Ni-mo-ce magnesia-alumina spinel catalyst, its preparation method and application

Abstract

This invention provides a Ni-Mo-Ce magnesium aluminum spinel catalyst, its preparation method, and its applications, relating to the field of catalytic reforming for hydrogen production from hydrocarbon fuels. The Ni-Mo-Ce magnesium aluminum spinel catalyst of this invention comprises a MgAl2O4 spinel support and CeO2, Ni, and Mo supported on the MgAl2O4 spinel support; wherein the mass fraction of Ni is 5-20 wt.%, the mass fraction of Mo is 0.5-5 wt.%, the mass fraction of CeO2 is 3-20 wt.%, and the balance is the MgAl2O4 spinel support. This invention constructs a Ni-Mo-Ce magnesium aluminum spinel composite catalyst system by loading CeO2 onto the MgAl2O4 spinel support and further introducing Ni and Mo components. This achieves synergistic regulation among stable dispersion of Ni active sites, preferential capture and migration conversion of sulfur species, and surface carbon oxidation removal, showing promising application prospects in on-site reforming for hydrogen production from sulfur-containing liquid hydrocarbon fuels, mobile hydrogen supply systems, and fuel cell hydrogen supply devices.

Description

Technical Field

[0001] This invention relates to the field of catalytic reforming of hydrocarbon fuels for hydrogen production, and particularly to a Ni-Mo-Ce magnesium aluminum spinel catalyst, its preparation method, and its application. Background Technology

[0002] With the development of on-site hydrogen supply applications such as distributed energy systems, portable power supply devices, and solid oxide fuel cells, reforming hydrogen production technology using liquid hydrocarbon fuels as the hydrogen source carrier has attracted increasing attention. Compared with high-pressure hydrogen storage, liquid hydrocarbon fuels have advantages such as high energy density, mature storage and transportation systems, good safety, and strong compatibility with existing fuel infrastructure, making them suitable for mobile energy supply and distributed hydrogen production scenarios. However, liquid hydrocarbon fuels, especially long-chain alkane fuels, typically involve multiple reaction steps in steam reforming, including adsorption activation, CH bond breaking, C / C bond cracking, intermediate conversion, and water-gas shift reaction. The reaction pathway is complex, and under high-temperature conditions, deep cracking, dehydrogenation, and polymerization reactions can easily occur, resulting in carbon deposits such as filamentous carbon, amorphous carbon, or graphitized carbon, which can cause catalyst active site shielding, pore blockage, and reaction performance degradation.

[0003] Ni-based catalysts, due to their low cost, abundant resources, and high activity in hydrocarbon reforming, have become a promising non-precious metal catalyst system for hydrogen production from liquid hydrocarbon fuels. However, in actual liquid fuel reforming processes, Ni-based catalysts still suffer from problems such as high-temperature sintering, sulfur poisoning, and carbon deposition deactivation. On the one hand, Ni metal particles tend to migrate and grow in the high-temperature steam reforming environment, leading to reduced metal dispersion and fewer effective active sites. On the other hand, diesel, aviation kerosene, biodiesel, or their model fuels often contain ppm-level sulfur impurities. These sulfur impurities can be converted into H2S or other sulfur-containing intermediates under reforming conditions and interact strongly with Ni active sites, forming a stable sulfide capping layer, thereby inhibiting the adsorption and activation of hydrocarbon fuels and steam on the catalyst surface. Furthermore, the presence of sulfur species may alter surface reaction pathways, promoting carbon deposition and further exacerbating catalyst deactivation.

[0004] Currently, to improve the stability of Ni-based catalysts in the reforming process of sulfur-containing liquid hydrocarbon fuels, methods such as noble metal modification, introduction of a second metal additive, regulation of support structure, or pre-desulfurization of fuel are commonly employed. While noble metal modification can improve sulfur resistance, its high material cost hinders large-scale application. Pre-desulfurization of fuel increases system complexity, equipment size, and operating costs. Simply relying on conventional supports to improve metal dispersion is insufficient to simultaneously address the issues of stable sulfur species coverage and continuous carbon deposition. Therefore, achieving synergistic regulation of sulfur capture, sulfur migration and conversion, stable metal particle dispersion, and carbon deposition inhibition while maintaining the low cost and high reforming activity of Ni-based catalysts is a pressing technical challenge in the field of steam reforming hydrogen production from sulfur-containing liquid hydrocarbon fuels.

[0005] MgAl2O4 spinel supports possess high thermal stability, mechanical stability, and metal anchoring ability, which is beneficial for inhibiting the sintering of Ni metal particles under high-temperature conditions. However, their ability to inhibit the migration, transformation, and carbon deposition oxidation of sulfur species is limited. Mo components have a strong affinity for sulfur and can preferentially interact with sulfur species in sulfur-containing reaction environments, thus delaying the poisoning of Ni active sites by sulfur species to some extent. CeO2 has oxygen storage and release capabilities, and its surface Ce... 3+ / Ce 4+ Reversible oxidation and oxygen vacancy structures facilitate the activation of water molecules, surface oxygen migration, and the oxidative removal of carbon species.

[0006] However, introducing Mo or CeO2 alone is still insufficient to simultaneously achieve sulfur capture, sulfur desorption conversion, and carbon deposition inhibition. Therefore, it is necessary to construct a Ni-based composite catalyst system that combines a stable support, a sulfur-regulating component, and a redox aid to improve the long-term stability of the catalyst in the steam reforming process of sulfur-containing liquid hydrocarbon fuels. Summary of the Invention

[0007] In view of this, the present invention provides a Ni-Mo-Ce magnesium aluminum spinel catalyst, its preparation method, and its applications. The present invention constructs a Ni-Mo-Ce magnesium aluminum spinel composite catalyst system by loading CeO2 onto a MgAl2O4 spinel support and further introducing Ni and Mo components. This achieves synergistic regulation among stable dispersion of Ni active sites, preferential capture and migration conversion of sulfur species, and surface carbon oxidation removal. It shows promising application prospects in on-site reforming of sulfur-containing liquid hydrocarbon fuels for hydrogen production, mobile hydrogen supply systems, and fuel cell hydrogen supply devices.

[0008] The first aspect of the present invention provides a Ni-Mo-Ce magnesium aluminum spinel catalyst, comprising a MgAl2O4 spinel support and CeO2, Ni and Mo supported on the MgAl2O4 spinel support; The composition includes 5-20 wt.% Ni, 0.5-5 wt.% Mo, 3-20 wt.% CeO2, and the balance is MgAl2O4 spinel support.

[0009] Preferably, in the Ni-Mo-Ce magnesium aluminum spinel catalyst, the mass fraction of Ni is 8~12 wt.%, the mass fraction of Mo is 1~3 wt.%, and the mass fraction of CeO2 is 8~12 wt.%.

[0010] Preferably, in the Ni-Mo-Ce magnesium aluminum spinel catalyst, the mass fraction of Ni is 10 wt.%, the mass fraction of Mo is 2 wt.%, the mass fraction of CeO2 is 10 wt.%, and the balance is MgAl2O4 spinel support.

[0011] Preferably, the MgAl2O4 spinel support has a lamellar or layered aggregate structure, CeO2 is dispersed on the surface of the MgAl2O4 spinel support, and the reduced catalysts Ni and Mo are distributed on the surface of the support in a metallic state, an oxidized state, or both.

[0012] A second aspect of the present invention provides a method for preparing the Ni-Mo-Ce magnesium aluminum spinel catalyst, comprising the following steps: S1. Magnesium salt, aluminum salt and complexing agent are added to solvent and mixed to obtain precursor solution; the precursor solution is heated to form gel; the gel is dried and calcined to obtain MgAl2O4 spinel support; S2. The cerium salt solution is impregnated onto the MgAl2O4 spinel support, and after drying and calcination, a CeO2-MgAl2O4 composite support is obtained. S3. Impregnate the CeO2-MgAl2O4 composite support with nickel salt and molybdenum salt solutions, and obtain the catalyst precursor after drying and calcination; S4. The catalyst precursor is reduced in a hydrogen-containing atmosphere to obtain the Ni-Mo-Ce magnesium aluminum spinel catalyst.

[0013] Preferably, in step S1, the magnesium salt is magnesium nitrate, the aluminum salt is aluminum nitrate, and the complexing agent is citric acid; the molar ratio of Mg, Al, and citric acid is 1:2:4.5; the pH of the precursor solution is adjusted to 8; the precursor solution is heated in a water bath at 80°C to form a gel; the drying temperature is 220°C, and the drying time is 4 h; the calcination temperature is 800°C, and the calcination time is 5 h.

[0014] Preferably, in step S2, the cerium salt is cerium nitrate, the impregnation is an equal-volume impregnation, and the theoretical CeO2 loading is 3~20 wt.%; after impregnation, it is ultrasonicated at room temperature, then evaporated at 80℃, dried at 120℃, and then heated to 700℃ at 5℃ / min in air and held for 4 h. The theoretical loading is calculated based on the precursor feed amount, and the actual loading can be determined by ICP-OES.

[0015] Preferably, in step S3, the nickel salt is nickel nitrate and the molybdenum salt is ammonium molybdate; the impregnation is co-impregnation with equal volume; the theoretical Ni loading is 5~20 wt.% and the theoretical Mo loading is 0.5~5 wt.%; after impregnation, the mixture is ultrasonicated at room temperature, then the solvent is evaporated at 80°C, dried at 120°C, and then heated to 700°C at 5°C / min in air and held for 4 hours.

[0016] Preferably, in step S4, the hydrogen-containing atmosphere is H2 / N2, H2 / Ar, or H2 / He; the reduction temperature is 800℃, and the reduction time is 2 h.

[0017] The third aspect of the present invention provides the application of the Ni-Mo-Ce magnesium aluminum spinel catalyst in the steam reforming of sulfur-containing liquid hydrocarbon fuels to produce hydrogen.

[0018] Preferably, the sulfur-containing liquid hydrocarbon fuel includes C 10 ~C 20 Alkanes, diesel fuel, aviation kerosene, biodiesel, or model compounds thereof; the sulfur content of the sulfur-containing liquid hydrocarbon fuel is 10-200 ppm; the reaction temperature is 650-850℃; the water-to-carbon molar ratio is 2-5; and the liquid hourly space velocity is 5 mL·g. -1 ·h -1 .

[0019] Preferably, the sulfur-containing liquid hydrocarbon fuel is thiophene-containing n-hexadecane with a sulfur content of 50 ppm; the reaction temperature is 750°C; the water-to-carbon molar ratio is 3.0; and the liquid hourly space velocity is 5 mL·g. -1 ·h -1 .

[0020] Preferably, the Ni-Mo-Ce magnesium aluminum spinel catalyst can reduce the stable retention ratio of sulfur species on the catalyst surface and inhibit the formation of graphitized carbon deposits during the steam reforming of sulfur-containing liquid hydrocarbon fuels.

[0021] Compared with the prior art, the beneficial technical effects of the present invention are as follows: The Ni-Mo-Ce magnesium aluminum spinel catalyst provided by this invention uses MgAl2O4 spinel as a support, Ni as the main reforming active component, Mo as a sulfur capture and regulation aid, and CeO2 as a redox aid. This allows the catalyst to simultaneously exert metal dispersion stabilization, sulfur species regulation, and carbon deposition inhibition effects during the steam reforming of sulfur-containing liquid hydrocarbon fuels. The MgAl2O4 spinel support enhances the anchoring effect on Ni species, reducing the risk of Ni particle migration, agglomeration, and sintering during high-temperature reactions, thereby maintaining the number of effective active sites and the reforming reaction activity of the catalyst.

[0022] This invention introduces a Mo component to create preferential sites for capturing sulfur species on the catalyst surface, reducing the probability of sulfur species directly and continuously covering Ni active sites, thereby delaying the sulfur poisoning process at Ni active centers. The Mo component does not exist alone as an inert sulfur storage component, but rather participates in the regulation of surface sulfur behavior under sulfur-containing reaction environments together with the Ni active component and CeO2 redox component, making it easier for sulfur species to migrate, transform, or be removed, thus reducing the proportion of sulfur species stably retained on the catalyst surface.

[0023] This invention introduces CeO2 onto a MgAl2O4 spinel support, thereby increasing the oxygen vacancy concentration and redox cycle capacity of the catalyst surface. This promotes water vapor activation, surface reactive oxygen migration, and the oxidative removal of carbon species, thus inhibiting the excessive formation of graphitized and fibrous carbon deposits. The introduction of CeO2 also improves the catalyst's reducibility and forms a synergistic effect with the Mo component in sulfur capture, sulfur migration and conversion, and carbon deposit oxidation, enabling the catalyst to exhibit both good sulfur resistance and carbon deposition resistance under sulfur-containing liquid hydrocarbon fuel reforming conditions.

[0024] The catalyst described in this invention can reduce the continuous poisoning effect of sulfur species on Ni active sites during steam reforming of sulfur-containing liquid hydrocarbon fuels, decrease graphitization and carbon deposition, and extend the catalyst's stable operating time. Especially in the steam reforming reaction of sulfur-containing n-hexadecane model fuel, the Ni-Mo-Ce magnesium aluminum spinel catalyst exhibits a longer stable operating time and lower carbon deposition level compared to the Ni / MgAl catalyst without the introduction of Mo and CeO2. This demonstrates that this invention can effectively solve the problems of easy sulfur poisoning, easy carbon deposition, and insufficient long-term stability of traditional Ni-based catalysts in the reforming of sulfur-containing liquid hydrocarbon fuels, and has good practical application value. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] Figure 1 The figures show the fuel conversion rate versus reaction time of the catalysts in the sulfur-containing n-hexadecane steam reforming reaction of the present invention (examples and comparative examples). Figure 2 The following are the H2-TPR characterization results of the catalysts in the embodiments and comparative examples of the present invention, wherein, Figure 2 (a) shows the H2-TPR curves for different catalysts. Figure 2 (b) is a comparison of the reduction peak temperature and hydrogen consumption of different catalysts; Figure 3 The above are the Ni 2p XPS spectra of the catalysts in the embodiments and comparative examples of this invention after reduction treatment; Figure 4 The images show the microstructure of the catalysts in the embodiments and comparative examples of the present invention after the steam reforming reaction of sulfur-containing n-hexadecane, including TEM and SEM images of the catalysts after the reaction. Figure 5 The thermogravimetric analysis (TGA) diagrams of the catalysts in the embodiments and comparative examples of this invention after the sulfur-containing n-hexadecane steam reforming reaction are shown. The TG samples are not the end-of-life samples; some samples continued to run for a period of time after the test deactivation. Figure 6 The above are the Raman spectra of the catalysts in the embodiments and comparative examples of the present invention after the sulfur-containing n-hexadecane steam reforming reaction. Figure 7 Electron paramagnetic resonance (EPR) spectra of MgAl2O4 spinel support and CeO2-MgAl2O4 composite support; Figure 8 This is a graph showing the comparison of residual sulfur content, sulfur absorption rate, and sulfur absorption rate in the catalysts of the embodiments and comparative examples of the present invention after the steam reforming reaction of sulfur-containing n-hexadecane. Figure 9 The 3d XPS spectra of Mo and Mo in NiMo / MgAl catalyst before and after the sulfur-containing n-hexadecane steam reforming reaction are shown. 0 Mo 4+ Mo 6+ Relative content change graph; Figure 10 Ce 3d XPS spectra and Ce 3d XPS spectra of Ni / Ce-MgAl catalyst before and after the sulfur-containing n-hexadecane steam reforming reaction. 4+ Ce 3+ Relative content change graph; Figure 11 XPS spectra of Mo 3d and Ce 3d in the NiMo / Ce-MgAl catalyst before and after the sulfur-containing n-hexadecane steam reforming reaction, and Mo 0 Mo 4+ Mo 6+ and Ce 4+ Ce 3+ Relative content change graph; Figure 12The curves showing the change in fuel conversion rate with reaction time during the n-hexadecane steam reforming reaction using NiMo / Ce-MgAl catalyst under different sulfur content fuel conditions. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise specified, all experiments were repeated three times, and the results are expressed as averages.

[0029] Example 1: A method for preparing a NiMo / Ce-MgAl catalyst, the steps of which are as follows: Preparation of S1 and MgAl2O4 spinel support: MgAl2O4 spinel support was prepared by sol-gel method. Mg(NO3)2·6H2O and Al(NO3)3·9H2O were weighed according to the molar ratio of Mg:Al=1:2 and dissolved in an appropriate amount of deionized water to form a mixed metal salt solution. Then, citric acid was added as a complexing agent according to the molar ratio of Mg(NO3)2·6H2O, Al(NO3)3·9H2O:citric acid=1:2:4.5. The system was continuously magnetically stirred at room temperature to ensure complete complexation. The pH of the solution was adjusted to 8 with ammonia water. The resulting mixed solution was then placed in an 80℃ water bath and continuously stirred and heated. As the solvent evaporated, the system gradually transformed into a homogeneous gel. The resulting gel was dried at 220℃ for 4 h. After drying, the obtained precursor was placed in a muffle furnace and calcined at 800℃ for 5 h in air atmosphere at a heating rate of 5℃ / min. After natural cooling to room temperature, the MgAl2O4 spinel support was obtained by grinding. Preparation of S2 and Ce-MgAl composite support: Weigh the MgAl2O4 spinel support obtained from S1, prepare a Ce(NO3)3·6H2O aqueous solution, load Ce using the equal volume impregnation method, control the theoretical CeO2 loading to be 10 wt.%, and sonicate at room temperature for 30 min after impregnation; then evaporate to dryness at 80℃, dry at 120℃ for 4 h, and then calcine in air atmosphere under the following conditions: heat up to 700℃ at 5℃ / min, hold for 4 h to obtain the Ce modified support, denoted as Ce-MgAl; Preparation of S3, NiMo / Ce-MgAl catalyst precursors: Preparation of Ni(NO3)2·6H2O and (NH4)6Mo7O 24A mixed impregnation solution of 4H₂O was used, with the theoretical metal loading controlled as follows: Ni 10 wt.% and Mo 2 wt.%. Ni and Mo were simultaneously loaded onto the Ce-MgAl support surface using an equal-volume co-impregnation method. After ultrasonication at room temperature for 30 min, the solvent was evaporated at 80℃. The resulting solid was dried at 120℃ for 4 h and then calcined in air. The calcination procedure was as follows: heating to 700℃ at a rate of 5℃ / min, holding at that temperature for 4 h, and cooling to obtain the catalyst precursor, denoted as NiMo / Ce-MgAl. S4. Catalyst Formation: Weigh a certain amount of catalyst sample, compress it into tablets, crush it, and then pass it through 60-mesh and 100-mesh sieves. Take a sample with a particle size of about 200 μm for reaction testing. S5. In-situ reduction of catalyst: Before the catalyst reaction test, in-situ reduction is carried out. The catalyst and quartz sand are thoroughly mixed and then packed into a quartz fixed-bed reactor. The mass ratio of catalyst to quartz sand is 1:3. Activation is carried out under a reducing atmosphere. The reducing gas is 10 vol.% H2 / N2, and the gas flow rate is controlled at 30 mL / min. The temperature is increased to 800℃ at 5℃ / min and kept at this temperature for 2 h. Then, it is switched to the reaction system.

[0030] Comparative Example 1 The difference from Example 1 is that step S2 in Example 1 is omitted, and CeO2 loading is not performed; in step S3 of Example 1, the MgAl2O4 spinel support obtained in S1 is used as the support, and Ni is loaded only with Ni(NO3)2·6H2O impregnation solution, without adding (NH4)6Mo7O. 24 Ni / MgAl catalyst was obtained by controlling the theoretical Ni loading to 10 wt.% using ·4H2O.

[0031] The remaining preparation conditions, calcination conditions, molding conditions, and in-situ reduction conditions are the same as in Example 1.

[0032] Comparative Example 2 The difference from Example 1 is that step S2 in Example 1 is omitted, and CeO2 loading is not performed; in step S3 of Example 1, the MgAl2O4 spinel support obtained in S1 is used as the support, and Ni(NO3)2·6H2O and (NH4)6Mo7O are used. 24 Ni and Mo were simultaneously loaded into a 4H2O mixed impregnation solution, with the theoretical Ni loading at 10 wt.% and the theoretical Mo loading at 2 wt.%, to obtain a NiMo / MgAl catalyst.

[0033] The remaining preparation conditions, calcination conditions, molding conditions, and in-situ reduction conditions are the same as in Example 1.

[0034] Comparative Example 3 The difference from Example 1 is that in step S3 of Example 1, only Ni(NO3)2·6H2O impregnation solution is used to load Ni, and (NH4)6Mo7O is not added. 24 Ni / Ce-MgAl catalyst was obtained by controlling the theoretical Ni loading to 10 wt.% using ·4H2O.

[0035] The remaining preparation conditions, calcination conditions, molding conditions, and in-situ reduction conditions are the same as in Example 1.

[0036] Test Example 1: Performance Test of Sulfur-Containing n-Hexadecane Steam Reforming The catalysts obtained in Example 1 and Comparative Examples 1-3 were tested for their sulfur-containing n-hexadecane steam reforming performance. The reforming performance evaluation was conducted in a fixed-bed continuous flow reactor. The model fuel was n-hexadecane, and the sulfur source was thiophene. The sulfur content in the fuel was adjusted to wS = 50 ppm, and a high-precision injection pump was used to deliver the liquid fuel and water. The reaction conditions were controlled as follows: reaction temperature 750℃, water-to-carbon ratio (S / C) 3.0, and liquid hourly space velocity (LHSV) 5 mL·g. -1 ·h -1 .

[0037] The gaseous products generated during the reaction are condensed and dehydrated before being analyzed by an online gas chromatograph. The concentrations of H2, CO, CO2, CH4, C2H4, and C2H6 are recorded, and the fuel conversion rate and stable operating life are calculated. The criterion for stable operating life is that the conversion rate remains consistently above 80%.

[0038] The yield calculation formula is as follows: Where: FH2 is the hydrogen volumetric flow rate, n C16H34 V is the molar flow rate of hexadecane. m This represents the molar volume of the gas.

[0039] The test results are shown in Table 1.

[0040] Table 1. Catalyst lifespan, average hydrogen yield, carbon deposit content, and sulfur content under conditions of fuel containing 50 ppm sulfur.

[0041] The results showed that the stable operating time of Ni / MgAl was approximately 24 h, while that of NiMo / Ce-MgAl reached approximately 90 h, indicating that the synergistic introduction of Mo and Ce significantly improved the long-term stability of the catalysts during the reforming process of sulfur-containing liquid hydrocarbon fuels. Further analysis revealed that the main components of the reformate gas showed little difference among the four catalysts during the stable operating phase: H2 volume fraction remained at approximately 70 vol.%, CO at approximately 12 vol.%, CO2 at approximately 17 vol.%, and CH4 concentration remained at a low level. This suggests that the catalyst deactivation behavior mainly stemmed from differences in sulfur poisoning and carbon deposition, rather than differences in initial reforming activity.

[0042] Test Example 2: H2-TPR and Ni 2p XPS Analysis H2-TPR analysis was performed on the catalysts obtained in Example 1 and Comparative Examples 1-3, and the results are as follows: Figure 2 As shown, the Ni / MgAl catalyst exhibits a significant reduction peak in the low-temperature region, indicating the presence of some weakly bound Ni species within the catalyst. After Mo modification, the reduction peak position shifts, and combined with 2p XPS analysis of the reduced Ni, it can be found that the Ni in the Mo-doped sample... 0 The binding energy decreased from 853.2 eV to 852.4 eV, indicating that the addition of Mo promoted the formation of the NiMo bimetallic alloy structure.

[0043] For Ce-containing systems, two broad, weak reduction peaks appear in the 150–450 °C range, corresponding to the reduction of surface oxygen species and Ce4, respectively. + To Ce 3+ The conversion process. Simultaneously, the overall hydrogen consumption of the Ce-modified catalyst increased, indicating that CeO2 can promote metal region reduction. NiMo / Ce-MgAl combines the dual advantages of Mo promoting electronic regulation and Ce promoting reducibility, thus exhibiting superior reduction characteristics.

[0044] Test Example 3: Microscopic Morphology Analysis After Long-Term Testing The catalyst was characterized by TEM and SEM after long-term testing, and the results are as follows: Figure 4 As shown, all catalysts exhibited varying degrees of carbon deposition, with a dense graphite fiber network forming on the Ni / MgAl surface, indicating significant carbon buildup. In contrast, only a small amount of fibrous carbon deposition was observed on the NiMo / Ce-MgAl surface, while Ni nanoparticles were still visible at the catalyst edges. No significant particle growth was observed compared to fresh catalysts, indicating that the catalysts of this invention possess good resistance to sintering.

[0045] Test Example 4: TG and Raman Analysis TG and Raman analyses were performed on the deactivated catalyst, and the results are as follows: Figure 5 and Figure 6As shown, all samples exhibited significant weight loss peaks in the 600–700 °C range, corresponding to the carbon deposition oxidation process. Among them, the Ce-containing catalyst showed an additional low-temperature weight loss stage in the 300–600 °C range, indicating the presence of more easily oxidized amorphous carbon on the catalyst surface. NiMo / MgAl showed the highest weight loss ratio, approximately 57 wt.%, while Ni / Ce-MgAl showed the lowest carbon deposition level, approximately 30 wt.%. Despite undergoing a longer reaction cycle, the Ce-modified catalyst still exhibited significantly lower carbon deposition than the undoped Ce system, further demonstrating that CeO2 can effectively suppress carbon deposition during the reforming process of liquid hydrocarbon fuels.

[0046] In the Raman results, all samples exhibited typical D and G band characteristics, indicating that the carbon deposits are mainly composed of disordered carbon and graphitized carbon. Combined with the TG results, it can be seen that the unmodified system formed more severe graphite fiber carbon deposits, while the Ce-modified system showed a decrease in the degree of graphitization of carbon deposits, indicating that Ce promotes the formation of carbon species that are easier to oxidize and remove, thus exhibiting superior anti-carbon deposit ability.

[0047] Test Case 5 EPR Analysis The catalyst was subjected to EPR testing, and the results are as follows: Figure 7 As shown, the Ce-modified catalyst exhibits a significant oxygen vacancy signal, indicating that CeO2 successfully increased the oxygen vacancy concentration on the catalyst surface. The increase in oxygen vacancies promotes surface oxygen migration and water molecule activation, thereby enhancing the oxidation of carbon deposits and the conversion of sulfur-containing species. The NiMo / Ce-MgAl catalyst exhibits the strongest oxygen vacancy signal, indicating that the synergistic effect of Mo and Ce increases the active oxygen concentration on the catalyst surface.

[0048] Test Example 6: ICP-OES and XPS Sulfur Behavior Analysis ICP-OES and XPS analyses of the catalysts after the reaction revealed significantly different absorption behaviors for sulfur. The NiMo / Ce-MgAl catalyst exhibited the longest stable operating time but the lowest sulfur content, indicating that the catalyst of this invention does not achieve sulfur resistance through simple "sulfur storage," but rather through a synergistic mechanism of preferential sulfur capture by Mo and sulfur migration and oxidative removal by Ce, thereby reducing the surface stable sulfur coverage and significantly improving long-term sulfur resistance.

[0049] Figure 9 The XPS spectra of Mo 3d orbitals before and after the NiMo / MgAl catalyst test and the Mo 3d orbital spectra before and after the reaction are shown. 0 / Mo4 + / Mo 6+ Percentage; Figure 10 The XPS spectra of Ce 3d orbitals before and after the Ni / Ce-MgAl catalyst test and Ce 4 orbitals before and after the reaction are shown. + / Ce 3+ Percentage; Figure 11 The XPS spectra of Mo 3d and Ce 3d orbitals before and after the NiMo / Ce-MgAl catalyst test are shown, as well as the Mo 3d orbital spectra before and after the reaction. 0 / Mo4 + / Mo 6+ and Ce4 + / Ce 3+ The above results collectively demonstrate that Mo and CeO2 do not simply play a parallel role in the reforming of sulfur-containing liquid fuels, but rather exert a synergistic effect in sulfur capture, sulfur migration, redox cycle, and carbon deposition inhibition.

[0050] Example 2 The difference from Example 1 is that the theoretical loading of Ni is controlled to be 5 wt.%, the theoretical loading of Mo is 0.5 wt.%, and the theoretical loading of CeO2 is 3 wt.%, thus obtaining the NiMo / Ce-MgAl catalyst.

[0051] The remaining preparation conditions, calcination conditions, molding conditions, reduction conditions, and reaction testing conditions are the same as in Example 1.

[0052] The test results were as follows: stable operating life was 10 hours, average H2 yield was 68.5%, carbon deposit content was 20 wt.%, and residual sulfur content was 155.3 ppm.

[0053] Example 3 The difference from Example 1 is that the theoretical loading of Ni is controlled to be 20 wt.%, the theoretical loading of Mo is 5 wt.%, and the theoretical loading of CeO2 is 20 wt.%, thus obtaining the NiMo / Ce-MgAl catalyst.

[0054] The remaining preparation conditions, calcination conditions, molding conditions, reduction conditions, and reaction testing conditions are the same as in Example 1.

[0055] The test results are as follows: stable operating life is 50 h, average H2 yield is 77.4%, carbon deposit content is 59 wt.%, and residual sulfur content is 692.4 ppm.

[0056] Example 4 The difference from Example 1 is that the theoretical loading of Ni is controlled to be 8 wt.%, the theoretical loading of Mo is 1 wt.%, and the theoretical loading of CeO2 is 8 wt.%, thus obtaining the NiMo / Ce-MgAl catalyst.

[0057] The remaining preparation conditions, calcination conditions, molding conditions, reduction conditions, and reaction testing conditions are the same as in Example 1.

[0058] The test results are as follows: stable operating life is 75 h, average H2 yield is 79.2%, carbon deposit content is 41 wt.%, and residual sulfur content is 219.3 ppm.

[0059] Example 5 The difference from Example 1 is that the theoretical loading of Ni is controlled to be 12 wt.%, the theoretical loading of Mo is 3 wt.%, and the theoretical loading of CeO2 is 12 wt.%, thus obtaining the NiMo / Ce-MgAl catalyst.

[0060] The remaining preparation conditions, calcination conditions, molding conditions, reduction conditions, and reaction testing conditions are the same as in Example 1.

[0061] The test results were as follows: stable operating life was 68 h, average H2 yield was 82.1%, carbon content was 36 wt.%, and residual sulfur content was 344.3 ppm.

[0062] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A Ni-Mo-Ce magnesium aluminum spinel catalyst, characterized in that, Includes a MgAl2O4 spinel support and CeO2, Ni and Mo supported on the MgAl2O4 spinel support; The composition of Ni is 5-20 wt.%, the composition of Mo is 0.5-5 wt.%, the composition of CeO2 is 3-20 wt.%, and the balance is MgAl2O4 spinel support.

2. The Ni-Mo-Ce magnesium aluminum spinel catalyst according to claim 1, characterized in that, In the catalyst, the mass fraction of Ni is 8-12 wt.%, the mass fraction of Mo is 1-3 wt.%, and the mass fraction of CeO2 is 8-12 wt.%.

3. The Ni-Mo-Ce magnesium aluminum spinel catalyst according to claim 1, characterized in that, In the catalyst, the mass fraction of Ni is 10 wt.%, the mass fraction of Mo is 2 wt.%, the mass fraction of CeO2 is 10 wt.%, and the balance is MgAl2O4 spinel support.

4. The Ni-Mo-Ce magnesium aluminum spinel catalyst according to claim 1, characterized in that, The MgAl2O4 spinel support has a lamellar or layered aggregate structure, the CeO2 is dispersed on the surface of the MgAl2O4 spinel support, and Ni and Mo are distributed on the surface of the support in a metallic state, an oxidized state, or both.

5. The method for preparing the Ni-Mo-Ce magnesium aluminum spinel catalyst according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Magnesium salt, aluminum salt and complexing agent are added to solvent and mixed to obtain precursor solution; the precursor solution is heated to form gel; the gel is dried and calcined to obtain MgAl2O4 spinel support; S2. The cerium salt solution is impregnated onto the MgAl2O4 spinel support, and after drying and calcination, a CeO2-MgAl2O4 composite support is obtained. S3. Impregnate the CeO2-MgAl2O4 composite support with nickel salt and molybdenum salt solutions, and obtain the catalyst precursor after drying and calcination; S4. The catalyst precursor is reduced in a hydrogen-containing atmosphere to obtain the Ni-Mo-Ce magnesium aluminum spinel catalyst.

6. The preparation method according to claim 5, characterized in that, In step S1, the molar ratio of Mg, Al and citric acid is 1:2:4.

5.

7. The preparation method according to claim 5, characterized in that, In step S2, the cerium salt is cerium nitrate, the impregnation is an equal-volume impregnation, and the theoretical CeO2 loading is 3~20 wt.%; after impregnation, it is ultrasonicated at room temperature, then evaporated at 80℃, dried at 120℃, and then heated to 700℃ at 5℃ / min and held for 4 h in air atmosphere; in step S3, the nickel salt is nickel nitrate, and the molybdenum salt is ammonium molybdate; the impregnation is an equal-volume co-impregnation; the theoretical Ni loading is 5~20 wt.% and the theoretical Mo loading is 0.5~5 wt.%; after impregnation, it is ultrasonicated at room temperature, then evaporated at 80℃, dried at 120℃, and then heated to 700℃ at 5℃ / min and held for 4 h in air atmosphere.

8. The preparation method according to claim 5, characterized in that, In step S4, the hydrogen-containing atmosphere is H2 / N2, H2 / Ar, or H2 / He; the reduction temperature is 800℃, and the reduction time is 2 h.

9. The application of a Ni-Mo-Ce magnesium aluminum spinel catalyst in steam reforming of sulfur-containing liquid hydrocarbon fuels for hydrogen production, characterized in that, The catalyst is the Ni-Mo-Ce magnesium aluminum spinel catalyst according to any one of claims 1 to 4 or the Ni-Mo-Ce magnesium aluminum spinel catalyst prepared by the method according to any one of claims 5 to 8.

10. The application according to claim 9, characterized in that, The sulfur-containing liquid hydrocarbon fuel includes C 10 ~C 20 Alkanes, diesel fuel, aviation kerosene, biodiesel, or model compounds thereof; the sulfur content of the sulfur-containing liquid hydrocarbon fuel is 10-200 ppm; the reaction temperature is 650-850℃; the water-to-carbon molar ratio is 2-5; and the liquid hourly space velocity is 5 mL·g. -1 ·h -1 .

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