Defect-rich oxygen and noble metal nanoparticle decorated radial transition-rare earth metal oxide porous nanosheet clusters, methods of preparation and applications

Abstract

The present application relates to a kind of rich in defective oxygen and noble metal nanoparticle modified radial transition group-rare earth metal oxide porous nanosheet cluster, preparation method and application.The preparation method of the nanosheet cluster includes the following steps: first, transition group-rare earth metal precursor is prepared using hydrothermal method, then by calcination, obtain the radial transition group-rare earth metal oxide porous nanosheet cluster rich in defective oxygen, finally, using photoreduction method, prepare the radial transition group-rare earth metal oxide porous nanosheet cluster rich in defective oxygen and noble metal nanoparticle modification.The nanosheet cluster is constructed heterojunction by transition group metal oxide and rare earth metal oxide, presents radial structure, surface is rich in hole, noble metal nanoparticle and defective oxygen, can be applied to gas sensing, electrochemical sensing, photoelectric sensing and biosensing field.

Description

Technical Field

[0001] This invention relates to a radially arranged porous nanosheet cluster of transition metal oxides rich in defective oxygen and modified with noble metal nanoparticles, its preparation method, and its applications, belonging to the field of sensing technology. This invention employs a function-oriented sensing material design and modification technique. First, a transition metal precursor is prepared via a hydrothermal method. Then, a radially arranged porous nanosheet cluster of transition metal oxides rich in defective oxygen is obtained through high-temperature calcination. Finally, a photoreduction method is used to prepare the radially arranged porous nanosheet cluster of transition metal oxides rich in defective oxygen and modified with noble metal nanoparticles. Background Technology

[0002] With increasing public awareness of living environment quality and health, gas sensing technology is playing an increasingly important role in environmental monitoring, industrial safety, and smart healthcare. For example, in industrial production and health monitoring, hydrogen (H2) is widely used as a clean and efficient energy carrier; however, its concentration in the air exceeding 4 v / v% easily forms explosive mixtures, requiring highly sensitive leak detection technology. Ammonia (NH3) is highly corrosive and toxic, and its elevated concentration can harm human health. Furthermore, emerging technologies for detecting exhaled breath hold promise for smart healthcare applications, including home-based online monitoring. Hydrogen sulfide (H2S) has been shown to be associated with various oral and visceral diseases. Gas sensors can be used to detect trace gaseous biomarkers in exhaled breath, potentially enabling non-invasive early disease diagnosis. Existing research indicates that semiconductor metal oxide materials, modified with noble metal catalysis, can significantly promote the reaction process between gas molecules and adsorbed oxygen, improving sensing response and selectivity. In particular, the radial nanosheet cluster structure, due to its high specific surface area and open spatial configuration, is conducive to the rapid adsorption and desorption of gas molecules, which can improve sensing response and recovery. Further constructing a porous structure on the nanosheet surface will increase the effective adsorption area and shorten the gas diffusion path, thereby improving sensing sensitivity and dynamic response.

[0003] The key breakthrough for this type of sensing function lies in the innovative development of core sensing materials. For example, in October 2023, the journal *Materials Horizons* reported on a method using porous SnO2 nanosheets for room-temperature NH3 sensing (Mater. Horiz. 2024, 11, 184). Another example is the research published in February 2025, "An atomic Ru-driven SnO2 sensor can detect ppb-level H2S with high sensitivity and selectivity" (ACS Sens. 2025, 10, 1093), which demonstrates that an atomic Ru-driven SnO2 sensor can achieve ppb-level H2S sensing, potentially applicable to the early diagnosis of human diseases.

[0004] Despite the significant progress made in the above research, gas sensing detection still faces challenges such as low sensing response, difficulty in signal capture, efficient adsorption and desorption of target gas on the surface of sensing materials, as well as challenges related to operating temperature, low detection limit, resistance to moisture interference, stability, selectivity, and sensitivity. These challenges often rely on the design of sensing materials with specific structures, while also considering the simplicity and reproducibility of the preparation process. Summary of the Invention

[0005] This invention addresses existing technical challenges by providing a radially porous nanosheet cluster of transition metal oxides (TMOs) rich in defective oxygen and modified with noble metal nanoparticles, along with its preparation method and applications. First, a TMO precursor is prepared using a hydrothermal method. Then, a calcination process yields radially porous TMO nanosheet clusters rich in defective oxygen. Finally, a photoreduction method is used to prepare the same radially porous TMO nanosheet clusters modified with noble metal nanoparticles. This nanosheet cluster establishes a heterojunction interface between the TMOs and rare earth metal oxides. Simultaneously, the modification with noble metal nanoparticles provides a synergistic catalytic effect, reducing the activation energy of gas reactions and improving detection sensitivity and selectivity. Furthermore, the porous nanosheet structure of the nanosheet cluster not only provides a high specific surface area and abundant gas transport channels but also enhances the adsorption and diffusion behavior of target gas molecules. It has broad application prospects in gas sensing, electrochemical detection, photoelectric sensing, and biosensing. The invention is detailed below.

[0006] This invention discloses a radially arranged porous nanosheet cluster of transition metal oxides (TMOs) modified with defective oxygen and noble metal nanoparticles. The nanosheets are self-assembled from TMO and rare earth metal oxide nanosheets, with individual nanosheets having a thickness of 1-20 nanometers (nm) and a cluster size of 1-10 micrometers (μm). The nanosheet clusters possess a highly open porous network with pore sizes of 2-20 nm. The surface of the nanosheet clusters is modified with noble metal nanoparticles, the particle size of which is 5-20 nm. The preparation steps are as follows:

[0007] (1) Hydrothermal preparation of transition metal precursors: 0.01-0.5 mM transition metal source and 0.1-5 g auxiliary agent were added to deionized water and stirred for 0.5-10 h to obtain solution A. Then, 0.01-0.5 mM rare earth metal salt was added to solution A and stirred for 0.5-10 h to obtain solution B. Solution B was then transferred to a reaction vessel and placed in an oven at 80-200 degrees Celsius for 4-20 h to obtain transition metal precursors.

[0008] (2) Synthesis of radially porous nanosheets of transition metal oxides rich in defective oxygen by high-temperature calcination: The above-mentioned transition metal precursors were calcined in a muffle furnace at 100-400 °C at a heating rate of 1-10 °C per minute (°C / min) for 0.5-10 h under a specific atmosphere. Radially porous nanosheets of transition metal oxides rich in defective oxygen were obtained.

[0009] (3) Preparation of radial transition metal oxide porous nanosheets rich in defect oxygen and noble metal nanoparticles by photoreduction method: Mix 0.01-0.2 mol / L (M) alcohol compound with deionized water to obtain solution C. Disperse the above radial transition metal oxide porous nanosheets uniformly in solution C to obtain mixture D. Then add 0.01-0.5 mM noble metal precursor E to mixture D and keep it under light for 0.5-10 h. Finally, rinse the sample with deionized water and alcohol compound and dry it.

[0010] The present invention discloses a radially arranged porous nanosheet cluster of transition metal oxides rich in defective oxygen and modified with noble metal nanoparticles. Its microstructure is characterized by: a three-dimensional nanosheet cluster structure, consisting of a large number of porous two-dimensional nanosheets with a thickness of 1-20 nm stacked and arranged radially to form an ellipsoidal porous structure, wherein defective oxygen accounts for 20-60% of the oxygen content in the material; the diameter of the nanosheet clusters is mainly distributed between 1-10 μm, the nanosheet clusters are spherical, and have an open porous network; and noble metal nanoparticles with a particle size of 5-20 nm are uniformly modified on the surface of the nanosheets, with uniform particle distribution and no aggregation.

[0011] The present invention describes a method for preparing radially packed transition metal-rare earth metal oxide porous nanosheets modified with defective oxygen and noble metal nanoparticles. In step (1), the transition metal source is selected from nitrate hydrates, chlorides, sulfate hydrates, or organic acid salt hydrates of transition metal elements, including but not limited to zinc nitrate (Zn(NO3)2), zinc chloride (ZnCl2), iron nitrate (Fe(NO3)3), copper acetate (Cu(CH3COO)2), copper chloride (CuCl2), nickel chloride (NiCl2), or... One or more of nickel nitrate (Ni(NO3)2); the auxiliary agent includes, but is not limited to, one or more of urea, ammonia, sodium citrate, polyvinylpyrrolidone or polyethylene glycol; the rare earth metal salt is selected from nitrates, chlorides, sulfates or organic acid salts of rare earth metals, including, but not limited to, one or more of samarium nitrate (Sm(NO3)3), cerium nitrate (Ce(NO3)3), lanthanum nitrate (La(NO3)3), lanthanum acetate (La(CH3COO)3) or cerium chloride (CeCl3).

[0012] The method for preparing radial transition metal oxide porous nanosheets modified with defective oxygen and noble metal nanoparticles according to the present invention is characterized in that the noble metal precursor in step (3) is one or a mixture of chloroauric acid (HAuCl4), chloroplatinic acid (H2PtCl6) or palladium chloride (PdCl2).

[0013] The method for preparing radial transition metal-rare earth metal oxide porous nanosheet clusters rich in defective oxygen and modified with noble metal nanoparticles according to the present invention is characterized in that the light source in step (3) is one or more of the following mixed light sources: ultraviolet lamp, blue lamp or xenon lamp.

[0014] This invention provides sensing applications for radial transition metal-rare earth metal oxide porous nanosheet clusters modified with noble metal nanoparticles, which can be applied to the detection of H2S, NH3, nitric oxide (NO), H2, nitrogen dioxide (NO2), carbon monoxide (CO), carbon dioxide (CO2), volatile organic compounds (VOCs), and human exhaled breath, as well as electrochemical sensing, photoelectric sensing, and biosensing.

[0015] The application of gold nanoparticle-modified radial zinc oxide-samarium oxide porous nanosheets (hereinafter referred to as Au@ZnO / Sm2O3MPs) in gas sensing is illustrated below:

[0016] (1) Preparation of gas sensing components: Weigh an appropriate amount (10-100 mg) of Au@ZnO / Sm2O3MPs sensing material, add an appropriate amount of terpineol, and uniformly coat the resulting slurry onto the surface of the ceramic tube electrode after stirring. Finally, place it in an oven to dry. Solder the ceramic tube coated with the sensitive material to the terminal block of the gas sensing base with solder, and insert a Ni-Cr alloy resistance wire inside the ceramic tube to regulate the working temperature.

[0017] (2) Sensing application: The Au@ZnO / Sm2O3MPs sensing material in this invention has a porous nanosheet structure containing a heterostructure of zinc oxide, samarium oxide and noble metal nanoparticles. The porous nanostructure of this material provides a large specific surface area and provides abundant gas diffusion paths, thereby improving sensing performance. The surface of this material is enriched with defect oxygen, which can be applied to the fields of hazardous gas leak detection and human exhaled breath diagnosis. Attached Figure Description

[0018] Figure 1 The 3D model of the material's morphology and structure and large-scale scanning electron microscope (SEM) images are shown; (a) 3D model of the morphology and structure of Au@ZnO / Sm2O3MPs; (b) large-scale SEM images of Au@ZnO / Sm2O3MPs.

[0019] Figure 2 The morphological and structural characterization images of the materials are as follows: (a) Scanning electron microscope (SEM) image of Au@ZnO / Sm2O3MPs; (b) Transmission electron microscope (TEM) image of Au@ZnO / Sm2O3MPs; (c) Partial TEM image of Au@ZnO / Sm2O3MPs; (d) High-resolution TEM image of Au@ZnO / Sm2O3MPs; (e) 1-4 Elemental distribution diagram of Au@ZnO / Sm2O3MPs.

[0020] Figure 3 The O 1s X-ray photoelectron spectrum of (a) Au@ZnO / Sm2O3MPs is shown.

[0021] Figure 4 The sensing response curves of Au@ZnO / Sm2O3MPs at 220°C for (a) H2S, (b) NH3, (c) toluene and (d) benzaldehyde. Detailed Implementation

[0022] The present invention will now be described through specific embodiments. Unless otherwise specified, all technical means used in this invention are methods well known to those skilled in the art. Furthermore, the embodiments should be understood as illustrative, not limiting the scope of the invention; the essence and scope of the invention are defined only by the claims. For those skilled in the art, various changes or modifications to the material composition and dosage in these embodiments without departing from the essence and scope of the invention are also within the scope of protection of this invention. All raw materials and reagents used in this invention are commercially available.

[0023] Example 1

[0024] (1) Preparation of Zn-Sm precursor by hydrothermal method: 0.1 mM Zn(NO3)2 and 1 g urea were added to deionized water and stirred for 2 h to obtain solution A; 0.05 mM Sm(NO3)3 was added to solution A and stirred for another 2 h to obtain solution B; solution B was transferred to a reaction vessel and placed in an oven at 160 ℃ for 12 h to obtain Zn-Sm precursor.

[0025] (2) High-temperature calcination synthesis of radial ZnO-Sm2O3 porous nanosheets rich in defective oxygen: The above precursor was placed in a muffle furnace in air atmosphere at 300℃ and the heating rate was 5℃ / min. The temperature was held for 3h to obtain radial ZnO-Sm2O3 porous nanosheets rich in defective oxygen.

[0026] (3) Preparation of radial ZnO-Sm2O3 porous nanosheets rich in defect oxygen and modified with Au nanoparticles by photoreduction method: 0.05 M ethanol was mixed with deionized water to obtain solution C. 100 mg of calcined product was dispersed in solution C to obtain mixture D. 0.1 mM HAuCl4(E) was added to mixture D and irradiated under a xenon lamp for 4 h. Finally, it was rinsed with deionized water and ethanol and dried.

[0027] Example 2

[0028] (1) Preparation of Fe-Ce precursor by hydrothermal method: 0.2mM Fe(NO3)3, 1g ammonia and 1g polyethylene glycol were added to deionized water and stirred for 4h to obtain solution A; 0.05mM Ce(NO3)3 was added to solution A and stirred for 3h to obtain solution B; solution B was transferred to a reaction vessel and placed in an oven at 180℃ for 10h to obtain Fe-Ce precursor.

[0029] (2) High-temperature calcination synthesis of radial Fe2O3-CeO2 porous nanosheets rich in defective oxygen: The above precursor was placed in a muffle furnace under a nitrogen atmosphere at 350℃ and the heating rate was 3℃ / min. The temperature was held for 4h to obtain radial Fe2O3-CeO2 porous nanosheets rich in defective oxygen.

[0030] (3) Preparation of radial Fe2O3-CeO2 porous nanosheets rich in defect oxygen and modified with Pt-Au nanoparticles by photoreduction method: 0.1 M methanol, 0.1 M glycerol and deionized water were mixed to obtain solution C. 100 mg of calcined product was dispersed in solution C to obtain mixture D. 0.1 mM H2PtCl6 and 0.02 mM HAuCl4 (E) were added to mixture D and placed under a UV lamp for 6 h. Finally, it was rinsed with deionized water and ethanol and dried.

[0031] Example 3

[0032] (1) Preparation of Zn-La precursor by hydrothermal method: 0.18 mM ZnCl2, 1.5 g sodium citrate and 2 g polyvinylpyrrolidone were added to deionized water and stirred for 1 h to obtain solution A; 0.04 mM La(NO3)3 was added to solution A and stirred for 2 h to obtain solution B; solution B was transferred to a reaction vessel and placed in an oven at 140 ℃ for 8 h to obtain Zn-La precursor.

[0033] (2) High-temperature calcination synthesis of radial ZnO-La2O3 porous nanosheets rich in defective oxygen: The precursor was calcined in an air atmosphere muffle furnace at 250℃ with a heating rate of 2℃ / min and held for 4h to obtain radial ZnO-La2O3 porous nanosheets rich in defective oxygen.

[0034] (3) Preparation of radial ZnO-La2O3 porous nanosheets rich in defect oxygen and modified with Pd-Pt nanoparticles by photoreduction method: 0.1 M butanol, 0.1 M glycerol and deionized water were mixed to obtain solution C. 100 mg of calcined product was dispersed in solution C to obtain mixture D. 0.04 mM PdCl2 and 0.1 mM H2PtCl6 (E) were added to mixture D and placed under a UV lamp for 6 h. Finally, it was rinsed with deionized water and ethanol and dried.

[0035] Example 4

[0036] (1) Preparation of Cu-Sm precursor by hydrothermal method: 0.05 mM Cu(CH3COO)2, 1 g urea and 2.5 g polyethylene glycol were added to deionized water and stirred for 0.5 h to obtain solution A; 0.02 mM Sm(NO3)3 was added to solution A and stirred for another 1 h to obtain solution B; solution B was transferred to a reaction vessel and placed in an oven at 120 ℃ for 6 h to obtain Cu-Sm precursor.

[0037] (2) High-temperature calcination synthesis of radial CuO-Sm2O3 porous nanosheets rich in defective oxygen: The precursor was calcined in a muffle furnace under an argon atmosphere at 300℃ with a heating rate of 5℃ / min and held for 1h to obtain radial CuO-Sm2O3 porous nanosheets rich in defective oxygen.

[0038] Radial CuO-Sm2O3 porous nanosheets rich in defective oxygen and modified with Pd nanoparticles were prepared by photoreduction: 0.1 M propanol, 0.1 M ethylene glycol and deionized water were mixed to obtain solution C. 100 mg of the calcined product was dispersed in solution C to obtain mixture D. 0.05 mM PdCl2 (E) was added to mixture D and irradiated under a UV lamp for 6 h. Finally, the mixture was rinsed with deionized water and ethanol and dried.

[0039] Example 5

[0040] (1) Preparation of Zn-Ce precursor by hydrothermal method: 0.1 mM Zn(NO3)2, 1 g ammonia and 1 g polyvinylpyrrolidone were added to deionized water and stirred for 3 h to obtain solution A; 0.03 mM Ce(NO3)3 was added to solution A and stirred for another 3 h to obtain solution B; solution B was transferred to a reaction vessel and placed in an oven at 200 ℃ for 16 h to obtain Zn-Ce precursor.

[0041] (2) High-temperature calcination synthesis of radial ZnO-CeO2 porous nanosheets rich in defective oxygen: The precursor was calcined in a muffle furnace under nitrogen atmosphere at 400℃ with a heating rate of 10℃ / min and held for 4h to obtain radial ZnO-CeO2 porous nanosheets rich in defective oxygen.

[0042] (3) Preparation of radial ZnO-CeO2 porous nanosheets rich in defect oxygen and modified with Pt-Au nanoparticles by photoreduction method: 0.05 M ethanol, 0.05 M glycerol and deionized water were mixed to obtain solution C. 100 mg of calcined product was dispersed in solution C to obtain mixture D. 0.1 mM H2PtCl6 and 0.02 mM HAuCl4 (E) were added to mixture D and placed under a UV lamp for 8 h. Finally, it was rinsed with deionized water and ethanol and dried.

[0043] Example 6

[0044] (1) Preparation of Ni-La precursor by hydrothermal method: 0.08mM Ni(NO3)2, 1.25g urea and 1g sodium citrate were added to deionized water and stirred for 5 h to obtain solution A; 0.04mM La(NO3)3 was added to solution A and stirred for 4 h to obtain solution B; solution B was transferred to a reaction vessel and placed in an oven at 160℃ for 10 h to obtain Ni-La precursor.

[0045] (2) High-temperature calcination synthesis of radial NiO-La2O3 porous nanosheets rich in defective oxygen: The precursor was calcined in a muffle furnace under a nitrogen atmosphere at 280℃ with a heating rate of 3℃ / min and held for 3h to obtain radial NiO-La2O3 porous nanosheets rich in defective oxygen.

[0046] (3) Preparation of radial NiO-La2O3 porous nanosheets rich in defect oxygen and modified with Pd nanoparticles by photoreduction method: 0.1M methanol and deionized water were mixed to obtain solution C. 100mg of calcined product was dispersed in solution C to obtain mixture D. 0.08mM PdCl2(E) was added to mixture D and irradiated under blue light for 3 h. Finally, it was rinsed with deionized water and ethanol and dried.

[0047] Example 7

[0048] (1) Preparation of Ni-Sm precursor by hydrothermal method: 0.12mM Ni(NO3)2, 0.5g ammonia and 1g polyvinylpyrrolidone were added to deionized water and stirred for 2 h to obtain solution A; 0.06mM Sm(NO3)3 was added to solution A and stirred for another 2 h to obtain solution B; solution B was transferred to a reaction vessel and placed in an oven at 150℃ for 8 h to obtain Ni-Sm precursor.

[0049] (2) High-temperature calcination synthesis of radial NiO-Sm2O3 porous nanosheets rich in defect oxygen: The precursor was calcined in an air atmosphere muffle furnace at 320℃ with a heating rate of 5℃ / min and held for 2h to obtain radial NiO-Sm2O3 porous nanosheets rich in defect oxygen.

[0050] (3) Preparation of radial NiO-Sm2O3 porous nanosheets rich in defect oxygen and modified with Pt nanoparticles by photoreduction method: 0.15 M methanol, 0.05 M glycerol and deionized water were mixed to obtain solution C. 100 mg of calcined product was dispersed in solution C to obtain mixture D. 0.12 mM H2PtCl6(E) was added to mixture D and placed under a xenon lamp for 5 h. Finally, it was rinsed with deionized water and ethanol and dried.

[0051] Example 8

[0052] (1) Preparation of Ni-Ce precursor by hydrothermal method: 0.12mM NiCl2, 2g sodium citrate and 1g polyethylene glycol were added to deionized water and stirred for 3 h to obtain solution A; 0.04mM Ce(NO3)3 was added to solution A and stirred for another 3 h to obtain solution B; solution B was transferred to a reaction vessel and placed in an oven at 180℃ for 14 h to obtain Ni-Ce precursor.

[0053] (2) High-temperature calcination synthesis of radial NiO-CeO2 porous nanosheets rich in defective oxygen: The precursor was calcined in a muffle furnace under an argon atmosphere at 350℃, with a heating rate of 8℃ / min and a holding time of 3h to obtain radial NiO-CeO2 porous nanosheets rich in defective oxygen.

[0054] (3) Preparation of radial NiO-CeO2 porous nanosheets rich in defect oxygen and modified with Au nanoparticles by photoreduction method: 0.1 M butanol, 0.1 M ethylene glycol and deionized water were mixed to obtain solution C. 100 mg of calcined product was dispersed in solution C to obtain mixture D. 0.12 mM HAuCl4(E) was added to mixture D and placed under a UV lamp for 6 h. Finally, it was rinsed with deionized water and ethanol and dried.

[0055] Example 9

[0056] (1) Preparation of Fe-La precursor by hydrothermal method: 0.12 mM Fe(NO3)3, 1 g ammonia and 3 g sodium citrate were added to deionized water and stirred for 4 h to obtain solution A; 0.04 mM La(NO3)3 was added to solution A and stirred for another 4 h to obtain solution B; solution B was transferred to a reaction vessel and placed in an oven at 140 ℃ for 12 h to obtain Fe-La precursor.

[0057] (2) High-temperature calcination synthesis of radial Fe2O3-La2O3 porous nanosheets rich in defective oxygen: The precursor was calcined in a muffle furnace under a nitrogen atmosphere at 260℃, with a heating rate of 2℃ / min and a holding time of 2h to obtain radial Fe2O3-La2O3 porous nanosheets rich in defective oxygen.

[0058] (3) Preparation of radial Fe2O3-La2O3 porous nanosheets rich in defect oxygen and modified with Au nanoparticles by photoreduction method: 0.05 M ethanol, 0.05 M glycerol and deionized water were mixed to obtain solution C. 100 mg of calcined product was dispersed in solution C to obtain mixture D. 0.08 mM HAuCl4(E) was added to mixture D and irradiated under a blue light lamp for 4 h. Finally, it was rinsed with deionized water and ethanol and dried.

[0059] Example 10.

[0060] (1) Preparation of Cu-La precursor by hydrothermal method: 0.10 mM Cu(CH3COO)2 and 2.5 g urea were added to deionized water and stirred for 2 h to obtain solution A; 0.05 mM La(NO3)3 was added to solution A and stirred for another 2 h to obtain solution B; solution B was transferred to a reaction vessel and placed in an oven at 170 ℃ for 10 h to obtain Cu-La precursor.

[0061] (2) High-temperature calcination synthesis of radial CuO-La2O3 porous nanosheets rich in defect oxygen: The precursor was calcined in a muffle furnace under an air atmosphere at 300℃, with a heating rate of 5℃ / min and a holding time of 2h to obtain radial CuO-La2O3 porous nanosheets rich in defect oxygen.

[0062] (3) Preparation of radial CuO-La2O3 porous nanosheets rich in defect oxygen and modified with Au nanoparticles by photoreduction method: 0.1 M butanol, 0.05 M glycerol and deionized water were mixed to obtain solution C. 100 mg of calcined product was dispersed in solution C to obtain mixture D. 0.18 mM HAuCl4(E) was added to mixture D and placed under a xenon lamp for 4 h. Finally, it was rinsed with deionized water and ethanol and dried.

Claims

1. A radially arranged porous nanosheet cluster of transition metal oxides modified with defective oxygen and noble metal nanoparticles, its preparation method and application, characterized in that, The radial transition metal oxide porous nanosheet clusters are formed from transition metal oxides and rare earth metal oxide nanosheets, and the surface of the nanosheet clusters is modified with noble metal nanoparticles.

2. The nanosheet cluster according to claim 1, characterized in that, The microstructure consists of an ellipsoidal porous structure formed by stacking two-dimensional nanosheets with a thickness of 1-20 nm, with a nanosheet cluster diameter of 1-10 μm and a pore size of 2-20 nm; the noble metal nanoparticles have a particle size of 5-20 nm.

3. The nanosheet cluster according to claim 1, characterized in that, Defect oxygen accounts for 20-60% of the oxygen content in the material (detected by the O 1s orbital peak fitting method of X-ray photoelectron spectroscopy).

4. A method for preparing the nanosheet clusters according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Hydrothermal preparation of transition metal precursors: 0.01-0.5 mM transition metal source and 0.1-5 g auxiliary agent were added to deionized water and stirred for 0.5-10 h to obtain solution A. Then, 0.01-0.5 mM rare earth metal salt was added to solution A and stirred for 0.5-10 h to obtain solution B. Solution B was then transferred to a reaction vessel and placed in an oven at 80-200 degrees Celsius for 4-20 h to obtain transition metal precursors. (2) Synthesis of radially porous nanosheets of transition metal oxides rich in defective oxygen by high-temperature calcination: The above-mentioned transition metal precursors were placed in a muffle furnace at 100-400℃, with a heating rate of 1-10℃ / min, and calcined for 0.5-10 h under a specific atmosphere. Radially porous nanosheets of transition metal oxides rich in defective oxygen were obtained. (3) Preparation of radial transition metal oxide-rare earth metal oxide porous nanosheets rich in defect oxygen and noble metal nanoparticles by photoreduction method: Mix 0.01-0.2 mol / L (M) alcohol compound with deionized water to obtain solution C. Disperse the above transition metal oxide-rare earth metal oxide porous nanosheets uniformly in solution C to obtain mixture D. Then add 0.01-0.5 mM noble metal precursor E to mixture D and keep it under a specific light source for 0.5-10 h. Finally, rinse the sample with deionized water and alcohol compound and dry it.

5. The method for preparing radially arranged transition metal-rare earth metal oxide porous nanosheet clusters rich in defective oxygen and modified with noble metal nanoparticles according to claim 1, characterized in that: In step (1), the transition metal source is selected from one or more of zinc nitrate (Zn(NO3)2), zinc chloride (ZnCl2), iron nitrate (Fe(NO3)3), copper acetate (Cu(CH3COO)2), copper chloride (CuCl2), nickel chloride (NiCl2) or nickel nitrate (Ni(NO3)2).

6. The method for preparing radially arranged transition metal-rare earth metal oxide porous nanosheet clusters rich in defective oxygen and modified with noble metal nanoparticles according to claim 1, characterized in that: The auxiliary agent mentioned in step (1) is selected from one or more of urea, ammonia, sodium citrate, polyvinylpyrrolidone or polyethylene glycol; the rare earth metal salt precursor mentioned in step (1) is selected from one or more of samarium nitrate (Sm(NO3)3), cerium nitrate (Ce(NO3)3), lanthanum nitrate (La(NO3)3), lanthanum acetate (La(CH3COO)3) or cerium chloride (CeCl3).

7. The method for preparing radially arranged transition metal-rare earth metal oxide porous nanosheet clusters rich in defective oxygen and modified with noble metal nanoparticles according to claim 1, characterized in that: The specific atmosphere mentioned in step (2) is selected from one or more mixed atmospheres of air, nitrogen, and argon.

8. The method for preparing radially arranged transition metal-rare earth metal oxide porous nanosheet clusters rich in defective oxygen and modified with noble metal nanoparticles according to claim 1, characterized in that: The noble metal precursor E mentioned in step (3) is selected from one or more of chloroauric acid (HAuCl4), chloroplatinic acid (H2PtCl6) or palladium chloride (PdCl2); the alcohol compound mentioned in step (3) is selected from one or more of methanol, ethanol, propanol, butanol, ethylene glycol, propylene glycol, and glycerol; the specific light source mentioned in step (3) is selected from one or more of ultraviolet lamps, blue lamps or xenon lamps.

9. The application of the radially arranged transition metal-rare earth metal oxide porous nanosheet clusters modified with defective oxygen and noble metal nanoparticles according to claim 1, characterized in that: Used for gas sensing, electrochemical sensing, photoelectric sensing and biosensing.

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