Preparation and Application of a Yolk-Shell Structure-Based Hydrodesulfurization Catalyst Based on Hydrogen Overflow

Abstract

This invention discloses the preparation and application of a hydrogen overflow-based yolk-shell structured hydrodesulfurization catalyst. The preparation method includes (1) adding nickel nitrate hexahydrate to glycerol, isopropanol, and deionized water, and performing a solvothermal reaction on the green solution to obtain a solid spherical nickel composite precursor. (2) mixing the nickel composite precursor with an ethanol solution of thioacetamide, and adding an aqueous solution of ammonium heptamolybdate to obtain a suspension. The suspension is then subjected to a solvothermal reaction to obtain the yolk-shell structured catalyst. This application employs a confined sulfidation coupled in-situ intercalation strategy to controllably derive a yolk-shell structured catalyst with abundant NiMoS phase. Under the action of confined sulfidation, organic molecules can be intercalated in situ and assist in the construction of a stable 1T-MoS2 with short plate length and low stacking, thereby promoting the full exposure of the "rim" site. This catalyst uses the core NiS2 as an auxiliary active phase to initiate a hydrogen overflow effect, and promotes the synergy of the two active phases through the yolk-shell structure, thereby achieving ultra-deep desulfurization of oil products.

Description

Technical Field

[0001] This invention relates to a method for preparing and applying a yolk-shell structured bulk phase hydrodesulfurization catalyst based on hydrogen overflow, which belongs to the field of unsupported molybdenum-based catalytic materials in the field of oil hydrotreating in industrial catalysis. Background Technology

[0002] In recent years, with the deepening of crude oil extraction, its quality has deteriorated. High-sulfur crude oil produces large amounts of toxic gases during combustion, posing serious threats to the environment and human health. To address these issues, countries are actively developing various desulfurization methods to reduce the sulfur content in fuel oil. Currently, hydrodesulfurization (HDS) technology has become an important means of producing ultra-low sulfur fuels due to its excellent desulfurization performance, high sustainability, and low economic cost. Traditional HDS catalysts are typically used for the direct desulfurization (DDS) of small-molecule heterocyclic sulfides (such as thiophene and dibenzothiophene (DBT)). However, the desulfurization effect on the bulky and sterically hindered 4,6-dimethyldibenzothiophene (4,6-DMDBT) is not significant, making it one of the most difficult pollutants to degrade in fuel oil. The desulfurization process of 4,6-DMDBT often involves the planar adsorption of benzene rings onto the catalyst and pre-hydrogenation saturation to reduce steric hindrance (hydrogenation reaction (HYD) pathway). However, current industrial HDS catalysts are mainly single-phase MoS2 with long plate lengths, whose catalytic activity for HDS is limited only by the edge-coordinated unsaturated sites. This results in 4,6-DMDBT desulfurization being limited by adsorption sites and active hydrogen. Therefore, the fundamental approach to achieving deep desulfurization depends on designing HDS catalysts with abundant adsorption sites, especially those materials with additional hydrogen activation and migration capabilities.

[0003] In the HDS system, NiS x (CoS x It can serve as an auxiliary active phase (donor) to activate H2 and provide hydrogen spillover (H2). so The acceptor phase (MoS2) receives the migrated H+. so This generates more unsaturated sulfur vacancies and -SH groups, thereby further improving the activity and reaction pathway selectivity of HDS. Gil-Llambías et al. used γ-Al₂O₃ for physical separation, confirming that CoS… x or NiS x It promotes the growth of MoS2, thereby improving the HDS activity of the catalyst (Appl. Catal. A Gen., 274(2004) 303-309). Castillo-Villalon et al. investigated the interaction between CoMoS and CoS2 by adjusting the Co / (Co+Mo) ratio while keeping the number of CoMoS2 active sites essentially unchanged. xThe synergistic effect of the catalysts on the activity of HDS was investigated, and highly active HDS catalysts were obtained (Catal. Today, 394-396 (2022) 41-49). Therefore, designing multi-active phase HDS catalysts with hydrogen spillover effect can improve the hydrodesulfurization capacity of traditional NiMoS / CoMoS with the assistance of additional active sites. However, the transfer of active hydrogen to the acceptor phase often requires a long distance, resulting in slow consumption of active hydrogen and a reduced reaction rate. For example, Escalona et al. studied the effect of Co9S8 and MoS8 on the activity of HDS. x The study investigated the effect of distance between the donor and acceptor on the synergistic effect, finding that the synergistic effect weakened with increasing distance between the donor and acceptor, leading to a decrease in HDS catalytic efficiency (Catal. Today, 282(2017)214-221). Therefore, constructing catalysts with hydrogen spillover capabilities at the nanoscale, shortening the migration distance of active substances, and increasing the variety of active phases are of great significance for achieving ultra-deep hydrodesulfurization of oil products.

[0004] Currently, relevant literature and patents report that egg yolk-shell nanoreactors have broad application prospects and great potential in HDS systems. Egg yolk-shell nanoreactors are nanomaterials that encapsulate particles in a hollow structure, possessing strong thermal stability and adjustable pore size and shell thickness. The adjustable porosity in the egg yolk-shell structure not only exposes more active sites for reactants but also shortens the migration distance of active species. Chinese patent CN 116943678A discloses a method for preparing a yolk-shell structure bulk phase hydrogenation refining catalyst. This invention uses soluble sodium salt as a raw material to improve the distribution state of active metals, increase the active centers and dispersion of the catalyst, and improve the catalyst utilization rate and mechanical strength. Chinese patent CN116603564A discloses a core-shell molecular sieve@transition metal doped—molybdenum disulfide / carbon composite catalyst. This invention uses a ternary material synthesis method. High dispersion of molybdenum species is achieved through the amino groups in the positively charged polymer, improving metal utilization. However, the catalysts prepared by the above methods are all limited by the semiconductor properties and poor electron transport characteristics of traditional MoS2, which is not conducive to the transport of active hydrogen and thus reduces the hydrodesulfurization reaction rate. Phase engineering plays a crucial role in regulating the physicochemical properties of MoS2. Compared with the trigonal prism structure of traditional 2H-MoS2, 1T-MoS2 adopts an octahedral coordination mode, which has unfilled empty orbitals near the Fermi level. Therefore, 1T-MoS2 exhibits higher electron transferability, which is beneficial to promoting the transfer of active hydrogen in the HDS process and improving the HDS activity of the catalyst. Chinese patent CN 112316959A has confirmed that some intercalated molecules (such as those containing -OH) can enter MoS2 nanosheets and inject electrons into the Mo 4d orbitals, which is expected to lower the energy barrier from 2H to 1T, making the application of 1T-MoS2 in the HDS reaction possible. Meanwhile, the presence of intercalated molecules prevents the excessive growth of MoS2 nanosheets, which is conducive to the generation of MoS2 with short plate lengths and low stacking, thereby providing more "rim" sites and promoting the adsorption of 4,6-DMDBT. Therefore, the superior structural characteristics of 1T-MoS2 constructed by molecular intercalation overcome the shortcomings of the 2H-MoS2 catalyst currently used in industry, and promote the deep desulfurization of 4,6-DMDBT macromolecules.

[0005] However, current technology cannot simultaneously deliver the donor (NiS) x or CoS x The binding of the acceptor (NiMoS / CoMoS) and 1T-MoS2 into the same nanoparticle limits the improvement of the activity, selectivity and stability of the HDS system catalyst. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention aims to provide a method for preparing a yolk-shell structured hydrodesulfurization catalyst based on hydrogen overflow, thereby improving its hydrodesulfurization performance in oil refining. This catalyst solves the problems of slow reaction rates and low active site utilization caused by a single active phase and long active hydrogen migration pathways by constructing an auxiliary active phase with additional hydrogen activation capabilities at the nanoscale. Organic matter is used to inhibit the growth of sulfide clusters and facilitate their intercalation, constructing a stable 1T-MoS2 with short plate lengths and low stacking, promoting active hydrogen transfer. This catalyst exhibits excellent HDS performance and high pathway selectivity in oil refining, and is expected to become an important candidate material for ultra-deep desulfurization systems.

[0007] The first aspect of this invention discloses a yolk-shell structured hydrodesulfurization catalyst based on hydrogen overflow, wherein the mass percentage of Ni is 10-30 wt.%, the mass percentage of Mo is 10-40 wt.%, NiMoS accounts for 20-90% of the total Ni species content of the catalyst, and the Mo sulfidation degree (Mo sulfidation The percentage is 40-80%.

[0008] The active phase MoS2 mainly exists stably as a 1T phase with an average length of 0-6 nm and an average number of stacking layers of 1-5. Based on the total number of stacking layers, the proportion of layers with 2-3 layers is 40-70%, preferably 40-70%.

[0009] The second aspect of this invention discloses a technical solution for preparing the yolk-shell structured bulk phase hydrodesulfurization catalyst based on hydrogen overflow as described above, as follows:

[0010] S1: Mix glycerol, isopropanol and deionized water in a certain proportion and add nickel nitrate hexahydrate. Stir to obtain a green transparent solution.

[0011] S2: The solution obtained in the solvothermal reaction step S1 yields a solid spherical nickel composite precursor;

[0012] S3: Mix the nickel composite precursor obtained in step S2 with the ethanol solution of thioacetamide and stir until homogeneous. Add an aqueous solution of ammonium molybdate to obtain a suspension.

[0013] S4: The suspension obtained in step S3 is subjected to a solvothermal reaction and then washed and dried to obtain an egg yolk-shell structure catalyst;

[0014] Alternatively, it may include the following preparation steps:

[0015] S1: Mix glycerol, isopropanol and deionized water in a certain proportion, add nickel nitrate hexahydrate and molybdenum acetylacetonate, and stir to obtain a transparent solution;

[0016] S2: The solution obtained in the solvothermal reaction step S1 yields a solid spherical nickel-molybdenum composite precursor;

[0017] S3: Mix the nickel-molybdenum composite precursor obtained in step S2 with the ethanol solution of thioacetamide and stir until homogeneous. Add an aqueous solution of ammonium molybdate to obtain a suspension.

[0018] S4: The suspension obtained in step S3 is subjected to a solvothermal reaction and then washed and dried to obtain a hollow structure catalyst.

[0019] Preferably, in step S1, the feeding ratio of glycerol, isopropanol and deionized water is 5-9 mL: 45-60 mL: 0-2 mL; and the mass ratio of nickel nitrate hexahydrate and molybdenum acetylacetonate is 0.06-0.1 g: 0-0.1 g.

[0020] Preferably, the temperature of the solvothermal reaction in step S2 is 180-220℃ and the time is 8-12h.

[0021] Preferably, in step S3, the mass ratio of nickel composite precursor / nickel-molybdenum composite precursor, thioacetamide and ammonium molybdate is 0-0.05g: 0.14-0.35g: 0-0.25g.

[0022] Preferably, the temperature of the solvothermal reaction in step S4 is 180-220℃ and the time is 2-8h; or a two-step heating method: the first step is 100-150℃ and held for 0-3h, and the second step is 180-220℃ and held for 2-8h.

[0023] The third aspect of this invention discloses the application of a yolk-shell structure bulk phase catalyst based on hydrogen overflow as described above in hydrodesulfurization.

[0024] Preferably, the yolk-shell structured bulk phase catalyst based on hydrogen overflow is used for hydrodesulfurization of DBT and 4,6-DMDBT at a temperature of 220-300℃ and a pressure of 4-6.5MPa.

[0025] The working principle of this invention is as follows:

[0026] This catalyst employs a novel confined sulfidation-coupled in-situ intercalation strategy to precisely design a nanoreactor with a stable yolk-shell structure for efficient hydrodesulfurization. The method involves a simple solvothermal synthesis of a nickel composite precursor. Subsequently, Ni is slowly released using the Ostwald ripening effect. 2+ And glycerol, to control the 1T-MoS2 derivative with abundant "rim" sites. This strategy has three advantages in regulating the structure of yolk-shell nanoreactors: (i) through the slow release of Ni 2+(i) Controllable construction of NiMoS active sites was achieved at the atomic level, thereby improving the apparent activity of the catalyst. (ii) Stable 1T-MoS2 was constructed by in-situ intercalation of glycerol molecules at the molecular level through the coordination dissociation reaction of the nickel composite precursor. The high viscosity and high density of glycerol can increase the steric hindrance of MoS2 core growth, resulting in MoS2 with long short plates and low stacking, which is beneficial to exposing more "rim" sites and improving the intrinsic activity of the catalyst. (iii) The confined sulfidation strategy controls the yolk-shell structure of the catalyst at the nanoscale, shortens the migration distance of active hydrogen, and improves the hydrodesulfurization reaction rate. The NiS2 core phase and NiMoS shell have different functions in the HDS reaction, realizing the synergistic effect between multiple active phases. Therefore, this invention not only provides a new method for the application of highly active 1T-MoS2 in HDS, but also provides theoretical guidance for the rational design and controllable construction of efficient hydrogen overflow HDS catalysts.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Ni is gradually released through the Ostwald ripening effect 2+ By constructing a NiMoS active phase and controlling its derivation and content, the density of active material in the catalyst can be increased.

[0029] (2) By utilizing the intercalation effect of glycerol, stable 1T-MoS2 nanosheets with short plate lengths and low stacking are derived, generating more edge sites. The benzene ring in the 4,6-DMDBT molecule is adsorbed to the active center through planar adsorption, thereby facilitating the HYD pathway and improving the selectivity of the catalyst.

[0030] (3) The Mo-S bond energy of 1T-MoS2 is small, which is conducive to the breaking of Mo-S bond to form new sulfur vacancies, thereby increasing the concentration of active centers in the HDS reaction.

[0031] (4) The 1T-MoS2 in the catalyst has a unique structure with metal-like properties, which greatly improves the conductivity of the catalyst, thereby increasing the electron migration rate on the catalyst surface and increasing the possibility of overflow hydrogen production.

[0032] (5) The voids in the yolk-shell structure not only expose more active sites for reactants, but also provide a uniform environment for heterogeneous catalysis.

[0033] (6) The dense shell allows the catalyst to maintain the yolk-shell structure during the cyclic reaction, thus improving the catalyst's lifespan.

[0034] (7) The yolk-shell structure shortens the distance of active hydrogen migration at the nanoscale, which helps the transfer and consumption of active hydrogen and improves the reaction rate of HDS.

[0035] (8) The egg yolk-shell structure phase catalyst of the present invention has the characteristics of simple operation, short production cycle and mild preparation conditions, which is of great significance for actual industrial production.

[0036] (9) The yolk-shell structure phase catalyst based on hydrogen overflow described in this invention exhibits extremely high HDS activity and selectivity. Under relatively mild reaction conditions, it can reduce the sulfur content in simulated oil from 500 ppm to below 10 ppm, thus achieving ultra-deep desulfurization of simulated oil. Attached Figure Description

[0037] Figure 1 The X-ray diffraction (XRD) patterns of the catalysts prepared in the examples and comparative examples reflect the phase structure of each catalyst. In the present invention, the internal core phase of each sulfide-state catalyst is mainly NiS2, and the outer shell is mainly NiMoS. The diffraction peaks at 2θ of 9.1°, 31.6° and 53.6° correspond to the (002) crystal plane of hexagonal 1T-MoS2 (PDF#01-089-2905) and the (200) and (311) crystal planes of simple cubic NiS2 (PDF#00-011-0099), respectively, proving the successful preparation of multiphase composite materials. Since glycerol can play a supporting and protective role in the MoS2 layer, the interlayer spacing of MoS2 is increased, making it mainly exist as the 1T phase. Compared with other catalysts, the (002) crystal plane of H-Cat is shifted at a high angle. This is because the nickel-molybdenum composite precursor lacks a large amount of Mo in the solution. 6+ This slows down the formation of the rigid outer shell of MoS2, causing the loss of glycerol molecules and resulting in the formation of the 2H phase.

[0038] Figure 2 The Raman spectra of the catalysts prepared in the examples are shown below, further analyzing the phase structure of the catalysts. Generally, the Raman spectra at 146, 238, 283, and 336 cm⁻¹ are obtained. -1 The characteristic peaks at this location belong to J1, J2, E of 1T-MoS2. 1g And J3 vibration mode, while 379 and 402cm -1 The characteristic peaks at these locations belong to the E of 2H-MoS2. 1 2g and A 1gVibrational modes. Comparative results show that YS-Cat-5h, MM-NiS2 / MoS2, and P-MoS2 exhibit strong characteristic peaks of 1T-MoS2, while H-Cat mainly shows characteristic peaks of the 2H phase, consistent with XRD analysis results. This indicates that glycerol released by the Ostwald ripening effect enters the MoS2 lamellar structure, transforming the MoS2 lattice into a 1T phase structure. Therefore, the yolk-shell YS-Cat-5h catalyst can be controllably derived using a confined sulfidation coupled in-situ intercalation strategy, fully exposing active sites and forming stable 1T-MoS2.

[0039] Figure 3 Scanning electron microscopy (SEM) of the nickel composite precursor prepared in Example 1 Figure 3 a) Figure and SEM image of the yolk-shell structure phase hydrodesulfurization catalyst YS-Cat-5h. Figure 3 b) Image, Transmission Electron Microscopy (TEM) Figure 3 c) Figure, High-magnification transmission electron microscope (HRTEM), Figure 3 d) The graph and the corresponding element distribution (Mapping) graph ( Figure 3 e). This invention utilizes a self-sacrificial template method to controllably derive highly active transition metal sulfides, constructing nanomaterials with an eggshell structure. Mapping data shows that Ni, Mo, and S elements are uniformly distributed on the YS-Cat-5h catalyst. Mo exists only on the outer shell of YS-Cat-5h, while Ni exists in both the core and shell. XRD results indicate that the YS-Cat-5h catalyst consists of eggshell nanospheres composed of a Ni-doped MoS2 shell (NiMoS) and a NiS2 core. Furthermore, due to glycerol limiting MoS2 growth and the strong reducing power of thioacetamide inducing more nuclei, more MoS2 clusters with short plate lengths and low stacking numbers are derived. The core phase NiS2 within the catalyst generates active hydrogen, which transfers to the outer shell NiMoS, generating more unsaturated sulfur vacancies and -SH groups, thereby improving the catalyst's HDS activity and reaction pathway selectivity, achieving ultra-deep desulfurization of oil products.

[0040] Figure 4 SEM images of the sulfide catalysts prepared in Comparative Examples 1, 2, 3, and 4 (for each sulfide state catalyst) Figure 4 ad) and TEM image ( Figure 4 In the initial stage of the sulfidation reaction, S is produced by the high-temperature decomposition of TAA. 2- Ni released from the ion-nickel composite precursor 2+ and Mo present in the solution 6+ A reaction occurs, forming a rigid NiMoS shell around the nickel composite precursor nanospheres, while adsorbed Ni... 2+The surrounding glycerol molecules remain within the MoS2 nanosheets. During further sulfidation, the continuous dissipation of the nickel composite precursor leads to a gradual shrinkage of the core phase and a gradual thickening of the shell. However, due to the solvothermal reaction process, Ni... 2+ and S 2- The different diffusion rates of Ni create a significant gap (100 nm) between the shell and the core, resulting in a yolk-shell nanoreactor with fully exposed active sites. When the reaction time is too long, Ni... 2+ All of them are related to Mo in the solution 6+ and S 2- The reaction results in the loss of the NiS2 core, forming hollow spheres. Therefore, Ni is gradually released through the Ostwald ripening effect. 2+ Promote Ni 2+ The active phase NiMoS was converted to the maximum extent and an auxiliary active phase NiS2 core was constructed to improve the HDS activity of the catalyst.

[0041] Figure 5 SEM images of the solid spherical nickel-molybdenum composite precursor and the catalysts prepared in Examples 3, 4, and 5. Figure 5 a) and TEM image ( Figure 5 Compared to Example 1, the solid spherical nickel-molybdenum composite precursor directly generated a hollow catalyst under the same synthesis conditions. Figure 5 b). This indicates a lack of significant Mo in the solution. 6+ The presence of [a certain substance] makes it difficult to ensure the rapid formation of the rigid shell of MoS2, leading to the loss of various components of the catalyst, which is detrimental to the generation of the hydrogen spillover effect. Furthermore, P-MoS2, due to the loss of precursor dispersion, self-assembles into dandelion-shaped nanosheets to reduce surface energy. Figure 5 c), and it exists only in the form of single-phase MoS2. The MM-NiS2 / MoS2 catalyst, obtained by uniformly mixing NiS2 and MoS2 through mechanical milling, has nanosheets aggregated and intertwined together. Figure 5 d) This would hinder the exposure of active sites in the HDS reaction. Therefore, by utilizing the Ostwald ripening effect to controllably construct a YS-Cat-5h catalyst with a yolk-shell structure, a short-distance (100 nm) hydrogen overflow path can be provided for the HDS reaction, thus constructing an HDS nanoreactor.

[0042] Figure 6The HDS reaction network for DBT and 4,6-DMDBT shows that the main products are tetrahydrodibenzothiophene (THDBT), hexahydrodibenzothiophene (HHDBT), biphenyl (BP), cyclohexylbenzene (CHB), 3,3′-dimethylbiphenyl (3,3′-DMBP), 3,3′-dimethylbicyclohexane (3,3′-DMBCH), 3,3′-dimethylcyclohexylbenzene (3,3′-DMCHB), 4,6-hexahydrodimethyldibenzothiophene (4,6-HHDMDBT), and 4,6-tetrahydrodimethyldibenzothiophene (4,6-THDMDBT). Taking DBT as an example, in the DDS pathway, the CS bond first breaks to generate BP. In the HYD pathway, one benzene ring of DBT is first saturated with H2 to generate THDBT and HHDBT, and then the CS bond is cleaved, with the final product being CHB. The HDS reaction of 4,6-DMDBT also involves two parallel reaction pathways: one is the DDS pathway, where the CS bond in 4,6-DMDBT first breaks to generate 3,3′-DMBP, then partially hydrogenates 3,3′-DMCHB, and further hydrogenates to generate 3,3′-DMBCH; the other is the HYD pathway, where one benzene ring in 4,6-DMDBT first partially hydrogenates to generate 4,6-THDMDBT and 4,6-HHDMDBT, then the CS bond breaks to generate 3,3′-DMCHB, or further hydrogenates to generate 3,3′-DMBCH. The pathway selectivity is expressed as the ratio of the total concentration of products from the HYD pathway to the total concentration of products from the DDS pathway.

[0043] Figure 7 This is a graph showing the HDS performance and selectivity analysis of each catalyst in the comparative examples. The horizontal axis represents the duration of the solvothermal reaction stage during catalyst preparation, and the vertical axis represents the performance parameters during the hydrodesulfurization catalytic process. The 4,6-DMDBT conversion rate exhibits an inverted U-shaped curve with increasing solvothermal time. This is due to the slow release of Ni from the nickel composite precursor during the initial stage of sulfidation. 2+ With the large amount of Mo present in the solution 6+ and S 2- The reaction produces a NiMoS shell. As the solvothermal reaction proceeds, the nickel composite precursor continuously decomposes, and the sulfidation degree and NiMoS content of the sample gradually increase. When the reaction reaches a certain stage, the nickel composite precursor is completely consumed, and NiMoS begins to decompose into two phases, leading to a decrease in the sulfidation degree and NiMoS content of the catalyst, thereby reducing the 4,6-DMDBT conversion rate. Furthermore, S... HYD / DDSThe trend is similar to that of the conversion rate, which is because the length and stacking number of MoS2 plates can be controlled by adjusting the sulfidation time. Shorter, lower-stacked MoS2 plates have more edge-coordinated unsaturated sites, which facilitates the entry of more Ni atoms into the edge positions of MoS2, promoting the adsorption and dissociation of molecular hydrogen into active hydrogen, thereby improving the selectivity of the HYD reaction. Therefore, by utilizing the Ostwald ripening effect to controllably construct the yolk-shell catalyst, the content of NiS2 and NiMoS can be reasonably adjusted to promote the full utilization of each phase, thereby improving the HDS activity of the catalyst.

[0044] Figure 8 This paper describes a method for preparing a yolk-shell structured bulk phase hydrodesulfurization catalyst based on hydrogen overflow and its mechanism of application in hydrogenation reactions. A confined sulfidation coupled in-situ intercalation strategy allows for controllable adjustment of the catalyst's morphology, chemical composition, and other physicochemical properties, influencing its hydrogenation activity and pathway selectivity. This influence is mainly attributed to the control exerted by the intercalated molecules on the active phase content and the number of stacking layers, resulting in a high level of multiphase synergistic effect in the catalyst. Detailed Implementation

[0045] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, but the scope of protection of the present invention is not limited to the embodiments.

[0046] In the following examples, unless otherwise specified, the materials and reagents used are all commercially available products commonly used in the field, and the methods and operations used are all conventional technical means in the field.

[0047] A yolk-shell structured hydrodesulfurization catalyst based on hydrogen overflow is disclosed, comprising a core phase and a shell phase. The core phase is NiS2, and the shell phase is NiMoS (Ni-MoS2), wherein Ni accounts for 10-30 wt.% by mass, Mo accounts for 10-40 wt.% by mass, NiMoS accounts for 20-90% of the total Ni species content of the catalyst, and the Mo sulfidation degree (Mo...) is... sulfidation The percentage of MoS2 is 40-80%. The MoS2 mainly exists as the 1T phase, with an average length of 0-6 nm and an average number of stacking layers of 1-5. Based on the total number of stacking layers, the proportion of layers with 2-3 layers is 40-70%, preferably 40-70%.

[0048] Example 1

[0049] (1) Dissolve 145 mg of nickel nitrate hexahydrate in a mixed solution of 7.50 mL of glycerol and 52.5 mL of isopropanol, add 1 mL of deionized water, stir at 800 rpm for 40 min, then transfer the solution to a 200 °C reactor and maintain for 10 h. After cooling to room temperature, centrifuge to collect the product, obtaining a solid spherical nickel composite precursor.

[0050] (2) First, 0.050 g of the nickel composite precursor was ultrasonically dispersed in 10 mL of ethanol to obtain a homogeneous solution. Next, 15 mL of an ethanol solution of thioacetamide (0.244 g) was added, and the mixture was stirred for 20 min. Then, 15 mL of an aqueous solution of ammonium heptamolybdate (0.143 g) was added, and the mixture was stirred for 10 min. The mixed solution was transferred to a reactor and reacted at 200 °C for 5 h. The black precipitate was collected by centrifugation to obtain the yolk-shell structured catalyst YS-Cat-5h.

[0051] Example 2

[0052] (1) Dissolve 145 mg of nickel nitrate hexahydrate in a mixed solution of 7.50 mL of glycerol and 52.5 mL of isopropanol, add 1 mL of deionized water, stir at 800 rpm for 40 min, then transfer the solution to a 200 °C reactor and maintain for 10 h. After cooling to room temperature, centrifuge to collect the product, obtaining a solid spherical nickel composite precursor.

[0053] (2) First, 0.050 g of nickel composite precursor was ultrasonically dispersed in 10 mL of ethanol to obtain a homogeneous solution. Next, 15 mL of an ethanol solution of thioacetamide (0.244 g) was added and stirred for 20 min. The mixed solution was transferred to a reactor and reacted at 200 °C for 5 h. The black precipitate was collected by centrifugation to obtain the catalyst P-NiS2.

[0054] Example 3

[0055] 0.143 g of ammonium heptamolybdate was ultrasonically dispersed in 10 mL of deionized water to obtain a homogeneous solution. 15 mL of an ethanol solution of 0.244 g of thioacetamide was added, and the mixture was stirred for 20 min. The mixture was then transferred to a reactor and reacted at 200 °C for 5 h. The black precipitate was collected by centrifugation to obtain the catalyst P-MoS2.

[0056] Example 4

[0057] Equimolar amounts of P-MoS2 and P-NiS2 were mechanically ground to obtain the catalyst MM-NiS2 / MoS2.

[0058] Example 5

[0059] This example provides a method for preparing a hollow-structured phase hydrodesulfurization catalyst, including the outer shell of the catalyst prepared in Example 1.

[0060] (1) Dissolve 0.080 g of molybdenum acetylacetonate and 0.080 g of nickel nitrate hexahydrate in a mixed solution of 7.50 mL of glycerol and 52.5 mL of isopropanol, and add 1 mL of deionized water. Stir at 800 rpm for 40 min, then transfer the solution to a 200 °C reactor and maintain for 10 h. After cooling to room temperature, centrifuge to collect the product, obtaining a solid spherical nickel-molybdenum composite precursor.

[0061] (2) First, 0.050 g of the nickel-molybdenum composite precursor was ultrasonically dispersed in 10 mL of ethanol to obtain a homogeneous solution. Next, 15 mL of an ethanol solution of thioacetamide (0.244 g) was added, and the mixture was stirred for 20 min. Then, 15 mL of an aqueous solution of ammonium heptamolybdate (0.143 g) was added, and the mixture was stirred for 10 min. The mixed solution was transferred to a reactor and reacted at 200 °C for 5 h. The black precipitate was collected by centrifugation to obtain the hollow catalyst H-Cat.

[0062] Comparative Example 1

[0063] The synthesis process is basically the same as in Example 1, except that the reaction time in the reactor described in step (2) is changed to 2h, and the other conditions are the same as in Example 1, to obtain catalyst YS-Cat-2h.

[0064] Comparative Example 2

[0065] The synthesis process is basically the same as in Example 1, except that the reaction time in the reactor described in step (2) is changed to 4h, and the other conditions are the same as in Example 1, to obtain catalyst YS-Cat-4h.

[0066] Comparative Example 3

[0067] The synthesis process is basically the same as in Example 1, except that the reaction time in the reactor described in step (2) is changed to 6h, and the other conditions are the same as in Example 1, to obtain catalyst YS-Cat-6h.

[0068] Comparative Example 4

[0069] The synthesis process is basically the same as in Example 1, except that the reaction time in the reactor described in step (2) is changed to 8h, and the other conditions are the same as in Example 1, to obtain catalyst YS-Cat-8h.

[0070] Table 1. XPS data of the catalysts prepared in the examples and comparative examples.

[0071]

[0072] a :Mo sulfidation % = Mo 4+ Area%÷(Mo) 4+ Area%+Mo 5+Area%+Mo 6+ Area%

[0073] b :[NiMoS]%=NiMoS Area%÷(Ni x S y Area% + NiMoS Area% + Ni 2+ Area%

[0074] Table 2. Elemental analysis results of the catalysts prepared in the examples and comparative examples.

[0075]

[0076] Application Example 1

[0077] The performance of each catalyst was evaluated using a decane solution of DBT with a sulfur content of 500 ppm as a simulated oil. The hydrodesulfurization of DBT was carried out in a 100 mL batch reactor at a reaction pressure of 6 MPa, a reaction temperature of 300 °C, a reaction time of 4 h, a catalyst dosage of 50 mg, and a reaction liquid volume of 30 mL. The evaluation results of each catalyst are shown in Table 3.

[0078] Table 3. HDS activity and product distribution of catalysts for DBT in different embodiments.

[0079]

[0080]

[0081] a Measurements were taken when the DBT conversion rate was approximately 50%.

[0082] Application Example 2

[0083] The performance of each catalyst was evaluated using a n-decane solution of 4,6-DMDBT with a sulfur content of 500 ppm as a simulated oil. Hydrodesulfurization of 4,6-DMDBT was carried out in a 100 mL batch reactor at a reaction pressure of 6 MPa, a reaction temperature of 300 °C, a reaction time of 4 h, a catalyst dosage of 50 mg, and a reaction liquid volume of 30 mL. The evaluation results of each catalyst are shown in Tables 4 and 5.

[0084] Table 4. HDS activity and product distribution of catalysts for 4,6-DMDBT in different embodiments.

[0085]

[0086] a Measurements were taken when the 4,6-DMDBT conversion was approximately 50%.

[0087] Table 5. HDS activity and product distribution of different comparative catalysts for 4,6-DMDBT.

[0088]

[0089] As shown in the table above, the HDS activity and HYD selectivity of catalyst YS-Cat-5h are significantly higher than those of other catalysts. This is because the slow release of glycerol under the Ostawald ripening effect leads to increased solvent resistance during sulfidation, which restricts the growth of MoS2 due to mass transfer limitations. TAA, with its strong reducing properties, can induce more MoS2 nuclei, ultimately resulting in shorter MoS2 nanosheets with fewer stacked layers, thus generating more "rim" sites. The benzene ring in the 4,6-DMDBT molecule can be adsorbed onto the active center through planar adsorption, thereby promoting the HYD reaction. Furthermore, the yolk-shell structure constructed at the nanoscale exhibits a hydrogen spillover effect. The core NiS2 can act as an additional active site to activate hydrogen and spill over to the outer NiMoS phase. Electron-rich 1T-MoS2 can assist in the transfer of active hydrogen, promoting the hydrogen spillover effect. Therefore, ultra-deep hydrodesulfurization of oil products is achieved through multiphase synergy.

[0090] The above embodiments are only used to help understand the core ideas and methods of this application. For those skilled in the art, appropriate modifications can be made to this application without departing from the premises and working principles, and these modifications also fall within the scope of protection of the claims of this application.

Claims

1. A yolk-shell structured bulk phase hydrodesulfurization catalyst based on hydrogen overflow, characterized in that: The catalyst consists of an internal core phase and an external shell layer. The internal core phase is a NiS2 phase, and the external shell layer is a NiMoS phase, specifically Ni-MoS2. The shell layer thickness is no more than 1 / 3 of the catalyst radius. In the shell layer, MoS2 exists stably as a 1T phase. Glycerol is used to increase the interlayer spacing of MoS2 and controllably generate small-scale MoS2 with an average length of 0-6 nm (not zero). The average number of stacked layers is 1-5, with 40-70% having 2-3 layers. Based on the total number of stacked layers, the mass percentage of Ni is 10-30 wt.%, the mass percentage of Mo is 10-40 wt.%, NiMoS accounts for 20-90% of the total Ni species content, and the Mo sulfidation degree (Mo...) is... sulfidation The percentage is 40-80%.

2. A method for preparing a yolk-shell structured bulk phase hydrodesulfurization catalyst based on hydrogen overflow as described in claim 1, characterized in that, Includes the following steps: S1: Mix glycerol, isopropanol and deionized water in a certain proportion and add nickel nitrate hexahydrate. Stir to obtain a green transparent solution. S2: The solution obtained in the solvothermal reaction step S1 yields a solid spherical nickel composite precursor; S3: Mix the nickel composite precursor obtained in step S2 with the ethanol solution of thioacetamide and stir until homogeneous. Add an aqueous solution of ammonium heptamolybdate to obtain a suspension. S4: The suspension obtained in step S3 is subjected to a solvothermal reaction and then washed and dried to obtain an egg yolk-shell structure catalyst; Alternatively, the preparation steps may include the following: S1: Mix glycerol, isopropanol and deionized water in a certain proportion, add nickel nitrate hexahydrate and molybdenum acetylacetonate, and stir to obtain a transparent solution; S2: The solution obtained in the solvothermal reaction step S1 yields a solid spherical nickel-molybdenum composite precursor; S3: Mix the nickel-molybdenum composite precursor obtained in step S2 with the ethanol solution of thioacetamide and stir until homogeneous. Add an aqueous solution of ammonium heptamolybdate to obtain a suspension. S4: The suspension obtained in step S3 is subjected to a solvothermal reaction and then washed and dried to obtain a hollow structure catalyst.

3. The method for preparing a yolk-shell structured hydrodesulfurization catalyst based on hydrogen overflow according to claim 2, characterized in that, In step S1, the feeding ratio of glycerol, isopropanol and deionized water is 5-9 mL: 45-60 mL: 0-2 mL, and the amount of deionized water is not 0; the mass ratio of nickel nitrate hexahydrate and molybdenum acetylacetonate is 0.06-0.1 g: 0-0.1 g.

4. The preparation method of the yolk-shell structure phase hydrodesulfurization catalyst based on hydrogen overflow according to claim 2, characterized in that, In step S2, the temperature of the solvothermal reaction is 180-220 °C, and the time is 8-12 h.

5. The preparation method of the yolk-shell structured bulk phase hydrodesulfurization catalyst based on hydrogen overflow according to claim 2, characterized in that, In step S3, the mass ratio of nickel composite precursor / nickel-molybdenum composite precursor, thioacetamide, and ammonium heptamolybdate is 0-0.05 g: 0.14-0.35 g: 0-0.25 g, and the mass of the nickel composite precursor / nickel-molybdenum composite precursor and ammonium heptamolybdate is not 0.

6. The preparation method of the yolk-shell structure phase hydrodesulfurization catalyst based on hydrogen overflow according to claim 2, characterized in that, In step S4, the temperature of the solvothermal reaction is 180-220 ℃ and the time is 2-8 h; or a two-step heating method: the first step is 100-150 ℃ and held for 0-3 h with a time not of 0, and the second step is 180-220 ℃ and held for 2-8 h.

7. The application of the catalyst as described in claim 1 in hydrodesulfurization.

8. The application according to claim 7, characterized in that, The yolk-shell structured bulk catalyst is used for the hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene at a temperature of 220-300 °C and a pressure of 4-6.5 MPa.

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