Surface-confined atomically dispersed pt@sio 2-n catalyst, preparation method therefor and use thereof

Abstract

Disclosed in the present invention are a surface-confined atomically dispersed Pt@SiO2-N catalyst, a preparation method therefor and a use thereof. According to the present invention, on the basis of an atomic layer deposition (ALD) technology, it is reported for the first time that, by using amino-functionalized grafted porous SiO2 flower-like nanospheres as a carrier, a surface-confined atomically dispersed Pt@SiO2-N catalyst is prepared by regulating ALD deposition parameters. The size of Pt metal is precisely regulated from single atoms, clusters to nanoparticles. The single-atom and cluster coexisting catalyst shows excellent catalytic hydrogenation activity and selectivity for p-chloronitrobenzene. According to the catalyst of the present invention, the defect of a traditional SiO2 supported catalyst that is prone to agglomeration is greatly ameliorated, the utilization rate and stability of metal atoms are greatly improved, and this synthesis strategy can be popularized to preparation of other heterogeneous catalysts.

Description

Surface-confined atomically dispersed Pt@SiO2-N catalyst and its preparation method and application Technical Field

[0001] The present invention belongs to the technical field of atomically dispersed catalysts, and specifically relates to a surface-confined atomically dispersed Pt@SiO2-N catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Atomically dispersed catalysts have an ultra-high atomic utilization rate, saving metal, especially precious metal, while also enabling the regulation of catalytic activity, selectivity, and stability. Consequently, they have attracted widespread attention from researchers both domestically and internationally. Numerous reports have reported on atomically dispersed catalysts supported on common carbon materials (e.g., graphene, carbon nanotubes, and C3N4) and oxide supports (e.g., reducible TiO2, CeO2, and non-reducible MgO, Al2O3), demonstrating excellent catalytic performance. Atomically dispersed catalysts have enormous potential for industrial and enzyme catalysis. SiO2, with its low cost, excellent wear resistance, and high thermal and chemical stability, is a commonly used catalyst support in laboratories and industry, finding widespread application in catalysis, adsorption separation, and biomedicine. However, due to its limited surface groups, supported metal particles tend to aggregate, grow, or detach, making the preparation of highly dispersed, active, and stable supported SiO2 catalysts a significant challenge. In particular, the preparation of atomically dispersed supported SiO2 catalysts has yet to be clearly reported.

[0003] SiO2-supported catalysts prepared by traditional methods have defects such as large particle size, uneven distribution, easy aggregation and poor stability, which hinder the establishment of structure-activity relationship and its industrial application.

[0004] Summary of the Invention

[0005] The present invention aims to provide a method for preparing a highly active, highly selective, and highly stable Pt@SiO2-N catalyst for the selective hydrogenation of p-chloronitrobenzene, wherein Pt metal is loaded on the surface of amino-functionalized porous SiO2 in an atomically dispersed form. This allows for free diffusion of reactant molecules and improved metal atom utilization while fully utilizing the metal size effect to regulate catalytic reaction performance.

[0006] ALD is an advanced thin film and particle deposition technology that allows precise control of film thickness, metal particle size, and dispersion at the atomic level—features that are difficult to achieve with other traditional methods. In light of the shortcomings of existing technologies, the present invention leverages the advantages and features of ALD technology. By manipulating parameters such as pulse time, number of cycles, and deposition kinetics, the present invention applies a Pt ALD process to surface-functionalized SiO2-N to produce a surface-confined, atomically dispersed Pt@SiO2-N catalyst. This catalyst can achieve the complete catalytic conversion of p-chloronitrobenzene and its derivatives, yielding the target product with high selectivity.

[0007] The present invention is specifically implemented by the following technical solutions:

[0008] The first aspect of the present invention provides a surface-confined atomically dispersed Pt@SiO2-N catalyst, wherein Pt metal is supported on the surface of amino-functionalized porous SiO2 in an atomically dispersed form.

[0009] As a further illustration of the present invention, the loading amount of the Pt metal is 0.1-3 wt %, and the size of the Pt metal can be precisely controlled from nanoparticles, clusters / atomic clusters to single atoms.

[0010] As a further illustration of the present invention, the Pt metal is uniformly anchored in the surface pores of SiO2.

[0011] As a further illustration of the present invention, the catalyst carrier is a dendritic porous SiO2 nanosphere with a size (50-900nm), a specific surface area (80-260m 2 / g), pore volume (0.5-2.5cm 3 / g) and pore size (0.3-80nm) can be precisely adjusted.

[0012] A second aspect of the present invention provides a method for preparing the surface-confined atomically dispersed Pt@SiO2-N catalyst described in any one of the above, the method comprising the following steps:

[0013] S1: preparing a SiO2 support by a solvent thermal synthesis method, and then performing surface amino-functionalized grafting on the SiO2 support to obtain an amino-functionalized SiO2-N support; uniformly coating the SiO2-N support on a quartz plate with ethanol, and naturally air-drying the support for later use;

[0014] S2: The SiO2-N carrier obtained in step 1 is placed in an ALD vacuum reaction chamber for Pt deposition, and an atomically dispersed Pt@SiO2-N surface confined catalyst is obtained by controlling the deposition parameters.

[0015] As a further illustration of the present invention, the preparation process of the amino-functionalized SiO2-N support described in S1 specifically includes:

[0016] Dissolve triethanolamine, hexadecyltrimethylammonium bromide, and sodium dodecylsulfonate in deionized water to form a mixed solution, and stir at 25-100°C for 0.5-6 hours; then, add a certain concentration of ethyl orthosilicate solution to the mixed solution, and continue stirring for 0.5-6 hours; after the reaction is completed, wash the reaction solution with alcohol and water, centrifuge, dry, and then calcine at 450-900°C in air atmosphere for 2-9 hours to obtain a SiO2 carrier;

[0017] 3-Aminopropyltriethoxysilane is dissolved in toluene, a certain amount of the SiO2 carrier is added under stirring conditions, and then the temperature is raised to 50-100°C and stirring is continued for 12-60 hours. After the reaction is completed, the amino-functionalized SiO2-N carrier is obtained by centrifugation, alcohol washing and water washing, and then the amino-functionalized SiO2-N carrier is vacuum dried at 60°C for 12 hours.

[0018] The above-mentioned solvent thermal synthesis method can realize batch preparation of SiO2 carriers (from grams to kilograms).

[0019] As a further illustration of the present invention, the deposition parameters during the Pt ALD process in S2 are:

[0020] The deposition temperature of the reaction chamber is controlled at 160-320°C, the heating temperature of the Pt metal precursor is 45-80°C, the pulse time is 0.2-15s, the exposure time is 1-45s, the number of cycles is 1-60, and the N2 carrier gas flow rate is 20-80mL / min.

[0021] As a further illustration of the present invention, the precursor of the Pt metal is one of (trimethyl)cyclopentadienylplatinum and platinum acetylacetonate, the reaction gas is one of H2, O2 and O3, and the content of the reaction gas is 0.5-99 vol%.

[0022] As a further illustration of the present invention, the Pt ALD process adopts one of a holding mode and a flow mode.

[0023] The third aspect of the present invention further provides the use of the above-mentioned surface-confined atomically dispersed Pt@SiO2-N catalyst in the reaction of selective hydrogenation of p-chloronitrobenzene to prepare p-chloroaniline.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The present invention adopts the strategy of "physical and chemical co-anchoring" to design and synthesize highly active and highly stable atomically dispersed catalysts. In terms of physical means of anchoring metals, the SiO2 nano-flower balls with a multi-level porous structure can effectively inhibit the migration, growth and shedding of Pt particles; at the same time, the Pt particles are confined in the surface pores of SiO2, and the surface confinement structure makes the mass transfer of reactants not a problem. In terms of chemical means of anchoring metals, the present invention first uses chemical grafting to functionalize the surface amino groups of inert SiO2, which will provide sites for metal precursor anchoring and metal deposition growth in the subsequent Pt ALD process; and then finely control parameters such as precursor pulse time, exposure time and ALD kinetics to achieve precise control of Pt size and the proportion of different species; through the combination of chemical grafting and ALD technology, an atomically dispersed catalyst with high dispersion characteristics, high activity and high stability can be finally obtained.

[0026] The structure of the catalyst of the present invention is precisely controllable and can be prepared in batches. The loading amount and size of the active components of the obtained catalyst are simply controllable and have excellent catalytic performance. The catalyst is applied to the reaction of selective hydrogenation of p-chloronitrobenzene to prepare p-chloroaniline, and can obtain high reaction activity, selectivity and stability. The occurrence of side reactions such as dechlorination and coupling can also be effectively suppressed, thereby improving the reaction selectivity. Moreover, the catalyst can be easily separated and recovered after the reaction is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a scanning electron microscope image and a transmission electron microscope image of porous SiO2 nanospheres in Example 1 of the present invention; wherein (a) is a scanning electron microscope image and (b) is a transmission electron microscope image;

[0028] FIG2 is a diagram of Pt in Example 1 of the present invention. SA High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image of @SiO2-N catalyst;

[0029] FIG3 is a diagram of Pt in Example 2 of the present invention. SA+NC HAADF-STEM image of @SiO2-N catalyst;

[0030] FIG4 is a graph showing the Pt after 4 cycles in Example 2 of the present invention. SA+NC HAADF-STEM image of @SiO2-N catalyst;

[0031] FIG5 is a diagram of Pt in Example 3 of the present invention. SA+NP HAADF-STEM image of @SiO2-N catalyst;

[0032] Figure 6 is the HAADF-STEM image of the Pt@SiO2 catalyst without amino functionalization grafting. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Example 1: A surface-confined atomically dispersed Pt SA The preparation method of @SiO2-N single-atom catalyst specifically includes the following steps:

[0035] (1) Preparation of porous SiO2 nanospheres and their amino functionalization: 3.48 g of triethanolamine, 15.2 g of hexadecyltrimethylammonium bromide, and 3.8 g of sodium dodecylsulfonate were dissolved in 500 mL of deionized water to form a mixed solution, which was stirred at 80°C for 1 h; then, ethyl orthosilicate solution (145.8 g of ethyl orthosilicate dissolved in 500 mL of aqueous solution) was added to the above mixed solution, and the mixture was stirred at 80°C for 2 h; after the reaction, the white precursor was obtained by centrifugation (12,000 rpm, 10 min) and alcohol washing; the mixture was dried at 60°C for 12 h; and finally, the dried white powder was calcined at 750°C for 4.5 h to obtain porous SiO2 nanospheres for use. Amino functionalization of the carrier: 10 mL of 3-aminopropyltriethoxysilane was dissolved in 100 mL of toluene, and then 1 g of the above-mentioned SiO2 nanospheres was added under stirring conditions and stirred at 80°C for 48 hours. After the reaction, the amino-functionalized SiO2-N carrier was centrifuged, washed with alcohol and then washed with water, and then vacuum dried at 60°C for 12 hours.

[0036] (2) Preparation of atomically dispersed catalyst: 10 mg of amino-functionalized SiO2-N carrier was evenly coated on a quartz plate with ethanol. After natural air drying, it was placed in an ALD vacuum reaction chamber for Pt deposition: the pressure in the chamber was 50 Pa, the temperature in the chamber was 250 ° C, the heating temperature of the precursor (trimethyl)cyclopentadienyl platinum was 60 ° C, the reaction gas was O3, the N2 carrier gas flow rate was 50 mL / min, the pulse and exposure of (trimethyl)cyclopentadienyl platinum were 0.8 s and 20 s respectively, and the number of cycles was 12. By controlling the deposition parameters, surface-confined atomically dispersed Pt SA @SiO2-N catalyst, in which the Pt loading is 0.3wt%.

[0037] The Pt obtained in the above preparation process SA The HAADF-STEM image of the @SiO2-N catalyst, as shown in Figure 2, shows that Pt is evenly distributed on the support in the form of single atoms, and no Pt nanoparticles or clusters are found.

[0038] Catalyst evaluation was conducted in a batch reactor. 0.3 mmol of p-chloronitrobenzene was dissolved in ethanol and transferred to a 50 mL autoclave. 10 mg of the prepared catalyst was added to the autoclave. The air in the autoclave was replaced with hydrogen three times. The autoclave was then pressurized to 0.8 MPa and gradually heated to 80°C for 6 hours with magnetic stirring. After the reaction was complete, the reaction mixture was cooled to room temperature and the pressure was released. The catalyst-containing reaction mixture was filtered through an organic filter membrane. The filtrate was analyzed by high-performance gas chromatography (Thermo Fisher Scientific 1300) and showed approximately 3.5% conversion of p-chloronitrobenzene and 99% selectivity for the target product, p-chloroaniline.

[0039] Example 2: A surface-confined single atom-cluster coexisting Pt SA+NC The preparation method of @SiO2-N catalyst specifically comprises the following steps:

[0040] (1) Preparation of porous SiO2 nanospheres and their amino functionalization: 3.48 g of triethanolamine, 15.2 g of hexadecyltrimethylammonium bromide, and 3.8 g of sodium dodecylsulfonate were dissolved in 500 mL of deionized water to form a mixed solution, which was stirred at 80°C for 1 h; then, ethyl orthosilicate solution (145.8 g of ethyl orthosilicate dissolved in 500 mL of aqueous solution) was added to the above mixed solution, and the mixture was stirred at 80°C for 2 h; after the reaction, the white precursor was obtained by centrifugation (12,000 rpm, 10 min) and alcohol washing; the mixture was dried at 60°C for 12 h; and finally, the dried white powder was calcined at 750°C for 6 h to obtain porous SiO2 nanospheres for use. Carrier amino functionalization: 10 mL of 3-aminopropyltriethoxysilane was dissolved in 100 mL of toluene, and then 1 g of the above-mentioned SiO2 nanospheres was added under stirring conditions and stirred at 80°C for 48 hours. After the reaction was completed, the amino-functionalized SiO2-N carrier was centrifuged, washed with alcohol and then washed with water, and then vacuum dried at 60°C for 12 hours.

[0041] (2) Preparation of atomically dispersed catalyst: 10 mg of amino-functionalized SiO2-N carrier was evenly coated on a quartz plate with ethanol, and then placed in an ALD vacuum reaction chamber for Pt deposition: the pressure in the chamber was 50 Pa, the pressure in the chamber was 250 ° C, the heating temperature of the precursor (trimethyl) cyclopentadienyl platinum was 60 ° C, the reaction gas was O3, the N2 carrier gas flow rate was 50 mL / min, the pulse and exposure of (trimethyl) cyclopentadienyl platinum were 0.8 s and 20 s respectively, and the number of cycles was 25. By controlling the deposition parameters, atomically dispersed Pt was obtained. SA+NC @SiO2 surface confined catalyst, in which the Pt loading is 0.6wt%.

[0042] The Pt obtained in the above preparation process SA+NCThe HAADF-STEM image of the @SiO2-N catalyst, as shown in Figure 3, shows that a high density of Pt single atoms and a small number of clusters coexist on the carrier, among which single atoms still occupy the absolute number; and these clusters are composed of loose atoms, which still show the characteristics of atomic-level dispersion.

[0043] Catalyst evaluation was conducted in a batch reactor. p-Chloronitrobenzene was dissolved in ethanol and transferred to a 50 mL autoclave. 10 mg of the prepared catalyst was added to the autoclave, and the air in the autoclave was repeatedly replaced with hydrogen three times. The reaction was heated to 80°C and allowed to react for 1.5 hours. After cooling to room temperature and releasing the pressure, the catalyst-containing reaction mixture was filtered through an organic filter membrane. High-performance gas chromatography analysis of the filtrate revealed 99% conversion of p-chloronitrobenzene and 99% selectivity for the target product, p-chloroaniline. The filtered catalyst was reused four times under the above experimental conditions. Gas chromatography analysis of the conversion of p-chloronitrobenzene and the selectivity for p-chloroaniline from the four experiments is shown in the following table:

[0044] The data in the table show that the conversion rate of m-phenylenediamine and the yield of resorcinol did not decrease significantly after the catalyst was reused four times. Analysis of the catalyst after four reuses showed that the surface still contained a high density of single atoms, indicating that the catalyst has good stability.

[0045] Pt after 4 cycles SA+NC The HAADF-STEM image of the @SiO2-N catalyst is shown in Figure 4. It can be seen that the microstructure of the catalyst remains intact, and the high-density Pt single atoms are still evenly distributed on the support without obvious aggregation, indicating that the catalyst has excellent stability.

[0046] Example 3: A surface-confined single atom-nanoparticle coexisting Pt SA+NP The preparation method of @SiO2-N catalyst specifically comprises the following steps:

[0047] (1) Preparation of porous SiO2 nanospheres and their amino functionalization: 3.48 g of triethanolamine, 15.2 g of hexadecyltrimethylammonium bromide, and 3.8 g of sodium dodecylsulfonate were dissolved in 500 mL of deionized water to form a mixed solution, which was stirred at 80°C for 1 h; then, ethyl orthosilicate solution (145.8 g of ethyl orthosilicate dissolved in 500 mL of aqueous solution) was added to the above mixed solution, and the mixture was stirred at 80°C for 2 h; after the reaction, the white precursor was obtained by centrifugation (12,000 rpm, 10 min) and alcohol washing; the mixture was dried at 60°C for 12 h; and finally, the dried white powder was calcined at 750°C for 6 h to obtain porous SiO2 nanospheres for use. Carrier amino functionalization: 10 mL of 3-aminopropyltriethoxysilane was dissolved in 100 mL of toluene, and then 1 g of the above-mentioned SiO2 nanospheres was added under stirring conditions and stirred at 80°C for 48 hours. After the reaction was completed, the amino-functionalized SiO2-N carrier was centrifuged, washed with alcohol and then washed with water, and then vacuum dried at 60°C for 12 hours.

[0048] (2) Preparation of atomically dispersed catalyst: 10 mg of amino-functionalized SiO2-N carrier was evenly coated on a quartz plate with ethanol. After natural air drying, it was placed in an ALD vacuum reaction chamber for Pt deposition: the pressure in the chamber was 50 Pa, the temperature in the chamber was 250 ° C, the heating temperature of the precursor (trimethyl)cyclopentadienyl platinum was 60 ° C, the reaction gas was O3, the N2 carrier gas flow rate was 50 mL / min, the pulse and exposure of (trimethyl)cyclopentadienyl platinum were 0.8 s and 20 s respectively, and the number of cycles was 40. By controlling the deposition parameters, surface-confined atomically dispersed Pt SA+NP @SiO2-N catalyst, in which the Pt loading is 1.5wt%.

[0049] The Pt obtained in the above preparation process SA+NP The HAADF-STEM image of the @SiO2-N catalyst, as shown in Figure 5, shows that the density of single atoms is further increased and coexists with a small amount of Pt nanoparticles on the support.

[0050] Catalyst evaluation was conducted in a batch reactor. 0.3 mmol of p-chloronitrobenzene was dissolved in ethanol and transferred to a 50 mL autoclave. 10 mg of the prepared catalyst was added to the autoclave. The air in the autoclave was replaced with hydrogen three times. The autoclave was then pressurized to 0.8 MPa and gradually heated to 80°C for 1 hour with magnetic stirring. After the reaction was complete, the reaction mixture was cooled to room temperature and the pressure was released. The catalyst-containing reaction mixture was filtered through an organic filter membrane. High-performance gas chromatography (HPLC) analysis of the filtrate (Thermo Fisher Scientific 1300) revealed a conversion of p-chloronitrobenzene of 99% and an 84% selectivity for the target product, p-chloroaniline.

[0051] Comparative Example 1: A method for preparing a non-amino functionalized grafted Pt@SiO2 catalyst, comprising the following steps:

[0052] (1) Preparation of porous SiO2 nanospheres: 3.48 g of triethanolamine, 15.2 g of hexadecyltrimethylammonium bromide, and 3.8 g of sodium dodecylsulfonate were dissolved in 500 mL of deionized water to form a mixed solution, which was stirred at 80°C for 1 h. Then, ethyl orthosilicate solution (145.8 g of ethyl orthosilicate dissolved in 500 mL of aqueous solution) was added to the mixed solution, and the mixture was stirred at 80°C for 2 h. After the reaction, the white precursor was obtained by centrifugation (12,000 rpm, 10 min) and alcohol washing. The mixture was dried at 60°C for 12 h. Finally, the dried white powder was calcined at 750°C for 6 h to obtain porous SiO2 nanospheres for use.

[0053] (2) Preparation of Pt@SiO2 catalyst: Take 10 mg of the above-mentioned porous SiO2 nanosphere carrier and coat it evenly with ethanol on a quartz plate. After natural air drying, place it in an ALD vacuum reaction chamber for Pt deposition: the pressure in the chamber is 50 Pa, the pressure in the chamber is 250°C, the heating temperature of the precursor (trimethyl)cyclopentadienylplatinum is 60°C, the reaction gas is O3, the N2 carrier gas flow rate is 50 mL / min, the pulse and exposure of (trimethyl)cyclopentadienylplatinum are 0.8 s and 20 s respectively, the number of cycles is 25, and a Pt@SiO2 catalyst without amino functionalized grafting is obtained.

[0054] Figure 6 is a HAADF-STEM image of the Pt@SiO2 catalyst without amino functionalization grafting; it can be seen from the figure that the Pt particles are unevenly dispersed and easily fall off the support.

[0055] It should be noted that, in this document, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0056] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A surface confined atomically dispersed Pt@SiO2-N catalyst, characterized in that: Pt metal is supported on the surface of amino-functionalized porous SiO2 in an atomically dispersed form.

2. The surface confined atomically dispersed Pt@SiO2-N catalyst according to claim 1, characterized in that: The loading amount of the Pt metal is 0.1-3 wt %.

3. The surface confined atomically dispersed Pt@SiO2-N catalyst according to claim 1, characterized in that: The Pt metal is uniformly anchored in the surface pores of SiO2.

4. The surface confined atomically dispersed Pt@SiO2-N catalyst according to claim 1, characterized in that: The catalyst carrier is a dendritic porous SiO2 nanosphere, the size of which is 50-900nm and the specific surface area is 80-260m 2 / g, pore volume is 0.5-2.5cm 3 / g, pore size is 0.3-80nm.

5. A method for preparing the surface confined atomically dispersed Pt@SiO2-N catalyst according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: S1: preparing a SiO2 carrier by a solvent thermal synthesis method, and then performing surface amino functionalization grafting on the SiO2 carrier to obtain an amino functionalized SiO2-N carrier; coating the SiO2-N carrier evenly on a quartz sheet with ethanol, and naturally air-drying it for later use; S2: The SiO2-N carrier obtained in step 1 is placed in an ALD vacuum reaction chamber for Pt deposition, and an atomically dispersed Pt@SiO2-N surface confined catalyst is obtained by controlling the deposition parameters.

6. The method for preparing the surface confined atomically dispersed Pt@SiO2-N catalyst according to claim 5, characterized in that: The preparation process of the amino-functionalized SiO2-N carrier described in S1 specifically includes: Dissolve triethanolamine, hexadecyltrimethylammonium bromide and sodium dodecylsulfonate in deionized water to form a mixed solution, and stir at 25-100°C for 0.5-6h; then, add a certain concentration of ethyl orthosilicate solution to the mixed solution, and continue stirring for 0.5-6h; after the reaction is completed, wash the reaction solution with alcohol, wash with water, centrifuge, dry, and then calcine at 450-900°C in air atmosphere for 2-9h to obtain a SiO2 carrier; Dissolve 3-aminopropyltriethoxysilane in toluene, add a certain amount of the SiO2 carrier under stirring, then heat to 50-100°C and continue stirring for 12-60 hours; after the reaction is completed, obtain the amino-functionalized SiO2-N carrier after centrifugation, alcohol washing and water washing, and then vacuum dry the amino-functionalized SiO2-N carrier at 60°C for 12 hours.

7. The method for preparing the surface confined atomically dispersed Pt@SiO2-N catalyst according to claim 5, characterized in that: The deposition parameters during the Pt ALD process in S2 are: The deposition temperature of the reaction chamber is controlled at 160-320°C, the heating temperature of the Pt metal precursor is 45-80°C, the pulse time is 0.2-15s, the exposure time is 1-45s, the number of cycles is 1-60, and the N2 carrier gas flow rate is 20-80mL / min.

8. The method for preparing the surface confined atomically dispersed Pt@SiO2-N catalyst according to claim 5, characterized in that: The precursor of the Pt metal is one of (trimethyl)cyclopentadienyl platinum and platinum acetylacetonate, the reaction gas is one of H2, O2 and O3, and the content of the reaction gas is 0.5-99 vol%.

9. The method for preparing the surface confined atomically dispersed Pt@SiO2-N catalyst according to claim 5, characterized in that: The Pt ALD process adopts one of the holding mode and the flow mode.

10. Use of the surface-confined atomically dispersed Pt@SiO2-N catalyst according to any one of claims 1 to 4 in the reaction of selective hydrogenation of p-chloronitrobenzene to prepare p-chloroaniline.

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