catalysts probably originates from the interfaces of alloy-oxide or alloy-hydroxide, in which the oxide or hydroxide promotes water dissociation and the alloy accelerates hydrogen combination. These new understandings will provide valuable guidance for the further exploration of advanced HER electrocatalysts.

Superhydrophilic and superaerophobic Ni–Mo alloy grown on 3D Ni foam with heterogeneous structure as self-standing electrocatalysts toward efficient alkaline HER

Hydrogen energy is the most promising clean energy at present and hydrogen production by electrocatalytic water splitting is the frontier technology of alternative energy in the future. Herein, the Ni–Mo alloy supported with nickel foam (NF) was prepared by hydrogen reduction strategy at high temperature. The catalytic activity and stability of NiMo@NF-x catalyst (x stands for temperature) with multistage (sheet/particle) array structure were studied under different temperatures. The performance of the catalyst was evaluated by contact angle and related electrochemical characterization. It was found that the surface of NiMo@NF-550 catalyst prepared at 550 °C had superhydrophilic and superaerophobic properties, which contributed to the deactivation of bubbles from the surface of the electrode and improved the efficiency of the catalytic reaction. Moreover, the multi-stage array structure of sheet/particle will form a greater specific surface area than the plain sheet structure, offering more reaction sites. These results indicate that the self-supported superhydrophilic and superaerophobic Ni–Mo catalysts have excellent electrocatalytic hydrogen evolution ability.

Catalytic Activity and Coke Resistance of Gasification Slag-Supported Ni Catalysts during Steam Reforming of Plastic Pyrolysis Gas

Pyrolysis gas from polyolefinic plastic waste is a hydrocarbon-rich feedstock for sustainable syngas production. The effect of Cr, Mo, and W promoters on the activity of gasification slag-supported Ni catalysts during the reforming of plastic pyrolysis gas was investigated (polyethylene and polypropylene mixed feedstock, Ni:promoter molar ratio = 4.5, 800 °C, steam-to-carbon molar ratio of 7). Based on 3 h reforming tests, all catalysts showed stable conversion efficiency, suggesting that gasification slag from municipal solid waste is a promising replacement material for traditionally used alumina supports. Moreover, the slag demonstrated good thermal stability and potential for catalyst recycling, justifying the economic benefit of valorizing the material. Interestingly, interaction between slags and promoters is evidenced by the formation of CaWO4 and CaMoO4 phases, which may have an impact on the reforming activity of bimetallic catalysts. Among the studied catalysts, the highest conversion efficiency of hydrocarbon compounds (76%), highest H2 (122.65 mmol Lfeed–1) and CO (49.34 mmol Lfeed–1) yields, and lowest coke deposition (0.06 wt %) were demonstrated by the Ni–Mo catalyst. The superior performance of Ni–Mo was accompanied by the growth of carbon nanotubes via a tip-growth mechanism, which was not observed in other catalysts. Spherical carbon nanocages and filamentous carbon nanofibers predominated in coke deposits of Ni, Ni–W, and Ni–Cr. The high syngas production efficiency of Ni–Mo could be attributed to the dispersion of metal by the growing carbon nanotubes providing the reaction sites for reforming and coke gasification reactions. Owing to these properties, Ni catalyst promoted by Mo and loaded on a gasification support has high potential for the syngas production from plastic pyrolysis gas.

Alloying effect of Ni-Mo catalyst in hydrogenation of N-ethylcarbazole for hydrogen storage.

Liquid organic hydrogen storage with N-ethylcarbazole (NEC) as a carrier is a very promising method. The use of precious metal hydrogenation catalysts restricts the development in industrial grade. Efficient and low-cost hydrogen storage catalysts are essential for its application. In this work, a Ni-Mo alloy catalyst supported by commercial activated carbon was synthesized by impregnation method, and the Ni-Mo ratio and preparation conditions were optimized. The catalyst was characterized by XRD, XPS, H2-TPR, SEM, and TEM. The results showed that the doping of Mo could dramatically promote the catalytic hydrogenation of N-ethylcarbazole by the Ni-based catalyst. More than 5.75 wt% hydrogenation could be achieved in 4h using the Ni-Mo catalyst, and the selectivity of the fully hydrogenated product 12H-NEC could be effectively improved. This result reduces the cost of hydrogenation catalysts by more than 90% and makes liquid organic hydrogen storage a scaled possibility.

On Stability of High-Surface-Area Al2O3, TiO2, SiO2-Al2O3, and Activated Carbon Supports during Preparation of NiMo Sulfide Catalysts for Parallel Deoxygenation of Octanoic Acid and Hydrodesulfurization of 1-Benzothiophene

NiMo sulfide catalysts were prepared by the impregnation of high surface area supports with an aqueous solution made of NiCO3·2Ni(OH)2, MoO3 and citric acid, followed by freeze drying and sulfidation in H2S/H2 mixture. N2 physisorption and X-ray diffraction were selected to investigate the amphoteric oxides Al2O3 and TiO2, acidic SiO2-Al2O3 and activated carbon supports, fresh prepared sulfide NiMo catalysts and spent catalysts after model parallel reaction of octanoic acid deoxygenation and 1-benzothiophene hydrodesulfurization. The studied mesoporous amphoteric oxides Al2O3 and TiO2 did not lead to highly active NiMo catalysts due to the low hydrothermal stability of these supports during the preparation of the active sulfide phase and deoxygenation reaction. The most active catalyst based on oxidic support was the NiMo sulfide supported on acidic mesoporous SiO2-Al2O3, which was explained by the increased stability of this support to the water and CO/CO2 mixture during the activation of the sulfidic phase and deoxygenation reaction. The extraordinarily high stability of the activated carbon support led to outstanding activities of the sulfidic NiMo/C catalyst.

Analysis by temperature-programmed reduction of the catalytic system Ni-Mo-Pd/Al2O3

Alumina-supported nickel catalysts are used to facilitate many reactions at various scales. However, the deactivation of these catalysts is an important problem that has prompted the search for solutions such as the addition of other metals that act as promoters. In this research, the interactions that form between the support and the metals have been studied, a fundamental property that directly affects the performance of the catalyst. With this idea, several Ni-Pd and Ni-Mo bimetallic and various Ni-Mo-Pd trimetallic samples have been prepared, and the reduction capacity of the oxide phases by temperatura-programmed reduction has been analyzed and studied. It has been found that in bimetallic catalysts, Pd favors the appearance of NiO species that are more easily reducible than Mo. In the same way, the data obtained from the trimetallic simples suggest that the impregnation order of Mo and Pd is not a determining factor in these catalysts. In addition, it has been found that the co-impregnation of Ni with Pd gives better results than the sequential impregnation of these metals. The results obtained have also shown that the order of nickel impregnation is decisive. In the case of Ni-Mo catalysts, by impregnating the molybdenum first, catalysts with better reducing properties can be obtained.

NiMo/C-HY catalyst prepared from doping zeolite slurry in a superabsorbent polymer for DBT and 4,6-DMDBT hydrodesulfurization

This study utilized the swelling properties of superabsorbent polymers (SAP) to adsorb zeolite sols and slurries to construct C-HY composites. The synthesized C-HY composites proved to be effective supports for NiMo catalysts in the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyl-dibenzothiophene (4,6-DMDBT). XRD, BET, SEM, TG, NH3-TPD, FTIR, H2-TPR, TEM and XPS were used to characterization the texutural structure, acidity and metal distribution of prepared NiMo/C-HY catalysts. By combining zeolite slurries with SAPs, HY can be efficiently incorporated into carbon substrate structure in three dimensions (3D), thereby changing the structural characteristics, morphology, acidity, and metal distribution of HDS catalysts. The conversion of DBT decreases sequentially: NiMo/C-HY-s > NiMo/C-HY-h > NiMo/C-HY-p > NiMo/C-HY-c, and the conversion of 4,6-DMDBT decreased sequentially: NiMo/C-HY-s > NiMo/C-HY-p > NiMo/C-HY-h ≫ NiMo/C-HY-c. The introduction of HY into the carbon support can increase the HDS reaction rate of NiMo/C by more than 1.2–1.5 times. The intrinsic reaction activity of NiMo/C-HY-s can even exceed that of traditional NiMo/Al2O3 catalysts. Based on the same Mo loading amount, the HDS activity of NiMo/C-HY-s is twice that of NiMo/Al2O3 in DBT HDS and 1.1–1.5 times that of NiMo/Al2O3 in 4,6-DMDBT HDS. It is thought that HY in carbon composites promotes C–S bond cleavage of sulfur-containing molecules in DBT HDS. The unique dispersion of Mo species induced by HY favors the formation of highly stacked NiMoS active phases, which may be the crucial in 4,6-DMDBT HDS.

Three-Dimensional Au(NiMo)/Ti Catalysts for Efficient Hydrogen Evolution Reaction.

In this study, NiMo catalysts that have different metal loadings in the range of ca. 28-106 µg cm-2 were electrodeposited on the Ti substrate followed by their decoration with a very low amount of Au-crystallites in the range of ca. 1-5 µg cm-2 using the galvanic displacement method. The catalytic performance for hydrogen evolution reaction (HER) was evaluated on the NiMo/Ti and Au(NiMo)/Ti catalysts in an alkaline medium. It was found that among the investigated NiMo/Ti and Au(NiMo)/Ti catalysts, the Au(NiMo)/Ti-3 catalyst with the Au loading of 5.2 µg cm-2 gives the lowest overpotential of 252 mV for the HER to reach a current density of 10 mA·cm-2. The current densities for HER increase ca. 1.1-2.7 and ca. 1.1-2.2 times on the NiMo/Ti and Au(NiMo)/Ti catalysts, respectively, at -0.424 V, with an increase in temperature from 25 °C to 75 °C.

Simultaneous hydrodesulfurization of thiophene and benzothiophene over NiMoS catalysts supported on γ-Al2O3 composites containing ZSM-5

Alumina composites containing microporous ZSM-5 (Z-5) and mesoporous ZSM-5 (MZ-5), corresponding to xZA and xMZA, were developed by incorporating Z-5 and MZ-5 into γ - Al2O3, respectively. The two series of NiMoS/xMZA and NiMoS/xZA catalysts were prepared with these two composites as supports, respectively, and were used for the simultaneous hydrodesulfurization (HDS) of thiophene (T) and benzothiophene (BT). The results show that NiMoS/xMZA series catalysts exhibit higher HDS activity than that of NiMoS/xZA and NiMoS/γ-Al2O3, and the HDS activity of NiMoS/xMZA catalysts increases with the increase of MZ-5. The high HDS activity can be mainly attributed to the synergistic effects of the efficient diffusing pore channels, high dispersion of type II NiMoS phases, suitable acidity, and moderate Mo-support interaction. Moreover, the product distribution of HDS shows that the NiMoS/xMZA catalysts possess the dominant direct desulfurization (DDS) selectivity and the selectivity increases with the increase of MZ-5 content due to more corner sites and suitable Brønsted (B) acid sites, whereas the NiMoS/xZA catalysts perform more excellent hydrogenation (HYD) selectivity, and the selectivity increases with the increase of Z-5 content because of the existence of more edge sites. Based on this, the possible reaction network for T and BT hydrodesulfurization over the catalysts are proposed.

Hydrodesulfurization over NiMo Catalysts Supported on Yolk‐shell Silica Materials with Controllable Cavity Size

AbstractNovel yolk‐shell (YS) mesoporous silica materials with different cavity sizes were successfully synthesized. Aluminium was bridged into the yolk‐shell framework of silica by a post synthesis method to improve the acidity of YS, namely Al‐YS. The corresponding NiMo/Al‐YS catalysts were also fabricated and used in the hydrodesulfurization (HDS) reaction of dibenzothiophene (DBT) and 4,6‐dimethyldibenzothiophene (4,6‐DMDBT). The NiMo/Al‐YS catalyst with the cavity size of 154 nm (NiMo/Al‐YS‐154) exhibits the superior conversions of DBT (99.2 %) and 4,6‐DMDBT (96.1 %) at 340 °C, 4.0 MPa, 10 h−1, highest kHDS (13.4×10−4 mol g−1 h−1 for DBT and 8.9 mol g−1 h−1 for 4,6‐DMDBT) and highest TOF for DBT (3.7 h−1) and 4,6‐DMDBT (2.3 h−1) among the investigated catalysts. The appropriate cavity size of NiMo/Al‐YS‐154 catalyst plays the key role in obtaining its superior HDS catalytic performance. Furthermore, the possible reaction networks of DBT and 4, 6‐DMDBT HDS over NiMo/Al‐YS‐x catalysts were also presented.

Evaluation of kraft and hydrolysis lignin hydroconversion over unsupported NiMoS catalyst

Catalytic hydroconversion of Kraft and hydrolysis lignins was for the first time compared in a batch reactor over an unsupported NiMoS-SBA catalyst. We also report the effect of key reaction parameters on the yields and properties of the products. The results obtained at 20 wt% catalyst loading for hydrolysis lignin showed the highest monomer yield of 76.0 wt%, which consisted of 39 wt% aromatics with the lowest alkylphenolics yield of 10.1 wt%. Identical operating conditions, 400 °C, 80 bar, 5 h at 10 wt% catalyst loading, were used to compare both lignins and the highest monomer yield (64.3 wt%) was found for the hydrolysis lignin, consisting of 16.0 wt% alkylphenolics and 20.1 wt% aromatic compounds. These values are considerably higher than those for Kraft lignin with its 47.0 wt% monomer yield. We suggest that the reason for high yields of monomeric units from hydrolysis lignin is that it is more reactive due to its lower ash and sulfur contents and the chemical structural differences compared to the Kraft lignin. More precisely, the bio-oil from hydrolysis lignin contained higher yields of small molecules, sourced from ring-opening of cellulose in the hydrolysis lignin, which could stabilize the reactive oligomeric groups. These yields were two to seven times higher from kraft and hydrolysis lignin, respectively, compared to those obtained without catalyst. The results showed that the NiMoS-SBA catalyst is a promising catalyst for reductive depolymerization of lignin and in addition that the regenerated catalyst had good stability for multiple reaction cycles.

Novel Route to Produce Hydrocarbons from Woody Biomass Using Molten Salts.

The thermochemical decomposition of woody biomass has been widely identified as a promising route to produce renewable biofuels. More recently, the use of molten salts in combination with pyrolysis has gathered increased interest. The molten salts may act as a solvent, a heat transfer medium, and possibly also a catalyst. In this study, we report experimental studies on a process to convert woody biomass to a liquid hydrocarbon product with a very low oxygen content using molten salt pyrolysis (350–450 °C and atmospheric pressure) followed by subsequent catalytic conversions of the liquids obtained by pyrolysis. Pyrolysis of woody biomass in molten salt (ZnCl2/NaCl/KCl with a molar composition of 60:20:20) resulted in a liquid yield of 46 wt % at a temperature of 450 °C and a molten salt/biomass ratio of 10:1 (mass). The liquids are highly enriched in furfural (13 wt %) and acetic acid (14 wt %). To reduce complexity and experimental issues related to the production of sufficient amounts of pyrolysis oils for further catalytic upgrading, model studies were performed to convert both compounds to hydrocarbons using a three-step catalytic approach, viz., (i) ketonization of acetic acid to acetone, (ii) cross-aldol condensation between acetone and furfural to C8–C13 products, followed by (iii) a two-stage catalytic hydrotreatment of the latter to liquid hydrocarbons. Ketonization of acetic acid to acetone was studied in a continuous setup over a ceria–zirconia-based catalyst at 250 °C. The catalyst showed no signs of deactivation over a period of 230 h while also achieving high selectivity toward acetone. Furfural was shown to have a negative effect on the catalyst performance, and as such, a separation step is required after pyrolysis to obtain an acetic-acid-enriched fraction. The cross-aldol condensation reaction between acetone and furfural was studied in a batch using a commercial Mg/Al hydrotalcite as the catalyst. Furfural was quantitatively converted with over 90% molar selectivity toward condensed products with a carbon number between C8 and C13. The two-stage hydrotreatment of the condensed product consisted of a stabilization step using a Ni-based Picula catalyst and a further deep hydrotreatment over a NiMo catalyst, in both batch setups. The final product with a residual 1.5 wt % O is rich in (cyclo)alkanes and aromatic hydrocarbons. The overall carbon yield for the four-step approach, from pinewood biomass to middle distillates, is 21%, assuming that separation of furfural and acetic acid after the pyrolysis step can be performed without losses.

Hydrotreatment of Supercritical Carbon Dioxide Extracts of Hydrothermal Liquefaction Lignocellulosic Biocrude

Raw lignocellulosic biocrude produced by hydrothermal liquefaction and its supercritical carbon dioxide extract (SE) were hydrotreated at 350–405 °C and for 2–6 h utilizing commercial CoMo and NiMo catalysts. The hydrotreatment reduced the oxygen content of the SE down to 1.6 wt %, while the minimum oxygen content of the hydrotreated biocrude (HBC) was 3.1 wt %. No coke formation was observed in the hydrotreatment of the SE, while the yield of coke was 13 wt % when processing the raw biocrude. The hydrotreated SE (HSE) samples exhibited molecular weights 24–61% lower than that of the HBC samples, with larger low-boiling fractions (up to diesel). The better quality of the HSE and the absence of coke, together with the lower metal content of SE (0.2 g/kg) versus BC (8.5 g/kg), suggest that the implementation of hydrotreatment on SEs, instead of raw lignocellulosic biocrude, is a promising option.

A Highly Active NiMoAl Catalyst Prepared by a Solvothermal Method for the Hydrogenation of Methyl Acrylate

In this study, a series of Ni10MoxAl composite metal oxide (Ni10MoxAl, NiO = 10 wt.%, x = 2.5, 5, 10, 15, 20 wt.%) catalysts with different Mo content were prepared by a solvothermal method using a water—ethanol system. By employing various characterization technologies, it was confirmed that the suitable amount of the Mo element can not only promote the dispersion of the Ni species but also inhibit the formation of the inactive NiAl2O4 phase. Consequently, the hydrogenation activity of the Ni10MoxAl catalysts was affected by the particle size of the active components and the amount of the NiAl2O4 phase. As a result, the Ni10Mo10Al catalyst showed the best catalytic performance on methyl acrylate hydrogenation, and the yield of methyl propionate can be increased from 53.7% to 89.5% at 100 °C and 1 MP H2, compared with the Ni10Mo10/γ–Al2O3 catalyst prepared by a traditional impregnation method. The stability of the Ni10Mo10Al catalyst was also investigated, and the catalyst can run stably for 23 h. The novel strategy adopted in this article provides a new direction for the preparation of high activity Ni–Mo catalysts.

A NiMo-YSZ catalyst support layer for regenerable solid oxide fuel cells running on isooctane

A catalyst-layer supported single cell consisting of a porous YSZ backbone support and NiMo catalyst is developed for solid oxide fuel cells running on isooctane/air. The reforming and electrochemical performance of the catalyst-layer supported single cell is comparatively studied with conventional anode supported single cell applied with a thin NiMo-YSZ reforming layer. The NiMo-YSZ catalyst support layer could efficiently catalyze the partial oxidation of isooctane in air, producing H2 and CO for the anode electrochemical oxidation. As a result, the single cells display enhanced initial electrochemical performance and performance stability compared with the cell without the catalyst in isooctane/air at 750 °C. On the other hand, carbon species could still be identified in the NiMo-YSZ catalyst after operating the single cells for 12 h, which deteriorates the reforming and electrochemical performance. To improve the electrochemical performance stability, the catalyst layer is in-situly regenerated by redox treatment to burn out the carbon deposits. The conventional Ni metal-based anode supported cell is susceptible to redox condition and the occasional oxidation of the Ni metal containing support results in 37.8 % performance loss only after one redox cycle. By applying the robust catalyst-layer supported cell developed in this work, the cell could maintain over 90 % of its initial electrochemical performance after two redox cycles. Feeding 15 ml min−1 air to the anode channel for 5 min is found to be effective to burn out the carbon species in the catalyst support layer, which suppresses the deterioration of catalytic activity and enhance electrochemical performance stability of the single cell. The results demonstrate the benefits of the catalyst-layer supported single cell design for in-situ catalyst regeneration.

The Features of the CCVD of Trichloroethylene Over Microdispersed Ni and Ni–Mo Catalysts

The Features of the CCVD of Trichloroethylene Over Microdispersed Ni and Ni–Mo Catalysts

Critical insights from alloys and composites of Ni-based electrocatalysts for HER on NaCl electrolyte

It is critical to minimize the cost of materials and inputs used in hydrogen production and to create solutions for large-scale generation to reduce the cost of hydrogen produced. Seawater is a natural low-cost electrolyte with high Na + and Cl - concentrations, among other soluble salts. Chloride ions allow a highly corrosive media to the materials typically used as electrodes. In this work, we have prepared and tested different Ni-based catalysts for hydrogen evolution in NaCl-containing solutions. NiMo alloy, Ni(WO 3 ), and Ni(Nb 2 O 5 ) composites are compared and studied from a critical point of view to find a viable solution for catalysis in seawater electrolysis. The NiMo catalyst presents a higher dissolution rate in the NaCl medium than all synthesized catalysts. Furthermore, Ni-based composites showed improved durability due to a decrease in dissolution, and an increase in catalytic activity when using Nb 2 O 5 as the dispersed phase. The Ni(Nb 2 O 5 ) electrodes presented the higher catalytic activity in NaCl solution, even higher than that found in NiMo catalyst. • Different strategies for the synthesis of catalysts for the electrogeneration of H 2 in NaCl electrolyte are analysed. • NiMo catalyst presents higher dissolution in the NaCl medium than the composite synthesized catalysts. • The use of composites improves the catalyst durability, reducing the dissolution. • A remarkable increase of the current density was found when using the Ni(Nb 2 O 5 ) catalyst.

Effects of Al introduction methods for Al-SBA-15 on NiMoS active phase morphology and hydrodesulfurization reaction selectivities

A series of Al-SBA-15 were synthesized with three Al introduction methods and different Si/Al molar ratios. The introduction methods included the direct synthesis (DS), post-synthesis grafting (PG) and impregnation synthesis (IM) method. The Si/Al molar ratios of Al-SBA-15 materials were 20, 10 and 5 respectively. The corresponding NiMoS catalysts were performed by hydrodesulfurization (HDS) recations of dibenzothiophene (DBT) to analyze reaction behavior. The characterization results of N2-physisorption, X-ray diffraction and 27Al NMR presented that the Al introduction method has a direct effect on the physical and chemical properties of Al-SBA-15. PG method could introduce most of Al atoms into the framework of parent- material, which was opposed to the IM method. The DS method could better maintain the pore structure advantages of the Al-SBA-15. The PG-NiMo catalyst had the strongest metal-support interaction, and the NiMoS slabs presented the lowest average stacking number over this catalyst. The reaction results showed that DS-NiMo catalyst obtained the highest HDS activity, and PG-NiMo catalyst presented the highest HDS hydrogenolysis selectivity of DBT. It is speculated that the frame-work Al has strong metal interaction with metal oxide precursor, and the morphology of NiMoS Phase has important effect on the selectivity of DBT HDS.

Low-Temperature Efficient Hydrogen Production from Raw Biomass on the Ni–Mo Catalyst

Low-Temperature Efficient Hydrogen Production from Raw Biomass on the Ni–Mo Catalyst

Influence of the support on activity and stability of Ni and Ni-Mo catalysts in the hydroprocessing of fatty acids into motor fuels components

Ni/zeolite catalyst, as well as a series of modified molybdenum MoNi/zeolite catalysts (zeolite = ZSM-5, ZSM-23, MOR, Y) were investigated in the hydroprocessing of an undiluted fatty acid mixture in a batch reactor at a temperature of 350 °C and an initial hydrogen pressure of 60 bar. The highest conversion (70 %) of the fatty acid mixture was achieved over ZSM-5 supported catalytic system in 7 h. The fresh and spent catalytic systems were characterized by XRD, TEM, TPR-H2, TPD-NH3, CHNS. Influence of the support, and the modifier, on the catalytic activity, stability under reaction conditions, and selectivity to iso-alkanes were shown. Leaching of the active component from the surface of all catalysts was found. The largest amount of residual nickel was observed in catalysts based on ZSM-5 zeolite - ca.57 % of the initial metal content. Modification with molybdenum did not improve the stability of catalysts to metal leaching.