Pt and MnOx nanoparticle in-situ loaded NH2-MIL-101 (Fe) photocatalyst as well as preparation method and application thereof

Abstract

The invention discloses a Pt and MnOx nanoparticle in-situ loaded NH2-MIL-101 (Fe) photocatalyst as well as a preparation method and application thereof, and belongs to the technical field of photocatalyst preparation. The preparation method disclosed by the invention comprises the following steps: firstly, carrying out coordination reaction by adopting a simple solvothermal method and taking 2-aminoterephthalic acid as an organic ligand and FeCl3. 6H2O as a metal salt to synthesize NH2-MIL-101 (Fe), then sequentially loading MnOx NPs and Pt NPs respectively by adopting photodeposition and chemical reduction processes, and finally synthesizing the NH2-MIL-101 (Fe) (Pt-NM-101 / MnOx) composite catalyst loaded with the MnOx NPs and the Pt NPs, the problems of high energy consumption and environmental pollution of a traditional industrial nitrogen fixation Hayer-Bosch method are obviously solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photocatalyst preparation, and specifically relates to a Pt and MnO x Nanoparticle in-situ loaded NH2-MIL-101 (Fe) photocatalyst, preparation method and application thereof. Background Art

[0002] Ammonia (NH3) is an important industrial raw material that plays an important role in the fertilizer, pharmaceutical, explosive and textile industries. In addition, due to its high energy density (4.3 kW h kg -1 ) and clean emissions, it is also an ideal zero-carbon energy carrier. At present, the world's ammonia is mainly obtained from the industrial synthesis Haber-Bosch method. However, the Haber-Bosch process needs to be carried out under harsh reaction conditions, that is, high temperature (450-550 ℃) and high pressure (15-25 MPa) with the help of iron-based catalysts to synthesize NH3 using high-purity N2 and H2. This traditional process consumes 1% of the world's energy and produces about 2% of CO2 emissions in the chemical industry. The energy required for photocatalytic synthesis of ammonia (PNRR) is solar energy. Due to its inexhaustible advantage, it has become a hot topic of research in recent years and is also considered to be an effective solution to replace the Haber-Bosch process. However, efficient electron-hole separation efficiency in PNRR is the key to improving the efficiency of solar energy utilization. Therefore, how to construct a highly active catalyst by improving the electron-hole separation efficiency is an urgent problem that researchers need to solve.

[0003] The coupling of photocatalysts and co-catalysts is an efficient method for electron-hole separation. The introduction of different co-catalysts can promote the oxidation and reduction half reactions respectively. Oxidation co-catalysts, including CuO x 、CoO x and MnO x They tend to capture holes for oxidation reactions, while reduction co-catalysts including Ru, Pd and Pt tend to capture electrons for reduction reactions. In addition, metal organic framework materials (MOFs) with high photosensitivity, regular pores, ultra-high specific surface area and adjustable structural functions are considered to be ideal catalysts for photocatalytic synthesis of ammonia. However, compared with a single oxidation or reduction active site, it is still a difficult problem to design nanoparticle active sites on photocatalysts that can simultaneously perform N2 reduction and H2O oxidation, and combine the corresponding half reactions in the photocatalytic system to provide a more sufficient hydrogen source and more electrons for the multi-electron process of N2 hydrogenation. Summary of the invention

[0004] The present invention aims to provide a Pt and MnO xNanoparticle in-situ loaded NH2-MIL-101 (Fe) photocatalyst and its preparation method and application are used to solve the technical problems of high energy consumption and environmental pollution of the traditional industrial nitrogen fixation Haber-Bosch method.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The invention discloses a Pt and MnO x The preparation method of nanoparticle in-situ loaded NH2-MIL-101 (Fe) photocatalyst comprises the following steps: 2-aminoterephthalic acid, FeCl3·6H2O and a solvent are stirred and mixed, and then subjected to a hydrothermal reaction to obtain an NH2-MIL-101(Fe) catalyst; After mixing NH2-MIL-101(Fe) catalyst, MnSO4 and water, the reaction was carried out under light conditions and constant temperature conditions. After the reaction, NM-101 / MnO x ; NM-101 / MnO x and water, then add H2PtCl6·6H2O aqueous solution, and then add reducing agent and stabilizer dropwise to obtain Pt and MnO x Nanoparticles were in situ loaded with NH2-MIL-101(Fe) photocatalyst.

[0006] Furthermore, in the step of obtaining NH2-MIL-101(Fe), the mass ratio of the 2-aminoterephthalic acid, FeCl3·6H2O and the solvent (DMF) is (0.206 g~0.210 g): (0.675 g ~ 0.680 g): (25 mL~ 26 mL); the solvent is DMF.

[0007] Furthermore, in the step of obtaining NH2-MIL-101(Fe), the temperature of the hydrothermal reaction is 110°C and the time is 24 hours.

[0008] Further, NM-101 / MnO x In the step, the mass ratio of the NH2-MIL-101(Fe) catalyst, MnSO4 and water is (0.1 g ~ 0.105 g): (0.3 g ~ 0.31 g): (50 mL ~ 52 mL).

[0009] Furthermore, the illumination condition is to use a 300W xenon lamp plus a 420 nm filter for 1 hour; and the constant temperature condition is 25°C.

[0010] Furthermore, after the NH2-MIL-101(Fe) catalyst, MnSO4 and water were mixed, the reaction was carried out under light conditions and constant temperature conditions. After the reaction was completed, the reaction product was dried in a freeze dryer for 6 to 6.2 h to obtain NM-101 / MnO x .

[0011] Furthermore, the NM-101 / MnO x The dosage ratio of water, reducing agent and stabilizer is (0.1 g~0.105 g): (20 mL~22 mL): (700 uL ~705 uL): (5 mg~ 7 mg).

[0012] Furthermore, the reducing agent is 1 mol ml -1 of NaBH4 aqueous solution; the stabilizer is citric acid.

[0013] The present invention also discloses Pt and MnO prepared by the above preparation method. x Nanoparticles were in situ loaded with NH2-MIL-101(Fe) photocatalyst.

[0014] The present invention also discloses the above-mentioned Pt and MnO x Application of nanoparticle in situ loaded NH2-MIL-101(Fe) photocatalyst in photocatalytic conversion of nitrogen to ammonia.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a Pt and MnO x The preparation method of nanoparticle in-situ loaded NH2-MIL-101(Fe) photocatalyst is firstly to synthesize NH2-MIL-101(Fe) by a simple solvothermal method with 2-aminoterephthalic acid as an organic ligand and FeCl3·6H2O as a metal salt for coordination reaction, and then to load MnO in turn by photodeposition and chemical reduction process. x NPs and Pt NPs, and finally synthesized MnO x NH2-MIL-101(Fe) (Pt@NM-101 / MnO x ) composite catalyst, in which amino-functionalized NH2-MIL-101(Fe) is used as a carrier. The introduction of amino groups in this material can enhance the photocatalyst's absorption capacity for light in a specific band, so that more light energy is converted into chemical energy, thereby improving the photocatalytic nitrogen fixation performance; in addition, MnO xThe in-situ dispersion of amino-functionalized NH2-MIL-101(Fe) on nanoparticles promoted the oxidation of H2O and provided more available proton hydrogen for N2 reduction. The further introduction of Pt nanoparticles was beneficial for capturing more photogenerated electrons and promoting the multi-electron transfer reaction process of N2 reduction. x The synergistic effect of the NH2-MIL-101(Fe) composite photocatalyst of nanoparticles is used to increase the yield of ammonia synthesis by photocatalytic conversion of nitrogen, which significantly solves the high energy consumption and environmental pollution problems of the traditional industrial nitrogen fixation Haber-Bosch method. The preparation process of this method is simple, low-cost, and the raw materials are easily available.

[0016] The present invention also discloses Pt and MnO prepared by the above preparation method. x Nanoparticles in situ loaded NH2-MIL-101 (Fe) photocatalyst, the catalyst containing Pt and MnO x Nanoparticle-loaded NH2-MIL-101(Fe), Pt and MnO x In situ dispersed nanoparticles, among which, in Pt@NM-101 / MnO x The reduction reaction in the composite photocatalyst occurs on PtNPs, and the oxidation reaction occurs on MnOx NPs. x The composite catalyst not only effectively improves the separation efficiency of photogenerated electrons and holes, but also achieves the synergistic promotion of oxidation and reduction half-reactions, thereby improving the photocatalytic nitrogen fixation activity.

[0017] The present invention also discloses the above-mentioned Pt and MnO x The application of nanoparticle in-situ loaded NH2-MIL-101(Fe) photocatalyst in photocatalytic conversion of nitrogen to synthesize ammonia. The experimental results show that compared with the unmodified NH2-MIL-101(Fe) material, the Pt@NM-101 / MnO x The nitrogen fixation activity of the composite photocatalyst was significantly improved, and its ammonia production increased by about 4.56 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 NH2-MIL-101(Fe), NM-101 / MnO x , Pt@NM-101 and Pt and MnO prepared in Examples 1 to 3 x XRD pattern of nanoparticles in situ loaded NH2-MIL-101(Fe) photocatalyst; Figure 2 Pt and MnO prepared in Example 2 of the present invention xSEM image of nanoparticles in situ loaded with NH2-MIL-101(Fe) photocatalyst; Figure 3 Pt and MnO prepared in Example 2 of the present invention x TEM image of nanoparticles in situ loaded with NH2-MIL-101(Fe) photocatalyst; Figure 4 Pt and MnO prepared in Example 2 of the present invention x HRTEM image of nanoparticles in situ loaded NH2-MIL-101(Fe) photocatalyst; Figure 5 NH2-MIL-101(Fe), NM-101 / MnO x , Pt@NM-101 and Pt and MnO prepared in Example 2 x UV-visible absorption spectrum of the nanoparticle in-situ loaded NH2-MIL-101(Fe) photocatalyst; Figure 6 NH2-MIL-101(Fe), NM-101 / MnO x , Pt@NM-101 and Pt and MnO prepared in Example 2 x Transient photocurrent response diagram of nanoparticles in situ loaded NH2-MIL-101(Fe) photocatalyst; Figure 7 NH2-MIL-101(Fe), NM-101 / MnO x , Pt@NM-101 and Pt and MnO prepared in Example 2 x Impedance diagram of nanoparticles in situ loaded NH2-MIL-101(Fe) photocatalyst; Figure 8 NH2-MIL-101(Fe), NM-101 / MnO x , Pt@NM-101 and Pt and MnO prepared in Example 2 x Activity spectrum of photocatalytic conversion of nitrogen to ammonia by in situ nanoparticle-loaded NH2-MIL-101(Fe) photocatalyst. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0020] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0021] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0022] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0023] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0024] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0025] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0026] Example 1 A Pt and MnO x The preparation method of nanoparticle in-situ loaded NH2-MIL-101 (Fe) photocatalyst comprises the following steps: 0.206 mg of 2-aminoterephthalic acid and 0.675 mg of FeCl3·6H2O were weighed and added to 25 ml of DMF. The suspension was stirred at room temperature for 30 minutes, and then the mixture was hydrothermaled at 110°C for 24 hours in a polytetrafluoroethylene liner (100 mL). After the precipitate was cooled to room temperature, it was separated from the reaction mixture by suction filtration and thoroughly washed with DMF, ethanol and water to remove any unreacted starting materials. Finally, the obtained solid was dried in a freeze dryer for 6 hours to obtain NH2-MIL-101(Fe) powder (labeled as NM-101); 0.1 g of the prepared NH2-MIL-101(Fe) powder, 0.3 g of MnSO4·H2O and 50 mL of water were placed in a reactor, respectively, and irradiated with a 300 W xenon lamp plus a 420 nm filter for 1 h. At the same time, the reactor was kept at a constant temperature of 25 °C by circulating condensed water to react. After the reaction was completed, the obtained reactant was rinsed with water, and then the obtained solid was dried in a freeze dryer for 6 h to obtain NM-101 / MnO x ; The prepared 0.1 g NM-101 / MnO x Add 20 mL of deionized water to form a mixed solution, and add 500uL of 10 mg mL -1 After stirring evenly, 1.5 mL of 0.1 mol L H2PtCl6·6H2O aqueous solution was added dropwise -1 NaBH4 aqueous solution as a reducing agent and 5 mg citric acid as a stabilizer to obtain Pt and MnO x Nanoparticles in situ loaded NH2-MIL-101(Fe) photocatalyst (Pt@NM-101 / MnO x -1).

[0027] Example 2 A Pt and MnO x The preparation method of nanoparticle in-situ loaded NH2-MIL-101 (Fe) photocatalyst comprises the following steps: 0.206 mg of 2-aminoterephthalic acid and 0.675 mg of FeCl3·6H2O were weighed and added to 25 ml of DMF. The suspension was stirred at room temperature for 30 minutes, and then the mixture was hydrothermaled at 110°C for 24 hours in a polytetrafluoroethylene liner (100 mL). After the precipitate was cooled to room temperature, it was separated from the reaction mixture by suction filtration and thoroughly washed with DMF, ethanol and water to remove any unreacted starting materials. Finally, the obtained solid was dried in a freeze dryer for 6 hours to obtain NH2-MIL-101(Fe) powder.

[0028] 0.1 g of the prepared NH2-MIL-101(Fe) powder, 0.3 g of MnSO4·H2O and 50 mL of water were placed in a reactor, respectively, and irradiated with a 300 W xenon lamp plus a 420 nm filter for 1 h. At the same time, the reactor was kept at a constant temperature of 25 °C by circulating condensed water to react. After the reaction was completed, the obtained reactant was rinsed with water, and then the obtained solid was dried in a freeze dryer for 6 h to obtain NM-101 / MnO x ; The prepared 0.1 g NM-101 / MnO x Add 20 mL of deionized water to form a mixed solution, add 700uL of 10 mg mL -1 After stirring evenly, 1.5 mL of 0.1 mol L H2PtCl6·6H2O aqueous solution was added dropwise -1 NaBH4 aqueous solution as a reducing agent and 5 mg citric acid as a stabilizer to obtain Pt and MnO x Nanoparticles in situ loaded NH2-MIL-101(Fe) photocatalyst (Pt@NM-101 / MnO x -2).

[0029] Example 3 A Pt and MnO x The preparation method of nanoparticle in-situ loaded NH2-MIL-101 (Fe) photocatalyst comprises the following steps: 0.206 mg of 2-aminoterephthalic acid and 0.675 mg of FeCl3·6H2O were weighed and added to 25 ml of DMF. The suspension was stirred at room temperature for 30 minutes, and then the mixture was hydrothermaled at 110°C for 24 hours in a polytetrafluoroethylene liner (100 mL). After the precipitate was cooled to room temperature, it was separated from the reaction mixture by suction filtration and thoroughly washed with DMF, ethanol and water to remove any unreacted starting materials. Finally, the obtained solid was dried in a freeze dryer for 6 hours to obtain NH2-MIL-101(Fe) powder.

[0030] 0.1 g of the prepared NH2-MIL-101(Fe) powder, 0.3 g of MnSO4·H2O and 50 mL of water were placed in a reactor, respectively, and irradiated with a 300 W xenon lamp plus a 420 nm filter for 1 h. At the same time, the reactor was kept at a constant temperature of 25 °C by circulating condensed water to react. After the reaction was completed, the obtained reactant was rinsed with water, and then the obtained solid was dried in a freeze dryer for 6 h to obtain NM-101 / MnO x ; The prepared 0.1 g NM-101 / MnOx Add 20 mL of deionized water to form a mixed solution, and add 900uL of 10 mg mL -1 After stirring evenly, 1.5 mL of 0.1 mol L H2PtCl6·6H2O aqueous solution was added dropwise -1 NaBH4 aqueous solution as a reducing agent and 5 mg citric acid as a stabilizer to obtain Pt and MnO x Nanoparticles in situ loaded NH2-MIL-101(Fe) photocatalyst (Pt@NM-101 / MnO x -3).

[0031] Figure 1 NH2-MIL-101(Fe), NM-101 / MnO x , Pt@NM-101 and Pt and MnO prepared in Examples 1 to 3 x From the XRD pattern of the nanoparticles in situ loaded NH2-MIL-101(Fe) photocatalyst, it can be seen that the XRD of the sample is consistent with the main peak of the NH2-MIL-101(Fe) simulated phase, which proves the successful synthesis of the composite material.

[0032] Figure 2 Pt and MnO prepared in Example 2 of the present invention x SEM image of the nanoparticles in situ loaded with NH2-MIL-101(Fe) photocatalyst, which exhibits a regular and slightly rough octahedral morphology with an average diameter of about 500 nm. Figure 3 Pt and MnO prepared in Example 2 of the present invention x TEM image of the nanoparticles in situ loaded with NH2-MIL-101(Fe) photocatalyst, which exhibits a regular octahedral morphology with an average diameter of about 500 nm. Figure 4 Pt and MnO prepared in Example 2 of the present invention x HRTEM image of nanoparticles in situ loaded NH2-MIL-101(Fe) photocatalyst, loaded with MnO x After adding Pt, the target sample Pt@NM-101 / MnO x -2, MnO with a size of about 3 nm was clearly observed. x The presence of Pt@NM-101 / MnO nanoparticles (d = 0.193 nm) and Pt nanoparticles with a size of about 5 nm (d = 0.223 nm) indicates that x -2 composite catalyst was successfully prepared.

[0033] Figure 5 NH2-MIL-101(Fe), NM-101 / MnOx , Pt@NM-101 and Pt and MnO prepared in Example 2 x UV-visible absorption spectrum of nanoparticle in-situ loaded NH2-MIL-101(Fe) photocatalyst, through Pt and MnO x In-situ loading of nanoparticles, composite photocatalyst Pt@NM-101 / MnO x The light absorption range is further improved.

[0034] Figure 6 NH2-MIL-101(Fe), NM-101 / MnO x , Pt@NM-101 and Pt and MnO prepared in Example 2 x The transient photocurrent response diagram of the nanoparticle in situ loaded NH2-MIL-101(Fe) photocatalyst shows that Pt@NM-101 / MnO x -3 has a stronger photocurrent density, indicating that Pt@NM-101 / MnO x -3 has a stronger charge transfer rate.

[0035] Figure 7 NH2-MIL-101(Fe), NM-101 / MnO x , Pt@NM-101 and Pt and MnO prepared in Example 2 x The impedance diagram of the nanoparticles in situ loaded NH2-MIL-101(Fe) photocatalyst shows that Pt@NM-101 / MnO x -3 has a lower interfacial charge transfer resistance, indicating that Pt@NM-101 / MnO x -3 has a stronger charge transfer rate.

[0036] Weigh NH2-MIL-101(Fe), NM-101 / MnO x , Pt@NM-101 and Pt and MnO prepared in Example 2 x The nanoparticles were loaded with 30 mg of NH2-MIL-101(Fe) photocatalyst in situ. Six experiments were set up. The six samples were dispersed in a quartz photocatalytic reactor containing 100 mL of deionized water and connected to a circulating water cooling system to maintain a controlled temperature of 25 °C. The light source was a 300 W xenon lamp (282 mW·cm -2 First, the dispersion was heated in the dark with high-purity N2 (80 mL min -1) was bubbled and magnetically stirred for 30 min to make the N2 in the solution saturated and to achieve the purpose of removing oxygen in the reactor. Subsequently, the xenon lamp light source was turned on, and 1 mL of the dispersion was taken out every 60 min, and the photocatalyst was separated by centrifugation at 5000 rpm to obtain a clear solution. The concentration of NH3 in the supernatant was determined by Nessler's reagent spectrophotometry, and the result was as follows: Figure 8 The curve shown; from Figure 8 It can be seen that the samples of Examples 1 to 5 have significantly improved efficiency in photocatalytic conversion of nitrogen to ammonia compared with the unmodified NH2-MIL-101(Fe). + The yield was significantly improved, and Example 5 was the best, with its activity increased by 4.2 times.

[0037] Using NH2-MIL-101(Fe) as a carrier, the material has excellent light absorption and photosensitivity properties, can effectively absorb solar energy and convert it into photogenerated carriers. x The nanoparticles were in situ loaded on the NH2-MIL-101(Fe) matrix, which not only effectively improved the separation efficiency of photogenerated electrons and holes, but also achieved the synergistic promotion of oxidation and reduction half-reactions, thereby improving the photocatalytic nitrogen fixation activity. x The synergistic effect of the NH2-MIL-101 (Fe) composite photocatalyst of nanoparticles is used to increase the yield of photocatalytic conversion of nitrogen to synthesize ammonia, which significantly solves the high energy consumption and environmental pollution problems of traditional industrial nitrogen fixation. The preparation process of this method is simple, low-cost, and the raw materials are easily available.

[0038] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A Pt and MnO x The method for preparing nanoparticles in-situ loaded NH2-MIL-101 (Fe) photocatalyst is characterized in that: The following steps are involved: 2-aminoterephthalic acid, FeCl3·6H2O and a solvent are stirred and mixed, and then subjected to a hydrothermal reaction to obtain an NH2-MIL-101(Fe) catalyst; After mixing NH2-MIL-101(Fe) catalyst, MnSO4 and water, the reaction was carried out under light conditions and constant temperature conditions. After the reaction, NM-101 / MnO x ; NM-101 / MnO x and water, then add H2PtCl6·6H2O aqueous solution, and then add reducing agent and stabilizer dropwise to obtain Pt and MnO x Nanoparticles were in situ loaded with NH2-MIL-101(Fe) photocatalyst.

2. A Pt and MnO according to claim 1 x The method for preparing nanoparticles in-situ loaded NH2-MIL-101 (Fe) photocatalyst is characterized in that: In the step of obtaining NH2-MIL-101(Fe), the mass ratio of the 2-aminoterephthalic acid, FeCl3·6H2O and the solvent (DMF) is (0.206 g~0.210 g): (0.675 g ~ 0.680 g): (25 mL~ 26 mL); the solvent is DMF.

3. A Pt and MnO according to claim 1 x The method for preparing nanoparticles in-situ loaded NH2-MIL-101 (Fe) photocatalyst is characterized in that: In the step of obtaining NH2-MIL-101(Fe), the temperature of the hydrothermal reaction is 110°C and the time is 24 hours.

4. A Pt and MnO according to claim 1 x The method for preparing nanoparticles in-situ loaded NH2-MIL-101 (Fe) photocatalyst is characterized in that: Get NM-101 / MnO x In the step, the mass ratio of the NH2-MIL-101(Fe) catalyst, MnSO4 and water is (0.1 g ~ 0.105 g): (0.3 g ~ 0.31 g): (50 mL ~ 52 mL).

5. A Pt and MnO according to claim 1 x The method for preparing nanoparticles in-situ loaded NH2-MIL-101 (Fe) photocatalyst is characterized in that: The illumination condition is to use a 300W xenon lamp plus a 420 nm filter for 1 hour; the constant temperature condition is 25°C.

6. A Pt and MnO according to claim 1 x The method for preparing nanoparticles in-situ loaded NH2-MIL-101 (Fe) photocatalyst is characterized in that: After mixing NH2-MIL-101(Fe) catalyst, MnSO4 and water, the reaction was carried out under light conditions and constant temperature conditions. After the reaction, the reaction product was dried in a freeze dryer for 6 to 6.2 h to obtain NM-101 / MnO x .

7. A Pt and MnO according to claim 1 x The method for preparing nanoparticles in-situ loaded NH2-MIL-101 (Fe) photocatalyst is characterized in that: Get Pt and MnO x In the step of in-situ loading of NH2-MIL-101(Fe) photocatalyst on nanoparticles, the NM-101 / MnO x The dosage ratio of water, reducing agent and stabilizer is (0.1 g~0.105 g): (20 mL~22 mL): (700 uL ~705 uL): (5 mg~ 7 mg).

8. A Pt and MnO according to claim 1 x The method for preparing nanoparticles in-situ loaded NH2-MIL-101 (Fe) photocatalyst is characterized in that: The reducing agent is 1 mol ml -1 of NaBH4 aqueous solution; the stabilizer is citric acid.

9. A Pt and MnO x Nanoparticles in-situ loaded NH2-MIL-101 (Fe) photocatalyst, characterized in that: The method is prepared by any one of claims 1 to 8.

10. Pt and MnO according to claim 9 x Application of nanoparticle in situ loaded NH2-MIL-101(Fe) photocatalyst in photocatalytic conversion of nitrogen to ammonia.

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