Two-dimensional carbon-based porous metal oxide composite material, preparation method and application

Abstract

The invention provides a two-dimensional carbon-based porous metal oxide composite material and a preparation method thereof.The preparation method of the two-dimensional carbon-based porous metal oxide composite material comprises the following steps that ammonium salt, oligosaccharide and a transition metal precursor are added into a mortar and ground to prepare uniform powder; adding the two-dimensional carbon-based material dispersion liquid into the obtained powder, and grinding into a pasty mixture; and calcining the pasty mixture at a certain temperature. The two-dimensional carbon-based porous metal oxide composite material, which is simply and conveniently synthesized by ingeniously utilizing the polyhydroxy anchoring effect of oligosaccharide and the gas generated by decomposition of ammonium salt, has an ultrathin two-dimensional structure, a porous structure and a high specific surface area; the optical, electrical, mechanical and catalytic properties of the two-dimensional carbon-based porous metal oxide composite material are improved, and the two-dimensional carbon-based porous metal oxide composite material has wide application prospects in the fields of energy storage, catalysis, sensing and the like.

Description

Technical Field

[0001] The present invention belongs to the field of nanomaterials and their preparation, and specifically relates to a two-dimensional carbon-based porous metal oxide composite material, a preparation method and an application thereof. Background Art

[0002] Metal oxides are widely available, cheap and easy to obtain. Although they have advantages such as high catalytic activity and chemical stability, they have poor electrical conductivity, large volume expansion and insufficient stability, which limits their application in fields such as energy storage and catalysis. Two-dimensional carbon-based materials have high conductivity, large specific surface area and excellent mechanical strength, but lack sufficient active sites, resulting in insufficient electrochemical or catalytic performance. However, their surfaces are modifiable and can be surface functionalized to adapt to different fields. By combining carbon-based materials with metal oxides, the carbon-based materials serve as conductive skeletons to alleviate the volume effect of metal oxides; the metal oxides provide high-density active sites to compensate for the intrinsic inertness of carbon materials. In existing composite preparation methods, the composite materials obtained by physical mixing or simple loading have weak interface bonding and are prone to falling off during application, resulting in rapid performance degradation. Secondly, metal oxide particles are prone to agglomeration during high-temperature treatment, resulting in a reduction in the effective contact area with the carbon-based material. In addition, metal oxides are prone to crystallization migration, and their two-dimensional porous structure is difficult to precisely control. Summary of the Invention

[0003] In view of the above-mentioned technical defects in the prior art, the technical problem to be solved by the present invention is to provide a two-dimensional carbon-based porous metal oxide composite material and a preparation method. By introducing oligosaccharides as chelating agents and ammonium salts as leavening agents, different two-dimensional carbon-based porous metal oxide composite materials can be obtained by simply grinding and calcining after adding the precursor.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for preparing a two-dimensional carbon-based porous metal oxide composite material, comprising the following steps:

[0006] Adding oligosaccharides, ammonium salts and metal salt precursors into a mortar and grinding to obtain a uniform mixture powder;

[0007] adding an aqueous dispersion of the two-dimensional carbon-based material to the mixture powder in a mortar and grinding to prepare a paste-like mixture;

[0008] The paste-like mixture is calcined to obtain a two-dimensional carbon-based porous metal oxide composite material.

[0009] Further preferably, a method for preparing a two-dimensional carbon-based porous metal oxide composite material comprises the following steps:

[0010] Step A: Add 250-500 mg of oligosaccharide, 250-500 mg of ammonium salt and 10-20 mg of metal salt precursor into a mortar and grind to obtain a uniform mixture powder;

[0011] Step B: adding 100-200 μL of an aqueous dispersion of the two-dimensional carbon-based material to the above mixture powder in a mortar, and grinding the mixture to prepare a paste-like mixture; the concentration of the aqueous dispersion of the two-dimensional carbon-based material is 5-10 mg / mL;

[0012] Step C: preheating an oven to 500-800° C., and then placing the paste mixture in the oven and calcining it for 1-2 hours to obtain a two-dimensional carbon-based porous metal oxide composite material.

[0013] Preferably, the two-dimensional carbon-based material is one or more of graphene oxide, reduced graphene oxide, and graphitic carbon nitride.

[0014] Preferably, the oligosaccharide is one or more of glucose, fructose, lactose, sucrose, ribose and maltose.

[0015] Preferably, the ammonium salt is one or more of ammonium oxalate, ammonium nitrate, ammonium acetate, ammonium carbonate, ammonium chloride and ammonium bicarbonate.

[0016] Preferably, the metal salt precursor is one or more of metal nitrate, metal acetate and metal chloride.

[0017] Preferably, the calcination conditions for preparing the two-dimensional carbon-based porous metal oxide composite material are 500-800° C. for 1-2 hours.

[0018] The present invention has the following beneficial effects compared to the prior art:

[0019] The present invention allows the solid-phase precursors to be uniformly mixed through simple grinding. The polyhydroxy structures of the oligosaccharides can be adsorbed on the surface of the two-dimensional carbon-based material through non-covalent interactions and anchor metal ions, allowing the calcined metal oxide nanoparticles to fit tightly to the surface of the two-dimensional carbon-based material. The composite material can maintain a two-dimensional structure, and due to the random aggregation of the grains, mesopores are formed on the surface of the two-dimensional carbon-based material, greatly increasing the exposure of active sites. In addition, the method of the present invention has a simple preparation process, a wide range of raw materials, and greatly reduces the complexity and cost of preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a scanning electron microscope image of the two-dimensional porous indium oxide / graphene oxide composite material provided in Example 1 of the present invention;

[0022] Figure 2 This is a scanning electron microscope image of the two-dimensional porous indium oxide / graphite carbon nitride composite material provided in Example 2 of the present invention;

[0023] Figure 3 This is a scanning electron microscope image of the two-dimensional porous indium oxide / reduced graphene oxide composite material provided in Example 3 of the present invention;

[0024] Figure 4 This is a scanning electron microscope image of the two-dimensional porous tin oxide / graphene oxide composite material provided in Example 4 of the present invention;

[0025] Figure 5 This is a scanning electron microscope image of the two-dimensional porous indium tin oxide / graphene oxide composite material provided in Example 5 of the present invention;

[0026] Figure 6 This is a scanning electron microscope image of the two-dimensional porous indium aluminum oxide / graphene oxide composite material provided in Example 6 of the present invention;

[0027] Figure 7 This is a scanning electron microscope image of the two-dimensional porous indium tin oxide / graphene oxide composite material provided in Example 9 of the present invention;

[0028] Figure 8 This is the concentration gradient response curve of the two-dimensional porous indium oxide / graphene oxide composite material provided in Example 1 of the present invention to ofloxacin;

[0029] Figure 9 This is the concentration gradient response curve of the two-dimensional porous indium tin oxide / graphene oxide composite material provided in Example 5 of the present invention to moxifloxacin; DETAILED DESCRIPTION

[0030] The technical problems, technical solutions, and advantages of the present invention are described in detail below with reference to exemplary embodiments. The exemplary embodiments described below are intended only to illustrate the present invention and are not to be construed as limiting the present invention. Those skilled in the art will appreciate that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless otherwise defined herein, should not be interpreted in an idealized or overly formal sense.

[0031] A method for preparing a two-dimensional carbon-based porous metal oxide composite material comprises the following steps:

[0032] Step A: Add oligosaccharides, ammonium salts and metal salt precursors to a mortar and grind to obtain a uniform mixture powder; the oligosaccharide is one or more of glucose, fructose, lactose, sucrose, ribose and maltose, and the amount added is 250-500 mg; the ammonium salt is one or more of ammonium oxalate, ammonium nitrate, ammonium acetate, ammonium carbonate, ammonium chloride and ammonium bicarbonate, and the amount added is 250-500 mg; the metal salt precursor is one or more of metal nitrate, metal acetate and metal chloride, and the amount added is 10-20 mg; the main function of this step is to mix the precursors evenly and use oligosaccharides to anchor metal ions, so that a uniform product can be obtained in the subsequent chemical reaction. Further, the metal salt precursor is at least one of indium nitrate, tin acetate and aluminum nitrate; further preferably, the metal salt precursor is a mixture of indium nitrate and tin acetate in a mass ratio of (1-3): (1-3).

[0033] Step B: Add an aqueous dispersion of the two-dimensional carbon-based material to the powdered mixture in a mortar and grind the mixture to form a paste. The amount of the aqueous dispersion added is 100-200 μL, with a concentration of 5-10 mg / mL. This step is primarily intended to uniformly mix all precursors and to allow the metal ions to adhere tightly to the surface of the two-dimensional carbon-based material using the oligosaccharides.

[0034] Step C: Preheat the oven to 500-800°C, place the paste mixture in the oven and calcine for 1-2 hours to obtain a two-dimensional carbon-based porous metal oxide composite material. This calcination step ensures the complete decomposition of oligosaccharides and the crystallization of metal oxides, and finally obtains a pure two-dimensional carbon-based porous metal oxide composite material. The obtained two-dimensional carbon-based porous metal oxide composite material has two-dimensional structural characteristics. The crystallized metal oxide nanoparticles randomly aggregate on the surface of the two-dimensional carbon-based material to form a porous structure, making the composite material a sandwich-shaped two-dimensional porous structure, which significantly increases the specific surface area of ​​the material and the exposure of active sites, which is conducive to its better performance in applications.

[0035] The present invention provides a method for preparing a two-dimensional carbon-based porous metal oxide composite material. Oligosaccharide molecules, which contain polyhydroxyl functional groups that can anchor metal ions and interact non-covalently with the two-dimensional carbon-based material, can cause the metal ions to crystallize and aggregate closely on the surface of the two-dimensional carbon-based material. The decomposition of ammonium salts can generate a large amount of gas. During calcination, the gas generated by the decomposition of the ammonium salt can help blow the paste-like mixture into two-dimensional sheets, preventing the material from stacking into blocks, thereby producing a two-dimensional carbon-based porous metal oxide composite material.

[0036] Ammonium salt, oligosaccharide and metal salt precursor are added to a crucible and ground into fine powder so that they are evenly mixed. Subsequently, a dispersion of the two-dimensional carbon-based material is added to the powder mixture and ground thoroughly to form a uniform paste-like mixture. Due to the interaction between the oligosaccharide and the metal salt precursor and the two-dimensional carbon-based material, the metal salt precursor will adhere closely to the surface of the two-dimensional carbon-based material. During the calcination reaction stage, the decomposition of the ammonium salt will produce a large amount of gas and blow the paste-like mixture into a two-dimensional sheet. At the same time, the metal salt precursor adsorbed on the surface of the two-dimensional carbon-based material will decompose and crystallize and aggregate to form metal oxide grains on the surface of the two-dimensional carbon-based material. By precisely controlling the calcination temperature and time, the generated metal oxide grains mature and aggregate on the surface of the two-dimensional carbon-based material due to surface energy to form porous metal oxide. Subsequently, after calcination until the carbon produced by the oligosaccharide is completely removed, a two-dimensional carbon-based porous metal oxide composite material can be obtained. The preparation method of the present invention is simple and efficient, and the raw materials are cheap and easily available. The prepared two-dimensional carbon-based porous metal oxide composite material has excellent two-dimensional porous structure and nanocomposite properties, showing good practicality and broad application prospects.

[0037] Example 1:

[0038] A method for preparing a two-dimensional porous indium oxide / graphene oxide composite material comprises the following steps:

[0039] Step A: 300 mg of sucrose, 300 mg of ammonium nitrate, and 10 mg of indium nitrate were added to a mortar and ground into a uniform mixture powder;

[0040] Step B: 150 μL of a 6 mg / mL aqueous dispersion of graphene oxide was added to the above mixture powder in a mortar and ground to prepare a paste-like mixture;

[0041] Step C: preheating an oven to 500° C., and then placing the paste mixture in the oven and calcining it for 1 hour to obtain a two-dimensional porous indium oxide / graphene oxide composite material.

[0042] See also Figure 1 The obtained two-dimensional porous indium oxide / graphene oxide composite material has a two-dimensional structure, and the indium oxide grains aggregate on the graphene oxide to form a porous structure.

[0043] Example 2:

[0044] A method for preparing a two-dimensional porous indium oxide / graphite phase carbon nitride composite material comprises the following steps:

[0045] Step A: 300 mg of sucrose, 300 mg of ammonium nitrate, and 10 mg of indium nitrate were added to a mortar and ground into a uniform mixture powder;

[0046] Step B: 150 μL of a 6 mg / mL aqueous dispersion of graphitic carbon nitride was added to the above mixture powder in a mortar and ground to prepare a paste-like mixture;

[0047] Step C: preheating an oven to 500° C., and then placing the paste mixture in the oven and calcining it for 1 hour to obtain a two-dimensional porous indium oxide / graphite-phase carbon nitride composite material.

[0048] See also Figure 2 The obtained two-dimensional porous indium oxide / graphite carbon nitride composite material has a two-dimensional structure, and the indium oxide grains aggregate on the graphite carbon nitride to form a porous structure.

[0049] Example 3:

[0050] A method for preparing a two-dimensional porous indium oxide / reduced graphene oxide composite material comprises the following steps:

[0051] Step A: 300 mg of sucrose, 300 mg of ammonium nitrate, and 10 mg of indium nitrate were added to a mortar and ground into a uniform mixture powder;

[0052] Step B: 150 μL of an aqueous dispersion of reduced graphene oxide (6 mg / mL) was added to the above mixture powder in a mortar and ground to prepare a paste-like mixture;

[0053] Step C: preheating an oven to 500° C., and then placing the paste mixture in the oven and calcining it for 1 hour to obtain a two-dimensional porous indium oxide / reduced graphene oxide composite material.

[0054] See also Figure 3 The obtained two-dimensional porous indium oxide / reduced graphene oxide composite material has a two-dimensional structure, and the indium oxide grains aggregate on the reduced graphene oxide to form a porous structure.

[0055] Example 4:

[0056] A method for preparing a two-dimensional porous tin oxide / graphene oxide composite material comprises the following steps:

[0057] Step A: Add 300 mg of sucrose, 300 mg of ammonium nitrate, and 10 mg of tin acetate into a mortar and grind to obtain a uniform mixture powder;

[0058] Step B: 150 μL of a 6 mg / mL aqueous dispersion of graphene oxide was added to the above mixture powder in a mortar and ground to prepare a paste-like mixture;

[0059] Step C: preheating an oven to 500° C., and then placing the paste mixture in the oven and calcining it for 1 hour to obtain a two-dimensional porous tin oxide / graphene oxide composite material.

[0060] See also Figure 4 The obtained two-dimensional porous tin oxide / graphene oxide composite material has a two-dimensional structure, and the tin oxide grains aggregate on the graphene oxide to form a porous structure.

[0061] Example 5:

[0062] A method for preparing a two-dimensional porous indium tin oxide / graphene oxide composite material comprises the following steps:

[0063] Step A: 300 mg of sucrose, 300 mg of ammonium nitrate, 5 mg of indium nitrate, and 5 mg of tin acetate were added to a mortar and ground into a uniform mixture powder;

[0064] Step B: 150 μL of a 6 mg / mL aqueous dispersion of graphene oxide was added to the above mixture powder in a mortar and ground to prepare a paste-like mixture;

[0065] Step C: preheating an oven to 500° C., and then placing the paste mixture in the oven and calcining it for 1 hour to obtain a two-dimensional porous indium tin oxide / graphene oxide composite material.

[0066] See also Figure 5The obtained two-dimensional porous indium tin oxide / graphene oxide composite material has a two-dimensional structure, and the indium oxide and tin oxide grains aggregate on the graphene oxide to form a porous structure.

[0067] Example 6:

[0068] A method for preparing a two-dimensional porous indium aluminum oxide / graphene oxide composite material comprises the following steps:

[0069] Step A: 300 mg of sucrose, 300 mg of ammonium nitrate, 5 mg of indium nitrate, and 5 mg of aluminum nitrate were added to a mortar and ground into a uniform mixture powder;

[0070] Step B: 150 μL of a 6 mg / mL aqueous dispersion of graphene oxide was added to the above mixture powder in a mortar and ground to prepare a paste-like mixture;

[0071] Step C: preheating an oven to 500° C., and then placing the paste mixture in the oven and calcining it for 1 hour to obtain a two-dimensional porous indium aluminum oxide / graphene oxide composite material.

[0072] See also Figure 6 The obtained two-dimensional porous indium aluminum oxide / graphene oxide composite material has a two-dimensional structure, and indium oxide grains and amorphous aluminum oxide aggregate on graphene oxide to form a porous structure.

[0073] Example 7:

[0074] A method for preparing a two-dimensional porous alumina / graphene oxide composite material comprises the following steps:

[0075] Step A: Add 300 mg of sucrose, 300 mg of ammonium nitrate, and 10 mg of aluminum nitrate into a mortar and grind to obtain a uniform mixture powder;

[0076] Step B: 150 μL of a 6 mg / mL aqueous dispersion of graphene oxide was added to the above mixture powder in a mortar and ground to prepare a paste-like mixture;

[0077] Step C: preheating an oven to 500° C., and then placing the paste mixture in the oven and calcining it for 1 hour to obtain a two-dimensional porous alumina / graphene oxide composite material.

[0078] Example 8:

[0079] A method for preparing a two-dimensional porous tin oxide aluminum / graphene oxide composite material comprises the following steps:

[0080] Step A: Add 300 mg of sucrose, 300 mg of ammonium nitrate, 5 mg of tin acetate, and 5 mg of aluminum nitrate into a mortar and grind to obtain a uniform mixture powder;

[0081] Step B: 150 μL of a 6 mg / mL aqueous dispersion of graphene oxide was added to the above mixture powder in a mortar and ground to prepare a paste-like mixture;

[0082] Step C: preheating an oven to 500° C., and then placing the paste mixture in the oven and calcining it for 1 hour to obtain a two-dimensional porous tin oxide aluminum / graphene oxide composite material.

[0083] Example 9:

[0084] A method for preparing a two-dimensional porous indium tin oxide / graphene oxide composite material (adding PEG-400) comprises the following steps:

[0085] Step A: Add 300mg of sucrose, 300mg of ammonium nitrate, 5mg of PEG-400, 5mg of indium nitrate, and 5mg of tin acetate to a mortar and pestle and slowly grind to a uniform, wet mixture powder. The addition of PEG-400 imparts excellent plasticity to the powder system, facilitating subsequent dispersion. Furthermore, PEG-400 generates gas-induced pore formation during calcination and inhibits agglomeration during the nucleation phase, resulting in a well-organized, porous heterojunction structure that significantly enhances the exposure and crystallization quality of the gas-sensing active sites.

[0086] Step B: 150 μL of graphene oxide aqueous dispersion (6 mg / mL) was added to the mortar containing the mixture powder and continued to grind to prepare a paste-like mixture.

[0087] Step C: preheating an oven to 500° C., and then placing the paste mixture in the oven and calcining it for 1 hour to obtain a two-dimensional porous indium tin oxide / graphene oxide composite material.

[0088] See also Figure 7 The obtained material has a clear two-dimensional structure. Indium oxide and tin oxide grains aggregate on the surface of graphene oxide to form a uniform porous structure with a more concentrated pore size distribution and clearer boundaries.

[0089] Application Example 1:

[0090] This application example provides the sensing detection results of 1000 ppb ofloxacin using the two-dimensional porous indium oxide / graphene oxide composite material of the present invention at 250°C.

[0091] The specific test method includes the following steps:

[0092] Step A, dispersing the two-dimensional porous indium oxide / graphene oxide composite material prepared in Example 1 in anhydrous ethanol and grinding it into a slurry, wherein the mass ratio of the two-dimensional porous indium oxide / graphene oxide composite material to anhydrous ethanol is 1:10;

[0093] Step B: evenly apply 1 μL of slurry material on the substrate of the MEMS test element (1×1 mm 2 ) and let it dry;

[0094] Step C, heating the test element coated with the two-dimensional porous indium oxide / graphene oxide composite material to 250° C. and aging for 48 hours;

[0095] Step D: placing the test element coated with the two-dimensional porous indium oxide / graphene oxide composite material in a NanoRay MA1.0 gas sensing test system, adjusting the temperature to 250° C., and sequentially injecting 1000 ppb ofloxacin and recording the response value;

[0096] like Figure 8 As shown, the response value of the material in Example 1 to 1000 ppb ofloxacin is 6.1.

[0097] Application Example 2:

[0098] This application example provides the sensing detection results of 1000 ppb ofloxacin using the two-dimensional porous indium oxide / graphite phase carbon nitride composite material of the present invention at 250°C.

[0099] The specific test method includes the following steps:

[0100] Step A, dispersing the two-dimensional porous indium oxide / graphite-phase carbon nitride composite material prepared in Example 2 in anhydrous ethanol and grinding it into a slurry, wherein the mass ratio of the two-dimensional porous indium oxide / graphite-phase carbon nitride composite material to anhydrous ethanol is 1:10;

[0101] Step B: evenly apply 1 μL of slurry material on the substrate of the MEMS test element (1×1 mm 2 ) and let it dry;

[0102] Step C, heating the test element coated with the two-dimensional porous indium oxide / graphite phase carbon nitride composite material to 250° C. and aging for 48 hours;

[0103] In step D, a test element coated with a two-dimensional porous indium oxide / graphite carbon nitride composite material was placed in a NanoRay MA1.0 gas sensing test system. The temperature was adjusted to 250°C, and 1000 ppb moxifloxacin concentrations were injected successively and the response values ​​were recorded. The response value of the material in Example 2 to 1000 ppb moxifloxacin was 5.5.

[0104] Application Example 3:

[0105] This application example provides the sensing detection results of 1000 ppb ofloxacin using the two-dimensional porous indium oxide / graphite phase carbon nitride composite material of the present invention at 250°C.

[0106] The specific test method includes the following steps:

[0107] Step A, dispersing the two-dimensional porous indium oxide / reduced graphene oxide composite material prepared in Example 3 in anhydrous ethanol and grinding it into a slurry, wherein the mass ratio of the two-dimensional porous indium oxide / reduced graphene oxide composite material to anhydrous ethanol is 1:10;

[0108] Step B: evenly apply 1 μL of slurry material on the substrate of the MEMS test element (1×1 mm 2 ) and let it dry;

[0109] Step C, heating the test element coated with the two-dimensional porous indium oxide / reduced graphene oxide composite material to 250° C. and aging for 48 hours;

[0110] In step D, a test element coated with a two-dimensional porous indium oxide / reduced graphene oxide composite material was placed in a NanoRay MA1.0 gas sensing test system, the temperature was adjusted to 250°C, and 1000 ppb moxifloxacin concentrations were injected successively and the response values ​​were recorded. The response value of the material in Example 3 to 1000 ppb moxifloxacin was 5.1.

[0111] Application Example 4:

[0112] This application example provides the sensing detection results of 1000 ppb ofloxacin using the two-dimensional porous tin oxide / graphene oxide composite material of the present invention at 250°C.

[0113] The specific test method includes the following steps:

[0114] Step A, dispersing the two-dimensional porous tin oxide / graphene oxide composite material prepared in Example 4 in anhydrous ethanol and grinding it into a slurry, wherein the mass ratio of the two-dimensional porous tin oxide / graphene oxide composite material to anhydrous ethanol is 1:10;

[0115] Step B: evenly apply 1 μL of slurry material on the substrate of the MEMS test element (1×1 mm 2 ) and let it dry;

[0116] Step C, heating the test element coated with the two-dimensional porous tin oxide / graphene oxide composite material to 250° C. and aging for 48 hours;

[0117] In step D, a test element coated with a two-dimensional porous tin oxide / graphene oxide composite material was placed in a NanoRay MA1.0 gas sensing test system, the temperature was adjusted to 250°C, and 1000 ppb moxifloxacin concentrations were injected successively and the response values ​​were recorded. The response value of the material in Example 4 to 1000 ppb moxifloxacin was 4.3.

[0118] Application Example 5:

[0119] This application example provides the sensing detection results of 1000 ppb ofloxacin using the two-dimensional porous indium tin oxide / graphene oxide composite material of the present invention at 250°C.

[0120] The specific test method includes the following steps:

[0121] Step A, dispersing the two-dimensional porous indium tin oxide / graphene oxide composite material prepared in Example 5 in anhydrous ethanol and grinding it into a slurry, wherein the mass ratio of the two-dimensional porous indium tin oxide / graphene oxide composite material to anhydrous ethanol is 1:10;

[0122] Step B: evenly apply 1 μL of slurry material on the substrate of the MEMS test element (1×1 mm 2 ) and let it dry;

[0123] Step C, heating the test element coated with the two-dimensional porous indium tin oxide / graphene oxide composite material to 250° C. and aging for 48 hours;

[0124] Step D: placing the test element coated with the two-dimensional porous indium tin oxide / graphene oxide composite material in a NanoRay MA1.0 gas sensing test system, adjusting the temperature to 250°C, and sequentially injecting 1000 ppb moxifloxacin concentrations and recording the response values;

[0125] like Figure 9 As shown, the response value of the material in Example 5 to 1000 ppb of moxifloxacin is 13.0.

[0126] Application Example 6:

[0127] This application example provides the sensing detection results of 1000 ppb ofloxacin using the two-dimensional porous indium aluminum oxide / graphene oxide composite material of the present invention at 250°C.

[0128] The specific test method includes the following steps:

[0129] Step A, dispersing the two-dimensional porous indium aluminum oxide / graphene oxide composite material prepared in Example 6 in anhydrous ethanol and grinding it to a slurry, wherein the mass ratio of the two-dimensional porous indium aluminum oxide / graphene oxide composite material to anhydrous ethanol is 1:10;

[0130] Step B: evenly apply 1 μL of slurry material on the substrate of the MEMS test element (1×1 mm 2 ) and let it dry;

[0131] Step C, heating the test element coated with the two-dimensional porous indium aluminum oxide / graphene oxide composite material to 250° C. and aging for 48 hours;

[0132] In step D, a test element coated with a two-dimensional porous indium aluminum oxide / graphene oxide composite material was placed in a NanoRay MA1.0 gas sensing test system, the temperature was adjusted to 250°C, and 1000 ppb moxifloxacin concentrations were injected successively and the response values ​​were recorded. The response value of the material in Example 6 to 1000 ppb moxifloxacin was 2.9.

[0133] Application Example 7:

[0134] This application example provides the sensing detection results of 1000 ppb ofloxacin using the two-dimensional porous alumina / graphene oxide composite material of the present invention at 250°C.

[0135] The specific test method includes the following steps:

[0136] Step A, dispersing the two-dimensional porous alumina / graphene oxide composite material prepared in Example 7 in anhydrous ethanol and grinding it into a slurry, wherein the mass ratio of the two-dimensional porous alumina / graphene oxide composite material to anhydrous ethanol is 1:10;

[0137] Step B: evenly apply 1 μL of slurry material on the substrate of the MEMS test element (1×1 mm 2 ) and let it dry;

[0138] Step C, heating the test element coated with the two-dimensional porous alumina / graphene oxide composite material to 250° C. and aging for 48 hours;

[0139] In step D, a test element coated with a two-dimensional porous alumina / graphene oxide composite material was placed in a NanoRay MA1.0 gas sensing test system, the temperature was adjusted to 250°C, and 1000 ppb moxifloxacin concentrations were injected successively and the response values ​​were recorded; the response value of the material in Example 7 to 1000 ppb moxifloxacin was 1.1.

[0140] Application Example 8:

[0141] This application example provides the sensing detection results of 1000 ppb ofloxacin using the two-dimensional porous tin oxide aluminum / graphene oxide composite material of the present invention at 250°C.

[0142] The specific test method includes the following steps:

[0143] Step A, dispersing the two-dimensional porous aluminum tin oxide / graphene oxide composite material prepared in Example 8 in anhydrous ethanol and grinding it to a slurry, wherein the mass ratio of the two-dimensional porous aluminum tin oxide / graphene oxide composite material to anhydrous ethanol is 1:10;

[0144] Step B: evenly apply 1 μL of slurry material on the substrate of the MEMS test element (1×1 mm2 ) and let it dry;

[0145] Step C, heating the test element coated with the two-dimensional porous tin oxide aluminum / graphene oxide composite material to 250° C. and aging for 48 hours;

[0146] In step D, a test element coated with a two-dimensional porous tin oxide aluminum / graphene oxide composite material was placed in a NanoRay MA1.0 gas sensing test system, the temperature was adjusted to 250°C, and 1000 ppb moxifloxacin concentrations were injected successively and the response values ​​were recorded. The response value of the material in Example 8 to 1000 ppb moxifloxacin was 3.2.

[0147] Application Example 9:

[0148] This application example provides the sensing detection results of 1000 ppb ofloxacin using the two-dimensional porous indium tin oxide / graphene oxide composite material of the present invention at 250°C.

[0149] The specific test method includes the following steps:

[0150] Step A, dispersing the two-dimensional porous indium tin oxide / graphene oxide composite material prepared in Example 9 in anhydrous ethanol and grinding it into a slurry, wherein the mass ratio of the two-dimensional porous indium tin oxide / graphene oxide composite material to anhydrous ethanol is 1:10;

[0151] Step B: evenly apply 1 μL of slurry material on the substrate of the MEMS test element (1×1 mm 2 ) and let it dry;

[0152] Step C, heating the test element coated with the two-dimensional porous indium tin oxide / graphene oxide composite material to 250° C. and aging for 48 hours;

[0153] In step D, a test element coated with a two-dimensional porous indium tin oxide / graphene oxide composite material was placed in a NanoRay MA1.0 gas sensing test system, the temperature was adjusted to 250°C, and 1000 ppb moxifloxacin concentrations were injected successively and the response values ​​were recorded. The response value of the material in Example 9 to 1000 ppb moxifloxacin was 17.0.

[0154] In the present invention, oligosaccharide molecules are used as bridges, which contain polyhydroxyl functional groups that can anchor metal ions, and there is a non-covalent interaction between the oligosaccharide molecules and the two-dimensional carbon-based materials, which can make the metal ions close to the surface of the two-dimensional carbon-based materials, crystallize and aggregate. By calcining, the generated metal oxides can be accurately controlled to mature and aggregate on the surface of the two-dimensional carbon-based materials, thereby determining the regularity and gas response performance of the composite material. Through systematic comparison, it was found that the heterojunction combination of indium oxide and tin oxide exhibited a significant synergistic enhancement effect. The reason is that: indium oxide and tin oxide both have a narrow band gap, high crystallinity at the calcining temperature, and the interaction between the precursor and the oligosaccharide is strong. During the calcining process, indium oxide and tin oxide grains are easy to grow and mature close to the two-dimensional carbon-based materials, and the two can grow and aggregate synergistically during calcination to form a regular two-dimensional porous heterojunction structure.

[0155] Experiments confirmed that the two-dimensional porous indium tin oxide / graphene oxide composite material (Example 5) had a response value of 13.0 to 1000 ppb ofloxacin, far higher than the composite materials of indium oxide alone (6.1) and tin oxide alone (4.3), demonstrating typical synergistic effects. In contrast, due to its high crystallization temperature and weak interaction between the precursor and oligosaccharides, aluminum oxide has difficulty forming a regular two-dimensional porous crystalline structure during calcination. When forming a heterojunction with indium oxide, the response value actually decreases (Example 6, 2.9). This shows that the indium oxide-tin oxide combination has unique advantages in terms of electronic structure matching and oligosaccharide compatibility.

[0156] The foregoing description is a preferred embodiment of the present invention. It should be noted that the present invention is not limited to the exemplary embodiments disclosed above. The essence of this description is merely to help those skilled in the relevant art comprehensively understand the specific details of the present invention. For those skilled in the art, various improvements and modifications, as well as readily conceivable changes or substitutions made within the technical scope of the present invention without departing from the principles of the present invention, should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a two-dimensional carbon-based porous metal oxide composite material, characterized in that: The steps include: Adding oligosaccharides, ammonium salts and metal salt precursors into a mortar and grinding to obtain a uniform mixture powder; adding an aqueous dispersion of the two-dimensional carbon-based material to the mixture powder in a mortar and grinding to prepare a paste-like mixture; The paste-like mixture is calcined to obtain a two-dimensional carbon-based porous metal oxide composite material.

2. The method for preparing the two-dimensional carbon-based porous metal oxide composite material according to claim 1, wherein: The steps include: Step A: Add 250-500 mg of oligosaccharide, 250-500 mg of ammonium salt and 10-20 mg of metal salt precursor into a mortar and grind to obtain a uniform mixture powder; Step B: adding 100-200 μL of the aqueous dispersion of the two-dimensional carbon-based material to the above mixture powder in a mortar, and grinding the mixture to prepare a paste-like mixture; Step C: preheating an oven, and then placing the paste mixture in the oven and calcining it to obtain a two-dimensional carbon-based porous metal oxide composite material.

3. The method for preparing the two-dimensional carbon-based porous metal oxide composite material according to claim 2, wherein: The two-dimensional carbon-based material is one or more of graphene oxide, reduced graphene oxide, and graphite-phase carbon nitride.

4. The method for preparing the two-dimensional carbon-based porous metal oxide composite material according to claim 2, wherein: The oligosaccharide is one or more of glucose, fructose, lactose, sucrose, ribose and maltose.

5. The method for preparing the two-dimensional carbon-based porous metal oxide composite material according to claim 2, wherein: The ammonium salt is one or more of ammonium oxalate, ammonium nitrate, ammonium acetate, ammonium carbonate, ammonium chloride and ammonium bicarbonate.

6. The method for preparing the two-dimensional carbon-based porous metal oxide composite material according to claim 2, wherein: The metal salt precursor is one or more of metal nitrate, metal acetate and metal chloride.

7. The method for preparing the two-dimensional carbon-based porous metal oxide composite material according to claim 2, wherein: The concentration of the aqueous dispersion of the two-dimensional carbon-based material is 5-10 mg / mL.

8. The method for preparing the two-dimensional carbon-based porous metal oxide composite material according to claim 2, wherein: The calcination conditions are 500-800°C for 1-2h.

9. A two-dimensional carbon-based porous metal oxide composite material, characterized in that: The invention is prepared by the method according to any one of claims 1 to 8.

10. The two-dimensional carbon-based porous metal oxide composite material according to claim 9 is used to prepare a gas-sensitive coating, wherein the gas-sensitive coating can respond to moxifloxacin.

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