Three-dimensional core-shell structure catalyst for hydrogen energy storage and preparation method thereof

Abstract

The invention discloses a preparation method of a three-dimensional core-shell structure catalyst for hydrogen energy storage. The preparation method specifically comprises the following steps: step 1, preparing lamellar Ti3C2Tx; step 2, preparing modified silicon balls; and step 3, preparing the three-dimensional core-shell structure catalyst according to products obtained in the step 1 and the step 2. The invention also discloses a three-dimensional core-shell structure catalyst for hydrogen energy storage. The catalyst prepared by the invention can realize stable dehydrogenation at a high temperature (350 DEG C), and the dehydrogenation efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of organic hydrogen carrier (LOHC) dehydrogenation technology, and relates to a three-dimensional core-shell structure catalyst for hydrogen energy storage. This invention also relates to a method for preparing a three-dimensional core-shell structure catalyst for hydrogen energy storage. Background Technology

[0002] Liquid organic hydrogen storage (LOHC) provides an alternative route for the safe, ambient temperature and pressure storage and transportation of hydrogen. Methylcyclohexane (MCH) is representative due to its high stability, compatibility with existing infrastructure, and high hydrogen storage density. MCH dehydrogenation is a high-temperature gas-solid multiphase reaction. During the reaction, reactant entry and product (H2 / toluene) exit, as well as bed heat and mass transfer, are coupled, which can easily lead to diffusion restriction and local heat accumulation, thereby amplifying side reactions and the risk of carbon deposition. Therefore, catalysts not only need high activity and high CH selectivity, but also must maintain site accessibility and structural stability under long-term high-temperature operation. Pt systems have excellent selectivity potential in LOHC dehydrogenation, but their cost and scarcity require reduced dosage and improved atom utilization. However, while existing single-atom / ultra-small cluster Pt can improve utilization, their low coordination structure has inherent kinetic instability at high temperatures, making them prone to migration and aggregation, leading to activity decay.

[0003] Traditional oxide supports have limited anchoring strength and anti-sintering ability for Pt, and relying solely on oxygen coordination often induces Pt growth accompanied by numerous low-activity, high-valence species, resulting in low loading but insufficient effective sites. While microporous / mesoporous confinement can enhance stability, it often comes at the cost of sacrificing site exposure, diffusion efficiency, and heat transfer efficiency, making it difficult to simultaneously guarantee stability and dehydrogenation efficiency. Two-dimensional MXenes, as potential supports, possess abundant defects and surface functional groups, providing a large number of anchoring sites. However, their sheets tend to self-assemble, leading to the shielding of active sites and obstruction of interfacial charges and transport channels, further exacerbating diffusion and heat transfer problems in the dehydrogenation process. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a three-dimensional core-shell structure catalyst for hydrogen energy storage. The catalyst prepared by this method can achieve stable dehydrogenation at high temperature (350°C) and improve dehydrogenation efficiency.

[0005] Another object of the present invention is to provide a three-dimensional core-shell structured catalyst for hydrogen energy storage.

[0006] The first technical solution adopted in this invention is a method for preparing a three-dimensional core-shell structure catalyst for hydrogen energy storage, which specifically includes the following steps:

[0007] Step 1, preparing Ti3C2T sheets x ; Step 2: Prepare modified silicon spheres; Step 3: Prepare a three-dimensional core-shell structured catalyst based on the products obtained in Step 1 and Step 2.

[0008] The first technical solution of this invention is further characterized by: The specific process of step 1 is as follows: Step 1.1: Weigh 1.6–2.4 g of LiF powder, measure 15–30 mL of concentrated hydrochloric acid, and 5–10 mL of deionized water. Step 1.2: Pour the LiF powder, deionized water and concentrated hydrochloric acid weighed in Step 1.1 into a polytetrafluoroethylene bottle, and heat it at 45℃~65℃ using a magnetic stirrer to fully dissolve the LiF powder in the hydrochloric acid to obtain a LiF / HCl mixed solution. Step 1.3: Add 1–1.5 g of Ti3AlC2MAX phase powder to a LiF / HCl mixed solution and stir for etching for 24–48 h. After the reaction is complete, pour the reaction solution into a plastic centrifuge tube, wash with deionized water, centrifuge for 5–15 min, discard the supernatant, add deionized water and centrifuge again, repeat washing until the pH of the supernatant is neutral, discard the supernatant, disperse the precipitate in 100 mL–200 mL of deionized water, sonicate in an ice-water bath for 2–3 h, then centrifuge the dispersion and take the dark green supernatant, which is the monolayer Ti3C2T x The dispersion was then freeze-dried for 24–48 h to obtain sheet-like Ti3C2T. x .

[0009] In step 1.3, the stirring etching speed is 350 rpm to 650 rpm.

[0010] In step 1.3, after washing the reaction solution with deionized water, the centrifugation speed is 3500 rpm to 5500 rpm.

[0011] In step 1.3, the ultrasonic power during ultrasonic treatment is 200W~300W.

[0012] The specific process of step 2 is as follows: Step 2.1: Add TEOS to anhydrous ethanol to prepare solution A; Step 2.2: Add NH4(OH) to ethanol to prepare solution B; Step 2.3: Magnetic stirring is performed on solution A obtained in step 2.1 and solution B obtained in step 2.2 respectively. Then, solution A is added dropwise to solution B, and the mixture is stirred for 6-12 hours. The resulting product is washed by centrifugation with distilled water and then dried overnight to obtain silica spheres. Step 2.4: Disperse the silica spheres prepared in step 2.3 in ethanol and then ultrasonically disperse them. Step 2.5: Dissolve 3-ATPS in an aqueous ethanol solution and stir for 0.5 to 1 hour; Step 2.6: The ultrasonically dispersed silica from step 2.4 is magnetically stirred under a nitrogen atmosphere for 0.5 to 1 hour, and the hydrolysis product 3-ATPS from step 2.5 is added. The reaction continues for 8 to 16 hours. The resulting solution is washed with deionized water and ethanol and centrifuged three times, and then vacuum dried to obtain modified silica.

[0013] The specific process of step 3 is as follows: Step 3.1, take the modified silica and Ti3C2T obtained in step 2. x The silica and Ti3C2T solutions were dispersed separately in deionized water and ultrasonicated for 30-60 minutes to obtain a uniformly dispersed silica solution and Ti3C2T solution. x Solution; Step 3.2, add silica solution and H2PtCl6 6H2O solution was added to Ti3C2T x In the solution, it is sonicated and then shaken overnight in a gas bath shaker; Step 3.3: The product obtained in step 3.2 is placed in a tube furnace and a reduction reaction is carried out in an argon-hydrogen mixed gas to obtain the catalyst for preparing a three-dimensional core-shell structure.

[0014] The second technical solution adopted in this invention is a three-dimensional core-shell structure catalyst for hydrogen energy storage, which is prepared by a method for preparing a three-dimensional core-shell structure catalyst for hydrogen energy storage.

[0015] The beneficial effects of this invention are: this invention uses Pt 0.6% / 40%SiO2@Ti3C2T x Based on a 215 nm three-dimensional core-shell structure, this method suppresses two-dimensional sheet stacking through three-dimensional open channels, enhances reactant / product diffusion and heat transfer, and leverages the defect sites of the MXene substrate to achieve effective anchoring and dispersion of Pt. This allows for a controllable reduction in Pt cluster size (from approximately 2.25 nm to 1.75 nm), maintaining a high proportion of active Pt(0) and high site accessibility even with low Pt dosage. Furthermore, it does not sacrifice toluene selectivity due to the introduction of silicon spheres, thus achieving a synergistic improvement in selectivity and long-term durability stability. This provides a generalizable structural paradigm and basis for the design of efficient, stable, and sustainable Pt-based catalysts for high-temperature alkane / cycloalkane dehydrogenation. Attached Figure Description

[0016] Figure 1(a) and Figure 1(b) are SEM images of the silicon spheres prepared and the modified silicon spheres prepared in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention; Figure 1(a) is the SEM image of the prepared silicon spheres; Figure 1(b) is the SEM image of the modified silicon spheres. Figure 2 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 1% / 40%SiO2@Ti3C2T x SEM image of the catalyst sample at -215 nm; Figure 3 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 1% / 40%SiO2@Ti3C2T x TEM image of the catalyst sample at -215 nm; Figure 4 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 1% / 40%SiO2@Ti3C2T x Dark-field HRTEM mapping of the catalyst sample at -215 nm; Figure 5 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 1% / 40%SiO2@Ti3C2T x HRTEM image of the catalyst sample at -215 nm and Pt particle size distribution. Figure 6 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 1% / 40%SiO2@Ti3C2T x XPS plot of Pt 4 catalyst sample at -215 nm f picture; Figure 7 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 0.6% / 40%SiO2@Ti3C2T x Performance diagram of MCH dehydrogenation catalysis by the -215 nm catalyst; Figure 8 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 0.6% / 40%SiO2@Ti3C2T x XRD patterns of MCH dehydrogenation before and after catalysis with a 215 nm catalyst; Figure 9 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 0.6% / 40%SiO2@Ti3C2T x Raman spectroscopy before and after MCH dehydrogenation catalyzed by the -215 nm catalyst. Detailed Implementation

[0017] The following detailed description is provided in conjunction with specific implementation methods.

[0018] The present invention discloses a method for preparing a three-dimensional core-shell structured catalyst for hydrogen energy storage, which specifically includes the following steps: Step 1, Obtain Ti3C2T sheets x Specifically: Weigh 1.6–2.4 g of LiF powder, measure 15–30 mL of concentrated hydrochloric acid (36 wt%), and 5–10 mL of deionized water. Pour the LiF powder, deionized water, and concentrated hydrochloric acid into a polytetrafluoroethylene bottle and heat to 45°C–65°C using a magnetic stirrer to fully dissolve the LiF powder in the hydrochloric acid (stirring for 5–10 min). Slowly add 1–1.5 g of Ti3AlC2MAX phase powder (200–400 mesh) to the LiF / HCl mixed solution (addition process 3–5 min). Observe a large number of bubbles emerging in the liquid, indicating the start of the reaction. Stir at a speed of 350 rpm–650 rpm and etch for 24–48 h. After the reaction is complete, pour the reaction solution into a plastic centrifuge tube, wash with deionized water, centrifuge at high speed (3500 rpm–5500 rpm) for 5–15 min, discard the supernatant, add deionized water, and centrifuge again. Wash repeatedly until the pH of the supernatant is neutral, then discard the supernatant. Disperse the precipitate in 100 mL–200 mL of deionized water and sonicate in an ice-water bath (200 W–300 W) for 2–3 h, then centrifuge the dispersion. Take the dark green supernatant, which is the monolayer Ti3C2T. x Dispersion. The dispersion was then freeze-dried for 24–48 h to obtain Ti3C2T sheets. x .

[0019] Step 2: Prepare modified silicon spheres; Step 2.1: Solution A was prepared by adding 3 mL of TEOS (tetraethyl silicate) to 2 mL of anhydrous ethanol, while solution B was prepared by adding 3–4 mL of NH₄(OH)₂ to 20–50 mL of ethanol. Solutions A and B were magnetically stirred separately for 30 minutes each. Then, solution A was added dropwise to solution B, and the mixture was stirred for 6–12 hours. The resulting product was washed several times by centrifugation with distilled water, and then dried overnight at 60°C to obtain silica spheres. Step 2.2: Disperse the prepared silica spheres in 5-10 mL of ethanol and sonicate for 30 minutes; dissolve 1-3 mL of 3-ATPS (3-aminopropyltriethoxysilane) in 10-20 mL of ethanol aqueous solution (ethanol to distilled water volume ratio of 1:1) and stir for 0.5-1 hour. The ultrasonically dispersed silica was magnetically stirred at 70°C for 0.5–1 hour under a nitrogen atmosphere, and the hydrolysis product 3-ATPS was slowly added. The reaction was continued for 8–16 hours. The resulting solution was further washed with deionized water and ethanol and centrifuged three times. Then it was dried overnight in a vacuum drying oven at 60°C to collect the modified silica.

[0020] Step 3, fabrication of a three-dimensional core-shell structure (three-dimensional Pt 0.6% / 40%SiO2@Ti3C2T x -n (where n represents the particle size of silicon spheres obtained with different ammonia concentrations) catalyst, specifically: Take a certain amount of modified SiO2 and Ti3C2T x Dispersed separately in 10-20 mL of deionized water (SiO2 and Ti3C2T) x The total mass is 0.3g, m=40% is the mass percentage of SiO2 to the total mass, take 0.12 g of modified SiO2, take 0.18 g of Ti3C2T x ( ), sonicate for 30-60 minutes. Then add a uniformly dispersed SiO2 solution and 1 mL of H2PtCl6. 6H2O (4.8 mg·mL -1 The solution was added to Ti3C2T x In the solution, the sample was sonicated for 30 min (m=40%) and then shaken overnight in a gas bath shaker at 60℃. The sample was then placed in a tube furnace and heated at 5℃ in an argon-hydrogen mixture (H2 / Ar volume ratio 9:1). min -1 The reduction reaction was carried out at 350℃ for 3 hours with a controlled heating rate to obtain Pt. 0.6% / 40%SiO2@Ti3C2T x catalyst.

[0021] Step 4, Three-dimensional porous Pt 0.6% / 40%SiO2@Ti3C2T x -n catalytic MCH dehydrogenation applications.

[0022] The conditions for the dehydrogenation reaction of methylcyclomethane in a fixed-bed reactor are: a dehydrogenation reaction temperature of 350℃, a dehydrogenation reaction pressure of 0.1–0.5 MPa, and a dehydrogenation reaction weight hourly space velocity of 5–20 h⁻¹. -1 .

[0023] Example 1 Weigh 2.2 g of lithium fluoride powder, measure 30 mL of concentrated hydrochloric acid (36 wt%), and 10 mL of deionized water. Pour the LiF powder, deionized water, and hydrochloric acid solution into a polytetrafluoroethylene bottle and heat to 55°C using a magnetic stirrer to fully dissolve the LiF powder in the hydrochloric acid (stirring for 5 min). Slowly add 1.3 g of Ti3AlC2MAX phase powder (400 mesh) to the LiF / HCl mixed solution (addition process 3 min). A large number of bubbles are observed emerging in the liquid, indicating the start of the reaction. Stir at 350 rpm and etch for 24 h. After the reaction is complete, pour the reaction solution into a plastic centrifuge tube, wash with deionized water, centrifuge at high speed (3500 rpm) for 5 min, discard the supernatant, add deionized water, and centrifuge again. Repeat washing until the pH of the supernatant is neutral, then discard the supernatant. The precipitate was dispersed in 100 mL of deionized water and sonicated (200 W) in an ice-water bath for 2 h. The dispersion was then centrifuged (5000 rpm) for 1 h. The dark green upper dispersion was collected and freeze-dried for 24 h to obtain lamellar Ti3C2T. x The obtained product was washed several times by centrifugation with distilled water and then dried overnight at 60 °C. Solution A was prepared by adding 3 mL of TEOS to 2 mL of anhydrous ethanol, while solution B was prepared by adding 3 mL of NH4(OH) to 30 mL of ethanol. Solutions A and B were magnetically stirred separately for 30 minutes. Then, solution A was added dropwise to solution B, and the mixture was stirred for 6 hours. The obtained product was washed several times by centrifugation with distilled water and then dried overnight at 60 °C. The silica spheres prepared above were dispersed in 5 mL of ethanol and ultrasonically dispersed for 30 minutes. 1 mL of 3-ATPS was dissolved in 10 mL of ethanol-water solution (ethanol to distilled water volume ratio of 1:1) and stirred for 0.5 hours. The ultrasonically dispersed silica was magnetically stirred at 70 °C for 0.5 hours under a nitrogen atmosphere, and the hydrolysis product 3-ATPS was slowly added. The reaction was continued for 8 hours. The resulting solution was further washed with deionized water and ethanol, and centrifuged three times. It was then dried overnight in a vacuum drying oven at 60°C, and the modified silica was collected. A certain amount of modified SiO2 and Ti3C2T were taken... x Dispersed separately in 10 mL of deionized water (SiO2 and Ti3C2T) x The total mass is 0.3g, of which 0.12g is modified SiO2 and 0.18g is Ti3C2T. x The mixture was ultrasonically treated for 30 minutes. Then, a uniformly dispersed SiO2 solution and 1 mL of H2PtCl6 were added. 6H2O (4.8 mg·mL) -1 The solution was added to Ti3C2T xIn the solution, the sample was sonicated for 30 min (m=40%) and then shaken overnight in a gas bath shaker at 60℃. The sample was then placed in a tube furnace and heated at 5℃ in an argon-hydrogen mixture (H2 / Ar volume ratio 9:1). min -1 The temperature was increased at a rate that allowed for a reduction reaction at 350°C for 3 hours. Pt was then obtained. 0.6% / 40%SiO2@Ti3C2T x -215 nm and Pt 1% / 40% SiO2@Ti3C2T x -215 nm catalyst. The conditions for the dehydrogenation of methylcyclomethane in a fixed-bed reactor were: a dehydrogenation temperature of 350 °C, a dehydrogenation pressure of 0.31 MPa, and a weight hourly space velocity of 7.7 h⁻¹. -1 .

[0024] Comparative Example 1 (The amount of silicon spheres was changed in step 3, m=20, 60 and 80%) Weigh 2.2 g of lithium fluoride powder, measure 30 mL of concentrated hydrochloric acid (36 wt%), and 10 mL of deionized water. Pour the LiF powder, deionized water, and hydrochloric acid solution into a polytetrafluoroethylene bottle and heat to 55°C using a magnetic stirrer to fully dissolve the LiF powder in the hydrochloric acid (stirring for 5 min). Slowly add 1.3 g of Ti3AlC2MAX phase powder (400 mesh) to the LiF / HCl mixed solution (addition process 3 min). A large number of bubbles are observed emerging in the liquid, indicating the start of the reaction. Stir at 350 rpm and etch for 24 h. After the reaction is complete, pour the reaction solution into a plastic centrifuge tube, wash with deionized water, centrifuge at high speed (3500 rpm) for 5 min, discard the supernatant, add deionized water, and centrifuge again. Repeat washing until the pH of the supernatant is neutral, then discard the supernatant. The precipitate was dispersed in 100 mL of deionized water and sonicated (200 W) in an ice-water bath for 2 h. The dispersion was then centrifuged (5000 rpm) for 1 h. The dark green upper dispersion was collected and freeze-dried for 24 h to obtain lamellar Ti3C2T. xThe obtained product was washed several times by centrifugation with distilled water and then dried overnight at 60 °C. Solution A was prepared by adding 3 mL of TEOS to 2 mL of anhydrous ethanol, while solution B was prepared by adding a certain amount of NH4(OH) to 30 mL of ethanol. Solutions A and B were magnetically stirred separately for 30 minutes. Then, solution A was added dropwise to solution B, and the mixture was stirred for 6 hours. The obtained product was washed several times by centrifugation with distilled water and then dried overnight at 60 °C. The silica spheres prepared above were dispersed in 5 mL of ethanol and ultrasonically dispersed for 30 minutes. 1 mL of 3-ATPS was dissolved in 10 mL of ethanol-water solution (ethanol to distilled water volume ratio of 1:1) and stirred for 0.5 hours. The ultrasonically dispersed silica was magnetically stirred at 70 °C for 0.5 hours under a nitrogen atmosphere, and the hydrolysis product 3-ATPS was slowly added. The reaction was continued for 8 hours. The resulting solution was further washed with deionized water and ethanol, and centrifuged three times. It was then dried overnight in a vacuum oven at 60°C to collect the modified silica. A certain amount of modified SiO2 and Ti3C2T were taken... x Dispersed separately in 10 mL of deionized water (SiO2 and Ti3C2T) x The total mass was 0.3 g), and the mixture was sonicated for 30 min. Then, a uniformly dispersed SiO2 solution and 1 mL of H2PtCl6 were added. 6H2O (8 mg·mL -1 The solution was added to Ti3C2T x In the solution, the sample was sonicated for 30 min (m = 20, 60, and 80% are the mass percentages of SiO2 relative to the total mass), and then shaken overnight in a gas bath shaker at 60°C. The sample was then placed in a tube furnace and heated at 5°C in an argon-hydrogen mixture (H2 / Ar volume ratio 9:1). min -1 The temperature was increased at a rate that allowed for a reduction reaction at 350°C for 3 hours. Pt was then obtained. 1% / 20%SiO2@Ti3C2T x -215nm, Pt 1% / 60%SiO2@Ti3C2T x -215 nm and Pt 1% / 80%SiO2@Ti3C2T x -215 nm catalyst. The conditions for the dehydrogenation of methylcyclomethane in a fixed-bed reactor were: a dehydrogenation temperature of 350 °C, a dehydrogenation pressure of 0.31 MPa, and a weight hourly space velocity of 7.7 h⁻¹. -1 .

[0025] Comparative Example 2 (Adjusting the amount of ammonia water in step 2 to 3 mL, 5 mL, 6 mL, 7 mL, and 8 mL can prepare silica microspheres with particle sizes of 70 nm, 215 nm, 450 nm, 675 nm, and 850 nm, respectively.) Weigh 2.2 g of lithium fluoride powder, measure 30 mL of concentrated hydrochloric acid (36 wt%), and 10 mL of deionized water. Pour the LiF powder, deionized water, and hydrochloric acid solution into a polytetrafluoroethylene bottle and heat to 55°C using a magnetic stirrer to fully dissolve the LiF powder in the hydrochloric acid (stirring for 5 min). Slowly add 1.3 g of Ti3AlC2MAX phase powder (400 mesh) to the LiF / HCl mixed solution (addition process 3 min). A large number of bubbles are observed emerging in the liquid, indicating the start of the reaction. Stir at 350 rpm and etch for 24 h. After the reaction is complete, pour the reaction solution into a plastic centrifuge tube, wash with deionized water, centrifuge at high speed (3500 rpm) for 5 min, discard the supernatant, add deionized water, and centrifuge again. Repeat washing until the pH of the supernatant is neutral, then discard the supernatant. The precipitate was dispersed in 100 mL of deionized water and sonicated (200 W) in an ice-water bath for 2 h. The dispersion was then centrifuged (5000 rpm) for 1 h. The dark green upper dispersion was collected and freeze-dried for 24 h to obtain lamellar Ti3C2T. x The obtained products were washed several times by centrifugation with distilled water and then dried overnight at 60 °C. Solution A was prepared by adding a certain amount of TEOS (5, 6, 7, and 8 mL of ammonia water) to 2 mL of anhydrous ethanol, while solution B was prepared by adding a certain amount of NH4(OH) to 30 mL of ethanol. Solutions A and B were magnetically stirred separately for 30 minutes. Then, solution A was added dropwise to solution B, and the mixture was stirred for 6 hours. The obtained products were washed several times by centrifugation with distilled water and then dried overnight at 60 °C. Silica microspheres with particle sizes of 70, 450, 675, and 850 nm were prepared. The prepared silica microspheres were dispersed in 5 mL of ethanol and ultrasonically dispersed for 30 minutes. 1 mL of 3-ATPS was dissolved in 10 mL of ethanol-water solution (ethanol to distilled water volume ratio of 1:1) and stirred for 0.5 hours. Ultrasonically dispersed silica was magnetically stirred at 70°C for 0.5 hours under a nitrogen atmosphere. The hydrolysis product 3-ATPS was slowly added, and the reaction continued for 8 hours. The resulting solution was further washed with deionized water and ethanol, and centrifuged three times. It was then dried overnight in a vacuum oven at 60°C to collect the modified silica. A certain amount of modified SiO2 and Ti3C2T were taken... x Dispersed separately in 10 mL of deionized water (SiO2 and Ti3C2T) xThe total mass was 0.3 g), and the mixture was sonicated for 30 min. Then, a uniformly dispersed SiO2 solution and 1 mL of H2PtCl6 were added. 6H2O (4.8 mg·mL -1 The solution was added to Ti3C2T x In the solution, the sample was sonicated for 30 min (m = 40%, which is the mass percentage of SiO2 to the total mass), and then shaken overnight in a gas bath shaker at 60℃. The sample was then placed in a tube furnace and heated at 5℃ in an argon-hydrogen mixture (H2 / Ar volume ratio 9:1). min -1 The temperature was increased at a rate that allowed for a reduction reaction at 350°C for 3 hours. Pt was then obtained. 0.6% / 40%SiO2@Ti3C2T x -70 nm, Pt 0.6% / 40%SiO2@Ti3C2T x -450 nm, Pt 0.6% / 40%SiO2@Ti3C2T x -675 nm and Pt 0.6% / 40%SiO2@Ti3C2T x -850 nm catalyst. The conditions for the dehydrogenation of methylcyclomethane in a fixed-bed reactor were: a dehydrogenation temperature of 350 °C, a dehydrogenation pressure of 0.31 MPa, and a weight hourly space velocity of 7.7 h⁻¹. -1 .

[0026] Comparative Example 3 (without step 1) Solution A was prepared by adding 3 mL of TEOS to 2 mL of anhydrous ethanol, while solution B was prepared by adding a certain amount of NH4(OH) to 30–50 mL of ethanol. Solutions A and B were magnetically stirred separately for 30 minutes. Then, solution A was added dropwise to solution B, and the mixture was stirred for 6 hours. The resulting product was washed several times by centrifugation with distilled water and then dried overnight at 60 °C. The prepared silica spheres were dispersed in 5 mL of ethanol and ultrasonically dispersed for 30 minutes. 1 mL of 3-ATPS was dissolved in 10 mL of an aqueous ethanol solution (ethanol to distilled water volume ratio 1:1) and stirred for 0.5 hours. The ultrasonically dispersed silica was magnetically stirred at 70 °C for 0.5 hours under a nitrogen atmosphere, and the hydrolysis product 3-ATPS was slowly added, with the reaction continuing for 8 hours. The resulting solution was further washed with deionized water and ethanol, and centrifuged three times, then dried overnight in a vacuum drying oven at 60 °C to collect the modified silica. 0.3 g of modified SiO2 was dispersed in 10 mL of deionized water and sonicated for 30 min. Then 1 mL of H2PtCl6 was added. 6H2O (8 mg·mL -1The solution was added to a uniformly dispersed SiO2 solution, sonicated for 30 min, and then shaken overnight in a 60℃ gas bath shaker. The sample was then placed in a tube furnace and heated at 5℃ in an argon-hydrogen mixture (H2 / Ar volume ratio 9:1). min -1 The temperature was increased at a rate that allowed for a reduction reaction at 350°C for 3 hours. Pt was then obtained. 1% / SiO2 catalyst. The conditions for the dehydrogenation reaction of methylcyclomethane in a fixed-bed reactor were: a dehydrogenation temperature of 350℃, a dehydrogenation pressure of 0.31 MPa, and a weight hourly space velocity of 7.7 h⁻¹. -1 .

[0027] Comparative Example 4 (without step 2) Weigh 2.2 g of lithium fluoride powder, measure 30 mL of concentrated hydrochloric acid (36 wt%), and 10 mL of deionized water. Pour the LiF powder, deionized water, and hydrochloric acid solution into a polytetrafluoroethylene bottle and heat to 55°C using a magnetic stirrer to fully dissolve the LiF powder in the hydrochloric acid (stirring for 5 min). Slowly add 1.3 g of Ti3AlC2MAX phase powder (400 mesh) to the LiF / HCl mixed solution (addition process 3 min). A large number of bubbles are observed emerging in the liquid, indicating the start of the reaction. Stir at 350 rpm and etch for 24 h. After the reaction is complete, pour the reaction solution into a plastic centrifuge tube, wash with deionized water, centrifuge at high speed (3500 rpm) for 5 min, discard the supernatant, add deionized water, and centrifuge again. Repeat washing until the pH of the supernatant is neutral, then discard the supernatant. The precipitate was dispersed in 100 mL of deionized water and sonicated (200 W) in an ice-water bath for 2 h. The dispersion was then centrifuged (5000 rpm) for 1 h. The dark green upper dispersion was collected and freeze-dried for 24 h to obtain lamellar Ti3C2T. x The obtained product was washed several times by centrifugation with distilled water, and then dried overnight at 60 °C. Take 0.3 g of Ti3C2T... x Disperse each ingredient separately in 10 mL of deionized water and sonicate for 30 min. Then add 1 mL of H₂PtCl₆. 6H2O (4.8 mg·mL -1 The solution was added to Ti3C2T x The solution was sonicated for 30 min and then shaken overnight in a gas bath shaker at 60 °C. The sample was then placed in a tube furnace and heated at 5 °C in an argon-hydrogen mixture (H2 / Ar volume ratio 9:1). min -1 The temperature was increased at a rate that allowed for a reduction reaction at 350°C for 3 hours. Pt was then obtained. 0.6% / Ti3C2T xCatalyst. The conditions for the dehydrogenation reaction of methylcyclomethane in a fixed-bed reactor are: a dehydrogenation temperature of 350 °C, a dehydrogenation pressure of 0.31 MPa, and a weight hourly space velocity (WHSV) of 7.7 h⁻¹. -1 .

[0028] Figure 1(a) and Figure 1(b) are SEM images of the silicon spheres prepared and the modified silicon spheres prepared in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention; Figure 1(a) is the SEM image of the prepared silicon spheres; Figure 1(b) is the SEM image of the modified silicon spheres; By comparing Figure 1(a) and Figure 1(b), it can be seen that there is no change on the surface of the silicon spheres before and after modification.

[0029] Figure 2 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 1% / 40%SiO2@Ti3C2T x SEM image of the catalyst sample at -215 nm; from Figure 2 It can be seen that the modified silicon spheres and Ti3C2T x Electrostatic self-assembly forms a three-dimensional core-shell structure.

[0030] Figure 3 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 1% / 40%SiO2@Ti3C2T x TEM image of the catalyst sample at -215 nm; from Figure 3 As can be seen, the Pt particles are small and evenly dispersed.

[0031] Figure 4 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 1% / 40%SiO2@Ti3C2T x Dark-field HRTEM mapping of the catalyst sample at -215 nm; from Figure 4 We can see Ti3C2T x Nanosheets are wrapped around modified silicon spheres, while Pt is mainly distributed in the Ti3C2T "shell". x On nanosheets.

[0032] Figure 5 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 1% / 40%SiO2@Ti3C2T x HRTEM image of the catalyst sample at -215 nm and Pt particle size distribution; from Figure 5The fitting analysis revealed that the average Pt particle size was 1.75 nm. This indicates that the core-shell structure reduces stacking, improves the accessibility of Pt active sites, and results in highly dispersed and small-sized platinum clusters.

[0033] Figure 6 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 1% / 40%SiO2@Ti3C2T x XPS plot of Pt 4 catalyst sample at -215 nm f Image; from Figure 6 It can be seen that, after fitting and peak-splitting analysis, the valence state distribution of Pt sub-nanometer clusters is mainly Pt(0), accounting for 63.84%, which is better than existing technologies. This is also the main reason for the good dehydrogenation effect of MCH. The Pt obtained in Comparative Example 3... 1% / SiO2 catalyst, with Pt 4+ Its presence is not conducive to dehydrogenation, thus resulting in poor catalytic activity.

[0034] Figure 7 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 0.6% / 40%SiO2@Ti3C2T x Performance graph of MCH dehydrogenation catalysis by the -215 nm catalyst; from Figure 7 As can be seen, the catalyst maintained good stability and activity throughout the 72-hour reaction, with the conversion rate remaining at 67%, and the activity decreasing by only 2.1% until the reaction ended. Its highest hydrogen release rate reached 456.42 mmol·g⁻¹. Pt -1 ·min -1 And it never fell below 440 mmol·g Pt -1 ·min -1 This also illustrates that the structural design of the catalyst and the controllable structure of Pt sub-nano clusters are crucial for improving the catalytic activity of MCH.

[0035] Figure 8 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 0.6% / 40%SiO2@Ti3C2T x XRD patterns of MCH dehydrogenation catalyzed by the -215 nm catalyst before and after; according to the spectral analysis, the characteristic peaks did not shift or additional peaks appeared, indicating that Pt 0.6% / 40%SiO2@Ti3C2T x The -215 nm catalyst exhibits stable properties during long-term reactions.

[0036] Figure 9 The Pt obtained in Example 1 of the preparation method of the three-dimensional core-shell structure catalyst for hydrogen energy storage of the present invention is shown. 0.6% / 40%SiO2@Ti3C2T x Raman spectroscopy of MCH dehydrogenation before and after catalysis at -215 nm catalyst. According to spectral analysis, for carbon-structured materials, both the D and G peaks are characteristic peaks of C atomic crystals, while Pt... 0.6% / 40%SiO2@Ti3C2T x -215 nm catalyst at 1378 cm⁻¹ -1 and 1585 cm -1 The characteristic peaks at these locations correspond to amorphous carbon and graphitic carbon, respectively. Their intensities are greater than those of I. D / I G To a certain extent, this reflects the degree of defects in material C. Comparing the strength ratio before and after catalyst use, there was no change, and no carbon deposition appeared on the surface. This is consistent with experimental results, indicating that Pt... 0.6% / 40%SiO2@Ti3C2T x -215 nm is an excellent catalyst that can be used for long-term stable catalytic dehydrogenation of MCH.

[0037] Table 1 shows the Pt obtained in Example 1. 0.6% / 40%SiO2@Ti3C2T x The -215 nm catalyst exhibited the best dehydrogenation effect on MCH. In Comparative Example 1, the dehydrogenation reaction efficiency first increased and then decreased with increasing silicon sphere ratio, indicating that an appropriate amount of silicon spheres is needed to optimally expose the Pt active sites on the catalyst and form a three-dimensional core-shell structure, which is beneficial for mass and heat transfer in heterogeneous catalytic reactions. Therefore, the catalytic effect was good, and the selectivity decreased with increasing silicon sphere ratio and particle size. This may be because the O groups on the surface of the silicon spheres in Comparative Example 3 have a strong ability to anchor Pt, forming Pt... 4+ High proportions of MCH result in different adsorption configurations on the catalyst surface, leading to poor activity and selectivity. In Comparative Example 2, as the silicon sphere particle size increases, the dehydrogenation effect initially increases and then decreases, with selectivity decreasing as the silicon sphere particle size increases. Comparative Example 3 exhibits the lowest selectivity. Comparative Example 4 shows higher activity than Comparative Example 3, primarily due to its surface Ti-O anchoring of Pt to form Pt clusters without Pt. 4+ The activity and selectivity of Pt are higher. 4+ Comparative Example 3 is better. Its activity is lower than that of Example 1, mainly because Ti3C2T x The stacking of Pt itself results in low accessibility to active sites.

[0038] Table 1 Comparison of catalyst dehydrogenation effects under different conditions

[0039] Example 2 Weigh 1.6 g of lithium fluoride powder, measure 15 mL of concentrated hydrochloric acid (36 wt%), and 5 mL of deionized water. Pour the LiF powder, deionized water, and hydrochloric acid solution into a polytetrafluoroethylene bottle and heat to 45°C using a magnetic stirrer to fully dissolve the LiF powder in the hydrochloric acid (stirring for 5 min). Slowly add 1 g of Ti3AlC2MAX phase powder (300 mesh) to the LiF / HCl mixed solution (addition process 4 min). A large number of bubbles are observed emerging in the liquid, indicating the start of the reaction. Stir at 550 rpm and etch for 36 h. After the reaction is complete, pour the reaction solution into a plastic centrifuge tube, wash with deionized water, centrifuge at high speed (4500 rpm) for 10 min, discard the supernatant, add deionized water, and centrifuge again. Repeat washing until the pH of the supernatant is neutral, then discard the supernatant. The precipitate was dispersed in 150 mL of deionized water and sonicated (260 W) in an ice-water bath for 2.5 h, followed by centrifugation (5000 rpm) for 1 h. The dark green upper dispersion was collected and freeze-dried for 36 h to obtain lamellar Ti3C2T. x The obtained product was washed several times by centrifugation with distilled water and then dried overnight at 60 °C. Solution A was prepared by adding 3 mL of TEOS to 2 mL of anhydrous ethanol, while solution B was prepared by adding 3.5 mL of NH4(OH) to 20 mL of ethanol. Solutions A and B were magnetically stirred separately for 30 minutes. Then, solution A was added dropwise to solution B, and the mixture was stirred for 10 hours. The obtained product was washed several times by centrifugation with distilled water and then dried overnight at 60 °C. The silica spheres prepared above were dispersed in 8 mL of ethanol and ultrasonically dispersed for 30 minutes. 2 mL of 3-ATPS was dissolved in 15 mL of ethanol-water solution (ethanol to distilled water volume ratio of 1:1) and stirred for 0.8 hours. The ultrasonically dispersed silica was magnetically stirred at 70 °C for 0.8 hours under a nitrogen atmosphere, and the hydrolysis product 3-ATPS was slowly added. The reaction continued for 10 hours. The resulting solution was further washed with deionized water and ethanol, and centrifuged three times. It was then dried overnight in a vacuum drying oven at 60°C, and the modified silica was collected. A certain amount of modified SiO2 and Ti3C2T were taken... x Dispersed separately in 15 mL of deionized water (SiO2 and Ti3C2T) x The total mass is 0.3g, of which 0.12g is modified SiO2 and 0.18g is Ti3C2T. x ( ), sonicated for 40 min. Then, a uniformly dispersed SiO2 solution and 1 mL of H2PtCl6 were added. 6H2O (4.8 mg·mL) -1 The solution was added to Ti3C2Tx In the solution, the sample was sonicated for 30 min (m=40%) and then shaken overnight in a gas bath shaker at 60℃. The sample was then placed in a tube furnace and heated at 5℃ in an argon-hydrogen mixture (H2 / Ar volume ratio 9:1). min -1 The temperature was increased at a rate that allowed for a reduction reaction at 350°C for 3 hours. Pt was then obtained. 0.6% / 40%SiO2@Ti3C2T x -215 nm and Pt 1% / 40% SiO2@Ti3C2T x -215 nm catalyst. The conditions for the dehydrogenation of methylcyclomethane in a fixed-bed reactor were: a dehydrogenation temperature of 350 °C, a dehydrogenation pressure of 0.1 MPa, and a weight hourly space velocity of 5 h⁻¹. -1 .

[0040] Example 3 Weigh 2.4 g of lithium fluoride powder, measure 30 mL of concentrated hydrochloric acid (36 wt%), and 10 mL of deionized water. Pour the LiF powder, deionized water, and hydrochloric acid solution into a polytetrafluoroethylene bottle and heat to 65°C using a magnetic stirrer to fully dissolve the LiF powder in the hydrochloric acid (stirring for 10 min). Slowly add 1.5 g of Ti3AlC2MAX phase powder (200 mesh) to the LiF / HCl mixed solution (addition process 5 min). Observe a large number of bubbles emerging in the liquid, indicating that the reaction has started. Stir at 650 rpm and etch for 48 h. After the reaction is complete, pour the reaction solution into a plastic centrifuge tube, wash with deionized water, centrifuge at high speed (5500 rpm) for 15 min, discard the supernatant, add deionized water, and centrifuge again. Repeat washing until the pH of the supernatant is neutral, then discard the supernatant. The precipitate was dispersed in 200 mL of deionized water and sonicated (300 W) in an ice-water bath for 3 h. The dispersion was then centrifuged (5000 rpm) for 1 h. The dark green upper dispersion was collected and freeze-dried for 48 h to obtain lamellar Ti3C2T. xThe obtained product was washed several times by centrifugation with distilled water and then dried overnight at 60 °C. Solution A was prepared by adding 3 mL of TEOS to 2 mL of anhydrous ethanol, while solution B was prepared by adding 4 mL of NH4(OH) to 50 mL of ethanol. Solutions A and B were magnetically stirred separately for 30 minutes. Then, solution A was added dropwise to solution B, and the mixture was stirred for 12 hours. The obtained product was washed several times by centrifugation with distilled water and then dried overnight at 60 °C. The silica spheres prepared above were dispersed in 10 mL of ethanol and ultrasonically dispersed for 30 minutes. 3 mL of 3-ATPS was dissolved in 20 mL of ethanol-water solution (ethanol to distilled water volume ratio of 1:1) and stirred for 1 hour. The ultrasonically dispersed silica was magnetically stirred at 70 °C for 1 hour under a nitrogen atmosphere, and the hydrolysis product 3-ATPS was slowly added. The reaction continued for 16 hours. The resulting solution was further washed with deionized water and ethanol, and centrifuged three times. It was then dried overnight in a vacuum drying oven at 60°C, and the modified silica was collected. A certain amount of modified SiO2 and Ti3C2T were taken... x Dispersed separately in 20 mL of deionized water (SiO2 and Ti3C2T) x The total mass is 0.3g, of which 0.12g is modified SiO2 and 0.18g is Ti3C2T. x ( ), sonicated for 60 min. Then, a uniformly dispersed SiO2 solution and 1 mL of H2PtCl6 were added. 6H2O (4.8 mg·mL -1 The solution was added to Ti3C2T x In the solution, the sample was sonicated for 30 min (m=40%) and then shaken overnight in a gas bath shaker at 60℃. The sample was then placed in a tube furnace and heated at 5℃ in an argon-hydrogen mixture (H2 / Ar volume ratio 9:1). min -1 The temperature was increased at a rate that allowed for a reduction reaction at 350°C for 3 hours. Pt was then obtained. 0.6% / 40%SiO2@Ti3C2T x -215 nm and Pt 1% / 40% SiO2@Ti3C2T x -215 nm catalyst. The conditions for the dehydrogenation of methylcyclomethane in a fixed-bed reactor were: a dehydrogenation temperature of 350 °C, a dehydrogenation pressure of 0.5 MPa, and a weight hourly space velocity of 20 h⁻¹. -1 .

[0041] Example 4 Compared with Example 1, the etching time in step 1 is 26 hours, and the remaining steps are the same as in Example 1.

[0042] Example 5 Compared with Example 1, in step 2, the time for adding solution A to solution B and stirring the mixture is 8 hours, and the remaining steps are the same as in Example 1.

[0043] Example 6 Compared with Example 1, in step 3, the ultrasonic treatment time is 55 minutes, and the remaining steps are the same as in Example 1.

Claims

1. A method for preparing a three-dimensional core-shell structured catalyst for hydrogen energy storage, characterized in that: Specifically, the steps include the following: Step 1, Preparation of Ti3C2T sheets x ; Step 2: Prepare modified silicon spheres; Step 3: Prepare a three-dimensional core-shell structured catalyst based on the products obtained in Step 1 and Step 2.

2. The method for preparing a three-dimensional core-shell structure catalyst for hydrogen energy storage according to claim 1, characterized in that: The specific process of step 1 is as follows: Step 1.1: Weigh 1.6–2.4 g of LiF powder, measure 15–30 mL of concentrated hydrochloric acid, and 5–10 mL of deionized water. Step 1.2: Pour the LiF powder, deionized water and concentrated hydrochloric acid weighed in Step 1.1 into a polytetrafluoroethylene bottle, and heat it at 45℃~65℃ using a magnetic stirrer to fully dissolve the LiF powder in the hydrochloric acid to obtain a LiF / HCl mixed solution. Step 1.3: Add 1–1.5 g of Ti3AlC2MAX phase powder to a LiF / HCl mixed solution and stir for etching for 24–48 h. After the reaction is complete, pour the reaction solution into a plastic centrifuge tube, wash with deionized water, centrifuge for 5–15 min, discard the supernatant, add deionized water and centrifuge again, repeat washing until the pH of the supernatant is neutral, discard the supernatant, disperse the precipitate in 100 mL–200 mL of deionized water, sonicate in an ice-water bath for 2–3 h, then centrifuge the dispersion and take the dark green supernatant, which is the monolayer Ti3C2T x The dispersion was then freeze-dried for 24–48 h to obtain sheet-like Ti3C2T. x .

3. The method for preparing a three-dimensional core-shell structure catalyst for hydrogen energy storage according to claim 2, characterized in that: In step 1.3, the stirring etching speed is 350 rpm to 650 rpm.

4. The method for preparing a three-dimensional core-shell structure catalyst for hydrogen energy storage according to claim 2, characterized in that: In step 1.3, after the reaction solution is washed with deionized water, the centrifugation speed is 3500 rpm to 5500 rpm.

5. The method for preparing a three-dimensional core-shell structure catalyst for hydrogen energy storage according to claim 2, characterized in that: In step 1.3, the ultrasonic power during ultrasonic treatment is 200W~300W.

6. The method for preparing a three-dimensional core-shell structure catalyst for hydrogen energy storage according to claim 2, characterized in that: The specific process of step 2 is as follows: Step 2.1: Add TEOS to anhydrous ethanol to prepare solution A; Step 2.2: Add NH4(OH) to ethanol to prepare solution B; Step 2.3: Magnetic stirring is performed on solution A obtained in step 2.1 and solution B obtained in step 2.2 respectively. Then, solution A is added dropwise to solution B, and the mixture is stirred for 6-12 hours. The resulting product is washed by centrifugation with distilled water and then dried overnight to obtain silica spheres. Step 2.4: Disperse the silica spheres prepared in step 2.3 in ethanol and then ultrasonically disperse them. Step 2.5: Dissolve 3-ATPS in an aqueous ethanol solution and stir for 0.5 to 1 hour; Step 2.6: The ultrasonically dispersed silica from step 2.4 is magnetically stirred under a nitrogen atmosphere for 0.5 to 1 hour, and the hydrolysis product 3-ATPS from step 2.5 is added. The reaction continues for 8 to 16 hours. The resulting solution is washed with deionized water and ethanol and centrifuged three times, and then vacuum dried to obtain modified silica.

7. The method for preparing a three-dimensional core-shell structure catalyst for hydrogen energy storage according to claim 6, characterized in that: The specific process of step 3 is as follows: Step 3.1, take the modified silica and Ti3C2T obtained in step 2. x The silica and Ti3C2T solutions were dispersed separately in deionized water and ultrasonicated for 30-60 minutes to obtain a uniformly dispersed silica solution and Ti3C2T solution. x Solution; Step 3.2, add silica solution and H2PtCl6 6H2O solution was added to Ti3C2T x In the solution, it is sonicated and then shaken overnight in a gas bath shaker; Step 3.3: The product obtained in step 3.2 is placed in a tube furnace and a reduction reaction is carried out in an argon-hydrogen mixed gas to obtain a three-dimensional core-shell structure.

8. A three-dimensional core-shell structure catalyst for hydrogen energy storage, prepared by the method described in any one of claims 1 to 7.

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