Atomically dispersed thermal catalyst, and laser preparation method and application thereof

Abstract

The application discloses an atomic-level dispersed thermal catalyst and a laser preparation method and application thereof. The laser preparation method comprises the following steps: mixing a cobalt source, hydrazine hydrate, ethylene glycol and graphene oxide and heating reaction to prepare a first solution; mixing an indium source, urea, a solvent and the first solution to form a second solution and performing hydrothermal reaction to prepare a first solid product; and applying a suspension liquid at least containing the first solid product and a chloroplatinic acid hexahydrate precursor to a surface of carbon paper and performing laser irradiation treatment to prepare the atomic-level dispersed thermal catalyst. The atomic-level dispersed novel catalyst synthesized by laser solid phase has a unique "atomic / atomic cluster-island-sea" structure thermal catalyst. The thermal catalyst has excellent stability and CO2 hydrogenation thermal catalytic performance, and has a wide prospect in the industrial application field of methanol.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal catalysis, and in particular relates to an atomic-level dispersed thermal catalyst and a laser preparation method and application thereof. Background Art

[0002] Massive carbon dioxide (CO2) emissions have led to global warming and ocean acidification, posing significant challenges to contemporary societal development. In heterogeneous catalysis, single-atom catalysts (SACs) have garnered widespread attention due to their high atomic utilization efficiency, catalytic activity, and selectivity. However, the application of atomically dispersed catalysts in industrial applications remains in its infancy. This is due to the complex and tedious preparation steps (including chemical synthesis and multiple high-temperature calcinations at temperatures up to 600°C to 900°C), stringent environmental requirements, and labor-intensive and time-consuming processes. Consequently, achieving controlled atomic dispersion on a support is extremely challenging. Another major issue is the poor stability of catalysts during continuous reactions. Atomically dispersed metal atoms tend to migrate or aggregate on the support, particularly under reducing gases such as H2 and CO in high-temperature thermal catalysis, where metal active sites are more susceptible to deactivation. Currently, long-term catalyst stability is a common challenge in thermal catalysis. For example, in the CO2 hydrogenation to methanol industry, copper-zinc-aluminum (Cu-ZnO-Al2O3) catalysts are relatively mature, but the CO2 conversion rate (10%-30%) is low and the methanol selectivity (about 60%-80%) is not high. The biggest problem with the catalyst is its poor stability. During the high-temperature continuous reaction, the generation of H2O covers the active sites of the catalyst, causing the catalyst to sinter and lead to failure.

[0003] In recent years, researchers have developed new material combinations, unique material structures, and new preparation methods to prepare thermal catalysts with high CO2 conversion and methanol selectivity. Patent documents such as CN117960169A and CN118649684A disclose the preparation of single-atom nano-island catalysts by coprecipitation and impregnation. The general characteristics of these synthesis methods are complex processes, many synthesis steps, complex processes, long reaction times, and the need for specific conditions. The efficiency of preparation is also relatively low, and single atoms react easily in a high-temperature environment and are easily aggregated and deactivated, resulting in unstable catalytic performance. However, the thermal catalysts prepared by these methods react easily in a high-temperature environment and are easily aggregated and deactivated, resulting in unstable catalytic performance. Therefore, it is urgent to develop a method for preparing single-atom dispersed materials quickly and efficiently, and the catalytic materials prepared can greatly improve the thermal catalytic stability of CO2 hydrogenation. Summary of the Invention

[0004] The main purpose of the present invention is to provide an atomically dispersed thermal catalyst and a preparation method and application thereof, so as to overcome the deficiencies of the prior art.

[0005] To achieve the aforementioned purposes of the application, the technical scheme adopted by the application comprises:

[0006] The embodiment of the application provides a laser preparation method of an atomically dispersed thermal catalyst, which comprises the following steps:

[0007] A cobalt source, a first reducing agent, a first solvent and graphene oxide are mixed and heated to react to obtain a first solution;

[0008] An indium source, a second reducing agent and a second solvent are mixed with the first solution to form a second solution and perform a hydrothermal reaction to obtain a first solid product;

[0009] A suspension containing at least the first solid product and a chloroplatinic acid hexahydrate precursor is applied to a surface of a substrate and subjected to laser irradiation treatment to obtain an atomically dispersed thermal catalyst.

[0010] The embodiment of the application further provides the atomically dispersed thermal catalyst obtained by the laser preparation method, and the thermal catalyst comprises graphene, composite nanometer oxide and single-atom Pt; wherein the graphene forms a limited "sea" structure, the composite nanometer oxide serves as a local "island" structure, and the Pt is atomically dispersed on the "island" structure.

[0011] The embodiment of the application further provides the use of the atomically dispersed thermal catalyst in the preparation of methanol by CO2 hydrogenation.

[0012] Compared with the prior art, the application has the beneficial effects that:

[0013] (1) The laser solid-phase synthesis atomically dispersed novel catalyst adopted by the application has a unique "atomically dispersed Pt-In2O3-Co3O4" composite nanometer island-two-dimensional graphene limited sea" structure, and the special structure realizes the dynamic limited effect on single atoms in the thermal catalysis process, and greatly improves the stability.

[0014] (2) The thermal catalyst prepared by the application has excellent CO2 hydrogenation thermal catalytic performance, and the prepared thermal catalyst has high CO2 conversion rate (30%), high methanol directional selectivity (90%) and ultra-high stability (400h) and the like in the CO2 hydrogenation reaction to prepare methanol.

[0015] (3) The thermal catalyst prepared by the application has wide industrial application prospects: the laser solid-phase synthesis method is fast, easy to operate in the environment atmosphere, and has potential universality and scalability, and can realize SAC controllable synthesis and large-scale production, and efficient conversion and utilization of CO2 resources. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 The atomically dispersed Pt modified nanocomposite "island-sea" synergistic Pt prepared in Example 1 of the present invention SA SEM electron microscope image of / In2O3-Co3O4 / rGO catalyst;

[0018] Figure 2 The atomically dispersed Pt modified nanocomposite "island-sea" synergistic Pt prepared in Example 1 of the present invention SA TEM electron microscope image of / In2O3-Co3O4 / rGO catalyst;

[0019] Figure 3 The Pt single atom modified nanocomposite "island-sea" synergistic Pt prepared in Example 1 of the present invention SAC AC-STEM spherical aberration electron microscopy image of / In2O3-Co3O4 / rGO catalyst;

[0020] Figure 4 The atomically dispersed Pt modified nanocomposite "island-sea" synergistic Pt prepared in Example 1 of the present invention SA Wavelet transform (WT) image of X-ray absorption near-edge structure (XANES) spectrum of / In2O3-Co3O4 / rGO catalyst;

[0021] Figure 5 The Pt single atom / atom cluster synergistically modified nanocomposite "island-sea" synergistic Pt prepared in Example 2 of the present invention SA_AC AC-STEM spherical aberration electron microscopy image of / In2O3-Co3O4 / rGO catalyst;

[0022] Figure 6 The Pt single atom-nanoparticle synergistically modified nanocomposite "island-sea" synergistic Pt prepared in Example 3 of the present invention SA_AC_NC AC-STEM spherical aberration electron microscopy image of / In2O3-Co3O4 / rGO catalyst;

[0023] Figure 7 The nanocomposite "island-sea" synergistic Pt prepared in Example 1 of the present invention is modified with Pt single atom / atom cluster. SA / In2O3-Co3O4 / rGO catalyst in CO2 hydrogenation reaction (pressure = 3.5MPa, temperature = 300°C, gas hourly space velocity GHSV = 24000cm 3 STP g , H2 / CO2= 3 / 1) in catalytic activity and stability test diagram. DETAILED DESCRIPTION

[0024] In view of the defects of the existing technology, the inventors of this case have proposed the technical solution of the present invention after long-term research and extensive practice. The main purpose is to use laser solid-phase synthesis technology to prepare a nano-scale "island-sea" synergistic thermal catalyst (Pt SA / In2O3-Co3O4 / rGO) for efficient CO2 hydrogenation to methanol, achieving a CO2 conversion of 30% and a methanol selectivity of >90%, exhibiting exceptionally long-term stability with no deactivation over 400 hours. This novel "atomic-level dispersion-composite nanoisland-two-dimensional confined sea" catalyst has the unique advantage of simultaneously achieving multi-level structural construction and single-atom anchoring modification in a single step under the multiple effects of laser-induced photochemical, thermal reduction, and thermal shock, enabling efficient CO2 resource conversion and utilization. This method is rapid, easy to operate in ambient atmosphere, and has the potential for versatility and scalability, enabling the controlled synthesis and large-scale production of SACs.

[0025] The technical solution of the present invention will be described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] Specifically, as one aspect of the technical solution of the present invention, a laser preparation method of an atomically dispersed thermal catalyst includes:

[0027] Mixing a cobalt source, a first reducing agent, a first solvent, and graphene oxide and heating them for reaction to prepare a first solution;

[0028] mixing an indium source, a second reducing agent, a second solvent and the first solution to form a second solution and performing a hydrothermal reaction to obtain a first solid product;

[0029] Furthermore, a suspension containing at least the first solid product and a hexahydrate chloroplatinic acid precursor is applied to a substrate surface and subjected to laser irradiation treatment to obtain an atomically dispersed thermal catalyst.

[0030] In some preferred embodiments, the laser preparation method specifically includes: mixing a cobalt source, graphene oxide and a first solvent, then adding a first reducing agent dilution solution, mixing and stirring in a water bath for 8 to 15 hours to obtain a first solution.

[0031] Furthermore, the usage ratio of the cobalt source, the first solvent, the graphene oxide and the first reducing agent dilution solution is 0.002-0.005 mol: 10-35 ml: 0.02-0.05 g: 10-30 mL.

[0032] Furthermore, the first reducing agent dilution liquid includes a hydrazine hydrate dilution liquid, and the hydrazine hydrate dilution liquid includes hydrazine hydrate and water; wherein the volume ratio of the hydrazine hydrate to water is 3~5:5~8.

[0033] Furthermore, the temperature of the water bath is 80-100°C.

[0034] Furthermore, the cobalt source includes any one or more combinations of cobalt nitrate hexahydrate, cobalt chloride hexahydrate, and cobalt sulfate hexahydrate, but is not limited thereto.

[0035] Furthermore, the first solvent includes ethylene glycol, but is not limited thereto.

[0036] In some preferred embodiments, the laser preparation method specifically includes:

[0037] Mixing the indium source, the second reducing agent, the second solvent and the first solution and stirring at room temperature for 30 to 60 minutes to form a second solution;

[0038] Furthermore, the second solution is subjected to a hydrothermal reaction at 120-180° C. for 12-20 hours, and then subjected to centrifugation, washing, and drying to obtain a first solid product.

[0039] Furthermore, the usage ratio of the indium source, the second reducing agent, the second solvent and the first solution is 0.005-0.008 mol: 0.68-0.85 g: 60-100 mL: 0.38-0.58 g.

[0040] Furthermore, the second solvent includes ethanol and water; wherein the volume ratio of the ethanol to water is 3-5:5-8.

[0041] Furthermore, the indium source includes any one or more combinations of indium nitrate hexahydrate, indium chloride, and indium sulfate, but is not limited thereto.

[0042] Furthermore, the drying process is carried out at a temperature of 50-80° C. and for a time of 8-18 hours.

[0043] In some preferred embodiments, the laser preparation method specifically includes:

[0044] The first solid product and the aqueous solution of chloroplatinic acid hexahydrate precursor are mixed and stirred for 16 to 24 hours to form a suspension, and then the suspension is brush-coated on the surface of the substrate and allowed to dry naturally; wherein the thickness of the suspension brush-coated is 100 to 200 μm;

[0045] Furthermore, the obtained carbon paper is subjected to laser irradiation treatment, and then washed and dried to obtain an atomically dispersed thermal catalyst; wherein the laser wavelength used in the laser irradiation treatment is 1064nm, the spot diameter is 260~520μm, the repetition frequency is 10-60kHz, the power is 40~100W, and the scanning speed is 1500~3000mm / s.

[0046] Furthermore, the laser irradiation treatment uses an infrared pulse laser.

[0047] Furthermore, the mass volume ratio of the first solid product to the chloroplatinic acid hexahydrate precursor aqueous solution is 0.30-0.63 g:20-50 mL, and the concentration of the chloroplatinic acid hexahydrate precursor aqueous solution is 5-25 mmol / L.

[0048] Furthermore, the aqueous solution of chloroplatinic acid hexahydrate precursor is a mixed solution of chloroplatinic acid hexahydrate and water; the concentration of the aqueous solution of chloroplatinic acid hexahydrate precursor is 5-25 mM.

[0049] Furthermore, the drying process is carried out at a temperature of 30-60° C. and for a time of 2-5 hours.

[0050] In some more specific embodiments, the method for preparing the atomically dispersed thermal catalyst comprises:

[0051] (1) Cobalt nitrate hexahydrate (Co(NO3)2·6H2O) and hydrazine hydrate dilution ( ), ethylene glycol and graphene oxide (GO) are mixed, stirred evenly, and heated to react for a period of time to obtain solution A;

[0052] (2) Add hydrated indium nitrate (In(NO3)3·6H2O), urea (CH4N2O), anhydrous ethanol and deionized water to solution A and stir evenly to obtain solution B;

[0053] (3) Solution B is put into the reaction lining of the reactor for hydrothermal reaction, centrifuged, repeatedly washed, filtered, and dried to obtain precipitate C;

[0054] (4) Powder C is placed in an aqueous solution of chloroplatinic acid hexahydrate precursor and stirred for a period of time. The suspension is then brushed onto carbon paper, removed, and allowed to dry naturally.

[0055] (5) The dried carbon paper is subjected to laser irradiation in an air atmosphere, washed with deionized water, and dried to obtain Pt atomically dispersed In2O3-Co3O4 nano-oxide composite "islands" supported on the graphene "sea" thermal catalyst, which can be written as Pt SA / In2O3-Co3O4 / rGO.

[0056] As preferred, in step (1), the mass of GO in solution A is 0.02-0.05 g, and the molar concentration of cobalt nitrate is 0.002-0.005 mol, which is added to 10-35 mL of ethylene glycol, and then a mixed solution of 10-30 mL of hydrazine hydrate and deionized water is added, with a volume ratio of 3-5:5-8 (preferably 3:5) for mixing and dilution.

[0057] As preferred, in step (1), the mixed solution A is stirred in a water bath for 8-15 h.

[0058] As preferred, in step (2), the mass of A in solution B is 0.38-0.58 g, the molar concentration of indium nitrate is 0.005-0.008 mol, and the amount of urea is 0.68-0.85 g, which is mixed with 60-100 mL of anhydrous ethanol and deionized water, with a volume ratio of anhydrous ethanol:deionized water = 3-5:5-8 (preferably 3:5), and stirred at room temperature for 30-60 min to obtain solution B.

[0059] As preferred, in step (3), B is put into the reaction liner of the reaction kettle, and reacted at 120-180°C for 12-20 h, followed by centrifugation, repeated washing with deionized water until the supernatant is neutral, and filtration to obtain precipitate C.

[0060] As preferred, in step (3), drying refers to drying in a blast oven at 50-80°C for 8-18 h.

[0061] As preferred, in step (4), 20-50 mL of a 5-25 mM aqueous solution of chloroplatinic acid hexahydrate precursor is added to 0.30-0.63 g of powder C, and stirred for 16-24 h.

[0062] As preferred, in step (4), the suspension is brush-coated on a support carbon paper with a thickness of 100-200 μm, and then taken out and naturally dried.

[0063] As preferred, in step (5), the laser wavelength used is 1064 nm, the repetition frequency is 10 kHz, the power is 40-100 W, the spot diameter is 260-520 μm, and the scanning speed is 1500-3000 mm / s.

[0064] As preferred, in step (5), drying is carried out in a blast oven at 30-60°C for 2-5 h.

[0065] As a further improvement of the above-mentioned scheme, the laser irradiation in step (5) can be controlled by adjusting the laser parameters, including the laser wavelength, laser power, laser pulse width, laser spot size, and laser scanning speed.

[0066] Another aspect of the embodiment of the present application also provides a thermal catalyst prepared by the above-mentioned laser preparation method, which comprises graphene, composite nano-oxide, and Pt single atom / atom cluster; wherein the graphene forms a confined "sea" structure, the composite nano-oxide serves as a local "island" structure, and the Pt single atom / atom cluster is atomically dispersed on the "island" structure.

[0067] Further, the composite nano-oxide is formed by In2O3 and Co3O4.

[0068] Further, the thermal catalyst has a three-dimensional structure.

[0069] The present application adopts laser solid-phase synthesis to prepare a novel atomic-level dispersed catalyst, which has a unique structure, i.e., "atomic-level dispersed Pt-In2O3-Co3O4 composite nano-island-two-dimensional graphene confined sea", wherein the two-dimensional graphene forms a confined structure (sea), the composite nano-oxide is a local "island" structure, and the metal Pt single atom / atom cluster is dispersed on the "island". The special structure is formed due to the multiple effects of photochemistry, thermal reduction, and thermal shock generated by the laser, and a multi-level structure construction and single atom anchoring modification are achieved in one step. In the thermal catalysis process, the migration of single atoms only occurs on the "nano-island" and does not occur between multiple "nano-islands", so that no obvious agglomeration and sintering occurs at high temperature, realizing the dynamic confinement effect of single atoms in the thermal catalysis process and greatly improving the stability.

[0070] The thermal catalyst prepared by the present application has excellent CO2 hydrogenation thermal catalytic performance: based on the interaction mechanism of laser and materials, a single atom and atom cluster coordinated composite nano-oxide structure is designed and constructed and is confined on a two-dimensional graphene, and through material selection and structure regulation, excellent CO2 hydrogenation to methanol performance is obtained, the metal precursor salt is directionally adsorbed on the carrier by using the different electronegativity of oxides, the laser accurate regulation of oxygen vacancy active sites is realized, and the prepared thermal catalyst exhibits excellent performance such as high CO2 conversion rate (30%), high methanol directional selectivity (90%), and ultra-high stability (400h) in the CO2 hydrogenation to methanol reaction.

[0071] Another aspect of the embodiment of the present application also provides the use of the above-mentioned atomic-level dispersed thermal catalyst in the preparation of methanol by CO2 hydrogenation.

[0072] The application provides a method for laser solid-phase synthesis of atomically dispersed catalysts, and the catalyst has a unique "island-sea" structure, that is, a carbon matrix forms a limited structure (sea), a composite nanometer oxide locally forms an "island" structure, and a metal single atom / atom cluster is dispersed on the "island", and the special structure can greatly improve the stability of a thermal catalytic process. The laser solid-phase synthesis process of a single atom is to anchor a metal atom on an oxygen vacancy of a nanometer oxide, and only by adjusting laser parameters, a type of precursor salt and a concentration, the catalyst material with the special structure can be finally formed, and the catalyst material has great application prospects in the field of thermal catalysis, such as CO2 hydrogenation to methanol.

[0073] The application realizes the construction of a unique "two-dimensional limited substrate sea-nanometer composite island-single atom / atom cluster" multistage microstructure and the controllable modification anchoring of atomically dispersed Pt under solid-phase conditions by laser in one step. The rich oxygen vacancy defects generated by laser action exhibit remarkable CO2 conversion rate, methanol directional selectivity and excellent long-term stability in the CO2 hydrogenation reaction.

[0074] The application provides the laser solid-phase controllable synthesis of an atomically dispersed (single atom-atom cluster-nanometer particle) composite "island-sea" system catalyst by easily adjusting the concentration of a metal precursor and laser processing parameters, effectively controlling the combination form of atoms on an oxide nanometer particle, and maximizing the synergistic catalytic effect. The application breaks through the technical difficulties in the traditional synthesis process, such as difficult environmental adjustment, poor controllability of single atom modification and difficulty in constructing a multistage structure with thermal stability.

[0075] The technical solutions of the application will be further described in detail in combination with several preferred embodiments and the accompanying drawings. The embodiments are implemented on the premise of the technical solutions of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following embodiments.

[0076] In the following examples, the experimental materials used in the examples are commercially available from conventional biochemical reagent companies, unless otherwise specified.

[0077] Embodiment 1

[0078] A method for laser solid-phase synthesis of a single atom-composite "island-sea" thermal catalyst, and the specific steps are as follows:

[0079] (1) 0.02 g of GO, 0.002 mol of cobalt nitrate hexahydrate, 10 mL of dilute hydrazine hydrate and 25 mL of ethylene glycol solution are mixed to form a uniform solution by ultrasonic dispersion, and the solution is uniformly stirred and heated for reaction for 8 h to obtain solution A;

[0080] (2) 0.38 g of the appropriate amount of solution A, 0.005 mol of In(NO3)3·6H2O indium nitrate, and 0.68 g of urea were added to 60 mL of a mixed aqueous solution (deionized water: deionized water = 30:50 mL) and stirred to obtain solution B;

[0081] (3) Solution B was placed in the reaction liner of the reaction kettle and reacted at 140°C for 15 h. After centrifugation and repeated washing with deionized water, precipitate C was obtained by filtration;

[0082] (4) 0.30 g of powder C was placed in 20 mL of a chloroplatinic acid hexahydrate precursor aqueous solution and stirred for 16 h at a concentration of 5 mM. The suspension was brushed onto carbon paper with a thickness of 100 μm, removed, and naturally dried;

[0083] (5) The dried carbon paper was subjected to laser irradiation at a wavelength of 1064 nm, a spot diameter of 260 μm, a repetition frequency of 10 kHz, a power of 40 W, and a scanning speed of 1500 mm / s. After washing the surface with deionized water and drying, a Pt single atom-modified "island-sea" synergistic catalyst, denoted as Pt SAC / In2O3-Co3O4 / rGO, was obtained. The morphology is shown in Figure 1-Figure 3 , and the wavelet transform spectrum of the X-ray absorption near-edge structure (XANES) is shown in Figure 4 .

[0084] The Pt single atom-atom cluster-modified nanocomposite "island-sea" synergistic Pt SA / In2O3-Co3O4 / rGO catalyst prepared above was tested for catalytic activity and stability in a CO2 hydrogenation reaction (pressure = 3.5 MPa, temperature = 300 °C, gas hourly space velocity GHSV = 24000 cm 3 STP g , H2 / CO2= 3 / 1). The test chart is shown in Figure 7 .

[0085] Example 2

[0086] A method for laser solid-phase synthesis of atom / atom cluster-composite "island-sea" thermal catalysts, the specific steps are as follows:

[0087] (1) 0.03 g of GO, 0.003 mol of cobalt nitrate hexahydrate, 15 mL of hydrazine hydrate, and 30 mL of ethylene glycol solution were mixed and ultrasonically dispersed to form a uniform solution. After stirring and heating for 10 h, solution A was obtained;

[0088] (2) 0.45 g of the appropriate amount of solution A, 0.006 mol of In(NO3)3·6H2O indium nitrate, and 0.75 g of urea were added to a mixed aqueous solution (deionized water: anhydrous ethanol = 30:50 mL) and stirred uniformly to obtain solution B;

[0089] (3) Solution B was poured into the reaction liner in the reaction kettle, and reacted at 140°C for 16 h. After centrifugation, deionized water was repeatedly washed, and the precipitate C was obtained by filtration;

[0090] (4) Powder C was placed in 30 mL of a chloroplatinic acid hexahydrate precursor aqueous solution and stirred for 20 h at a concentration of 10 mM. The suspension was brushed onto carbon paper with a thickness of 100 μm, removed, and naturally dried;

[0091] (5) The dried carbon paper was subjected to laser irradiation at a wavelength of 1064 nm, a spot diameter of 420 μm, a repetition frequency of 10 kHz, a power of 60 W, and a scanning speed of 2000 mm / s. After washing the surface with deionized water and drying, a Pt single atom / atomic cluster cooperatively modified "atom-nano island-sea" multi-level structure thermal catalyst was obtained, and the morphology is shown in Figure 5 .

[0092] Example 3

[0093] A method for laser solid-phase synthesis of an atomic cluster / nanoparticle-composite "island-sea" thermal catalyst, and the specific steps are as follows:

[0094] (1) 0.05 g of GO, 0.005 mol of cobalt nitrate hexahydrate, 20 mL of hydrazine hydrate, and 35 mL of ethylene glycol solution were mixed to form a uniform solution, which was stirred and heated for 12 h to obtain solution A;

[0095] (2) 0.55 g of the appropriate amount of solution A, 0.01 mol of In(NO3)3·6H2O cobalt nitrate, and 0.85 g of urea were added to a mixed aqueous solution (deionized water: anhydrous ethanol = 30:50 mL) and stirred uniformly to obtain solution B;

[0096] (3) Solution B was poured into the reaction liner in the reaction kettle, and reacted at 140°C for 18 h. After centrifugation, deionized water was repeatedly washed, and the precipitate C was obtained by filtration;

[0097] (4) Powder C was placed in 40 mL of a chloroplatinic acid hexahydrate precursor aqueous solution and stirred for 30 h at a concentration of 20 mM. The suspension was brushed onto carbon paper with a thickness of 100 μm, removed, and naturally dried;

[0098] The dry carbon paper is subjected to laser irradiation, laser wavelength 1064 nm, spot diameter 520 μm, repetition frequency 10 kHz, power 100 W, scanning speed 2500 mm / s, the surface is cleaned with deionized water, and after drying, a Pt atomic cluster / nanoparticle synergistically modified "atomic-nanometer island-sea" multi-level structure thermal catalyst is obtained, and the morphology is as shown in Figure 6 .

[0099] Example 4

[0100] A method for laser solid-phase synthesis of atomic / atomic cluster-composite "island-sea" thermal catalyst, the specific steps are as follows:

[0101] (1) 0.04 g GO, 0.0035 mol cobalt chloride hexahydrate, 20 mL hydrazine hydrate and 30 mL ethylene glycol solution are mixed to form a uniform solution by ultrasonic dispersion, and the solution is uniformly stirred and heated for 10 h to obtain solution A;

[0102] (2) 0.45 g of the appropriate A solution, 0.007 mol In(NO3)3·6H2O indium nitrate, and 0.8 g urea are added to a mixed aqueous solution (deionized water: anhydrous ethanol = 36:70 mL) to obtain solution B;

[0103] (3) Solution B is put into the reaction liner in the reaction kettle, and reacted at 145°C for 18 h, centrifuged, and repeatedly washed with deionized water to obtain precipitate C;

[0104] (4) Powder C is placed in 35 mL of a chloroplatinic acid hexahydrate precursor aqueous solution and stirred for 24 h at a concentration of 12 mM. The suspension is brushed on the carbon paper with a thickness of 100 μm, taken out, and naturally dried;

[0105] (5) The dry carbon paper is subjected to laser irradiation, laser wavelength 1064 nm, spot diameter 350 μm, repetition frequency 35 kHz, power 80 W, scanning speed 3000 mm / s, the surface is cleaned with deionized water, and after drying, a Pt single atom / atomic cluster synergistically modified "atomic-nanometer island-sea" multi-level structure thermal catalyst is obtained.

[0106] Example 5

[0107] A method for laser solid-phase synthesis of single atom-composite "island-sea" thermal catalyst, the specific steps are as follows:

[0108] (1) 0.02 g GO, 0.002 mol cobalt chloride hexahydrate, 10 mL dilute hydrazine hydrate and 20 mL ethylene glycol solution are mixed to form a uniform solution by ultrasonic dispersion, and the solution is uniformly stirred and heated for 8 h to obtain solution A;

[0109] (2) Add 0.38 g of solution A, 0.005 mol of indium chloride, and 0.68 g of urea to 60 mL of a mixed aqueous solution (anhydrous ethanol: deionized water = 30:50 mL) and stir evenly to obtain solution B;

[0110] (3) Solution B was added to the reaction lining of the reactor, reacted at 140°C for 20 h, centrifuged, repeatedly washed with deionized water, and filtered to obtain precipitate C;

[0111] (4) Place 0.30 g of powder C in 20 mL of 5 mM aqueous chloroplatinic acid hexahydrate precursor solution and stir for 16 h. Apply the suspension to a 200 μm thickness on carbon paper, remove, and allow to dry naturally.

[0112] (5) The dried carbon paper was irradiated with laser light at a wavelength of 1064 nm, a spot diameter of 300 μm, a repetition rate of 10 kHz, a power of 40 W, and a scanning speed of 1500 mm / s. The surface was cleaned with deionized water and dried to obtain a Pt single-atom modified "atom-nano island-sea" synergistic catalyst.

[0113] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments using other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0114] It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific implementation cases. Any technical variations made according to the technical solution of the present invention without departing from the scope of protection of the purpose of the present invention and the claims shall fall within the scope of protection of the present invention.

Claims

1. A laser preparation method for atomically dispersed thermal catalysts, characterized in that: include: Mixing a cobalt source, a first reducing agent, a first solvent, and graphene oxide and heating them for reaction to prepare a first solution; mixing an indium source, a second reducing agent, a second solvent and the first solution to form a second solution and performing a hydrothermal reaction to obtain a first solid product; and applying a suspension comprising at least the first solid product and a chloroplatinic acid hexahydrate precursor to a substrate surface and subjecting the substrate to laser irradiation to produce an atomically dispersed thermal catalyst; the substrate comprising carbon paper and / or carbon cloth; The thermal catalyst includes graphene, composite nano-oxide and Pt single atoms / atomic clusters; the graphene forms a confined "sea" structure, the composite nano-oxide serves as a local "island" structure, and the Pt single atoms / atomic clusters are atomically dispersed on the "island" structure.

2. The laser preparation method according to claim 1, characterized in that: Specifically include: The cobalt source, graphene oxide and the first solvent are mixed, and then the first reducing agent dilution solution is added and mixed, and the mixture is stirred in a water bath for 8 to 15 hours to prepare a first solution.

3. The laser preparation method according to claim 2, characterized in that: The usage ratio of the cobalt source, the first solvent, the graphene oxide and the first reducing agent dilution solution is 0.002-0.005 mol: 10-35 ml: 0.02-0.05 g: 10-30 mL.

4. The laser preparation method according to claim 2, characterized in that: The first reducing agent dilution liquid includes a hydrazine hydrate dilution liquid, and the hydrazine hydrate dilution liquid includes hydrazine hydrate and water; wherein the volume ratio of the hydrazine hydrate to water is 3-5:5-8.

5. The laser preparation method according to claim 2, characterized in that: The temperature of the water bath is 80-100°C.

6. The laser preparation method according to claim 2, characterized in that: The cobalt source includes any one or more of cobalt nitrate hexahydrate, cobalt chloride hexahydrate, and cobalt sulfate hexahydrate.

7. The laser preparation method according to claim 2, characterized in that: The first solvent includes ethylene glycol.

8. The laser preparation method according to claim 1, characterized in that: Specifically include: Mixing the indium source, the second reducing agent, the second solvent and the first solution and stirring at room temperature for 30 to 60 minutes to form a second solution; Furthermore, the second solution is subjected to a hydrothermal reaction at 120-180° C. for 12-20 hours, and then subjected to centrifugation, washing, and drying to obtain a first solid product.

9. The laser preparation method according to claim 8, characterized in that: The usage ratio of the indium source, the second reducing agent, the second solvent and the first solution is 0.005-0.008 mol: 0.68-0.85 g: 60-100 mL: 0.38-0.58 g.

10. The laser preparation method according to claim 8, characterized in that: The second reducing agent includes urea.

11. The laser preparation method according to claim 8, characterized in that: The second solvent includes ethanol and water; wherein the volume ratio of the ethanol to water is 3-5:5-8.

12. The laser preparation method according to claim 8, characterized in that: The indium source includes any one or more of indium nitrate hexahydrate, indium chloride, and indium sulfate.

13. The laser preparation method according to claim 8, characterized in that: The drying temperature is 50-80° C. and the drying time is 8-18 hours.

14. The laser preparation method according to claim 1, characterized in that: Specifically include: The first solid product and the aqueous solution of chloroplatinic acid hexahydrate precursor are mixed and stirred for 16 to 24 hours to form a suspension, and then the suspension is brush-coated on the surface of the substrate and allowed to dry naturally; wherein the thickness of the suspension brush-coated is 100 to 200 μm; Furthermore, the obtained substrate is subjected to laser irradiation treatment, and then washed and dried to obtain an atomically dispersed thermal catalyst; wherein the laser wavelength used in the laser irradiation treatment is 1064nm, the spot diameter is 260~520μm, the repetition frequency is 10-60kHz, the power is 40~100W, and the scanning speed is 1500~3000mm / s.

15. The laser preparation method according to claim 14, characterized in that: The mass volume ratio of the first solid product to the chloroplatinic acid hexahydrate precursor aqueous solution is 0.30-0.63 g:20-50 mL, and the concentration of the chloroplatinic acid hexahydrate precursor aqueous solution is 5-25 mmol / L.

16. The laser preparation method according to claim 14, characterized in that: The chloroplatinic acid hexahydrate precursor aqueous solution is a mixed solution of chloroplatinic acid hexahydrate and water, and the concentration of the chloroplatinic acid hexahydrate precursor aqueous solution is 5-25 mM.

17. The laser preparation method according to claim 14, characterized in that: The drying temperature is 30-60° C. and the drying time is 2-5 hours.

18. Atomically dispersed thermal catalyst prepared by the laser preparation method according to any one of claims 1 to 17.

19. The atomically dispersed thermal catalyst according to claim 18, characterized in that: The composite nano-oxide is formed by In2O3 and Co3O4.

20. Use of the atomically dispersed thermal catalyst according to claim 18 or 19 in the production of methanol by CO2 hydrogenation.

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