A method for synthesizing iron-nickel alloy loaded graphene nanocomposites in aqueous solution

Abstract

The application relates to the fields of new materials and photocatalysis, and specifically provides a method for synthesizing an iron-nickel alloy loaded graphene nanocomposite material in an aqueous solution. The method uses an LED lamp simulating the visible light section of sunlight as a light source under normal temperature and pressure, and in the presence of an organic dye molecule fluorescein as a photosensitizer, triethanolamine as an electron sacrificial agent, and graphene as a supporting material in an aqueous solution system, iron-nickel alloy loaded graphene nanocomposite material is generated by reducing ferric chloride salt and nickel chloride salt, the method overcomes the defects of complex process and high energy consumption of traditional material preparation, and has the advantages of simple process, low energy consumption, oxidation resistance, wide raw material source, uniform particle size distribution and the like. The nanocomposite material realizes catalytic decomposition of aminoborane to produce hydrogen and cascade reduction of nitrobenzene to produce aniline, and provides application prospects for cheap metal catalysts to catalyze decomposition of aminoborane and treatment of nitrobenzene organic refractory pollutants.

Description

Technical Field

[0001] This invention relates to the fields of new materials and photocatalysis, and specifically discloses a method for synthesizing iron-nickel alloy-supported graphene nanocomposites in aqueous solution. Background Technology

[0002] Solar energy, as the safest, most stable, and sustainably available clean energy source, delivers approximately 120 TW of energy to the Earth's surface annually. Looking at the spectral composition of solar energy, over 50% of solar radiation energy is in the visible light region, with the maximum energy wavelength around 475 nm. By exciting certain substances with visible light, causing electrons to transition within the material, a series of electron transfer reactions can produce the desired materials. Therefore, fully and efficiently utilizing visible light catalysis from solar energy is a clean, efficient, and practically significant method for material preparation.

[0003] Current methods for synthesizing nanoparticles reported in the literature require providing a certain amount of heat to the reaction system or generating heat within the system through various means. The main synthesis methods include: microemulsion methods, thermal decomposition methods, hydrothermal and solvothermal methods, sol-gel methods, phase transfer methods, microwave methods, liquid-liquid interface methods, and methods using ionic liquids. Compared with traditional synthesis methods, the synthesis of nanoparticles under visible light irradiation can be carried out in aqueous solutions at room temperature and pressure, offering advantages such as simple preparation processes, low energy consumption, wide availability of raw materials, and uniform particle size distribution.

[0004] Graphene, a novel two-dimensional nanomaterial, possesses advantages such as high specific surface area, high conductivity, high electron mobility, high light transmittance, and excellent adsorption properties due to its unique structure. When used as a carrier in the preparation of nanoparticles, it can regulate the nucleation and growth of surface nanoparticles, thereby accelerating the photocatalytic reaction and obtaining nanocomposite materials with ideal elemental composition and special structural morphology.

[0005] Alloy catalysts exhibit superior catalytic performance compared to single-metal catalysts due to the synergistic effect between the two metals, which facilitates electron transfer between them. Compared to noble metal-based catalysts, inexpensive non-noble metal catalysts are abundant and diverse, possessing significant economic value and sustainability, while also achieving excellent catalytic activity and stability. Forming nanocomposites with graphene imparts a larger specific surface area and more exposed active sites to the alloy particles, further enhancing the material's catalytic efficiency and stability.

[0006] Aminoboranes, as the simplest boron compounds, possess advantages such as high hydrogen content (19.6 wt%), solubility in polar solutions like water and methanol, and good stability, making them promising candidates for hydrogen storage materials. Currently, research on noble metal-based catalysts is the most systematic and mature, but their scarcity and high price significantly limit their application in catalytic reactions.

[0007] Nitrobenzene is a typical recalcitrant organic compound. Aniline is typically synthesized from nitrobenzene via hydrogenation catalyzed by transition metal-based catalysts under pressurized H2. However, its high price and scarcity limit its application. By activating a metal-based catalyst, aminoborane can decompose in a tandem system to generate a large amount of hydrogen, which is then adsorbed onto the surface of the metal catalyst to form active hydrogen. This active hydrogen then induces the in-situ hydrogenation of nitrobenzene to synthesize the corresponding aniline. This synthetic strategy shows great promise for treating recalcitrant organic pollutants. Summary of the Invention

[0008] This invention addresses the numerous shortcomings of existing technologies by providing a method for synthesizing iron-nickel alloy-supported graphene nanocomposites in aqueous solution. This method utilizes an LED lamp simulating the visible light range of sunlight as a light source under ambient temperature and pressure. In an aqueous system containing the organic dye fluorescein as a photosensitizer, triethanolamine as an electron sacrificial agent, and graphene as a supporting material, iron-nickel alloy-supported graphene nanocomposites are generated through the reduction of ferric chloride and nickel chloride salts. This method overcomes the drawbacks of complex processes and high energy consumption in traditional material preparation, offering advantages such as simple process, low energy consumption, oxidation resistance, wide availability of raw materials, and uniform particle size distribution. The nanocomposites of this invention enable the catalytic decomposition of aminoboranes to produce hydrogen and the tandem reduction of nitrobenzene to aniline, providing promising applications for the catalytic decomposition of aminoboranes and the treatment of recalcitrant organic pollutants such as nitrobenzene using inexpensive metal catalysts.

[0009] The specific technical solution of the present invention is as follows:

[0010] The inventors first provided a method for synthesizing iron-nickel alloy-supported graphene nanocomposites in aqueous solution, comprising the following steps:

[0011] First, at room temperature and pressure, a mixed metal salt of ferric chloride hexahydrate (FeCl3·6H2O) and nickel chloride hexahydrate (NiCl2·6H2O) is added to a mixed solvent in a molar ratio of 1:1. Then, the organic dye fluorescein (Fl, C) is added. 20 H 12 O5), whose molar ratio with the above mixed metal salt is 10:1; at the same time, 50 mg of graphene is added per millimole of metal salt; the mass-volume ratio of graphene to mixed solvent is 1:6 mg / mL, the volume percentage of triethanolamine (TEOA) in the mixed solvent is 1.25%, and the volume percentage of deionized water is 98.75%.

[0012] The above substances were mixed evenly in proportion and deoxygenated by passing high-purity nitrogen gas for 30 minutes. The deoxygenated mixed solution was placed under a visible white LED light source for illumination and stirred for 2 hours to prepare G / FeNi nanocomposite material. The visible white LED light source had a wavelength of λ≥420nm and a power of 30×3W.

[0013] Furthermore, the roles of each substance in the reaction process are as follows:

[0014] Organic dye molecule fluorescein C 20 H 12 Using O5 as a photosensitizer, ferric chloride and nickel chloride as catalyst precursors, triethanolamine as an electron sacrificial agent, and two-dimensional graphene as a supporting material, Fe was directly reduced in pure aqueous solution under visible white LED illumination. 3+ Ni 2+ Iron-nickel alloy nanoparticles with good crystallinity and stability are generated.

[0015] The reaction mechanism in the above reaction process is as follows:

[0016] Triethanolamine (TEOA) has three coordinating hydroxyl groups, which can coordinate with metal particles to form metal complexes. In alkaline solutions, metal ions react with TEOA and OH groups. - Coordination equilibrium, the photoreduction process initially involves the dissociation of metal ions from the M-TEOA (M represents metal particle) complex precursor and their reaction with OH-. - The complex forms a metal hydroxide, which is then reduced to nanoparticles under light irradiation. Under light irradiation, fluorescein (Fl) reaches an excited state, generating a singlet state of fluorescein (Fl). 1 In Fl*), the singlet state of fluorescein transfers excited-state electrons to the metal complex precursor, causing the metal ions to dissociate and be reduced to generate metal nanoparticles.

[0017] Two-dimensional graphene was added as a support material to a homogeneous solution system before light irradiation. During the light irradiation process, graphene can control the size and morphology of nanoparticle growth. Photoreduction generated FeNi nanoparticles with uniform and uniform particle size spherical shape, which were uniformly attached to the graphene surface and stably combined with it to form a nanocomposite material.

[0018] Graphene, as a supporting material, forms nanocomposite materials that regulate the morphology of nanoparticles and endow alloy particles with a larger specific surface area and abundant exposed active sites, thereby further improving the catalytic efficiency and stability of the materials.

[0019] The G / FeNi nanocomposite material prepared above is in solution state. It needs to stand for 30 minutes, discard the supernatant, add a small amount of deoxygenated anhydrous ethanol, sonicate for 10 minutes to clean, centrifuge for 10 minutes, repeat 3 times, finally wash with deoxyacetone, centrifuge, place in vacuum drying at 60℃ for 1 hour, grind, and collect the G / FeNi nanocomposite material. At this time, the FeNi nanomaterials attached to the layered graphene have a particle size of about 50nm, and the nanomaterials are spherical nanoparticles with relatively uniform particle size stably loaded on the graphene sheet material layer.

[0020] The G / FeNi nanocomposite material obtained above consists of spherical FeNi nanomaterials with uniform particle size stably attached to graphene, forming a sandwich-like composite material. This gives the alloy particles a larger specific surface area and abundant exposed active sites. Moreover, the metal particles loaded on the conductive graphene carbon material are less prone to agglomeration and deactivation, making their catalytic activity more excellent in subsequent applications.

[0021] After obtaining the above-mentioned G / FeNi nanocomposite material, the inventors further disclosed its specific applications as follows:

[0022] It is mainly used for the catalytic decomposition of aminoborane and the tandem treatment of toxic nitrobenzene pollutants. The specific usage process is as follows: There is no specific limit to the amount of aminoborane used, but for the sake of convenience, the following example uses the addition of 0.05g of aminoborane.

[0023] In the preparation process of the above-mentioned nanocomposite material, after adding graphene, 0.05g of aminoborane is directly added. Once the nanoparticles are formed, 1 Fl* can transfer electrons to G / FeNi to further catalyze the decomposition of aminoboranes to produce hydrogen.

[0024] Alternatively, the prepared composite material can be mixed with aminoborane: Take 0.05g of the G / FeNi nanocomposite material prepared above, add 10mL of deionized water, seal, and blow the solution with nitrogen gas for 5 minutes under slow stirring to remove air and dissolved oxygen in the reactor. Then add 0.05g of aminoborane, which will immediately decompose to produce hydrogen gas.

[0025] In the above application, the catalytic decomposition of aminoborane ends in about 10 minutes, producing a total of approximately 100 mL of hydrogen gas, which matches the theoretical hydrogen production from the added aminoborane.

[0026] Meanwhile, compared with the iron-nickel alloy system without graphene loading, the rate of H2 production from aminoborane catalyzed by G / FeNi was increased by nearly half.

[0027] Furthermore, in the above-mentioned catalytic decomposition of aminoborane, after the decomposition and hydrogen production begin, nitrobenzene can be added to treat the nitrobenzene. Every 10 mg of G / FeNi nanocomposite material can treat 0.005 mM of nitrobenzene, and this nanocomposite material can be reused. Preferably, the concentration of nitrobenzene is controlled at 0.01 mM / L when treating it.

[0028] After the reaction was completed, the solution after the reaction was measured according to the national standard <Determination of Aniline Compounds in Water - N-(1-Naphthyl)ethylenediamine azo Spectrophotometric Method>. The conversion rate of nitrobenzene to aniline was approximately 99.6%, and nitrobenzene was almost completely converted to aniline.

[0029] The beneficial effects of this invention are:

[0030] This invention provides a method for preparing iron-nickel alloy-supported graphene nanocomposites by visible light reduction of iron and nickel salts in aqueous solution. The method uses LEDs simulating the visible light range of sunlight as a light source for material preparation and synthesis at room temperature and pressure, overcoming the technical problems of complex processes and high energy consumption in traditional material preparation. The nanocomposites obtained by this invention, combined with the preparation method of this invention, enable the catalytic decomposition of aminoboranes to produce hydrogen and the tandem reduction of nitrobenzene to hydrogenate aniline, providing application prospects for the catalytic decomposition of aminoboranes and the tandem treatment of nitrobenzene, a recalcitrant organic pollutant, using inexpensive metal catalysts. Attached Figure Description

[0031] Figure 1 SEM image of FeNi prepared in Example 1.

[0032] Figure 2 TEM image of FeNi prepared in Example 1.

[0033] Figure 3 SEM elemental mapping distribution of FeNi was prepared for Example 1.

[0034] Figure 4 The TEM elemental mapping distribution of FeNi was prepared for Example 1.

[0035] Figure 5 The EDX elemental content distribution diagram of FeNi prepared in Example 1 is shown.

[0036] Figure 6 XPS image of FeNi prepared in Example 1.

[0037] Figure 7 This is a SEM image of the graphene added in Example 2.

[0038] Figure 8 SEM images of G / FeNi prepared in Example 2.

[0039] Figure 9 TEM image of G / FeNi prepared in Example 2.

[0040] Figure 10 SEM elemental mapping distribution of G / FeNi was prepared for Example 2.

[0041] Figure 11 TEM elemental mapping of G / FeNi was prepared for Example 2.

[0042] Figure 12 The EDX elemental content distribution diagram for G / FeNi prepared in Example 2 is shown.

[0043] Figure 13 XPS image of G / FeNi prepared in Example 2.

[0044] Figure 14 XRD patterns of FeNi, G / FeNi and graphene prepared in Examples 1 and 2.

[0045] Figure 15 These are images showing the actual nanoparticles produced after the reactions in Examples 1 and 2.

[0046] Figure 16 This is a comparison chart of hydrogen production rates for different catalytic systems used in Example 1.

[0047] Figure 17 To illustrate the hydrogen gas chromatogram generated by the reaction in Example 1,

[0048] Figure 18 A comparison graph showing the hydrogen production rates of different masses of graphene added to Application Example 1.

[0049] Figure 19 The diagram shows the application of FeNi and G / FeNi cycle catalytic hydrogen production in AB.

[0050] Figure 20 To determine the ultraviolet spectrum of aniline formed after the tandem reaction using the colorimetric method of Example 2,

[0051] Figure 21 To apply the solution after the reaction in Example 2 in DMSO-d6 solvent 1 H NMR spectrum. Detailed Implementation

[0052] The following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0053] In an embodiment of the present invention, a method for preparing iron-nickel alloy-supported graphene nanocomposites by visible light reduction of iron-nickel salts in aqueous solution is provided, with specific examples as follows:

[0054] 0.05 mmol FeCl3·6H2O, 0.05 mmol NiCl2·6H2O, 1 mmol fluorescein, and 5 mg graphene were placed in a 60 ml test tube. 0.375 mL of triethanolamine and 29.625 mL of deionized water were measured and added to the test tube to form a 30 ml aqueous solution. The solution was shaken well, a magnetic stir bar was added, and the tube was sealed with a rubber stopper. High-purity nitrogen gas was introduced for 20 minutes to remove oxygen. The test tube was then placed under an LED light source (visible white LED light source, λ≥420 nm, 30×3W). A magnetic stirrer was turned on, and the tube was stirred under light for 2 hours to prepare the G / FeNi nanocomposite material.

[0055] The collection process of G / FeNi nanocomposites requires a high degree of oxygen removal, which is crucial for successful collection. In the embodiments of this invention, the collection process of G / FeNi nanocomposites is provided, and the specific operations are as follows:

[0056] After the reaction was completed, the mixture was allowed to stand for 30 minutes, the supernatant was discarded, a small amount of deoxygenated anhydrous ethanol was added, and the mixture was ultrasonically washed for 10 minutes, centrifuged for 10 minutes, and repeated 3 times. Finally, the mixture was washed with deoxyacetone, centrifuged, and vacuum dried at 60°C for 1 hour. The mixture was then ground and the G / FeNi nanocomposite material was collected.

[0057] The G / FeNi nanocomposite material prepared by this invention can be used as a simple and inexpensive metal catalyst. Adding aminoborane during or after the preparation of the nanocomposite material will, once the nanoparticles are formed, 1 Fl* can transfer electrons to G / FeNi to further catalyze the decomposition of aminoboranes to produce hydrogen.

[0058] Furthermore, the nanocomposite material of the present invention can also be used in series to treat nitrobenzene organic pollutants during the catalytic decomposition of aminoborane, thereby reducing nitrobenzene to aniline via hydrogenation.

[0059] To enable those skilled in the art to better understand the technical solutions of this application, the technical solutions of this application will be described in detail below with reference to specific embodiments. Unless otherwise specified, experimental conditions not detailed in the embodiments are generally based on conventional conditions or conditions recommended by the reagent company; reagents, consumables, etc., used in the following embodiments can be obtained commercially unless otherwise specified.

[0060] Example 1: Preparation of iron-nickel alloy nanomaterials

[0061] Pour 0.05 mmol of FeCl3·6H2O, 0.05 mmol of NiCl2·6H2O, and 1 mmol of fluorescein into a 60 ml test tube. Measure 0.375 mL of triethanolamine and 29.625 mL of deionized water to form a 30 ml aqueous solution and pour it into the test tube. Shake well, add a magnetic stir bar, seal with a rubber stopper, and purge with high-purity nitrogen for 20 minutes to remove oxygen. Place the test tube under an LED light source and turn on the magnetic stirrer.

[0062] After reacting for 2 hours, the mixture was allowed to stand for 30 minutes, the supernatant was discarded, a small amount of deoxygenated anhydrous ethanol was added, and the mixture was ultrasonically cleaned for 10 minutes, centrifuged for 10 minutes, and repeated 3 times. Finally, the mixture was washed with deoxyacetone, centrifuged, and vacuum dried at 60°C for 1 hour. The mixture was then ground and collected to obtain FeNi alloy nanomaterials.

[0063] like Figure 1 As shown, SEM characterization tests revealed that the generated nanomaterials exhibited a disordered, layered nanosheet structure.

[0064] like Figure 2 As shown, TEM testing revealed the formation of sheet material corresponding to the SEM image, consisting of many small nanosheets tightly packed together. HRTEM showed that these nanosheets are crystalline and have bimetallic properties, with a lattice spacing of 0.203 nm, corresponding to the (110) crystal plane of the FeNi alloy.

[0065] like Figure 3 As shown, SEM elemental mapping distribution tests revealed that Fe and Ni were uniformly distributed throughout the selected material region, further confirming the bimetallic alloy nature of the material.

[0066] like Figure 4 As shown, TEM elemental mapping distribution tests further demonstrate that Fe and Ni are uniformly distributed within the selected material region, further proving that the material possesses bimetallic alloy properties.

[0067] like Figure 5 As shown, EDX testing confirmed that the mixture consisted of Fe and Ni in an elemental ratio of approximately 57:43, which is similar to the initial Fe added to the system. 3+ with Ni 2+ The proportions of the catalyst precursors are relatively close.

[0068] like Figure 6 As shown, XPS testing confirmed the presence of zero-valent elements in the generated nanoparticles, and the zero-valent metal generated by in-situ reduction is an active catalyst.

[0069] like Figure 14As shown, XRD testing reveals that the generated iron-nickel alloy nanoparticles exhibit a diffraction peak at approximately 2θ = 44°. The peak has a narrow half-width, high intensity, and almost no other impurity peaks, indicating good crystallinity, small and uniform particle size, and high purity. Therefore, the experimental results show that the FeNi bimetallic system has a diffraction peak different from that of a single metal, which originates from the synergistic effect between the two metals and the electron transfer between Fe(0) and Ni(0). This effect may cause the Ni nanoparticles to be very small in size and not show an XRD diffraction peak, or to be selectively exposed on the (110) crystal plane at approximately 2θ = 44°, thus giving the bimetallic FeNi a completely different catalytic effect.

[0070] Example 2: Preparation of iron-nickel alloy supported graphene nanocomposite material

[0071] Pour 0.05 mmol of FeCl3·6H2O, 0.05 mmol of NiCl2·6H2O, 1 mmol of fluorescein, and 5 mg of graphene into a 60 ml test tube. Measure 0.375 mL of triethanolamine and 29.625 mL of deionized water to form a 30 ml aqueous solution and pour it into the test tube. Shake well, add a magnetic stir bar, seal with a rubber stopper, and purge with high-purity nitrogen for 20 minutes to remove oxygen. Place the test tube under an LED light source and turn on the magnetic stirrer.

[0072] After reacting for 2 hours, the mixture was allowed to stand for 30 minutes, the supernatant was discarded, a small amount of deoxygenated anhydrous ethanol was added, and the mixture was ultrasonically washed for 10 minutes, centrifuged for 10 minutes, and repeated 3 times. Finally, the mixture was washed with deoxyacetone, centrifuged, and vacuum dried at 60°C for 1 hour. The mixture was then ground and collected to obtain the G / FeNi nanocomposite material.

[0073] like Figure 7 As shown, SEM testing of graphene before the reaction revealed that graphene is a very thin sheet structure with a very smooth surface and no particles were found.

[0074] like Figure 8 As shown, SEM testing revealed that FeNi alloy nanoparticles were uniformly dispersed on the sheet structure of graphene. Magnification further confirmed that the FeNi alloy had transformed from the original layered and aggregated nanostructure into spherical nanoparticles with more uniform particle size, which were stably loaded on graphene.

[0075] like Figure 9 As shown in the figure, TEM testing reveals that the FeNi alloy nanoparticles are relatively uniformly dispersed in a particulate form on the graphene sheets, and the FeNi alloy nanoparticles are firmly bonded to the graphene substrate, thus improving the material's stability. Figure 8Correspondingly, HRTEM more clearly reveals the metal particles fixed to the graphene sheet substrate, and the complex, interwoven lattice fringes indicate that the material has excellent crystallinity. Figure 14 The observed results are consistent.

[0076] like Figure 10 As shown, SEM elemental mapping distribution tests revealed that Fe and Ni were uniformly distributed throughout the selected material region, further confirming the bimetallic alloy nature of the material.

[0077] like Figure 11 As shown, TEM elemental mapping distribution tests further demonstrate that Fe and Ni are uniformly distributed within the selected material region, further proving that the material possesses bimetallic alloy properties.

[0078] like Figure 12 As shown, EDX testing revealed that Fe and Ni elements were successfully adsorbed onto graphene and uniformly distributed, with an element ratio of 47:53, which is basically consistent with the element ratio without graphene in Example 1.

[0079] like Figure 13 As shown, XPS testing confirmed the presence of zero-valent elements in the generated nanoparticles, and that they are consistent with... Figure 6 Compared to increasing the proportion of zero-valent elements, composite materials exhibit enhanced antioxidant properties.

[0080] like Figure 14 As shown, XRD analysis revealed that G / FeNi exhibited diffraction peaks consistent with those of the FeNi alloy, corresponding to the (110) crystal plane of the FeNi alloy, indicating that the FeNi alloy was successfully loaded onto graphene. Graphene showed a strong peak at 2θ = 26.3°, corresponding to its (002) diffraction. G / FeNi also showed the same diffraction peaks as graphene, indicating that the loading of the FeNi alloy did not significantly affect the structure of the graphene matrix.

[0081] like Figure 15 In Example 1, after the reaction, the resulting nanoparticle solution was black at the bottom, and the alloy formed was clearly visible on the inner wall. In Example 2, after the reaction, the resulting nanoparticle solution was black, and there was obvious composite material formed at the bottom.

[0082] Application Example 1: Catalytic decomposition of aminoboranes to produce hydrogen

[0083] In the preparation process of the above-mentioned nanocomposite material, after adding 0.05 mmol of FeCl3·6H2O, 0.05 mmol of NiCl2·6H2O, 1 mmol of fluorescein, 5 mg of graphene, 0.375 mL of triethanolamine, and 29.625 mL of deionized water to form a 30 mL aqueous solution, 0.05 g of aminoborane was added and shaken well. A magnetic stir bar was added, the tube was sealed with a rubber stopper, and high-purity nitrogen gas was purged for 20 minutes to remove oxygen. The test tube was then placed under an LED light source, and the magnetic stirrer was turned on. Once the nanoparticles are formed... 1 Fl* can transfer electrons to G / FeNi to further catalyze the decomposition of aminoboranes to produce hydrogen.

[0084] Alternatively, the prepared composite material can be mixed with aminoborane: Take 0.05g of the prepared G / FeNi nanocomposite material, add 10mL of deionized water, seal, and blow the solution with nitrogen gas for 5 minutes under slow stirring to remove air and dissolved oxygen in the reactor. Then add 0.05g of aminoborane, which will immediately decompose to produce hydrogen gas.

[0085] like Figure 16 As shown, in the graphene-loaded LED illumination system, after a photo-induction period of approximately 45 minutes, the generated iron-nickel alloy begins to catalyze the decomposition of aminoborane to produce hydrogen. Compared with the iron-nickel alloy system without graphene loading, the rate of catalytic hydrogen production from aminoborane is increased by nearly half throughout the catalytic process.

[0086] like Figure 17 As shown, the generated gas was detected, and the corresponding gas chromatogram of standard hydrogen gas showed that the retention time of the generated gas was 1.035 minutes, the concentration percentage was 100%, and the peak area was 380.4745. Therefore, it was determined that the photoreduction of iron-nickel alloy catalyzed the generation of aminoborane into hydrogen gas.

[0087] like Figure 18 As shown, different amounts of graphene were used to investigate the hydrogen production rate. Adding 5 mg of graphene increased the hydrogen production rate to approximately 10 minutes, demonstrating the most significant catalytic effect. With increasing graphene mass, the hydrogen production rate decreased. This is likely because excessive graphene blocked some light, hindering the effective absorption of light and the generation of excited-state electrons by the photosensitizer fluorescein. This slowed down the photocatalytic formation of the FeNi alloy, thus reducing the in-situ catalytic hydrogen production rate of aminoborane. Therefore, adding 5 mg of graphene is the most economical and optimal choice.

[0088] like Figure 19As shown, a material cycle stability test was conducted. After catalyzing the decomposition of aminoborane to hydrogen once, the original catalyst was used to add aminoborane five more times. We observed that the catalytic efficiency improved after adding graphene, and the catalyst activity was not affected by the addition of graphene. This proves that the decomposition of aminoborane is indeed due to the catalytic effect of the generated iron-nickel alloy, and that the generated catalyst exhibits excellent stability and catalytic activity.

[0089] The above application examples further demonstrate the generation and stability of the nanoparticles in Example 1 or 2, and catalytically decompose the aminoborane during the nanoparticle generation process.

[0090] Meanwhile, the amount of graphene used in Example 2 is explained.

[0091] Furthermore, it has been demonstrated that the graphene nanocomposite materials prepared by this invention outperform individual nanoalloy particles.

[0092] Application Example 2: Tandem treatment of nitrobenzene, a recalcitrant organic pollutant

[0093] In the above-mentioned catalytic decomposition of aminoborane, 0.05 mmol of FeCl3·6H2O, 0.05 mmol of NiCl2·6H2O, 1 mmol of fluorescein, 5 mg of graphene, 0.375 mL of triethanolamine, and 29.625 mL of deionized water are added to form a 30 mL aqueous solution. After adding 0.05 g of aminoborane, the decomposition and hydrogen production begin. Alternatively, when the prepared composite material is used in combination with aminoborane, 0.01 mM / L of nitrobenzene can be added. The series treatment process is completed after the aminoborane reaction is finished. According to calculations, 10 mg of G / FeNi nanocomposite material can treat 0.005 mM of nitrobenzene in this series process, and this nanocomposite material can be reused.

[0094] The solution after the reaction was measured according to the national standard <Determination of Aniline Compounds in Water - N-(1-Naphthyl)ethylenediamine azo Spectrophotometric Method>.

[0095] like Figure 20 As shown, after the tandem catalytic hydrogenation reduction reaction of nitrobenzene was completed, the solution after the reaction was standardized, and the absorbance at 545 nm was measured by a spectrophotometer. We found that the absorbance of Group A when zinc powder was added in the conventional way to reduce nitrobenzene to aniline was 0.278, and the absorbance of Group B when the tandem hydrogenation system reduced nitrobenzene to aniline was 0.277. The conversion rate of the system from nitrobenzene to aniline was approximately 99.6%.

[0096] like Figure 21As shown, the nuclear magnetic resonance results also indicate that nitrobenzene in the solution after the reaction was almost completely converted into aniline, which is consistent with the results of ultraviolet spectrophotometry.

[0097] The experimental results show that the tandem reduction of nitrobenzene achieved good results, providing a good idea for the application of subsequent treatment of recalcitrant organic pollutants.

[0098] The above embodiments are one specific implementation method selected by the present invention. Ordinary changes and substitutions made by those skilled in the art within the scope of this technical solution should be included within the protection scope of the present invention.

Claims

1. The application of synthesizing iron-nickel alloy loaded graphene nanocomposites in aqueous solution in catalyzing the decomposition of aminoborane and the tandem treatment of nitrobenzene, characterized in that, The synthesis method of the nanocomposite comprises the following steps: The mixed metal salt of iron chloride hexahydrate and nickel chloride hexahydrate is added in a mixed solvent according to a molar ratio of 1:1, and then the organic dye fluorescein is added, with a molar ratio of 10:1 to the mixed metal salt; at the same time, 50 mg of graphene is added per millimole of metal salt; the mass-volume ratio of graphene to the mixed solvent is 1:6 mg / mL; The above substances are uniformly mixed in proportion, deoxygenated by passing high-purity nitrogen for 30 minutes, and then placed under a visible white light LED light source for illumination and stirring for 2 hours to obtain the G / FeNi nanocomposite; the visible white light LED light source has a wavelength of 420 nm or more, and a power of 30*3 W.

2. The use according to claim 1, characterized in that: The volume ratio of triethanolamine in the mixed solvent is 1.25%, and the volume ratio of deionized water is 98.75%.

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