Thin-layer double-carrier anchored metal cluster catalyst as well as preparation method and application thereof

Abstract

The invention discloses a catalyst. According to the catalyst, metal nanoclusters are anchored on a thin layer of anatase-phase TiO2 on the surface of Al2O3. The invention also discloses a preparation method and application of the catalyst. The catalyst provided by the invention has high catalytic activity, high stability and carbon deposition resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and particularly relates to a thin-layer dual-support anchored metal cluster catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Dry reforming of methane (DRM) is an important reaction that catalytically converts methane (CH4) into syngas (H2 and CO) using carbon dioxide (CO2) as an oxidant. This process can not only synergistically convert the greenhouse gases CH4 and CO2, realizing the efficient recycling and high-value conversion of carbon resources, but also the produced syngas has a controllable H2 / CO molar ratio, which can be used for Fischer-Tropsch synthesis, methanol synthesis, and the production of other downstream chemicals (International Journal of Hydrogen Energy 103 (2022) 395-414). Therefore, the DRM reaction has important strategic significance in energy conversion and environmental governance and is considered one of the key technologies for achieving carbon neutrality and sustainable development.

[0003] The DRM reaction is usually carried out at high temperatures (700-900 °C), which poses high requirements for the activity, high selectivity, and long-term stability of the catalyst. Currently, the widely studied catalyst systems mainly include transition metal (such as Ni, Co, Fe) and noble metal (such as Pt, Pd, Rh, Ru, Ir) based catalysts. Among them, Ni-based catalysts have certain advantages in industrial applications due to their high CH4 activation ability and low cost, but they are easily affected by factors such as carbon deposition and sintering, resulting in rapid deactivation of the catalyst. In contrast, noble metal catalysts have stronger carbon deposition resistance and sintering resistance and can also maintain high stability; however, their high price limits large-scale industrial applications (Chemical Society Reviews 43 (2014) 7813-7837). Therefore, developing highly efficient catalysts with both high stability and carbon deposition resistance is an important direction in current DRM research. How to improve the stability of noble metal-based catalysts and reduce carbon deposition through reasonable catalyst design is one of the key challenges in current DRM catalysis research.

[0004] The support material plays a crucial role in the performance of catalysts, affecting the dispersion, thermal stability, and anti-coking ability of metals. Due to its high specific surface area and good mechanical stability, Al2O3 is widely used as a support for DRM catalysts (Green Chemistry 20 (2018) 2781-2787). However, its surface is rich in Lewis acid sites, which can promote carbon deposition and lead to rapid deactivation of the catalyst. To improve the stability and anti-coking ability of Al2O3, introducing a second-phase support has become an effective strategy. In recent years, TiO2 has received extensive attention in the design of catalyst supports because it has oxygen vacancies and excellent oxygen migration ability, which can promote the effective supply of oxygen species to the metal active centers and enhance the metal-support interaction (ACS Catalysis 14 (2024) 17582-17597). Therefore, constructing a TiO2-Al2O3 dual-support structure can take into account the advantages of both and overcome the limitations of single supports. However, the TiO2 loading methods reported in the existing literature, such as the impregnation method (Chemical Engineering Journal 427 (2022) 130951), the sol-gel method (ACS Catalysis 5 (2015) 438-447; Chemical Engineering Science 297 (2024) 12304), or the co-precipitation method (Chinese Journal of Chemical Engineering 72 (2024) 187-198), can construct a TiO2-Al2O3 dual-support structure, but it is usually difficult to uniformly form a stable TiO2 layer on the surface of Al2O3.

[0005] Therefore, the present invention is proposed. Summary of the Invention

[0006] The object of the present invention is to provide a catalyst in which metal nanoclusters are anchored on a thin layer of anatase TiO2 on the surface of Al2O3; wherein the anatase TiO2 thin layer grows in-situ on the surface of Al2O3; the in-situ grown TiO2 and Al2O3 form a tightly bound composite structure. In the preparation method of the catalyst of the present invention, TiO2 is uniformly deposited on the surface of Al2O3 to form a stable interfacial bond, realizing the controllable growth of the TiO2 layer. The thin layer structure is conducive to the effective regulation of the electronic state of TiO2 by Al2O3, thereby optimizing the charge transfer between TiO2 and metal nanoclusters and enhancing the catalytic activity and selectivity. It provides more anchoring sites for metal nanoclusters, enhances the dispersion of metals, and effectively reduces the sintering and agglomeration of metal particles. In addition, the oxygen vacancies and excellent oxygen migration ability of anatase TiO2 can provide active oxygen species during the catalytic reaction process, promoting the oxidative removal of coke deposition, thereby reducing carbon deposition and improving the long-term stability of the catalyst.

[0007] The technical solution of the present invention is as follows:

[0008] In the first aspect of the present invention, a catalyst is disclosed, which is a thin layer of anatase TiO2 with metal nanoclusters anchored on the surface of Al2O3; wherein the thin layer of anatase TiO2 grows in-situ on the surface of Al2O3. The catalyst includes components such as metals, metal oxide TiO2, and metal oxide Al2O3. The composition of the catalyst is denoted as M / T-xA, where: M = a metal such as Ir, Rh, Ru, Pt, or Pd, x represents the atomic ratio of Al / Ti, T represents TiO2, and A represents Al2O3.

[0009] Preferably, the particle size of the catalyst is 10 - 150 nm; the thickness of the thin layer of anatase TiO2 is 1 - 50 nm; and the particle size of the metal nanoclusters is 0.4 - 2.0 nm.

[0010] Preferably, the atomic ratio of Al to Ti in the catalyst is (0.1 - 50):1 (the range of x in M / T-xA); the loading amount of the metal is 1 - 5 wt% of the total amount of the catalyst; and the metal is one of Pt, Ru, Rh, Pd, or Ir.

[0011] In the second aspect of the present invention, a preparation method of the catalyst is disclosed, which includes the following steps:

[0012] (1) Preparation of the support: Add tetrabutyl titanate to a mixed solution of glycerol and ethanol in a certain proportion, mix evenly, and then add a certain amount of Al2O3 and mix evenly;

[0013] (2) Hydrothermal treatment: Hydrothermally crystallize the above mixed solution at a constant temperature of 160 - 200 °C for 10 - 30 h;

[0014] (3) Separation and drying: After the reaction, separate, wash, dry, and calcine the product for a period of time to obtain a composite support of TiO2 and Al2O3;

[0015] (4) Preparation of the active component metal precursor solution: Select an appropriate metal precursor and prepare a metal precursor solution;

[0016] (5) Loading of the active metal: Uniformly load the metal precursor solution prepared in step (4) onto the composite support of TiO2 and Al2O3 prepared in step (3) by the incipient wetness impregnation method;

[0017] (6) Drying and calcination: Dry and calcine the sample in step (5);

[0018] (7) Reduce the product obtained in step (6) with hydrogen to obtain the catalyst.

[0019] Preferably, in step (1), the molar ratio of glycerol to ethanol is (5:1)-(1:1); the addition amounts of tetrabutyl titanate and Al2O3 are such that the atomic ratio of Al to Ti is (0.1-50):1.

[0020] Preferably, in step (3), the calcination temperature is 400-600 °C and the time is 1-3 h; in step (6), the calcination temperature is 300-500 °C and the time is 1-3 h.

[0021] Preferably, in step (4), the metal precursor solution is one of soluble platinum salts, ruthenium salts, rhodium salts, palladium salts or iridium salts.

[0022] Preferably, in step (5), the metal loading is 1-5 wt% of the total catalyst; the hydrogen reduction conditions and steps in step (7) are: reducing the product obtained in step (6) under a hydrogen-nitrogen mixed atmosphere, the hydrogen ratio in the hydrogen-nitrogen mixed gas is 5-20 v / v%, the reduction temperature is 400-600 °C, and the reduction time is 1-3 h.

[0023] The third aspect of the present invention discloses the application of the catalyst in the methane dry reforming reaction; methane dry reforming converts greenhouse gases into high-value syngas, having both environmental and energy values.

[0024] Preferably, the conditions for the methane dry reforming reaction are: the mass space velocity is 10-80 mL·h -1 ·g cat -1 , the reaction temperature is 600-800 °C, and the reaction pressure is 0-0.2 Mpa.

[0025] Generally, the catalyst precursor obtained is not reduced, that is, in industrial production, the above step (7) is carried out under a hydrogen-nitrogen mixed atmosphere before the methane dry reforming reaction. The reduction conditions and steps are: reducing the product obtained in step (6) under a hydrogen-nitrogen mixed atmosphere, the hydrogen ratio in the hydrogen-nitrogen mixed gas is 5-20 v / v%, the reduction temperature is 400-600 °C, and the reduction time is 1-3 h; after the catalyst precursor is reduced to obtain the catalyst, the methane dry reforming reaction can be carried out.

[0026] The beneficial effects of the present invention:

[0027] The catalyst of the present invention is: metal nanoclusters anchored on a thin layer of anatase TiO2 in-situ grown on the surface of Al2O3; the catalyst of the present invention exhibits excellent anti-coking ability and long-term stability in the methane dry reforming reaction. The preparation method of the catalyst of the present invention adopts a hydrothermal method to in-situ grow a thin layer of anatase TiO2 on the surface of Al2O3, and metal nanoclusters are anchored on the thin layer of anatase TiO2; compared with the traditional impregnation method, sol-gel method or co-precipitation method, the preparation method of the present invention can realize the controllable growth of the TiO2 layer on the surface of Al2O3, form a uniform and stable TiO2 thin layer, thereby improving the dispersion of TiO2 and enhancing its binding force with the carrier Al2O3, improving the carrier stability and catalytic performance; at the same time, metal nanoclusters are anchored on the surface of TiO2, and the presence of TiO2 enhances the stability of the metal, effectively inhibiting the sintering and agglomeration of the metal under high-temperature conditions, ensuring the long-term high activity of the catalyst. In addition, the oxygen vacancies of TiO2 can effectively promote the migration and replenishment of oxygen species, promote the oxidative removal of coke during the reaction process, reduce the carbon deposition rate, thereby significantly improving the anti-coking ability of the catalyst and extending its service life. The intervention of Al2O3 can limit the growth of TiO2 grains by providing a large specific surface area, effectively inhibit the phase transformation of TiO2, and make TiO2 still maintain the anatase phase structure under high-temperature conditions, improving the stability of the catalyst. The thin layer structure is conducive to the effective regulation of the electronic state of TiO2 by Al2O3, thereby optimizing the charge transfer between TiO2 and metal nanoclusters and enhancing the catalytic activity and selectivity. The catalyst of the present invention overcomes the problems of easy coking of traditional M / Al2O3 catalysts under high-temperature conditions, easy sintering of metals, and performance degradation caused by the phase transformation of TiO2, providing a new catalyst with high catalytic activity, high stability and anti-coking ability for the methane dry reforming reaction, and having important industrial application value. Description of the Drawings

[0028] Figure 1 XRD patterns of the catalysts obtained in Examples 1-3 and Comparative Examples 1-2.

[0029] Figure 2 (a) N2 adsorption-desorption isotherms and (b) pore size distribution curves of the catalysts obtained in Examples 1-3 and Comparative Examples 1-2.

[0030] Figure 3 TEM images of the catalysts obtained in Example 2 (a and b) and Comparative Example 2 (c and d).

[0031] Figure 4 CO-DRIFTS spectra of the catalysts obtained in Examples 1-3 and Comparative Examples 1-2.

[0032] Figure 5 EPR image of the catalyst obtained in Example 2.

[0033] Figure 6 Performance graphs of the catalysts obtained in Examples 1-3 and Comparative Examples 1-2 for dry reforming of methane.

[0034] Figure 7 XRD spectra of the catalysts obtained in Examples 1-3 and Comparative Examples 1-2 after 20 h of dry reforming of methane.

[0035] Figure 8 TEM images of the catalysts obtained in Example 2(a) and Comparative Example 2(b) after 20 h of dry reforming of methane. Detailed implementation manners

[0036] The present invention will be further described in detail below through specific examples. The examples can enable those skilled in the art to understand the present invention more comprehensively, but do not limit the present invention in any way.

[0037] All the reagents used in the present invention are analytical pure reagents. The X-ray analysis and testing of the obtained products are determined by a D8-Focus X-ray diffractometer of Bruker Corporation. The N2 adsorption-desorption isotherm and pore size distribution curve of the obtained products are determined by a Micromeritics ASAP 2460M adsorption analyzer. The high-resolution field emission transmission electron microscope of the obtained products is carried out using an FEI-Talos F200X, and the acceleration voltage is 200 kV.

[0038] Example 1: Preparation of Pt / T-3A in which Pt nanoclusters are loaded on an anatase-phase TiO2 thin layer grown in-situ on the surface of Al2O3, including the following steps:

[0039] Step S1: Add 1 g of tetrabutyl titanate to a mixed solution of glycerol and ethanol with a molar ratio of 5:3, stir evenly, and gradually add 0.45 g of Al2O3 under stirring conditions; stir on a magnetic stirrer for 1 h to ensure uniform mixing of the solution;

[0040] Step S2: Transfer the above mixed solution to a 100 mL polytetrafluoroethylene-lined hydrothermal autoclave and crystallize at a constant temperature of 180 °C for 24 h;

[0041] Step S3: After the reaction, centrifuge the product and wash it several times with anhydrous ethanol to remove unreacted substances; put the washed sample in an oven at 60 °C and dry it for 12 h, and then calcine the dried sample at 400 °C for 1 h to obtain the T-3A support;

[0042] Step S4: Select chloroplatinic acid as the active metal precursor and prepare a metal precursor solution by mixing it with water;

[0043] Step S5: The metal precursor solution prepared in step (4) was uniformly loaded onto the T-3A support prepared in step (3) by the incipient wetness impregnation method, and the Pt loading was 3 wt%.

[0044] Step S6: The sample was dried in an oven at 60 °C for 12 h and finally calcined at 350 °C for 2 h;

[0045] Step S7: The product obtained in step (6) was reduced under a hydrogen-nitrogen mixed atmosphere. The hydrogen ratio in the hydrogen-nitrogen mixture was 10 v / v%, the reduction temperature was 400 °C, and the reduction time was 1 h; The catalyst was obtained and denoted as Pt / T-3A.

[0046] Example 2: Preparation of Pt / T-10A catalyst.

[0047] The amount of Al2O3 used was 1.5 g, and the Pt / T-10A catalyst was obtained. Other conditions were the same as in Example 1.

[0048] Example 3: Preparation of Pt / T-20A catalyst.

[0049] The amount of Al2O3 used was 3 g, and the Pt / T-20A catalyst was obtained. Other conditions were the same as in Example 1.

[0050] Comparative Example 1: Preparation of catalyst Pt / T (without Al2O3).

[0051] Step S1: 1 g of tetrabutyl titanate was added to a mixed solution of glycerol and ethanol with a molar ratio of 5:3, and stirred on a magnetic stirrer for 1 h to ensure uniform mixing of the solution;

[0052] Step S2: The same as in Example 1;

[0053] After the reaction, the product was centrifuged and washed several times with anhydrous ethanol to remove the unreacted substances. The washed sample was dried in an oven at 60 °C for 12 h, and then the dried sample was calcined at 400 °C for 1 h to obtain anatase TiO2 support;

[0054] Step S4: The same as in Example 1;

[0055] Step S5: The same as in Example 1;

[0056] Step S6: The same as in Example 1;

[0057] Step S7: The same as in Example 1, and the catalyst was obtained and denoted as Pt / T.

[0058] Comparative Example 2: Preparation of catalyst Pt / A (without anatase TiO2).

[0059] Step S1: Chloroplatinic acid was selected as the active metal precursor and formulated into a metal precursor solution with water. The metal precursor solution was uniformly loaded onto the Al2O3 support by the incipient wetness impregnation method, and the loading amount was 3 wt%.

[0060] Step S2: The same as step S6 in Example 1;

[0061] Step S3: The same as step S7 in Example 1; The catalyst obtained was denoted as Pt / A.

[0062] Application Example:

[0063] The methane dry reforming performance of the catalysts prepared in Examples 1-3 and Comparative Examples 1-2 was investigated using a fixed-bed stainless steel reactor. Usually, 100 mg (20-40 mesh) of the catalyst was uniformly mixed with an appropriate amount of quartz sand. Temperature monitoring was carried out using a K-type thermocouple, and its probe was directly placed inside the catalyst bed to ensure accurate measurement of the actual reaction temperature of the catalyst. Before the reaction, the catalyst was subjected to reduction pretreatment. A 10 v / v% H2 / N2 mixed gas was introduced at a flow rate of 100 mL·min -1 and the temperature was raised to 400 °C and maintained for 1 h. Subsequently, the temperature was raised to 700 °C, and the gas mixture (CH4∶CO2∶N2 = 1∶1∶1) was passed through the reactor at a flow rate of 90 mL·min -1 After the reaction, the gas was passed through a condensation device to remove moisture, and the reactants and products were quantitatively analyzed for the outlet gas by an on-line gas chromatograph (GC) equipped with a thermal conductivity detector (TCD).

[0064] The catalysts prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to performance tests; the catalysts obtained in the examples and comparative examples were characterized.

[0065] Test Example 1:

[0066] Figure 1XRD patterns of the catalysts prepared in Examples 1-3 and Comparative Examples 1-2. As can be seen from the figure, characteristic diffraction peaks of γ-Al2O3 exist at 2θ = 31.9°, 37.6°, 39.5°, 45.8°, 60.5° and 66.8°. They are respectively attributed to its (220), (311), (222), (400), (511) and (440) crystal planes. This indicates that the Pt / T-3A, Pt / T-10A, Pt / T-20A and Pt / A catalysts maintain the crystal phase structure of γ-Al2O3. In addition, characteristic diffraction peaks of anatase TiO2 are detected at 2θ = 25.3°, 37.8°, 48.0°, 53.9°, 55.1°, 62.7°, 68.8°, 70.3° and 75.0°. They are respectively attributed to the (101), (004), (200), (105), (211), (204), (116), (220) and (215) crystal planes of TiO2. With the decrease of Ti content, the intensity of the TiO2 diffraction peak gradually weakens, indicating that TiO2 shows a higher dispersion on the carrier surface. When the Ti / Al molar ratio is reduced to 1:10, the characteristic diffraction peak of anatase TiO2 is not observed, indicating that TiO2 has been highly dispersed on the surface of the Al2O3 carrier and no obvious crystal phase is formed. In addition, characteristic diffraction peaks of Pt are not detected in the XRD patterns of all catalysts, indicating that Pt is highly dispersed on the carrier and exists in the form of small sizes or disordered structures.

[0067] Figure 2 (a) N2 adsorption-desorption isotherms and (b) pore size distribution curves of the catalysts prepared in Examples 1-3 and Comparative Examples 1-2. As can be seen from the figure, the adsorption isotherms of all catalysts show typical type-IV characteristics and are accompanied by an H3-type hysteresis loop, indicating that the catalysts have a typical mesoporous structure. Among them, the specific surface areas and pore size distributions of the Pt / T-3A, Pt / T-10A, Pt / T-20A and Pt / A catalysts are relatively similar, while the Pt / T catalyst shows the lowest specific surface area, pore size and pore volume. This smaller pore structure may limit the mass transfer efficiency of reactants and products and reduce the stability of the catalyst under high-temperature conditions.

[0068] Test Example 2:

[0069] Figure 3 TEM images of the catalysts obtained in Example 2 and Comparative Example 2. As can be seen from the figure, in the Pt / T-10A catalyst, TiO2 wraps around the Al2O3 surface in the form of a thin layer, and the average particle size of Pt is smaller than that in Pt / A. This indicates that in the Pt / T-10A catalyst, the metal-support interaction between Pt and TiO2 effectively inhibits the growth and agglomeration of Pt, thereby improving the dispersion of Pt and making its particle size smaller.

[0070] Test Example 3:

[0071] Figure 4 CO-DRIFTS spectra of the catalysts prepared in Examples 1-3 and Comparative Examples 1-2. The two absorption peaks appearing in the spectra correspond to the vibration signals of CO linearly adsorbed on platinum atoms; with the increase of the Al2O3 content, both of these two absorption peaks show a blue shift. This indicates that Al2O3 can effectively regulate the electronic state of TiO2 and further affect the electronic structure of the metal nanoclusters anchored on the TiO2 surface. This electronic regulation effect optimizes the electronic distribution of the metal active centers, thereby enhancing the activity and selectivity of the catalyst.

[0072] Test Example 4:

[0073] Figure 5 EPR image of the catalyst prepared in Example 2. It can be seen from the figure that in the Pt / T-10A catalyst, a symmetric signal with a g value of 2.002 is detected, and this signal is attributed to oxygen vacancies. The oxygen vacancies and excellent oxygen migration ability of anatase TiO2 can provide active oxygen species during the catalytic reaction process, promote the oxidative removal of carbon deposition, and contribute to improving the anti-carbon deposition ability and long-term stability of the catalyst.

[0074] Test Example 5:

[0075] Figure 6 Respectively show the variation of methane conversion rate, carbon dioxide conversion rate and hydrogen-carbon ratio with time of the catalysts prepared in Examples 1-3 and Comparative Examples 1-2 in the dry reforming of methane reaction. The reaction duration is 20 h to evaluate their stability. It can be seen from the figure that after 20 h of reaction, the methane conversion rate, carbon dioxide conversion rate and hydrogen-carbon ratio of the Pt / T-3A, Pt / T-10A and Pt / T-20A catalysts hardly change; among them, the Pt / T-10A catalyst has better performance. While the catalytic activity of the Pt / T catalyst has always been poor; the catalytic activity of the Pt / A catalyst is initially high and gradually decreases as the reaction proceeds; after 20 h of reaction, the activity of the Pt / A catalyst drops rapidly.

[0076] Test Example 6

[0077] Figure 7XRD patterns of the catalysts prepared in Examples 1-3 and Comparative Examples 1-2 after 20 h of methane dry reforming reaction. As can be seen from the figure, for the Pt / A catalyst, its XRD pattern shows an obvious diffraction peak at 2θ = 26.3°, corresponding to the graphite carbon phase formed after the reaction. For the Pt / T catalyst, characteristic diffraction peaks of rutile phase TiO2 are detected at 2θ = 27.4°, 36.1°, 39.2°, 41.2°, 44.0°, 54.3°, 56.6°, 62.8°, 64.1°, 69.0° and 69.8°; respectively attributed to the (110), (101), (200), (111), (210), (211), (220), (002), (310), (301) and (112) crystal planes of TiO2; this indicates that after 20 h of methane dry reforming reaction, TiO2 has undergone a transformation from anatase phase to rutile phase, and the Pt / T catalyst shows diffraction peaks corresponding to rutile phase TiO2. This phase transformation usually has a negative impact on the catalytic performance; while in the XRD patterns of the catalysts of Pt / T-3A, Pt / T-10A and Pt / T-20A after 20 h of methane dry reforming reaction, no diffraction signal of rutile phase TiO2 is detected. This indicates that the presence of Al2O3 can improve the thermal stability of TiO2, effectively inhibit its transformation to rutile phase under high temperature conditions, and thus contribute to maintaining the structural stability and catalytic performance of the catalyst.

[0078] Test Example 7

[0079] Figure 8 TEM images of the catalysts in Example 2(a) and Comparative Example 2(b) after 20 h of methane dry reforming reaction. It can be seen that after 20 h of methane dry reforming reaction, the Pt of the Pt / T-10A catalyst still shows a relatively small particle size. This indicates that compared with Pt / A, the metal nanoclusters of Pt / T-10A are anchored on the surface of TiO2. The presence of TiO2 enhances the stability of the metal, effectively inhibits the sintering and agglomeration of the metal under high temperature conditions, and ensures the long-term high activity of the metal particles in the methane dry reforming reaction.

[0080] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A catalyst, characterized in that It is composed of metal nanoclusters anchored on a thin layer of anatase TiO2 on the Al2O3 surface.

2. The catalyst according to claim 1, characterized in that The particle size of the catalyst is 10-150nm; the thickness of the anatase phase TiO2 thin layer is 1-50nm; and the particle size of the metal nano cluster is 0.4-2.0nm.

3. The catalyst according to claim 1, characterized in that The atomic ratio of Al to Ti in the catalyst is (0.1-50):1; the metal loading is 1-5wt% of the total amount of the catalyst; and the metal is one of Pt, Ru, Rh, Pd or Ir.

4. The method for preparing the catalyst according to any one of claims 1 to 3, characterized in that: The steps include: (1) Preparing a carrier: adding tetrabutyl titanate to a mixed solution of glycerol and ethanol in a certain proportion, mixing evenly, and then adding a certain amount of Al2O3, mixing evenly; (2) hydrothermal treatment: subjecting the mixed solution to constant temperature hydrothermal crystallization at 160-200° C. for 10-30 h; (3) Separation and drying: After the reaction is completed, the product is separated, washed, dried, and calcined for a period of time to obtain an Al2O3 composite carrier coated with a thin layer of TiO2; (4) preparing an active component metal precursor solution: selecting an appropriate metal precursor and preparing a metal precursor solution; (5) Loading active metals: uniformly loading the metal precursor solution obtained in step (4) onto the Al2O3 composite support coated with a thin layer of TiO2 obtained in step (3) by an incipient wetness impregnation method; (6) Drying and calcining: drying and calcining the sample in step (5); (7) Reducing the product hydrogen obtained in step (6) to obtain the catalyst.

5. The preparation method according to claim 4, characterized in that: In step (1), the molar ratio of glycerol to ethanol is (5:1)-(1:1); the added amount of tetrabutyl titanate and Al2O3 is such that the atomic number ratio of Al to Ti is (0.1-50):

1.

6. The preparation method according to claim 4, characterized in that: The calcination temperature of step (3) is 400-600° C. and the time is 1-3 h; the calcination temperature of step (6) is 300-500° C. and the time is 1-3 h.

7. The preparation method according to claim 5, characterized in that: Step (4) The metal precursor is dissolved into one of soluble platinum salt, ruthenium salt, rhodium salt, palladium salt or iridium salt.

8. The preparation method according to claim 5, characterized in that: The metal loading in step (5) is 1-5wt% of the total amount of the catalyst; the hydrogen reduction conditions and steps in step (7) are as follows: the product obtained in step (6) is reduced in a hydrogen-nitrogen mixed atmosphere, the hydrogen ratio in the hydrogen-nitrogen mixed atmosphere is 5-20v / v%, the reduction temperature is 400-600°C, and the reduction time is 1-3h.

9. Use of the catalyst according to any one of claims 1 to 3 in methane dry reforming reaction.

10. The use according to claim 9, characterized in that: The conditions for methane dry reforming reaction are: mass space velocity is 10-80mL·h -1 ·g cat -1 , the reaction temperature is 600-800°C, and the reaction pressure is 0-0.2Mpa.

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