A single-site Ni / MoC catalyst and its preparation method and application

Abstract

The present invention discloses a single-site Ni / MoC catalyst and a preparation method and application thereof. The catalyst is prepared by a liquid phase synthesis method combined with a carbonization method: first, nickel acetylacetonate and molybdenum hexacarbonyl are used as precursors and mixed with a complexing agent to form a solution; then, an alloying reaction is carried out under an inert atmosphere to obtain a NiMo alloy, and then an in-situ carbonization treatment is carried out. The catalyst is used for a partial oxidation reaction of methane to achieve high activity and high selectivity to partially oxidize methane to produce synthesis gas. The catalyst has excellent resistance to carbon deposition. At the same time, the catalyst remains stable in a long-term performance test and has good industrial application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a unit-site Ni / MoC catalyst and a preparation method thereof, and application of the catalyst in preparing synthesis gas by partial oxidation of methane. Technical Background

[0002] At present, Japan, Europe and the United States, which are leading in the development of the hydrogen energy industry, mostly use distributed hydrogen production technology to supply hydrogen to hydrogen refueling stations. Hydrogen refueling stations in California, the United States and Japan use on-site hydrogen production methods such as water electrolysis and natural gas to supply hydrogen. Most hydrogen refueling stations in Europe supply hydrogen by water electrolysis. Domestic distributed on-site hydrogen production technology needs to be further improved and enhanced. The development of skid-mounted, intelligent, one-button-start natural gas distributed hydrogen production technology to meet the hydrogen demand of hydrogen refueling stations is of great significance to the establishment and formation of my country's hydrogen supply network and to meet the hydrogen demand of fuel cell vehicles.

[0003] Natural gas reforming to produce hydrogen is considered to be the most promising large-scale hydrogen production technology for the next generation. In recent years, with the continuous improvement of shale gas and methane hydrate development technology, how to efficiently convert large amounts of methane into energy (hydrogen energy) and chemicals (through synthesis gas conversion) has gradually become a key technical problem that needs to be solved urgently. Hydrogen energy, as a clean renewable energy carrier that is currently being vigorously promoted, has received great attention from the world, especially the rapid development of hydrogen fuel cell vehicles, which has made distributed hydrogen refueling stations an indispensable condition for promoting the use of hydrogen energy. Methane reforming to produce hydrogen is currently one of the main sources of hydrogen in industry. Methane steam reforming (MSR) is a key link in industrial hydrogen production. In addition to the industrialized methane steam reforming technology, the most studied technology is the partial oxidation of methane (POM) technology. The reaction formula of methane partial oxidation is: CH4+ 1 / 2O2→CO+2H2 (i.e., carbon monoxide and hydrogen are obtained through the oxidation of methane). Compared with steam reforming to produce hydrogen, the methane partial oxidation process is more suitable for distributed hydrogen production. It has the advantages of lower reaction temperature, lower energy consumption, shorter response time, small equipment scale and low equipment cost. It can be carried out with less catalyst loading and higher space velocity, thus potentially replacing the steam reforming reactor with large footprint and high energy consumption, further reducing the footprint of the device and improving the energy efficiency of the system.

[0004] The current bottleneck of hydrogen production by partial oxidation of methane is still the difficulty in obtaining cheap, stable and efficient catalysts. Among the catalysts for hydrogen production by partial oxidation of methane, noble metals such as Pt, Pd and Rh in Group VIII and non-noble metal supported catalysts such as Fe, Co and Ni all have high activity, but considering the catalytic performance and economy, Ni-based catalysts have more industrial application prospects. However, due to the low Tamman temperature of metal Ni (590°C), in the reforming reaction, under high temperature and oxidizing atmosphere, the active component Ni is prone to carbon deposition or sintering and agglomeration, resulting in a sharp decrease in the number of exposed active sites of the catalyst and deactivation. Currently, metal-support interaction (MSI) is widely used to stabilize Ni metal in order to achieve long-term, efficient, stable and distributed hydrogen production. However, the widely used method is to increase the exposure of active sites, such as adjusting the size of Ni particles. For example, Li et al. reported that Ni@SiO2 core-shell structure catalysts were used in the partial oxidation of methane. The study found that the activity and stability of the catalyst were closely related to the size of Ni particles. Under the coating of porous SiO2, the sintering and carbon deposition of the catalyst were significantly inhibited. However, for this strategy, Ni metal is still very easy to aggregate after long-term operation, and the atomic utilization efficiency is low, resulting in limited conversion rate and product selectivity (ChemCatChem, 2013, 5, 3781-3787.). In addition, the structure of the carrier can be changed, such as using metal oxides with strong anchoring ability and active oxygen supply capacity (such as perovskite, CeO2, La2O3) to anchor Ni atoms. Researchers further use perovskite, CeO2, La2O3 and other oxides as carriers or add additives as stable anchoring points to stabilize Ni atoms. At the same time, such oxides can provide active oxygen species to promote methane activation and improve synthesis gas selectivity. However, this strategy is limited by the oxygen supply capacity of the carrier, and its ability to anchor metal Ni is limited. It is also very easy to form a bulk spinel structure with the carrier, resulting in an irreversible structural transformation of the catalyst (Applied Catalysis B: Environmental, 2015, 164, 135-143.; Applied Catalysis B: Environmental, 2017, 202, 473-488). Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art. In view of the common problems in the existing methane partial oxidation reaction, such as the catalyst is easily deactivated by carbon deposition and sintering, the reaction temperature is high, the syngas selectivity is low, and the hydrogen production efficiency is low, a single-site Ni / MoC catalyst and a preparation method thereof, as well as the application of the catalyst in the methane partial oxidation reaction are provided.

[0006] Our research group has previously developed and applied for a Chinese invention patent "An intermetallic NiMo alloy catalyst, its preparation method and application" (application number 2022102710086, application date March 18, 2022); our research group continued to conduct research and development based on this achievement, constructing unit-site Ni atoms through the strong anchoring effect of MoC, and rationally optimizing the synergistic effect between the MoC carrier and Ni, achieving a CH4 conversion rate of 98.4% at 750°C, and CO and H2 selectivities of 99% and 98.9%, respectively; CH4 conversion rate of 96%, CO selectivity of 99.6%, and H2 selectivity of 99.6% at 720°C. In the 50h catalytic test, the conversion rate, selectivity and hydrogen-carbon ratio remained stable.

[0007] In order to solve the above technical problems, the present invention is implemented by the following technical solutions:

[0008] A single-site Ni / MoC catalyst and a preparation method thereof are carried out according to the following steps:

[0009] Step 1, weigh nickel acetylacetonate and molybdenum hexacarbonyl and uniformly disperse them in a solvent to prepare a precursor solution, wherein the molar ratio of the two metals Ni:Mo is (1-5): (1-10)

[0010] In step 1, select 60-70° C. and mechanically stir for 4-6 hours to form a precursor solution at a stirring speed of 100-300 revolutions per minute.

[0011] In step 1, the molar ratio of the two metals Ni:Mo is 1:(1-10).

[0012] In step 1, the solvent is oleylamine, oleic acid or benzyl ether.

[0013] Step 2: Place the precursor solution obtained in step 1 under an inert protective atmosphere, heat it from room temperature 20-25 degrees Celsius to 230-270 degrees Celsius at a rate of 10-20 degrees Celsius / min and keep it warm for 10-40 minutes to carry out alloying reaction, cool it naturally to room temperature 20-25 degrees Celsius, add anhydrous ethanol to precipitate the alloy.

[0014] In step 2, after anhydrous ethanol is added to precipitate the alloy, the alloy is washed with anhydrous ethanol and cyclohexane and centrifuged (such as at a centrifugal rate of 6000-10000 rpm), the lower alloy precipitate is retained, and after ultrasonic washing with cyclohexane, the alloy precipitate is ultrasonically dispersed in cyclohexane.

[0015] In step 2, the inert protective atmosphere is nitrogen, helium or argon.

[0016] In step 2, the temperature is raised to 230-250°C and kept warm for 20-30 minutes.

[0017] Step 3, the alloy obtained in step 2 is loaded on a carrier, and in a mixed atmosphere of hydrogen and inert protective gas, the temperature is raised to 550-600°C at a rate of 10-20°C / min, maintained for 2-4h, and then the temperature is raised to 800-900°C at a rate of 10-20°C / min, roasted and reduced for 6-10h, and naturally cooled to room temperature 20-25°C; in the mixed atmosphere, the volume percentage of hydrogen is 5-50%, and the gas flow rate is 50-500mL·min -1 .

[0018] In step 3, the support is commercial SBA-15 molecular sieve.

[0019] In step 3, the alloy obtained in step 2 is dispersed in cyclohexane by ultrasonication and then loaded on a carrier at a stirring rate of 300-600 rpm and a stirring temperature of 50-80°C.

[0020] In step 3, the inert protective gas is nitrogen, helium or argon.

[0021] In step 3, the volume percentage of hydrogen is 20-30%, and the gas flow rate is 100-300 mL·min -1 .

[0022] Step 4, placing the product obtained by calcination and reduction in step 3 in a mixed atmosphere of methane and inert protective gas, heating to 550-600°C at a rate of 10-20°C / min, maintaining for 2-4h, then heating to 800-1000°C at a rate of 10-20°C / min, carbonizing for 6-10h, and naturally cooling to room temperature of 20-25°C; in the mixed atmosphere, the volume percentage of methane is 5-50%, and the gas flow rate is 50-500mL·min -1 .

[0023] In step 4, the inert protective gas is nitrogen, helium or argon.

[0024] In step 4, the volume percentage of hydrogen is 20-30%, and the gas flow rate is 100-300 mL·min -1 .

[0025] The present invention is an application of the single-site Ni / MoC catalyst in the preparation of synthesis gas by partial oxidation of methane. The catalyst is placed in a fixed bed device for partial oxidation of methane. The reaction atmosphere ratio is CH4:Air:N2=10:25:65, and the total flow rate is 100-500 mL·min -1 , mass space velocity WHSV is 6000-60000mL CH4 g cat -1 h -1 .

[0026] The technical solution of the present invention stabilizes the active component Ni by constructing a single-site Ni to prevent sintering deactivation. At the same time, MoC, which has high catalytic activity and is not easy to form a bulk structure with Ni, is used as an auxiliary agent and also as a carrier of single-atom Ni, effectively stabilizing the metal Ni active site and serving as a site for activating oxygen, thereby greatly improving the product selectivity. The beneficial effects of the present invention are as follows:

[0027] (i) The single-site Ni / MoC catalyst developed in the present invention prepares a highly dispersed single-site Ni catalyst and provides a design method for single-atom Ni site catalysts at the nanoscale, which can construct high-density, highly dispersed catalytic active sites. The catalyst has high activity, high product selectivity, high stability and strong resistance to carbon deposition at a relatively low temperature of 720°C (lower than the high temperature of more than 800°C required by most catalysts).

[0028] (ii) The catalyst developed in the present invention is applied to the partial catalytic oxidation reaction of methane at a relatively low temperature (below 800°C), and has high activity and high product selectivity, which is much better than the Ni-based catalysts reported previously, and is even comparable to precious metal-based catalysts, making it cost-effective and advantageous in industrial applications, and having the potential for industrial application, which is conducive to industrial promotion and use.

[0029] (III) The single-site Ni / MoC catalyst of the present invention has the advantages of high activity, high product selectivity, high stability and strong resistance to carbon deposition in the methane reforming reaction, achieving a CH4 conversion rate of 98.4% at 750°C, and CO and H2 selectivities of 99% and 98.9%, respectively; a CH4 conversion rate of 96%, CO selectivity of 99.6%, and H2 selectivity of 99.6% at 720°C. In the stability test of more than 50 hours, the methane conversion rate, synthesis gas selectivity and hydrogen-carbon ratio remained stable.

[0030] Table 1. Performance comparison of the single-site Ni / MoC catalyst of the present invention and reported Ni-based catalysts

[0031]

[0032] Table 2. Performance comparison of the single-site Ni / MoC catalyst of the present invention and reported noble metal-based catalysts

[0033]

[0034]

[0035] NG in the table stands for Not Given, which is not given in the literature. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the test results of the cyclic stability and long-term stability of the catalyst of the present invention at 750° C. and 720° C.

[0037] Figure 2 This is a performance comparison chart of conversion rate and selectivity between the present catalyst and reported catalysts.

[0038] Figure 3 This is a diagram showing the HRTEM microstructure test results of the single-site Ni / MoC catalyst of the present invention.

[0039] Figure 4 It is the Raman spectrum of the single-site Ni / MoC catalyst of the present invention.

[0040] Figure 5 It is the XPS spectrum of the single-site Ni / MoC catalyst of the present invention.

[0041] Figure 6 It is the XRD spectrum diagram of the single-site Ni / MoC catalyst of the present invention.

[0042] Figure 7 This is the O2-TPO test diagram of the single-site Ni / MoC catalyst of the present invention.

[0043] Figure 8 Schematic diagram of the structure of the catalyst of the present invention. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below through specific examples. The following examples can enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way.

[0045] Embodiment 1:

[0046] Step 1, weighing 0.257 parts by mass (one part by mass is 1 g) of nickel acetylacetonate and 1.32 parts by mass (one part by mass is 1 g) of molybdenum hexacarbonyl, dissolving them in 50 mL of oleylamine to prepare a precursor solution, wherein the molar ratio of the two metals Ni:Mo is ensured to be 1:5, and stirring at 60° C. for 6 hours;

[0047] Step 2, the precursor solution obtained in step 1 is placed in a 250mL three-necked flask, and then heated to 250°C at a rate of 20°C / min under N2 atmosphere, maintained at this temperature for 30min, cooled naturally to room temperature, 100mL of anhydrous ethanol is added to precipitate the alloy, washed with anhydrous ethanol and cyclohexane three times respectively, and then centrifuged at 8000rpm, retaining the lower alloy deposit, ultrasonically washed with cyclohexane three times, and ultrasonically dispersed the alloy deposit in cyclohexane, loaded on a commercial SBA-15 molecular sieve (purchased from Nanjing Jicang Nano Technology Co., Ltd.), stirred at 60°C for 6h, and after the solvent was evaporated, the powder was placed in a tube furnace in a 20% H2 / He atmosphere (in the mixed atmosphere, the volume percentage of hydrogen is 20%), and the gas flow rate was 100mL min -1 The temperature was raised to 600°C at a rate of 10°C / min, maintained for 4 h, then raised to 800°C, and calcined for 6 h.

[0048] Step 3: Place the powder sample in step 2 in a tube furnace in a 20% CH4 / He atmosphere (the volume percentage of methane in the mixed atmosphere is 20%) at a gas flow rate of 100 mL min -1 The temperature was raised to 600°C at a rate of 10°C / min, maintained for 2h, then raised to 900°C and carbonized for 6h.

[0049] Step 4: Press the catalyst solid powder into tablets, sieve, take out the granular catalyst with a size of 20-40 mesh, and place it in a fixed bed device for methane partial oxidation reaction to test the reaction activity. The reaction atmosphere ratio is CH4:Air:N2=10:25:65, and the total flow rate is 100mL·min -1 , mass space velocity WHSV is 6000mL CH4 g cat -1 h -1 .

[0050] The methane conversion rate and syngas selectivity are calculated using the following formulas:

[0051] Conversion rate: (F CH4总 -F CH4余 ) / F CH4总

[0052] CO selectivity: F CO / (F CH4总 -F CH4余 )

[0053] H2 selectivity: F H2 / 2*(F CH4总 -F CH4余 )

[0054] At 720°C, the CH4 conversion rate reaches 96%, and the CO and H2 conversion rates are both 99.6%. That is, the application of the catalyst of the present invention in the partial oxidation reaction of methane can produce a mixed gas of methane, carbon monoxide and hydrogen. Figure 1 and 2 As shown, the catalyst of the present invention has a CH4 conversion rate of 96% and a H2 selectivity of 99.6% at 720°C, which is the highest performance among the current Ni-based catalysts and higher than most of the precious metal-based catalysts reported so far. The comparison point data are listed in Table 1 and Table 2. The catalyst of the present invention is used in cycles at 750°C and 720°C (reaction atmosphere CH4:Air:N2=10:25:65, total flow rate 100mL·min -1 ) can run continuously for more than 54 hours and still maintain good catalytic performance.

[0055] The reaction products H2 and CO were analyzed online by GC-2060 gas chromatograph from Shanghai Ruimin Instrument Co., Ltd., TCD thermal conductivity detector, chromatographic columns were TDX01 and 5A molecular sieve chromatographic columns; XRD characterization instrument was D8ADVANCE X-ray diffractometer from Bruke, Cu target Kα (60kV, 80mA, ), the characterization instrument used for XPS was a K-Alpha+ X-ray photoelectron spectrometer from ThermoScientific, and its X-ray source adopted an Al target (hν=1486.6eV), the characterization instrument used for Raman was a LabRAM HR Evolution laser confocal Raman spectrometer from HORIBA, the characterization instrument used for O2-TPO was a Micromeritics AutoChem II 2920 chemical adsorption instrument, the characterization instrument used for TEM was a FEI TecnaiG2 F20, and the characterization instrument used for HAADF-STEM was a JEM-ARM200F.

[0056] As attached Figure 3 As shown in the HRTEM microstructure magnification of the single-site Ni / MoC catalyst and the atomic height distribution of Ni and Mo, it is obvious that Ni is in a single-atom state on the (111) crystal plane of the close-packed hexagonal MoC. The bright spots represent Mo atoms, and the dark spots represent C atoms or Ni atoms. Figure 4 As shown in the figure, obvious Mo-C and Ni peaks are shown; Figure 5 As shown, the Mo 3d orbital peak spectrum shows a typical MoC peak, with a small amount of oxidized Mo on the surface. 3+ ; as attached Figure 6 As shown in the figure, the XRD peaks of typical MoC are shown, and there is no obvious peak of Ni crystal, which proves that Ni is single atom or monodisperse. Figure 7As shown, in the O2-TPO test after 50h of reaction under the same test conditions, the dotted line and the solid line correspond to the NiMo alloy and the single-site Ni / MoC catalyst, respectively, indicating that there is no obvious carbon deposition peak after the Ni / MoC catalyst reaction, that is, MoC acts as an auxiliary agent and a carrier of single atomic Ni, effectively stabilizing the metal Ni active sites.

[0057] Embodiment 2:

[0058] The preparation was carried out by the method of Example 1, the only difference being that the molar ratio of metal Ni:Mo in step (1) was 1:1. At 720°C, the CH4 conversion rate reached 95.2%, and the CO and H2 selectivities were both 99%.

[0059] Embodiment 3:

[0060] The preparation was carried out by the method of Example 1, except that the molar ratio of metal Ni:Mo in step (1) was 1:10. At 720°C, the CH4 conversion rate was 93.9%, and the CO and H2 selectivities were 91.2% and 98%, respectively.

[0061] Embodiment 4:

[0062] The preparation was carried out by the method of Example 1, the only difference being that the molar ratio of metal Ni:Mo in step (1) was 5:1. At 720°C, the CH4 conversion was 95%, and the CO and H2 selectivities were 96% and 99%, respectively.

[0063] Embodiment 5:

[0064] The preparation was carried out by the method of Example 1, the only difference being that the molar ratio of metal Ni:Mo in step (1) was 10:1. At 720°C, the CH4 conversion was 94%, and the CO and H2 selectivities were 95% and 99%, respectively.

[0065] Embodiment 6:

[0066] The preparation was carried out by the method of Example 1, except that the holding time in step (2) was 20 minutes. At 720°C, the CH4 conversion rate reached 96%, and the CO and H2 conversion rates were both 99.6%.

[0067] Embodiment 7:

[0068] The preparation was carried out by the method of Example 1, except that the holding time in step (2) was 40 minutes. At 720°C, the CH4 conversion rate reached 95.2%, and the CO and H2 conversion rates were both 99%.

[0069] According to the content of the present invention, the relevant process parameters of the invention technical solution are adjusted according to the content of the present invention, and the preparation of the single-site Ni / MoC catalyst can be achieved. After testing, the performance is basically consistent with the present invention. The above is an exemplary description of the present invention. It should be noted that without departing from the core of the present invention, any simple deformation, modification or equivalent replacement that other technicians in this field can make without spending creative labor falls within the protection scope of the present invention.

Claims

1. A single-site Ni / MoC catalyst, characterized in that: MoC is used as an additive and a carrier of single-atom Ni in the following steps: Step 1, weighing nickel acetylacetonate and molybdenum hexacarbonyl and uniformly dispersing them in a solvent to prepare a precursor solution, wherein the molar ratio of the two metals Ni:Mo is (1-5):(1-10); Step 2, placing the precursor solution obtained in step 1 under an inert protective atmosphere, heating from room temperature 20-25 degrees Celsius to 230-270 degrees Celsius at a rate of 10-20 degrees Celsius / min and keeping the temperature for 10-40 minutes to perform an alloying reaction, naturally cooling to room temperature 20-25 degrees Celsius, and adding anhydrous ethanol to precipitate the alloy; Step 3, the alloy obtained in step 2 is loaded on a carrier, and in a mixed atmosphere of hydrogen and inert protective gas, the temperature is raised to 550-600°C at a rate of 10-20°C / min, maintained for 2-4h, and then the temperature is raised to 800-900°C at a rate of 10-20°C / min, roasted and reduced for 6-10h, and naturally cooled to room temperature 20-25°C; in the mixed atmosphere, the volume percentage of hydrogen is 5-50%, and the gas flow rate is 50-500mL·min -1 ; Step 4, placing the product obtained by calcination and reduction in step 3 in a mixed atmosphere of methane and inert protective gas, heating to 550-600°C at a rate of 10-20°C / min, maintaining for 2-4h, then heating to 800-1000°C at a rate of 10-20°C / min, carbonizing for 6-10h, and naturally cooling to room temperature of 20-25°C; in the mixed atmosphere, the volume percentage of methane is 5-50%, and the gas flow rate is 50-500mL·min -1 .

2. A single-site Ni / MoC catalyst according to claim 1, characterized in that: In step 1, the molar ratio of the two metals Ni:Mo is 1:(1-10); the solvent is oleylamine, oleic acid or dibenzyl ether.

3. A single-site Ni / MoC catalyst according to claim 1, characterized in that: In step 2, the inert protective atmosphere is nitrogen, helium or argon; the temperature is raised to 230-250° C. and maintained for 20-30 minutes.

4. A single-site Ni / MoC catalyst according to claim 1, characterized in that: In step 3, the carrier is commercial SBA-15 molecular sieve; the inert protective gas is nitrogen, helium or argon; the volume percentage of hydrogen is 20-30%, and the gas flow rate is 100-300 mL·min -1 .

5. A single-site Ni / MoC catalyst according to claim 1, characterized in that: In step 4, the inert protective gas is nitrogen, helium or argon; the volume percentage of hydrogen is 20-30%, and the gas flow rate is 100-300 mL·min -1 .

6. A method for preparing a single-site Ni / MoC catalyst, characterized in that: Follow these steps: Step 1, weighing nickel acetylacetonate and molybdenum hexacarbonyl and uniformly dispersing them in a solvent to prepare a precursor solution, wherein the molar ratio of the two metals Ni:Mo is (1-5):(1-10); Step 2, placing the precursor solution obtained in step 1 under an inert protective atmosphere, heating from room temperature 20-25 degrees Celsius to 230-270 degrees Celsius at a rate of 10-20 degrees Celsius / min and keeping the temperature for 10-40 minutes to perform an alloying reaction, naturally cooling to room temperature 20-25 degrees Celsius, and adding anhydrous ethanol to precipitate the alloy; Step 3, the alloy obtained in step 2 is loaded on a carrier, and in a mixed atmosphere of hydrogen and inert protective gas, the temperature is raised to 550-600°C at a rate of 10-20°C / min, maintained for 2-4h, and then the temperature is raised to 800-900°C at a rate of 10-20°C / min, roasted and reduced for 6-10h, and naturally cooled to room temperature 20-25°C; in the mixed atmosphere, the volume percentage of hydrogen is 5-50%, and the gas flow rate is 50-500mL·min -1 ; Step 4, placing the product obtained by calcination and reduction in step 3 in a mixed atmosphere of methane and inert protective gas, heating to 550-600°C at a rate of 10-20°C / min, maintaining for 2-4h, then heating to 800-1000°C at a rate of 10-20°C / min, carbonizing for 6-10h, and naturally cooling to room temperature of 20-25°C; in the mixed atmosphere, the volume percentage of methane is 5-50%, and the gas flow rate is 50-500mL·min -1 .

7. The method for preparing a single-site Ni / MoC catalyst according to claim 6, characterized in that: In step 1, the molar ratio of the two metals Ni:Mo is 1:(1-10); the solvent is oleylamine, oleic acid or dibenzyl ether; in step 2, the inert protective atmosphere is nitrogen, helium or argon; the temperature is raised to 230-250°C and kept warm for 20-30 minutes.

8. The method for preparing a single-site Ni / MoC catalyst according to claim 6, characterized in that: In step 3, the carrier is commercial SBA-15 molecular sieve; the inert protective gas is nitrogen, helium or argon; the volume percentage of hydrogen is 20-30%, and the gas flow rate is 100-300 mL·min -1 .

9. The method for preparing a single-site Ni / MoC catalyst according to claim 6, characterized in that: In step 4, the inert protective gas is nitrogen, helium or argon; the volume percentage of hydrogen is 20-30%, and the gas flow rate is 100-300 mL·min -1 .

10. Use of the single-site Ni / MoC catalyst according to claim 1 in preparing synthesis gas by partial oxidation of methane.

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