CN110538652A - A kind of hydrotalcite-like material with sheet-shaped hierarchical porous structure, preparation method of catalyst and application of the catalyst in propane dehydrogenation - Google Patents

Abstract

The invention discloses a method for preparing a hydrotalcite-like material and a catalyst with a plate-shaped multi-level porous structure. The material is prepared by mixing a salt solution containing divalent and trivalent metal ions with a precipitant and performing a hydrothermal reaction. Then, the sheet-shaped hydrotalcite-like material is obtained after filtering, washing, drying and roasting; and the sheet-shaped multi-level porous structure hydrotalcite-like material or catalyst is obtained through multiple dipping, drying and roasting. The hydrotalcite-like material with sheet-shaped multi-level porous structure prepared by the method has the characteristics of large specific surface area, stable structure and thin sheet. The hydrotalcite-like catalyst with sheet-shaped hierarchical porous structure is used in propane dehydrogenation, because it has complex internal channels, high stability, and the thickness of the sheet is about 12nm, so it has high activity and life. The hydrotalcite-like material with sheet-shaped multi-level pore structure disclosed by the invention has a simple preparation process and has broad application prospects.

Description

A preparation method of a sheet-shaped multi-level porous structure hydrotalcite-like material, a catalyst, and the Application of Catalyst in Propane Dehydrogenation

technical field

The invention belongs to the technical field of catalytic materials, and in particular relates to a hydrotalcite-like material with sheet-shaped multi-level porous structure, a preparation method of a catalyst and an application of the catalyst in propane dehydrogenation.

Background technique

Propane dehydrogenation to propylene catalysts can be mainly divided into two categories: Pt-based catalysts and Cr-based catalysts. Cr-based catalysts will be deactivated rapidly due to carbon deposition, poor stability and toxicity, and cause harm to the environment; Pt-based catalysts have excellent catalytic performance, are green and environmentally friendly, and have development potential, but the active component Pt is easy to sinter and high temperature. The problem of deactivation due to coking and carbon deposition.

Hydrotalcite-like compounds (HT) is a compound assembled by the interaction between the positive charge of the main layer and the non-covalent bond between the anions between the layers. Due to its special structure, HT has many advantages. , such as laminate metal ions can be uniformly dispersed at the atomic level, the composition ratio of main laminate cations and interlayer anions can be adjusted, interlayer anions can be intercalated, and the structure topology can be transformed. The excellent properties of HT make it widely used in flame retardant materials, medicine, ion exchange, catalysis and other fields.

In the study of propane dehydrogenation supported by HT calcined products, Pt-based catalysts derived from HT showed good dehydrogenation activity and propylene selectivity due to its many advantages, but the calcined particles were easy to crush during the reaction. It leads to the sintering deactivation of the Pt-based metal center, and at the same time, the active center and the pores are easily covered by carbon deposits, which reduces the selectivity and bed blockage, so that the catalytic effect cannot be fully exerted.

Hierarchical porous structure HT materials have the characteristics of high specific surface area, stable structure, and thinner lamellae, and are currently the hotspots of HT research. The medium energy exists stably, and there is no thinner HT material that can be applied to high temperature reactions.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing sheet-shaped multi-level porous structure hydrotalcite-like materials. The method is simple, convenient, safe and green, and has broad application prospects. The hydrotalcite-like material with sheet-shaped hierarchical porous structure was applied to propane dehydrogenation reaction, showing high activity and stability.

The present invention is achieved through the following technical solutions:

A method for preparing a sheet-shaped hierarchical porous structure hydrotalcite-like material:

Step 1, using a polar solution to prepare a mixed solution of the first metal salt, the second metal salt and the precipitating agent, placing the mixed solution in an airtight kettle for hydrothermal reaction, and washing and drying the precipitate to obtain Sheet-shaped hydrotalcite-like materials;

The first metal salt is magnesium nitrate, nickel nitrate, zinc nitrate, cobalt nitrate, copper nitrate, manganese nitrate, ferrous nitrate, magnesium chloride, nickel chloride, zinc chloride, cobalt chloride, copper chloride, manganese chloride , one or more of ferrous chloride, magnesium sulfate, nickel sulfate, zinc sulfate, cobalt sulfate, copper sulfate, manganese sulfate, and ferrous sulfate; the second metal salt is aluminum nitrate, iron nitrate, cobalt nitrate , one or more of chromium nitrate, aluminum chloride, ferric chloride, cobalt chloride, chromium chloride, aluminum sulfate, iron sulfate, cobalt sulfate, chromium sulfate, the first metal salt and the second metal salt are The sum of the concentrations in the mixed solution is 0.01 to 1.5 mol/L;

The molar ratio of the first metal salt to the second metal salt is 1-6:1;

The precipitant is one or more of urea, triethanolamine, ammonia or hexamethyleneamine, and the molar ratio of the precipitant to the second metal salt is 1 to 30:1;

The reaction temperature of the hydrothermal reaction is 90-180°C, and the reaction time is 4-72 hours;

Step 2, using the dipping method to process the sheet-shaped hydrotalcite-like material obtained after step 1 is completed, first roasting the sheet-shaped hydrotalcite-like material to obtain a roasted product of the sheet-shaped hydrotalcite-like material; The roasted product of the sheet-shaped hydrotalcite-like material is immersed in an acidic solution or an alkaline solution for 2 to 10 hours, and the roasted product of the sheet-shaped hydrotalcite-like material impregnated with the acidic solution or alkaline solution is dried to obtain a sheet A hydrotalcite-like material with hierarchical porous structure; the pH value of the acidic solution is 1-4, and the pH value of the alkaline solution is 8-10.

A method for preparing a sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst:

Step 1, using a polar solution to prepare a mixed solution of the first metal salt, the second metal salt and the precipitating agent, placing the mixed solution in an airtight kettle for hydrothermal reaction, and washing and drying the precipitate to obtain Sheet-shaped hydrotalcite-like materials;

The first metal salt is magnesium nitrate, nickel nitrate, zinc nitrate, cobalt nitrate, copper nitrate, manganese nitrate, ferrous nitrate, magnesium chloride, nickel chloride, zinc chloride, cobalt chloride, copper chloride, manganese chloride , one or more of ferrous chloride, magnesium sulfate, nickel sulfate, zinc sulfate, cobalt sulfate, copper sulfate, manganese sulfate, and ferrous sulfate; the second metal salt is aluminum nitrate, iron nitrate, cobalt nitrate , one or more of chromium nitrate, aluminum chloride, ferric chloride, cobalt chloride, chromium chloride, aluminum sulfate, iron sulfate, cobalt sulfate, chromium sulfate, the first metal salt and the second metal The sum of the concentration of salt in the mixed solution is 0.01-1.5mol/L;

The molar ratio of the first metal salt to the second metal salt is 1-6:1;

The precipitant is one or more of urea, triethanolamine, ammonia or hexamethyleneamine, and the molar ratio of the precipitant to the second metal salt is 1 to 30:1;

The reaction temperature of the hydrothermal reaction is 90-180°C, and the reaction time is 4-72 hours;

Step 2, loading active metals, using an impregnation method to load active metals on the sheet-shaped hydrotalcite-like material obtained after the completion of step 1, and first roasting the sheet-shaped hydrotalcite-like material to obtain a sheet-shaped hydrotalcite-like material The roasted product of the active metal; the solution of the active metal is prepared with a polar solution, and the roasted product of the sheet-shaped hydrotalcite-like material is immersed in the solution of the active metal for 2 to 10 hours, and the active metal solution impregnated The calcined product of the sheet-shaped hydrotalcite-like material is dried and roasted to obtain a supported metal catalyst with a sheet-shaped multi-level porous structure hydrotalcite-like material as a precursor; the pH value of the solution of the active metal is 1 to 4 or 8 ~10;

The active metal compound is zinc nitrate, copper nitrate, cerium nitrate, indium nitrate, indium trichloride, tin tetrachloride, stannous chloride, gallium nitrate, chloroplatinic acid, dichlorodiammine platinum, tetrachloride Platinum ammine, chloroauric acid, silver hydroxide, palladium dichloride, palladium tetraammine dichloride, gold chloride, ruthenium trichloride, potassium chlororuthenate, rhodium nitrate, rhodium phosphate, rhodium chloride, rhodium sulfate one or more of them.

In the above technical solution, in step 1, the reaction temperature of the hydrothermal reaction is 100-120° C., and the reaction time is 12-24 hours.

In the above technical solution, in step 1, the hydrothermal reaction is completed in a polytetrafluoroethylene high-pressure hydrothermal kettle.

In the above technical solution, in step 1, the precipitate is washed and filtered with deionized water, and then dried. The drying process is at 60-120° C. for 4-36 hours.

In the above technical solution, in step 2, the drying process is drying at 60-120°C for 10-24 hours, and the roasting process is roasting at 400-600°C for 2-10 hours.

In the above technical solution, the process of loading the active metal is repeated at least twice, and the active metal compound used each time is different.

In the above technical solution, the loading amount of the active metal in the hydrotalcite-like material catalyst with sheet-shaped hierarchical porous structure is 0.01-5 wt%.

A method for preparing a sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst, comprising the following steps:

Step 1, preparing sheet-shaped hydrotalcite-like materials:

Use a polar solution to prepare a mixed solution of the first metal salt, the second metal salt and the precipitating agent, place the mixed solution in an airtight kettle for hydrothermal reaction, and the reaction temperature of the hydrothermal reaction is 100-120 ° C, the reaction time is 12 to 24 hours, the obtained precipitate is washed and filtered with deionized water, and then dried. The drying process is to dry at 100 ° C for 12 hours to obtain a sheet-shaped hydrotalcite-like material;

The first metal salt is magnesium nitrate, nickel nitrate, zinc nitrate, cobalt nitrate, copper nitrate, manganese nitrate, ferrous nitrate, magnesium chloride, nickel chloride, zinc chloride, cobalt chloride, copper chloride, manganese chloride , one or more of ferrous chloride, magnesium sulfate, nickel sulfate, zinc sulfate, cobalt sulfate, copper sulfate, manganese sulfate, ferrous sulfate, the concentration of the first metal salt in the mixed solution is 0.0032mol/L;

The second metal salt is one or more of aluminum nitrate, iron nitrate, cobalt nitrate, aluminum chloride, ferric chloride, cobalt chloride, aluminum sulfate, iron sulfate, cobalt sulfate, and the second metal salt is The concentration in the mixed solution is 0.0016mol/L;

The precipitant is one or more of urea, triethanolamine, ammonia or hexamethyleneamine, and the concentration of the precipitant is 1.54mol/L;

Step 2, loading active metals, using an impregnation method to load active metals on the sheet-shaped hydrotalcite-like material obtained after step 1, and first roasting the sheet-shaped hydrotalcite-like material at 600°C for 4 Hours, the calcined product of sheet-shaped hydrotalcite-like material is obtained; the solution of the active metal is prepared with a polar solution, and the calcined product of the sheet-shaped hydrotalcite-like material is immersed in the solution of the active metal for 2 to 8 hours , drying the calcined product of the sheet-shaped hydrotalcite-like material impregnated with the active metal solution, the process is to dry at 120° C. for 12 hours to obtain a sheet-shaped hierarchical porous structure hydrotalcite-like material; Roasting, the process is to roast at 550 ° C for 4 hours to obtain a sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst;

The active metal compound is zinc nitrate, copper nitrate, cerium nitrate, indium nitrate, indium trichloride, tin tetrachloride, stannous chloride, gallium nitrate, chloroplatinic acid, dichlorodiammine platinum, tetrachloride Platinum ammine, chloroauric acid, silver hydroxide, palladium dichloride, palladium tetraammine dichloride, gold chloride, ruthenium trichloride, potassium chlororuthenate, rhodium nitrate, rhodium phosphate, rhodium chloride, rhodium sulfate one or more of them;

The step 2 is repeated twice, and the active metal loaded each time is different.

Application of a hydrotalcite-like material catalyst with sheet-shaped multi-level porous structure in propane dehydrogenation reaction. The activation condition of the catalyst is under hydrogen atmosphere, 500-650°C, and the activation time is 0.5-3h; the propane dehydrogenation reaction temperature is 550-680°C, the mass space velocity of the reaction is 2-15h ^-1 .

Advantage of the present invention and beneficial effect are:

The preparation method provided by the present invention is simple, easy to obtain, safe and green, and the sheet-shaped hydrotalcite-like material is obtained by the hydrothermal method, and the new sheet-shaped hydrotalcite-like material precursor is grown on the original sheet-shaped hydrotalcite-like material precursor through multiple roasting and dipping in an acidic or alkaline solution. The hydrotalcite-like flakes can be used to obtain a hydrotalcite-like material with a hierarchical porous structure. If the acidic or alkaline impregnating solution in the later stage is replaced with a solution containing the target metal ion, the metal loading and the formation of multi-level channels can be carried out simultaneously. The hydrotalcite-like material with hierarchical porous structure prepared by the method has the characteristics of large specific surface area, stable structure and thin sheet, and has high activity and stability when applied to propane dehydrogenation.

The sheet-shaped multi-level hole structure hydrotalcite-like catalyst sheet thickness is about 12nm. When it is applied to propane dehydrogenation, the conversion rate of propane reaches 49.1%, the average selectivity of propylene is 95%, and the conversion rate does not drop significantly when the reaction is carried out for 50 hours. The hydrotalcite-like catalyst with sheet-shaped hierarchical porous structure prepared by the method of the present invention has open multi-level channels, which are conducive to the diffusion of reactants and products, avoiding carbon deposition directly covering the active center and quickly blocking the channels, and The sheet layer is thinner than the hydrotalcite obtained by the common method, which increases the utilization rate of the hydrotalcite, increases the dispersion of Pt and the interaction with the auxiliary agent In, thereby increasing the conversion rate and selectivity of propane dehydrogenation.

Description of drawings

FIG. 1 is a scanning electron micrograph of the sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH) prepared in Example 1.

FIG. 2 is a scanning electron micrograph of the sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Mg ₂ Al-LDH) loaded with platinum-indium prepared in Example 1. FIG.

3 is a transmission electron microscope image of the platinum-indium-supported plate-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Mg ₂ Al-LDH) prepared in Example 1.

Fig. 4 is the XRD pattern of the sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Mg ₂ Al-LDO) of the loaded platinum-indium prepared in embodiment 1,

Among them, a is the XRD pattern of ordinary hydrotalcite-like, and b is the XRD pattern of hydrotalcite-like sheet-shaped hierarchical porous structure.

Fig. 5 is a schematic diagram of the activity of the platinum-indium-loaded plate-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Mg ₂ Al-LDH) prepared in Example 1 applied to propane dehydrogenation.

FIG. 6 is a scanning electron micrograph of the hydrotalcite-like material (Mg ₂ Al-LDH) with sheet-shaped hierarchical porous structure prepared in Example 6. FIG.

Fig. 7 is the XRD figure of the hydrotalcite-like material (Mg ₂ Al-LDH) of sheet-shaped hierarchical porous structure prepared in embodiment 6,

Among them, a is the XRD pattern of ordinary hydrotalcite-like, and b is the XRD pattern of hydrotalcite-like sheet-shaped hierarchical porous structure.

FIG. 8 is a scanning electron micrograph of the hydrotalcite-like material (Mg ₂ Al-LDH) with sheet-shaped hierarchical porous structure prepared in Example 7. FIG.

Fig. 9 is the XRD figure of the hydrotalcite-like material (Mg ₂ Al-LDH) of sheet-shaped hierarchical porous structure prepared in embodiment 7,

Among them, a is the XRD pattern of ordinary hydrotalcite-like, and b is the XRD pattern of hydrotalcite-like sheet-shaped hierarchical porous structure.

For those skilled in the art, other related drawings can be obtained according to the above drawings without any creative effort.

Detailed ways

In order to enable those skilled in the art to better understand the solution of the present invention, the technical solution of the present invention will be further described below in conjunction with specific examples.

comparative example

A kind of method adopting co-precipitation method to prepare common hydrotalcite-like catalyst comprises the following steps:

Step 1, preparation of common hydrotalcite-like materials:

Magnesium nitrate hexahydrate (17.09g), aluminum nitrate nonahydrate (12.5g) were added to 100ml of deionized water and magnetically stirred for 30min to fully dissolve to make mixed solution A, sodium hydroxide (8g), sodium carbonate (10.6g) Add it into 100ml of deionized water and magnetically stir for 30min to fully dissolve to make a mixed solution B. Add the A and B solutions dropwise into a three-necked flask, stir vigorously during the dropping process, and control the pH to maintain it at 10. Aging in a water bath at 65°C for 12 hours. The obtained product was washed and filtered with deionized water, and then dried overnight at 100°C in a blast drying oven to obtain a common hydrotalcite-like material;

Step 2, loading active metals, using the impregnation method to load active metals on the common hydrotalcite-like material obtained after the completion of step 1, first roasting the common hydrotalcite-like material, and the roasting process is 2°C/min The rate of heating was calcined at 600°C for 4 hours in a muffle furnace to obtain a calcined product of a common hydrotalcite-like material. Take 1ml of indium nitrate (0.13mol/L, load capacity is 1.5wt%) solution and disperse it in 2ml of deionized water, put the calcined product of 1g of common hydrotalcite-like material into impregnation for 6h, and impregnate the said active metal salt The roasted product of the common hydrotalcite-like material in the solution is dried, and the process is to dry overnight at 120° C. in a blast drying oven to obtain a common hydrotalcite-like material loaded with indium; The heating rate of 2°C/min was roasted at 550°C for 4h to obtain the roasted product of the common hydrotalcite-like material loaded with indium; 0.4ml of chloroplatinic acid (0.039mol/L, loading capacity of 0.6wt%) solution was dispersed in 2ml of deionized In water, put 1 g of the calcined indium-loaded common hydrotalcite-like material into immersion for 2 hours, and then dry overnight at 120° C. in a blast drying oven to obtain a platinum-indium-loaded common hydrotalcite-like material; Calcined at 550°C for 4 hours at a heating rate of 2°C/min in a Furnace to obtain a common hydrotalcite-like material catalyst supported by platinum-indium; 0.4g of the 40-60 mesh catalyst was used for activity testing.

When this catalyst is applied to propane dehydrogenation, within 20 hours, the conversion rate rises from 28% to 47%, but the selectivity drops from the initial 98% to 87%, and the catalyst is prone to carbon deposition, and its life is short, showing instability sex.

Embodiment one

A method for preparing a catalyst (Pt-In-Mg ₂ Al-LDO) using a sheet-shaped hierarchical porous structure hydrotalcite material, comprising the following steps:

Step 1, preparation of sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH):

Magnesium nitrate hexahydrate (0.82g), aluminum nitrate nonahydrate (0.6g), and urea (6g) were added to 65ml of deionized water and magnetically stirred for 30min to fully dissolve to make a mixed solution, and the mixed solution was transferred to 100ml polytetrafluoroethylene The hydrothermal reaction is carried out in a vinyl fluoride high-pressure reactor. The reaction temperature of the high-pressure hydrothermal reaction is 100°C, and the reaction time is 20 hours. The obtained precipitate is washed and filtered with deionized water, and then placed in a blast drying oven at 120°C Dry overnight to obtain sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH);

Step 2, loading active metals, using an impregnation method to load active metals on the sheet-shaped hydrotalcite-like material obtained after step 1 is completed, first roasting the sheet-shaped hydrotalcite-like material obtained in step 1, the roasting process In order to roast at 600°C for 4 hours in a muffle furnace at a heating rate of 2°C/min, to obtain a calcined product (Mg ₂ Al-LDO) of sheet-shaped hydrotalcite-like material; take 0.92ml of indium nitrate (0.13mol/L, load 1.38wt%) solution is dispersed in 2ml deionized water, the calcined product (Mg ₂ Al-LDO) of 1g flake-shaped hydrotalcite-like material is put into immersion 6h, is impregnated with the flake-shaped active metal salt solution The calcined product of the hydrotalcite-like material is dried, and the process is to dry overnight at 120° C. in a blast drying oven to obtain a sheet-shaped hierarchical porous structure hydrotalcite-like material (In-Mg ₂ Al-LDH) loaded with indium; Carrying out calcination, the process is to calcine in a muffle furnace at a heating rate of 2°C/min at 550°C for 4h to obtain a calcined product (In-Mg ₂ Al-LDO) of a sheet-shaped hierarchical porous structure hydrotalcite-like material loaded with indium; Get 0.32ml chloroplatinic acid (0.039mol/L, loading capacity is 0.48wt%) solution and be dispersed in 2ml deionized water, the calcined product (In -Mg ₂ Al-LDO) for immersion for 2 hours, and then dried overnight at 120°C in a blast oven to obtain a platinum-indium-supported sheet-shaped hierarchical porous structure hydrotalcite-like material (Pt-In-Mg ₂ Al-LDH ); Finally, bake in a muffle furnace at a heating rate of 2°C/min at 550°C for 4h; obtain a platinum-indium sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Mg ₂ Al-LDO) ; Take 0.4g of the catalyst with a particle size of 40-60 mesh for activity test.

Sn, Ga, In, and some transition metals have been proven to form Pt-X bimetallic alloys when used together with Pt, which has a good stabilizing effect on Pt and can significantly improve the selectivity of propylene.

FIG. 1 is a scanning electron micrograph of the sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH) prepared in Example 1. It can be seen from this figure that the ordinary hexagonal plate-like hydrotalcite precursor synthesized by common hydrothermal method is stacked by multi-layer hydrotalcite sheets.

FIG. 2 is a scanning electron micrograph of the sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Mg ₂ Al-LDH) loaded with platinum-indium prepared in Example 1. FIG. After two impregnation and roasting recovery processes, the catalyst can maintain the original regular hexagonal sheet morphology, but the thick stacked sheets are peeled off to varying degrees, and new hydrotalcite sheets grow in the gaps to form multi-level channels. , making the hydrotalcite-like flakes thinner as a whole.

3 is a transmission electron microscope image of the platinum-indium-supported plate-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Mg ₂ Al-LDH) prepared in Example 1. It can be seen from the figure that there is a multi-level pore structure inside the hydrotalcite-like material with a sheet-shaped multi-level pore structure, and the edge of the hydrotalcite-like sheet is transparent, indicating that its thickness is very small.

4 is an X-ray diffraction pattern of the platinum-indium-loaded sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Mg ₂ Al-LDH) prepared in Example 1. As can be seen from this figure, the characteristic peaks ((003), (006), ( ₀₁₂ ) etc. ) is consistent with ordinary hydrotalcite, and it shows that this type of hydrotalcite still maintains the original crystal phase after being impregnated and burned twice.

The prepared platinum-indium-supported sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Mg ₂ Al-LDO) was applied in the process of propane dehydrogenation to propylene, and the reactor was a pressurized micro gas-solid Phase catalytic reaction device (customized by Tianda Beiyang Chemical Experimental Equipment Co., Ltd.), 0.4g of 40-60 mesh catalyst was placed in the furnace tube, and the temperature was raised to 600°C at a rate of 5°C/min, and _N2 gas was used to protect the temperature. After heating up, switch to H ₂ -N ₂ mixed gas and keep at 600°C for 2.5h for reduction. After the reduction, switch to propane gas mixture (ratio of parts by volume C ₃ H ₈ :H ₂ :N ₂ =16%:14%:70%) for reaction at 600°C with a gas mass space velocity of 3h ^-1 . The SP 2100 model gas chromatography was used for analysis and evaluation, and the conversion rate of propane and the selectivity of propylene were calculated.

Figure 5 is the conversion rate and propylene selectivity of the platinum-indium-supported plate-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Mg ₂ Al-LDO) prepared in Example 1 in the reaction of propane dehydrogenation to propylene sex data graph. It can be seen from the figure that the conversion rate of the catalyst in the reaction of propane dehydrogenation to propylene shows an inverted U-shaped curve, up to 49.1%, and there is no obvious decrease under the condition of reaction for 50 hours. As the reaction time increases, its selectivity will decrease, the average selectivity is 95%, and it drops to 90% when the reaction time is 50h. The hydrotalcite-like catalyst with sheet-shaped multi-level porous structure prepared by the method of the present invention has multi-level pores, and the sheet layer is thinner than the hydrotalcite-like catalyst obtained by the common method, which increases the utilization rate of the hydrotalcite-like catalyst and increases the Pt. Dispersion and interaction with the additive In, thereby increasing the conversion and selectivity of propane dehydrogenation.

Embodiment two

A method for preparing a catalyst (Pt-In-Mg ₂ Al-LDO) using a sheet-shaped hierarchical porous structure hydrotalcite material, comprising the following steps:

Step 1, preparation of sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH):

Magnesium nitrate hexahydrate (0.82g), aluminum nitrate nonahydrate (0.6g), and urea (6g) were added to 65ml of deionized water and magnetically stirred for 30min to fully dissolve to make a mixed solution, and the mixed solution was transferred to 100ml polytetrafluoroethylene The hydrothermal reaction is carried out in a vinyl fluoride high-pressure reactor. The reaction temperature of the hydrothermal reaction is 100°C, and the reaction time is 20 hours. The obtained precipitate is washed and filtered with deionized water, and then placed in a blast drying oven at 120°C overnight. Dry to obtain sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH);

Step 2, loading active metals, using an impregnation method to load active metals on the sheet-shaped hydrotalcite-like material obtained after step 1 is completed, first roasting the sheet-shaped hydrotalcite-like material obtained in step 1, the roasting process In order to roast at 600°C for 4 hours in a muffle furnace at a heating rate of 2°C/min, to obtain a calcined product (Mg ₂ Al-LDO) of sheet-shaped hydrotalcite-like material; take 0.92ml of indium nitrate (0.13mol/L, load 1.38wt%) solution is dispersed in 2ml deionized water, the calcined product (Mg ₂ Al-LDO) of 1g flake-shaped hydrotalcite material is put into immersion 2h, is impregnated with the flake-shaped active metal salt solution The calcined product of the hydrotalcite-like material (Mg ₂ Al-LDO) is dried, and the process is to dry overnight at 120°C in a blast drying oven to obtain a sheet-shaped hierarchical porous structure hydrotalcite-like material loaded with indium (In-Mg ₂ Al -LDH); then it is roasted, and the process is to roast at 550 °C for 4 h at a heating rate of 2 °C/min in a muffle furnace to obtain a calcined product of a sheet-shaped hierarchical porous structure hydrotalcite-like material loaded with indium (In- Mg ₂ Al-LDO); Get 0.32ml of chloroplatinic acid (0.039mol/L, loading capacity is 0.48wt%) solution and disperse in 2ml of deionized water, the sheet-shaped hierarchical porous structure water-like structure of loaded indium after 1g roasting The calcined product of the talc material (In-Mg ₂ Al-LDO) was impregnated for 2 hours, and then dried overnight at 120°C in a blast drying oven to obtain a sheet-shaped hierarchical porous structure hydrotalcite-like material loaded with platinum-indium (Pt- In-Mg ₂ Al-LDH); Finally, calcined at 550°C for 4h at a heating rate of 2°C/min in a muffle furnace to obtain a sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst loaded with platinum-indium (Pt-In- Mg ₂ Al-LDO); take 0.4g of 40-60 mesh catalyst for activity test.

The conversion rate of the catalyst in the reaction of propane dehydrogenation to propylene is as high as 47.58%, the selectivity decreases with the increase of time, and the average selectivity is 95%.

Embodiment three

A method for preparing a catalyst (Pt-In-Zn ₃ Fe-LDO) by using a sheet-shaped hierarchical porous structure hydrotalcite material, comprising the following steps:

Step 1, preparation of sheet-shaped hydrotalcite-like material (Zn ₃ Fe-LDH):

Zinc nitrate hexahydrate (7.251g), ferric nitrate nonahydrate (3.283g), and urea (6g) were added to 65ml of deionized water and magnetically stirred for 30min to fully dissolve to make a mixed solution, and the mixed solution was transferred to 100ml polytetrafluoroethylene The hydrothermal reaction is carried out in a vinyl fluoride high-pressure reactor. The reaction temperature of the hydrothermal reaction is 100°C, and the reaction time is 24 hours. The obtained precipitate is washed and filtered with deionized water, and then placed in a blast drying oven at 120°C overnight. Drying, to obtain sheet-shaped hydrotalcite-like material (Zn ₃ Fe-LDH);

Step 2, loading active metals, using an impregnation method to load active metals on the sheet-shaped hydrotalcite-like material obtained after step 1 is completed, first roasting the sheet-shaped hydrotalcite-like material obtained in step 1, the roasting process In order to roast at 600°C for 4h in a muffle furnace at a heating rate of 2°C/min, a calcined product (Zn ₃ Fe-LDO) of sheet-shaped hydrotalcite-like material is obtained; take 1ml of indium nitrate (0.13mol/L, loading capacity of 1.5wt%) solution was dispersed in 2ml deionized water, and the calcined product (Zn ₃ Fe-LDO) of 1g sheet-shaped hydrotalcite material was put into immersion for 6h, and the sheet-shaped hydrotalcite-like material impregnated with the active metal salt solution was The calcined product of the hydrotalcite material is dried, and the process is to dry overnight at 120°C in a blast drying oven to obtain a sheet-shaped hierarchical porous structure hydrotalcite-like material (In-Zn ₃ Fe-LDH) loaded with indium; Roasting, the process is to bake in a muffle furnace at a heating rate of 2°C/min at 550°C for 4h to obtain a calcined product (In-Zn ₃ Fe-LDO) of a sheet-shaped hierarchical porous structure hydrotalcite-like material loaded with indium; 0.4ml chloroplatinic acid (0.039mol/L, load capacity is 0.6wt%) solution is dispersed in 2ml deionized water, the calcined product (In- Zn ₃ Fe-LDO) was impregnated for 2 hours, and then dried overnight at 120°C in a blast drying oven to obtain a plate-shaped hierarchical porous structure hydrotalcite-like material loaded with platinum-indium (Pt-In-Zn ₃ Fe-LDH) ;Finally, calcined at 550°C for 4h at a heating rate of 2°C/min in a muffle furnace to obtain a sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Zn ₃ Fe-LDO) loaded with platinum-indium; 0.4 g of 40-60 mesh catalyst was used for activity test.

Embodiment four

A method for preparing a catalyst (Pt-In-Zn ₆ Al-LDO) using a sheet-shaped hierarchical porous structure hydrotalcite material, comprising the following steps:

Step 1, preparation of sheet-shaped hydrotalcite-like material (Zn ₆ Al-LDH):

Zinc nitrate hexahydrate (1.019g), aluminum nitrate nonahydrate (0.257g), and urea (6g) were added to 65ml of deionized water and magnetically stirred for 30min to fully dissolve to make a mixed solution, and the mixed solution was transferred to 100ml polytetrafluoroethylene Carry out hydrothermal reaction in vinyl fluoride high-pressure reaction kettle, the reaction temperature of the hydrothermal reaction is 180°C, the reaction time is 8 hours, the obtained precipitate is washed and filtered with deionized water, and then placed in a blast drying oven at 120°C overnight Dry to obtain sheet-shaped hydrotalcite-like material (Zn ₆ Al-LDH);

Step 2, loading active metals, using an impregnation method to load active metals on the sheet-shaped hydrotalcite-like material obtained after step 1 is completed, first roasting the sheet-shaped hydrotalcite-like material obtained in step 1, the roasting process In order to roast at 600°C for 4h in a muffle furnace at a heating rate of 2°C/min, a calcined product (Zn ₆ Al-LDO) of sheet-shaped hydrotalcite-like material is obtained; take 1ml of indium nitrate (0.13mol/L, loading capacity of 1.5wt%) solution was dispersed in 2ml deionized water, and the calcined product (Zn ₆ Al-LDO) of 1g plate-shaped hydrotalcite material was put into immersion for 6h, and the plate-shaped hydrotalcite-like material impregnated with the active metal salt solution was The calcined product of the hydrotalcite material is dried, and the process is to dry overnight at 120°C in a blast drying oven to obtain a sheet-shaped hierarchical porous structure hydrotalcite-like material (In-Zn ₆ Al-LDH) loaded with indium; Roasting, the process is to bake in a muffle furnace at a heating rate of 2°C/min at 500°C for 4h to obtain a calcined product (In-Zn ₆ Al-LDO) of a sheet-shaped hierarchical porous structure hydrotalcite-like material loaded with indium; 0.07ml chloroplatinic acid (0.039mol/L, load capacity is 0.1wt%) solution is dispersed in 2ml deionized water, the calcined product (In- Zn ₆ Al-LDO) was impregnated for 2 hours, and then dried overnight at 120°C in a blast drying oven to obtain a sheet-shaped hierarchical porous structure hydrotalcite-like material (Pt-In-Zn ₆ Al-LDH) loaded with platinum-indium ;Finally, calcined at 500°C for 4h at a heating rate of 2°C/min in a muffle furnace; a sheet-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Zn ₆ Al-LDO) loaded with platinum-indium was obtained; 0.4g catalyst of 40-60 mesh is used for activity test

Embodiment five

A method for preparing a catalyst (Pt-In-Mg ₂ Al-LDO) using a sheet-shaped hierarchical porous structure hydrotalcite material, comprising the following steps:

Step 1, preparation of sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH):

Magnesium nitrate hexahydrate (9.99g), aluminum nitrate nonahydrate (4.877g), and urea (6g) were added to 65ml of deionized water and magnetically stirred for 30min to fully dissolve to make a mixed solution, and the mixed solution was transferred to 100ml polytetrafluoroethylene The high-pressure hydrothermal reaction is carried out in a vinyl fluoride high-pressure reactor. The reaction temperature of the high-pressure hydrothermal reaction is 150 ° C, and the reaction time is 10 hours. The obtained precipitate is washed and filtered with deionized water, and then placed in a blast drying oven for 120 Dry overnight at ℃ to obtain sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH);

Step 2, loading active metals, using an impregnation method to load active metals on the sheet-shaped hydrotalcite-like material obtained after step 1 is completed, first roasting the sheet-shaped hydrotalcite-like material obtained in step 1, the roasting process In order to roast at 600°C for 4 hours in a muffle furnace at a heating rate of 2°C/min, to obtain a calcined product (Mg ₂ Al-LDO) of sheet-shaped hydrotalcite-like material; take 0.3ml of indium nitrate (0.13mol/L, load 0.5wt%) solution is dispersed in 2ml deionized water, the calcined product (Mg ₂ Al-LDO) of 1g flake-shaped hydrotalcite material is put into immersion 10h, is impregnated with the flake-shaped active metal salt solution The calcined product of the hydrotalcite-like material is dried, and the process is to dry overnight at 120° C. in a blast drying oven to obtain a sheet-shaped hierarchical porous structure hydrotalcite-like material (In-Mg ₂ Al-LDH) loaded with indium; Carrying out calcination, the process is to calcine in a muffle furnace at a heating rate of 2°C/min at 550°C for 4h to obtain a calcined product (In-Mg ₂ Al-LDO) of a sheet-shaped hierarchical porous structure hydrotalcite-like material loaded with indium; Get 0.13ml chloroplatinic acid (0.039mol/L, load capacity is 0.2wt%) solution and be dispersed in 2ml deionized water, the calcined product (In -Mg ₂ Al-LDO) was impregnated for 6 hours, and then dried overnight at 120°C in a blast oven to obtain a platinum-indium-supported sheet-shaped hierarchical porous structure hydrotalcite-like material (Pt-In-Mg ₂ Al-LDH ); finally, calcined at 550°C for 4h at a heating rate of 2°C/min in a muffle furnace to obtain a platinum-indium flake-shaped hierarchical porous structure hydrotalcite-like material catalyst (Pt-In-Mg ₂ Al-LDO); 0.4 g of 40-60 mesh catalyst was used for activity test.

Embodiment six

A method for preparing a sheet-shaped multi-level porous structure hydrotalcite-like material, comprising the following steps:

Step 1, preparation of sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH):

Magnesium nitrate hexahydrate (0.82g), aluminum nitrate nonahydrate (0.6g), and urea (6g) were added to 65ml of deionized water and magnetically stirred for 30min to fully dissolve to make a mixed solution, and the mixed solution was transferred to 100ml polytetrafluoroethylene The high-pressure hydrothermal reaction is carried out in a high-pressure vinyl fluoride reaction kettle. The reaction temperature of the high-pressure hydrothermal reaction is 100°C, and the reaction time is 20 hours. The obtained precipitate is washed and filtered with deionized water, and then placed in a blast drying oven for 120 Dry overnight at ℃ to obtain sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH);

Step 2, preparing a sheet-shaped hydrotalcite-like material with a hierarchical porous structure, impregnating the sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH) obtained after the completion of step 1, first The hydrotalcite-like material is roasted, and the roasting process is to roast at 600° C. in a muffle furnace for 4 hours at a heating rate of 2° C./min to obtain a calcined product (Mg ₂ Al-LDO) of a sheet-shaped hydrotalcite-like material; Prepared 3ml of dilute nitric acid (pH=1) solution, put 1g of the calcined product of sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDO) into immersion for 2h, and the roasting of the impregnated sheet-shaped hydrotalcite-like material The product is dried, and the process is to dry overnight at 120° C. in a forced air drying oven to obtain a hydrotalcite-like material (Mg ₂ Al-LDH) with a sheet-shaped hierarchical porous structure. The above-mentioned process is carried out at least twice.

The scanning electron microscope image of the sheet-shaped hierarchical porous structure hydrotalcite-like material (Mg ₂ Al-LDH) prepared according to the above steps shows the same porous surface structure as the metal-loaded sheet-shaped hierarchical porous structure hydrotalcite-like material; its XRD The characteristic peaks ((003), (006), (012), etc.) in the figure are consistent with ordinary hydrotalcites, and it shows that this type of hydrotalcites still maintains the original crystal phase after being impregnated and burned twice.

Embodiment seven

A method for preparing a sheet-shaped multi-level porous structure hydrotalcite-like material, comprising the following steps:

Step 1, preparation of sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH):

Magnesium nitrate hexahydrate (0.82g), aluminum nitrate nonahydrate (0.6g), and urea (6g) were added to 65ml of deionized water and magnetically stirred for 30min to fully dissolve to make a mixed solution, and the mixed solution was transferred to 100ml polytetrafluoroethylene The high-pressure hydrothermal reaction is carried out in a high-pressure vinyl fluoride reaction kettle. The reaction temperature of the high-pressure hydrothermal reaction is 100°C, and the reaction time is 20 hours. The obtained precipitate is washed and filtered with deionized water, and then placed in a blast drying oven for 120 Dry overnight at ℃ to obtain sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH);

Step 2, preparing a sheet-shaped multi-level porous hydrotalcite-like material, impregnating the sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDH) obtained after step 1 is completed, firstly, the sheet-shaped hydrotalcite-like material obtained in step 1 The hydrotalcite material is roasted, and the roasting process is to roast at 600 °C in a muffle furnace for 4 hours at a heating rate of 2 °C/min to obtain a roasted product of a sheet-shaped hydrotalcite-like material (Mg ₂ Al-LDO); take the pre-configured A good 3ml sodium hydroxide solution (pH=9.8), put the calcined product (Mg ₂ Al-LDO) of 1g sheet-shaped hydrotalcite-like material into immersion for 2h, and the roasting of the sheet-shaped hydrotalcite-like material after the impregnation The product is dried, and the process is to dry overnight at 120° C. in a forced air drying oven to obtain a hydrotalcite-like material (Mg ₂ Al-LDH) with a sheet-shaped hierarchical porous structure. The above-mentioned process is carried out at least twice.

The scanning electron microscope image of the sheet-shaped hierarchical porous structure hydrotalcite-like material (Mg ₂ Al-LDH) prepared according to the above steps shows the same porous surface structure as the metal-loaded sheet-shaped hierarchical porous structure hydrotalcite-like material; its XRD The characteristic peaks ((003), (006), (012) etc.) of the figure coincide with common hydrotalcites, and illustrate that this type of hydrotalcites still maintains the original crystal phase after being impregnated and burned twice; Compared with the hydrotalcite-like material with sheet-shaped hierarchical porous structure (Mg ₂ Al-LDH), each characteristic peak is higher, indicating that the crystal phase is better.

Relational terms such as "first" and "second", etc. are used only to distinguish one element from another element having the same name and do not necessarily require or imply any such actual relationship between these elements or order.

The present invention has been described as an example above, and it should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacements that can be made by those skilled in the art without creative labor all fall within the scope of this invention. protection scope of the invention.

Claims (10)

1. A method for preparing a sheet-shaped hierarchical pore structure hydrotalcite-like material is characterized by comprising the following steps:

step 1, preparing a mixed solution of a first metal salt, a second metal salt and a precipitator by using a polar solution, placing the mixed solution in an airtight kettle for hydrothermal reaction, washing and drying the obtained precipitate to obtain a sheet-shaped hydrotalcite-like material;

the first metal salt is one or more of magnesium nitrate, nickel nitrate, zinc nitrate, cobalt nitrate, copper nitrate, manganese nitrate, ferrous nitrate, magnesium chloride, nickel chloride, zinc chloride, cobalt chloride, copper chloride, manganese chloride, ferrous chloride, magnesium sulfate, nickel sulfate, zinc sulfate, cobalt sulfate, copper sulfate, manganese sulfate and ferrous sulfate; the second metal salt is one or more of aluminum nitrate, ferric nitrate, cobalt nitrate, chromium nitrate, aluminum chloride, ferric chloride, cobalt chloride, chromium chloride, aluminum sulfate, ferric sulfate, cobalt sulfate and chromium sulfate, and the sum of the concentrations of the first metal salt and the second metal salt in the mixed solution is 0.01-1.5 mol/L;

the molar ratio of the first metal salt to the second metal salt is 1-6: 1;

The precipitator is one or more of urea, triethanolamine, ammonia water or hexamethylene amine, and the molar ratio of the precipitator to the second metal salt is 1-30: 1;

the reaction temperature of the hydrothermal reaction is 90-180 ℃, and the reaction time is 4-72 hours;

step 2, treating the sheet hydrotalcite-like material obtained in the step 1 by adopting an impregnation method, and roasting the sheet hydrotalcite-like material to obtain a roasted product of the sheet hydrotalcite-like material; then soaking the roasted product of the sheet-shaped hydrotalcite-like material in an acid solution or an alkaline solution for 2-10 hours, and drying the roasted product of the sheet-shaped hydrotalcite-like material soaked with the acid solution or the alkaline solution to obtain the sheet-shaped hierarchical pore structure hydrotalcite-like material; the pH value of the acidic solution is 1-4, and the pH value of the alkaline solution is 8-10.

2. a method for preparing a sheet-shaped hierarchical pore structure hydrotalcite-like material catalyst is characterized by comprising the following steps:

Step 1, preparing a mixed solution of a first metal salt, a second metal salt and a precipitator by using a polar solution, placing the mixed solution in an airtight kettle for hydrothermal reaction, washing and drying the obtained precipitate to obtain a sheet-shaped hydrotalcite-like material;

the first metal salt is one or more of magnesium nitrate, nickel nitrate, zinc nitrate, cobalt nitrate, copper nitrate, manganese nitrate, ferrous nitrate, magnesium chloride, nickel chloride, zinc chloride, cobalt chloride, copper chloride, manganese chloride, ferrous chloride, magnesium sulfate, nickel sulfate, zinc sulfate, cobalt sulfate, copper sulfate, manganese sulfate and ferrous sulfate; the second metal salt is one or more of aluminum nitrate, ferric nitrate, cobalt nitrate, chromium nitrate, aluminum chloride, ferric chloride, cobalt chloride, chromium chloride, aluminum sulfate, ferric sulfate, cobalt sulfate and chromium sulfate, and the sum of the concentrations of the first metal salt and the second metal salt in the mixed solution is 0.01-1.5 mol/L;

The molar ratio of the first metal salt to the second metal salt is 1-6: 1;

the precipitator is one or more of urea, triethanolamine, ammonia water or hexamethylene amine, and the molar ratio of the precipitator to the second metal salt is 1-30: 1;

the reaction temperature of the hydrothermal reaction is 90-180 ℃, and the reaction time is 4-72 hours;

Step 2, loading active metal, loading the active metal on the sheet-shaped hydrotalcite-like material obtained after the step 1 by adopting an impregnation method, and roasting the sheet-shaped hydrotalcite-like material to obtain a roasted product of the sheet-shaped hydrotalcite-like material; preparing a solution of the active metal by adopting a polar solution, dipping the baked product of the sheet-shaped hydrotalcite-like material in the solution of the active metal for 2-10 hours, and drying and baking the baked product of the sheet-shaped hydrotalcite-like material dipped with the active metal solution to obtain a supported metal catalyst taking the sheet-shaped hierarchical pore structure hydrotalcite-like material as a precursor; the pH value of the active metal solution is 1-4 or 8-10;

The compound of the active metal is one or more of zinc nitrate, copper nitrate, cerium nitrate, indium trichloride, stannic chloride, stannous chloride, gallium nitrate, chloroplatinic acid, diammineplatinum dichloride, tetraamineplatinum nitrate, chloroauric acid, silver hydroxide, palladium dichloride, tetraaminepalladium dichloride, gold chloride, ruthenium trichloride, potassium ruthenate, rhodium nitrate, rhodium phosphate, rhodium chloride and rhodium sulfate.

3. The method according to claim 1 or 2, wherein in the step 1, the reaction temperature of the hydrothermal reaction is 100 to 120 ℃ and the reaction time is 12 to 24 hours.

4. the method according to claim 1 or 2, wherein in the step 1, the hydrothermal reaction is completed in a polytetrafluoroethylene high-pressure hydrothermal kettle.

5. the method according to claim 1 or 2, wherein in the step 1, the precipitate is washed and filtered by deionized water, and then is dried, wherein the drying process is carried out at 60-120 ℃ for 4-36 hours.

6. The method according to claim 1 or 2, wherein in the step 2, the drying process is performed at 60 to 120 ℃ for 10 to 24 hours, and the roasting process is performed at 400 to 600 ℃ for 2 to 10 hours.

7. the method of claim 2, wherein the step 2 loading of the reactive metal is repeated at least twice, each time with a different compound of the reactive metal.

8. The method according to claim 2, wherein the loading amount of the active metal in the sheet-shaped hierarchical pore structure hydrotalcite-like material catalyst is 0.01 to 5 wt%.

9. a method for preparing a sheet-shaped hierarchical pore structure hydrotalcite-like material catalyst is characterized by comprising the following steps:

step 1, preparing a sheet-shaped hydrotalcite-like material:

Preparing a mixed solution of a first metal salt, a second metal salt and a precipitator by using a polar solution, placing the mixed solution in an airtight kettle for hydrothermal reaction at the reaction temperature of 100-120 ℃ for 12-24 hours to obtain a precipitate, washing and filtering the precipitate by using deionized water, and then drying the precipitate, wherein the drying process is drying at the temperature of 100 ℃ for 12 hours to obtain a sheet-shaped hydrotalcite material;

the first metal salt is one or more of magnesium nitrate, nickel nitrate, zinc nitrate, cobalt nitrate, copper nitrate, manganese nitrate, ferrous nitrate, magnesium chloride, nickel chloride, zinc chloride, cobalt chloride, copper chloride, manganese chloride, ferrous chloride, magnesium sulfate, nickel sulfate, zinc sulfate, cobalt sulfate, copper sulfate, manganese sulfate and ferrous sulfate, and the concentration of the first metal salt in the mixed solution is 0.0032 mol/L;

the second metal salt is one or more of aluminum nitrate, ferric nitrate, cobalt nitrate, aluminum chloride, ferric chloride, cobalt chloride, aluminum sulfate, ferric sulfate and cobalt sulfate, and the concentration of the second metal salt in the mixed solution is 0.0016 mol/L;

The precipitator is one or more of urea, triethanolamine, ammonia water or hexamethylene amine, and the concentration of the precipitator is 1.54 mol/L;

step 2, loading active metal, loading the active metal on the sheet-shaped hydrotalcite-like material obtained in the step 1 by adopting an impregnation method, roasting the sheet-shaped hydrotalcite-like material at 600 ℃ for 4 hours to obtain a roasted product of the sheet-shaped hydrotalcite-like material; preparing a solution of the active metal by using a polar solution, dipping a roasted product of the sheet-shaped hydrotalcite-like material in the solution of the active metal for 2-8 hours, and drying the roasted product of the sheet-shaped hydrotalcite-like material dipped with the active metal solution at 120 ℃ for 12 hours to obtain the sheet-shaped hydrotalcite-like material with the hierarchical pore structure; then roasting the hydrotalcite-like material for 4 hours at 550 ℃ to obtain a sheet-shaped hierarchical pore structure hydrotalcite-like material catalyst;

the compound of the active metal is one or more of zinc nitrate, copper nitrate, cerium nitrate, indium trichloride, stannic chloride, stannous chloride, gallium nitrate, chloroplatinic acid, diammineplatinum dichloride, tetraamineplatinum nitrate, chloroauric acid, silver hydroxide, palladium dichloride, tetraaminepalladium dichloride, gold chloride, ruthenium trichloride, potassium ruthenate, rhodium nitrate, rhodium phosphate, rhodium chloride and rhodium sulfate;

and 2, repeating the step two times, wherein the active metal loaded each time is different.

10. the application of the sheet-shaped hierarchical pore structure hydrotalcite-like material catalyst prepared by the method of any one of claims 2 and 7 to 9 in propane dehydrogenation reaction is characterized in that the activation condition of the catalyst is 500-650 ℃ in hydrogen atmosphere, and the activation time is 0.5-3 h; the propane dehydrogenation reaction temperature is 550-680 ℃, and the mass space velocity of the reaction is 2-15 h < -1 >.