Silver-palladium-based catalyst and method for its preparation

Abstract

The application belongs to the technical field of photocatalysts, and provides a silver-palladium-based catalyst and a preparation method thereof.The method comprises the following steps: mixing graphene oxide, ethanol, azobisisobutyronitrile and 4-tert-butyl aniline, and performing a reaction to obtain a functionalized intercalated graphene oxide material; mixing the functionalized intercalated graphene oxide material, ethanol and a silver nitrate solution, and performing a reaction to obtain an intermediate product; mixing the intermediate product and a palladium acetate solution, and performing a reaction to obtain the silver-palladium-based catalyst.The use of the functionalized intercalated graphene oxide material provides more coordination sites, thereby causing firm adhesion and coordination assembly between metal nanoparticles and graphene oxide, and in addition, the use of the functionalized intercalated graphene oxide material is also conducive to inhibiting the recombination of photo-generated holes-electrons and improving the catalytic performance.The application prepares a composite catalyst which has good dispersity, a large pore size, high thermal stability and excellent light absorption and photocatalytic performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photocatalysts, in particular to a silver-palladium-based catalyst and a preparation method thereof. BACKGROUND

[0002] Solar energy, as a clean, sustainable and abundant energy, has great development potential. Effective collection of solar energy and its rational use have been a research goal of global high attention. In the past few decades of research, scientists have found that plasmonic nanostructures of noble metals Au, Ag and Cu exhibit unique photocatalytic effects under visible light. Plasmonic metal nanostructures can convert abundant solar energy into chemical energy through local surface plasmon resonance. Local surface plasmon resonance can greatly enhance the electric field near the metal nanoparticles, and the plasmonic enhanced electric field can focus light in the area close to the semiconductor nanostructure, increasing its light absorption, and the hot electrons generated under light irradiation are usually transferred to the lowest unoccupied molecular orbital, resulting in weakening of chemical bonds, thereby increasing the reaction rate. Plasmonic excitation can also cause the electrons of plasmonic nanocrystals to be injected into the conduction band of the semiconductor, thereby causing separation of electron-hole pairs and enhancing chemical reactions. However, single-component plasmonic Au, Ag and Cu nanoparticles can only drive limited chemical reactions. In recent years, researchers have found that bimetallic nanostructures have diversity in composition and structure selection. By combining Ag and Au with other plasmonic or other active metals to form bimetallic nanoparticles, the optical and catalytic activity can be effectively improved by utilizing the light response characteristics of plasmonic metals.

[0003] Although researchers have developed many types of bimetallic catalysts in recent years, most of them have focused on constructing alloy structures, and have not constructed catalysts from the perspective of plasmonic resonance excitation effect and modification of electron density. Compared with Au, Ag has the advantages of low work function and low cost. Therefore, it is of great significance to design a process scheme for constructing a heterogeneous catalyst with plasmonic resonance effect by adjusting the electron density of Ag and Pd atoms. SUMMARY

[0004] The present application aims to overcome the problems in the prior art and provide a silver-palladium-based catalyst and a preparation method thereof.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] The present application provides a preparation method of a silver-palladium-based catalyst, comprising the following steps:

[0007] (1) mixing graphene oxide, ethanol, azobisisobutyronitrile and 4-tert-butyl aniline, and reacting to obtain a functionalized intercalated graphene oxide material;

[0008] (2) mixing the functional intercalation graphene oxide material, ethanol and silver nitrate solution to obtain an intermediate product;

[0009] (3) mixing the intermediate product and palladium acetate solution to obtain the silver-palladium based catalyst.

[0010] Preferably, the mass-volume ratio of the graphene oxide, ethanol and azobisisobutyronitrile in step (1) is 120-180 mg: 10-20 mL: 25-35 mg.

[0011] The mass-mole ratio of the azobisisobutyronitrile and 4-tert-butyl aniline is 25-35 mg: 9-10 mmol.

[0012] Preferably, the temperature of the reaction in step (1) is 20-35℃, and the time is 2.5-3.5 h.

[0013] Preferably, the mass concentration of the silver nitrate solution in step (2) is 0.5-1.5 mg / mL.

[0014] Preferably, the mass-volume ratio of the functional intercalation graphene oxide material, ethanol and silver nitrate solution in step (2) is 45-55 mg: 5-15 mL: 0.5-1.5 mL.

[0015] Preferably, the xenon lamp power of the reaction in step (2) is 250-350 w, and the time of the reaction is 0.5-1.5 h.

[0016] Preferably, the mass concentration of the palladium acetate solution in step (3) is 0.5-1.5 mg / mL.

[0017] Preferably, the volume ratio of the silver nitrate solution in step (2) and the palladium acetate solution in step (3) is 0.5-1.5: 0.5-1.5.

[0018] Preferably, the xenon lamp power of the reaction in step (3) is 250-350 w, and the time of the reaction is 8-12 h.

[0019] The application also provides the silver-palladium based catalyst obtained by the preparation method.

[0020] The application has the following advantages:

[0021] The application provides a preparation method of a silver-palladium-based catalyst, comprising the following steps: mixing graphene oxide, ethanol, azobisisobutyronitrile and 4-tert-butyl aniline, and performing reaction to obtain a functional intercalated graphene oxide material; mixing the functional intercalated graphene oxide material, ethanol and a silver nitrate solution, and performing reaction to obtain an intermediate product; mixing the intermediate product and a palladium acetate solution, and performing reaction to obtain the silver-palladium-based catalyst. The functional groups, oxygen defects and introduced benzamide structures on the functional intercalated graphene oxide material provide more coordination sites, so that firm adhesion and coordination assembly between metal nanoparticles and graphene oxide are caused, and the AgPd bimetallic nano-alloy structure mainly exists in the form of coordination in the functional intercalated graphene oxide material. In addition, the high specific surface area of the functional intercalated graphene oxide material can provide more active sites to absorb reactant molecules, which is conducive to inhibiting the recombination of photo-generated holes and electrons and improving the catalytic performance.

[0022] The application uses the functional intercalated graphene oxide material with a high surface area to load AgPd bimetal, and a composite catalyst AgPd@4-tert-BzA / GO with good dispersion, large pore size, high thermal stability and excellent light absorption and photocatalytic performance is prepared. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a schematic diagram for preparing AgPd@4-tert-BzA / GO in embodiment 1;

[0024] Figure 2 It is a morphology characterization diagram of different materials in embodiment 1, Figure 2 Among them, (a1) is a SEM characterization diagram of Ag@4-tert-BzA / GO, (a2) is a mapping diagram of Ag@4-tert-BzA / GO, (a3) is an element distribution diagram of Ag@4-tert-BzA / GO, (b1) is a SEM characterization diagram of Pd@4-tert-BzA / GO, (b2) is a mapping diagram of Pd@4-tert-BzA / GO, (b3) is an element distribution diagram of Pd@4-tert-BzA / GO, (c1) is a SEM characterization diagram of AgPd@GO, (c2) is a mapping diagram of AgPd@GO, (c3) is an element distribution diagram of AgPd@GO, (d1) is a SEM characterization diagram of AgPd@4-tert-BzA / GO, (d2) is a mapping diagram of AgPd@4-tert-BzA / GO, and (d3) is an element distribution diagram of AgPd@4-tert-BzA / GO;

[0025] Figure 3 It is an EDS spectrum diagram (cps / eV-response value / eV) of different materials in embodiment 1,Figure 3 EDS spectra of (a) Ag@4-tert-BzA / GO, (b) Pd@4-tert-BzA / GO, (c) AgPd@GO, (d) AgPd@4-tert-BzA / GO;

[0026] Figure 4 HR-TEM characterization images of different materials in Example 1, Figure 4 HR-TEM characterization images of (a1) Ag@4-tert-BzA / GO, (a2) HR-TEM local magnification image of Ag@4-tert-BzA / GO, (b1) HR-TEM characterization image of Pd@4-tert-BzA / GO, (b2) HR-TEM local magnification image of Pd@4-tert-BzA / GO, (c1) HR-TEM characterization image of AgPd@GO, (c2) HR-TEM local magnification image of AgPd@GO, (d1) HR-TEM characterization image of AgPd@4-tert-BzA / GO, (d2) HR-TEM local magnification image of AgPd@4-tert-BzA / GO in Example 1;

[0027] Figure 5 Metal nanoparticle particle size distribution images (Particle size (nm)—Particle size (nm), Amount—Amount) of different materials in Example 1, (a) Metal nanoparticle particle size distribution image of Ag@4-tert-BzA / GO, (b) Metal nanoparticle particle size distribution image of Pd@4-tert-BzA / GO, (c) Metal nanoparticle particle size distribution image of AgPd@GO, (d) Metal nanoparticle particle size distribution image of AgPd@4-tert-BzA / GO;

[0028] Figure 6 Spectrograms (2Theta (°)—2θ (°), Intensity (a.u.)—Intensity (a.u.), Raman shift (cm -1 )—Raman shift (cm -1 ), Wavenumber (cm -1 )—Wavenumber (cm -1 ), Transmittance (%)—Transmittance (%)) of different materials in Example 1, Figure 6 (a) XRD spectrograms of different materials, (b) XRD spectrogram local magnification images of different materials, (c) Raman spectrograms of different materials, (d) FT-IR spectrograms of different materials in Example 1;

[0029] Figure 7 XPS spectra of different materials in Example 1 (B.E. (eV) - Binding Energy (eV), Intensity (a.u.) - Intensity (a.u.), Binding Energy (eV) - Binding Energy (eV)), Figure 7 , (a) is the XPS full element analysis spectrum of different materials, (b) is the Ag3d XPS spectrum of different materials, (c) is the Pd3d XPS spectrum of different materials, (d) is the C1s spectrum of the catalyst AgPd@4-tert-BzA / GO, (e) is the N1s spectrum of the catalyst AgPd@4-tert-BzA / GO, (f) is the O1s spectrum of the catalyst AgPd@4-tert-BzA / GO;

[0030] Figure 8 Thermogravimetric (TG)-Differential thermal analysis (DTA) analysis of different materials in Example 1 (Temperature (℃) - Intensity (a.u.), Weight (%) - Weight (%)), Figure 8 , (a) is the thermogravimetric (TG)-Differential thermal analysis (DTA) analysis of Ag@4-tert-BzA / GO, (b) is the thermogravimetric (TG)-Differential thermal analysis (DTA) analysis of Pd@4-tert-BzA / GO, (c) is the thermogravimetric (TG)-Differential thermal analysis (DTA) analysis of AgPd@GO, (d) is the thermogravimetric (TG)-Differential thermal analysis (DTA) analysis of AgPd@4-tert-BzA / GO;

[0031] Figure 9 Optical absorption performance of different materials in Example 1 (Wavelength (nm) - Wavelength (nm), Absorbance (a.u.) - Absorbance (a.u.), hv (eV) - Photon energy (eV), (Ahv) 2 (a.u.) - Photon absorption intensity (a.u.), B.E. (eV) - Binding Energy (eV), Intensity (a.u.) - Intensity (a.u)), Figure 9 , (a) is the UV-vis diffuse reflectance spectrum of different materials, (b) is the band gap width curve of different materials, (c) is the valence band position diagram of different materials;

[0032] Figure 10 Electrochemical performance of different materials in Example 1 (Voltage (V vs. Ag / AgCl) - Voltage (V vs. Ag / AgCl), Current density (mA / cm 2 ) - Current density (mA / cm 2Scanrate (mV / s) - scan rate (mV / s), Delta J (mA / cm 2 Electrochemical specific surface area (mA / cm 2 ), Figure 10 In the figure, (a) is an electrochemical cyclic voltammetry curve of Ag@4-tert-BzA / GO, (b) is an electrochemical cyclic voltammetry curve of Pd@4-tert-BzA / GO, (c) is an electrochemical cyclic voltammetry curve of AgPd@GO, (d) is an electrochemical cyclic voltammetry curve of AgPd@4-tert-BzA / GO, and (e) is a comparison diagram of electrochemical active surface areas of different materials.

[0033] Figure 11 In the figure, (a) is an electrochemical impedance spectrum of different materials, and (b) is a transient photocurrent response analysis diagram of different materials. Figure 11 In the figure, (a) is an electrochemical impedance spectrum of different materials, and (b) is a transient photocurrent response analysis diagram of different materials. DETAILED DESCRIPTION

[0034] The application provides a preparation method of a silver-palladium-based catalyst.

[0035] (1) mixing graphene oxide, ethanol, azobisisobutyronitrile and 4-tert-butyl aniline, and performing a reaction to obtain a functional intercalated graphene oxide material;

[0036] (2) mixing the functional intercalated graphene oxide material, ethanol and a silver nitrate solution, and performing a reaction to obtain an intermediate product;

[0037] (3) mixing the intermediate product and a palladium acetate solution, and performing a reaction to obtain the silver-palladium-based catalyst.

[0038] In the application, the mass-volume ratio of the graphene oxide, ethanol and azobisisobutyronitrile in step (1) is preferably 120-180 mg: 10-20 mL: 25-35 mg, further preferably 130-170 mg: 12-18 mL: 27-33 mg, and more preferably 150-160 mg: 15-17 mL: 28-30 mg.

[0039] In the application, the mass-mole ratio of the azobisisobutyronitrile and 4-tert-butyl aniline is preferably 25-35 mg: 9-10 mmol, further preferably 27-33 mg: 9.2-9.8 mmol, and more preferably 28-30 mg: 9.42-9.5 mmol.

[0040] In the present application, the mixing in step (1) is preferably that the graphene oxide and ethanol are initially mixed until the graphene oxide is completely dispersed, and then the azobisisobutyronitrile and 4-tert-butyl aniline are added for reaction.

[0041] In the present application, the temperature of the initial mixing is preferably 20-30℃, further preferably 22-28℃, and more preferably 25-26℃; and the ultrasonic frequency of the initial mixing is preferably 60-100Hz, further preferably 70-90Hz, and more preferably 75-80Hz.

[0042] In the present application, the ultrasonic frequency of the reaction in step (1) is preferably 60-100Hz, further preferably 70-90Hz, and more preferably 75-80Hz; the temperature is preferably 20-35℃, further preferably 25-30℃, and more preferably 27-28℃; and the time is preferably 2.5-3.5h, further preferably 2.7-3.3h, and more preferably 2.8-3h.

[0043] In the present application, after the reaction in step (1) is completed, the obtained system is sequentially subjected to standing, centrifugation, washing, and freeze-drying to obtain the functionalized intercalated graphene oxide material.

[0044] In the present application, the temperature of the standing is preferably 20-30℃, further preferably 22-28℃, and more preferably 25-27℃; the time of the standing is preferably 1.5-2.5h, further preferably 1.7-2.3h, and more preferably 2-2.1h; the rotation speed of the centrifugation is preferably 8000-12000r / min, further preferably 9000-11000r / min, and more preferably 9500-10000r / min; the time of the centrifugation is preferably 5-15min, further preferably 8-12min, and more preferably 9-10min; the washing is preferably carried out by sequentially performing dimethylformamide washing, anhydrous ethanol washing, and water washing; the number of times of the dimethylformamide washing, anhydrous ethanol washing, and water washing is independently preferably ≥2 times, further preferably ≥3 times, and more preferably ≥4 times; and the temperature of the freeze-drying is preferably -70--90℃, further preferably -75--85℃, and more preferably -78--83℃; and the time of the freeze-drying is preferably 12-36h, further preferably 18-30h, and more preferably 24-26h.

[0045] In the present application, the mass concentration of the silver nitrate solution in step (2) is preferably 0.5-1.5mg / mL, further preferably 0.7-1.3mg / mL, and more preferably 0.8-1mg / mL.

[0046] In the present application, the mass-volume ratio of the functionalized intercalated graphene oxide material, ethanol and silver nitrate solution in step (2) is preferably 45-55 mg: 5-15 mL: 0.5-1.5 mL, further preferably 47-53 mg: 7-13 mL: 0.7-1.3 mL, and more preferably 48-50 mg: 8-10 mL: 0.8-1.0 mL.

[0047] In the present application, the mixing in step (2) is preferably that the functionalized intercalated graphene oxide material and ethanol are first mixed preliminarily until the functionalized intercalated graphene oxide material is completely dispersed, and then the silver nitrate solution is added dropwise for reaction.

[0048] In the present application, the temperature of the preliminary mixing is preferably 20-30°C, further preferably 22-28°C, and more preferably 25-26°C; the ultrasonic frequency of the preliminary mixing is preferably 60-100 Hz, further preferably 70-90 Hz, and more preferably 75-80 Hz; and the time of the dropwise addition is preferably 10-30 min, further preferably 15-25 min, and more preferably 18-20 min.

[0049] In the present application, the xenon lamp power of the reaction in step (2) is preferably 250-350 w, further preferably 260-330 w, and more preferably 280-300 w; and the time of the reaction is preferably 0.5-1.5 h, further preferably 0.7-1.3 h, and more preferably 0.8-1.0 h.

[0050] In the present application, the mass concentration of the palladium acetate solution in step (3) is preferably 0.5-1.5 mg / mL, further preferably 0.7-1.3 mg / mL, and more preferably 0.8-1 mg / mL.

[0051] In the present application, the volume ratio of the silver nitrate solution in step (2) to the palladium acetate solution in step (3) is preferably 0.5-1.5: 0.5-1.5, further preferably 0.7-1.3: 0.7-1.3, and more preferably 0.8-1.0: 0.8-1.0.

[0052] In the present application, the mixing in step (3) is preferably that the palladium acetate solution is added dropwise into the intermediate product for reaction; and the time of the dropwise addition is preferably 10-30 min, further preferably 15-25 min, and more preferably 18-20 min.

[0053] In the present application, the xenon lamp power of the reaction in step (3) is preferably 250-350 w, further preferably 260-330 w, and more preferably 280-300 w; and the time of the reaction is preferably 8-12 h, further preferably 9-11 h, and more preferably 9.5-10 h.

[0054] In the present application, after the reaction of step (3) is completed, the obtained system is sequentially subjected to centrifugation, washing and vacuum drying to obtain the silver-palladium-based catalyst.

[0055] In the present application, the rotation speed of the centrifugation is preferably 8000-12000 r / min, further preferably 9000-11000 r / min, and more preferably 9500-10000 r / min; the centrifugation time is preferably 5-15 min, further preferably 8-12 min, and more preferably 9-10 min; the washing is preferably carried out by sequentially washing with anhydrous ethanol and water; the number of times of washing with anhydrous ethanol and water is independently preferably ≥ 2 times, further preferably ≥ 3 times, and more preferably ≥ 4 times; the vacuum drying is preferably carried out at a vacuum degree of 1x10 4 In the present application, the vacuum drying is carried out in a vacuum drying oven; the temperature of the vacuum drying is preferably 55-65℃, further preferably 57-63℃, and more preferably 58-60℃; the time of the vacuum drying is preferably 7-9 h, further preferably 7.5-8.5 h, and more preferably 8-8.3 h.

[0056] The present application also provides the silver-palladium-based catalyst obtained by the preparation method.

[0057] The technical solutions provided by the present application are described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0058] Example 1

[0059] 150 mg of graphene oxide and 15 mL of ethanol were mixed at a temperature of 25℃ and a frequency of 80 Hz until the graphene oxide was completely dispersed, then 30 mg of azobisisobutyronitrile and 9.42 mmol of 4-tert-butyl aniline were added, and the reaction was carried out at an ultrasonic frequency of 80 Hz and a temperature of 30℃ for 3 h. After the reaction was completed, the obtained system was allowed to stand at 25℃ for 2 h, then centrifuged at a rotation speed of 10000 r / min for 10 min, and the product was collected, washed with dimethylformamide 3 times, anhydrous ethanol 3 times, and water 3 times in sequence, and finally freeze-dried at -80℃ for 24 h to obtain a functionalized intercalated graphene oxide material (labeled as 4-tert-BzA / GO);

[0060] The 50 mg functional intercalated graphene oxide material and 10 mL ethanol were mixed at a temperature of 25°C and a frequency of 80 Hz until the functional intercalated graphene oxide material was completely dispersed, and then 1 mL of a silver nitrate solution with a mass concentration of 1 mg / mL was added dropwise (the dropping time was 20 min), and the reaction was carried out under 300 w xenon lamp irradiation for 1 h to obtain an intermediate product; 1 mL of a palladium acetate solution with a mass concentration of 1 mg / mL was added dropwise to the intermediate product (the dropping time was 20 min), and the reaction was continued under 300 w xenon lamp irradiation for 10 h; after the reaction was completed, centrifugation was performed at a speed of 10,000 r / min for 10 min, the product was collected, sequentially washed twice with anhydrous ethanol and twice with water, and finally vacuum dried at a vacuum degree of 10,000 Pa and a temperature of 60°C for 8 h to obtain the silver-palladium-based catalyst (labeled as AgPd@4-tert-BzA / GO).

[0061] The preparation schematic of AgPd@4-tert-BzA / GO in the embodiment is shown in Figure 1 As can be seen from Figure 1 , the synthesis of the silver-palladium-based catalyst can be divided into two steps: first, the formation of plasmonic AgNPs; the silver nitrate solution is added, the functional intercalated graphene oxide material is used, the microdomain structure of the amide bond is utilized, and under 250-350 w xenon lamp irradiation, the silver is first reduced to form AgNPs; second, the introduction of metal palladium to form an AgPd bimetallic alloy structure; under 250-350 w xenon lamp irradiation, the plasmonic AgNPs are activated, the palladium acetate solution is added, and Pd is efficiently and uniformly deposited; in the absence of any reducing agent, PdNPs are formed on the surface of AgNPs, thereby obtaining the silver-palladium-based catalyst.

[0062] The comparative example 1 of the embodiment was set, and other conditions in the embodiment 1 were controlled to be unchanged, and the step of adding the palladium acetate solution and continuing the reaction was omitted to obtain a silver-based catalyst (labeled as Ag@4-tert-BzA / GO).

[0063] The comparative example 2 of the embodiment was set, and other conditions in the embodiment 1 were controlled to be unchanged, and the step of adding the silver nitrate solution and reacting was omitted to obtain a palladium-based catalyst (labeled as Pd@4-tert-BzA / GO).

[0064] The comparative example 3 of the embodiment was set, and other conditions in the embodiment 1 were controlled to be unchanged, and the functional intercalated graphene oxide material was replaced by graphene oxide material to obtain a silver-palladium-loaded graphene oxide composite catalyst (labeled as AgPd@GO).

[0065] Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and AgPd@4-tert-BzA / GO were characterized respectively, and the morphology characterization diagrams of different materials in this example were obtained, as shown in Figure 2 Figure 2 Among them, (a1) is the SEM characterization diagram of Ag@4-tert-BzA / GO, (a2) is the mapping diagram of Ag@4-tert-BzA / GO, (a3) is the element distribution diagram of Ag@4-tert-BzA / GO, (b1) is the SEM characterization diagram of Pd@4-tert-BzA / GO, (b2) is the mapping diagram of Pd@4-tert-BzA / GO, (b3) is the element distribution diagram of Pd@4-tert-BzA / GO, (c1) is the SEM characterization diagram of AgPd@GO, (c2) is the mapping diagram of AgPd@GO, (c3) is the element distribution diagram of AgPd@GO, (d1) is the SEM characterization diagram of AgPd@4-tert-BzA / GO, (d2) is the mapping diagram of AgPd@4-tert-BzA / GO, (d3) is the element distribution diagram of AgPd@4-tert-BzA / GO). As can be seen from Figure 2

[0066] Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and AgPd@4-tert-BzA / GO were respectively subjected to EDS test, and the EDS spectrum diagrams of different materials in this example were obtained, as shown in Figure 3 Figure 3 Among them, (a) is the EDS spectrum diagram of Ag@4-tert-BzA / GO, (b) is the EDS spectrum diagram of Pd@4-tert-BzA / GO, (c) is the EDS spectrum diagram of AgPd@GO, (d) is the EDS spectrum diagram of AgPd@4-tert-BzA / GO). As can be seen from Figure 3 ​​​As can be seen, the loading of AgPd NPs in the catalyst AgPd@4-tert-BzA / GO is higher, which can be due to the large number of functional groups on the functional intercalated graphene oxide material and the larger specific surface area, which promotes better dispersion and fixation of AgPd nanoparticles on the functional intercalated graphene oxide material. Therefore, the highly uniform dispersion of AgPd nanoparticles on the functional intercalated graphene oxide material can be attributed to the functional groups and oxygen defects on the functional intercalated graphene oxide material and the introduced benzamide structure, which provides more coordination sites, resulting in firm adhesion and coordination assembly between metal nanoparticles and graphene oxide. The 3D framework of metal nanoparticles loaded on the functional intercalated graphene oxide material is beneficial to improve the interface contact, reduce the aggregation of hybrids, thereby enhancing the light response area and improving the catalytic activity. Secondly, the high specific surface area of the functional intercalated graphene oxide material can provide more active sites to absorb reactant molecules, which is beneficial to inhibit the recombination of photo-generated holes-electrons and improve the catalytic performance.

[0067] Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and AgPd@4-tert-BzA / GO were subjected to HR-TEM characterization and metal nanoparticle size distribution test, and the HR-TEM characterization graphs of different materials in this embodiment are shown in Figure 4 Figure 4 In the figure, (a1) is the HR-TEM characterization graph of Ag@4-tert-BzA / GO, (a2) is the HR-TEM local magnification graph of Ag@4-tert-BzA / GO, (b1) is the HR-TEM characterization graph of Pd@4-tert-BzA / GO, (b2) is the HR-TEM local magnification graph of Pd@4-tert-BzA / GO, (c1) is the HR-TEM characterization graph of AgPd@GO, (c2) is the HR-TEM local magnification graph of AgPd@GO, (d1) is the HR-TEM characterization graph of AgPd@4-tert-BzA / GO, and (d2) is the HR-TEM local magnification graph of AgPd@4-tert-BzA / GO); the metal nanoparticle size distribution graphs of different materials in this embodiment are shown in Figure 5 Figure 5 In the figure, (a) is the metal nanoparticle size distribution graph of Ag@4-tert-BzA / GO, (b) is the metal nanoparticle size distribution graph of Pd@4-tert-BzA / GO, (c) is the metal nanoparticle size distribution graph of AgPd@GO, and (d) is the metal nanoparticle size distribution graph of AgPd@4-tert-BzA / GO). From Figures 4-5 ​​As can be seen, the functionalized intercalated graphene oxide material presents a sheet structure with several wrinkles on the sheet, but without the multi-layer stacking of graphene oxide; when the metal nanoparticles are loaded on the functionalized intercalated graphene oxide material, they are uniformly dispersed and do not agglomerate at the edges, while when directly loaded on the graphene oxide sheet, the metal nanoparticles are deposited more and are mostly at the edges, which can be because after using the functionalized intercalated graphene oxide material, there are more micro-domain defects on the sheet, which can control the assembly of the nanoparticles; the clear lattice fringes with a d = 0.230 nm different from the Pd(111) crystal plane and the Ag(111) crystal plane appear on the catalyst AgPd@GO and AgPd@4-tert-BzA / GO, and the lattice fringe spacing is between the lattice spacing of the Pd(111) crystal plane (d = 0.225 nm) and the lattice spacing of the Ag(111) crystal plane (d = 0.235 nm), which can further illustrate that an alloy structure is formed in the catalyst AgPd@GO and AgPd@4-tert-BzA / GO; by normal distribution statistics of the nanoparticles, it is obtained that the average particle size of the catalyst AgPd@4-tert-BzA / GO is 7.0 nm, which is smaller than that on the catalyst AgPd@GO, which indicates that the use of the functionalized intercalated graphene oxide material has a larger interlayer spacing and coordination site, so that the dispersion of the metal nanoparticles is better.

[0068] ICP-MS tests were performed on Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and AgPd@4-tert-BzA / GO, and the ICP-MS test results of different materials in this example are shown in Table 1.

[0069] Table 1 ICP-MS test results of different materials

[0070] Catalyst Ag (wt%) Pd (wt%) Total amount of metal (wt%) Ag@4-tert-BzA / GO 0.11 0 0.11 Pd@4-tert-BzA / GO 0 1.1 1.1 AgPd@GO 0.23 1.18 1.41 AgPd@4-tert-BzA / GO 0.17 1.03 1.2

[0071] As can be seen from the data in Table 1, the total metal content of the catalyst AgPd@4-tert-BzA / GO is less than that of the metal silver and palladium alone, and the catalyst AgPd@GO, which is further related to the metal nanoparticle size distribution graph, the better the dispersion of the metal nanoparticles, the smaller the particle size, and the less likely to agglomerate. In other words, the micro-domain structure present on the functionalized intercalated graphene oxide material can control the dispersion and particle size of the metal nanoparticles.

[0072] Spectral tests were performed on GO, 4-tert-BzA / GO (abbreviated as t-BzA / GO), Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and AgPd@4-tert-BzA / GO, and the spectral graphs of different materials in this example were obtained, as shown in Figure 6 Figure 6 Among them, (a) is the XRD spectral graph of different materials, (b) is the local magnification of the XRD spectrum of different materials, (c) is the Raman spectrum of different materials, and (d) is the FT-IR spectrum of different materials.

[0073] From Figure 6 ​The crystal structure changes of the functionalized graphene oxide composite can be observed in (a) and (b). First, the diffraction peaks of the catalysts AgPd@4-tert-BzA / GO, AgPd@GO, Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, 4-tert-BzA / GO and GO are at 10.72°, 11.78°, 8.94°, 10.54°, 8.54° and 11.34°, respectively, which are attributed to the (001) crystal plane of graphene oxide. According to the Bragg equation, the interlayer distance of the (001) crystal plane of graphene oxide in the catalysts is 0.825 nm, 0.751 nm, 0.989 nm, 0.839 nm, 1.035 nm and 0.780 nm, respectively. It can be observed from the figure that the interlayer distance of the (001) crystal plane of graphene oxide decreases after the introduction of metal, which indicates that the interaction between the support material and the metal occurs after the introduction of the metal, resulting in a decrease in the interlayer distance and a decrease in the diffraction angle of the (001) crystal plane of graphene oxide. By comparing the catalysts AgPd@4-tert-BzA / GO, Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, it can be found in the figure that the interlayer distance of the (001) crystal plane of graphene oxide also shows a relative decrease after the introduction of metal Pd, which may be due to the larger electronegativity of metal Pd, which produces a local effect after coordination with the functional groups on the surface of graphene oxide, resulting in a decrease in the interlayer distance and a displacement of the crystal plane of graphene oxide. It can also be seen from the figure that weak characteristic absorption peaks appear at 37.98° and 39.9° in the catalyst AgPd@4-tert-BzA / GO, and the lower addition amount of metal Ag and metal Pd (0.17wt%, 1.03wt%) in the composite material results in weak XRD diffraction peak signals, which are attributed to the (111) crystal plane of metal Ag and the (111) crystal plane of metal Pd, respectively. By comparing the standard card, the (111) crystal plane of metal Ag and the (111) crystal plane of metal Pd have a blue shift, which may be due to the interaction between metal Ag and metal Pd, which causes a change in the crystal plane and a displacement, which can further indicate that the bimetallic alloy structure is formed to some extent.

[0074] From Figure 6 In (c), it can be observed that the G band in the Raman spectrum is related to the vibration of the sp2 hybrid plane of carbon atoms in the material, reflecting the symmetry and crystallinity of the graphite structure of the material, and the D band is related to the sp3 hybridization of carbon atoms, reflecting the degree of defects and disorder of the graphite structure. The intensity ratio of the D band to the G band (ID / IG) can reflect the degree of defects and relative concentration of the sp2 graphite structure of the material. The D band appears at 2500cm -1 ~ 3250cm -1The wide peaks of 2D, 2D', D+G of the Raman spectrum, the 2D peak is the second-order peak of the D band, which is a single peak in the single-layer graphene oxide, the 2D' peak is the second-order peak of the G band, and D+G is a combination of different momentum phonons, which requires defects to be activated, thus indicating that the material is a single-layer graphene oxide material. Compared with the catalysts AgPd@4-tert-BzA / GO, Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO and AgPd@GO, the peaks of the D band and the G band of AgPd@GO are located at 1355 cm -1 and 1589 cm -1 , respectively. It is found that the D band and the G band of the functionalized intercalated graphene oxide material loaded with metal Ag and metal Pd are shifted to a smaller wave number, which may be due to the introduction of new graphite structures after the functionalization of the graphene oxide with p-t-butylaniline, resulting in more defect structures. Meanwhile, compared with the catalyst AgPd@4-tert-BzA / GO and AgPd@GO, the ID / IG of the catalyst AgPd@4-tert-BzA / GO (AgPd@4-tert-BzA / GO: ID / IG = 0.928, AgPd@GO: ID / IG = 0.945) is reduced, which indicates that the graphite structure characteristics of the graphene oxide are restored to some extent after the functionalization of the graphene oxide with p-t-butylaniline.

[0075] From Figure 6 (d), it can be observed that, compared with the original material graphene oxide GO, the functionalized material and the material loaded with metal have a weakened signal intensity of the stretching vibration absorption peak of -OH at 3280 cm -1 , indicating that part of the hydroxyl groups on the surface of the functionalized graphene oxide and -OH on -COOH are reduced and broken; the catalysts AgPd@4-tert-BzA / GO, Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO and 4-tert-BzA / GO have a stretching vibration peak signal of C=O structure between amides at 1639 cm -1 and a stretching vibration absorption peak signal of C-N at 1369 cm -1 , indicating that the aniline successfully reacts with the carboxylic acid on the graphene oxide to form an amide bond; after loading the metal, a metal bond after the coordination of the metal with N and O appears at 880 cm -1 , and the stretching vibration peak intensity of N-H, C=O (-CONH-), and C-N at 2964 cm -1 , 1639 cm -1 , and 1369 cm -1 is significantly reduced, which is due to the coordination between the metal and the N and O atoms.

[0076] XPS spectra of Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and AgPd@4-tert-BzA / GO were analyzed, and the XPS spectra of different materials in this example were obtained, as shown in Figure 7 Figure 7 , wherein (a) is the XPS full element analysis spectrum of different materials, (b) is the Ag3d XPS spectrum of different materials, (c) is the Pd3d XPS spectrum of different materials, (d) is the C1s spectrum of the catalyst AgPd@4-tert-BzA / GO, (e) is the N1s spectrum of the catalyst AgPd@4-tert-BzA / GO, and (f) is the O1s spectrum of the catalyst AgPd@4-tert-BzA / GO.

[0077] From Figure 7 (a), it can be seen that the peaks at 340.2, 367.2, 400.1, 286.2 and 532.2 eV are from Pd, Ag, N, C and O elements, respectively, which reflects their coexistence in the sample. Figure 7 (b) and Figure 7 (c) study the related valence states of Pd and Ag, and it is obvious that in Figure 7 (b), two strong peaks at 374.2 eV (Ag3d3 / 2) and 368.2 eV (Ag3d5 / 2) are found, which are attributed to metallic Ag0, indicating that Ag is effectively reduced to zero valence under the irradiation of a 300 W xenon lamp. In addition, in Figure 7 (c), it is shown that Pd3d is divided into four peaks at 344.3, 338.7, 343.3 and 337.2 eV, which is completely consistent with the peaks of Pd(0) and Pd(II) species. Compared with the standard Pd0 (335.3 eV) and Ag0 (374.2 eV), the binding energies of Pd3d and Ag3d are shifted to higher binding energies, which is mainly attributed to the strong electronic interaction between Ag and Pd, indicating the existence of electron transfer from Ag to Pd, which further shows the formation of AgPd alloy. From Figure 7 ​As can be seen in (d), the C1s spectrum of the catalyst AgPd@4-tert-BzA / GO can be peak-fitted into five structures, the peaks centered at 283.8 eV, 284.8 eV, 286.8 eV, 288.5 eV and 290.1 eV are assigned to C=C bond, C-C bond, oxygen-containing functional groups (C-OH / C-O-C / C=O), amide bond (C=O / N), and π-π* structure (arising from sp2 carbon excitation transition) in the composite, respectively. As can be seen in (e) and (f), there are metal coordination forms with N and O at 398.6 eV and 530.1 eV, respectively, so it can be clearly seen from the spectra of O1s and N1s that the AgPd bimetallic nano-alloy structure mainly exists in the form of coordination in the functionalized intercalated graphene oxide material, which confirms that the material adjusts the coordination microenvironment of AgPd.

[0078] The thermal gravimetric (TG)-differential thermal analysis (DTA) of Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and AgPd@4-tert-BzA / GO was carried out to investigate the thermal stability of the catalyst AgPd@4-tert-BzA / GO, and different samples were heated from room temperature to 1000℃ at a heating rate of 10℃ / min in air atmosphere, and the flow rate of air was 60 mL / min; the thermal gravimetric (TG)-differential thermal analysis (DTA) diagrams of different materials in this example were obtained as shown in Figure 8 Figure 8 , in which (a) is the thermal gravimetric (TG)-differential thermal analysis (DTA) diagram of Ag@4-tert-BzA / GO, (b) is the thermal gravimetric (TG)-differential thermal analysis (DTA) diagram of Pd@4-tert-BzA / GO, (c) is the thermal gravimetric (TG)-differential thermal analysis (DTA) diagram of AgPd@GO, and (d) is the thermal gravimetric (TG)-differential thermal analysis (DTA) diagram of AgPd@4-tert-BzA / GO.

[0079] From Figure 8 ​As can be seen, two sharp endothermic peaks appear in the DTA curves of the four catalysts, and two main weight loss curves appear in the TG curves, so the thermal stability of the catalysts can be divided into two temperature gradients. The first stage is from room temperature to 200°C, and the weight loss in this stage is mainly due to the evaporation of oxygen-containing functional groups on graphene oxide in the form of water molecules when heated; the second weight loss stage is from 200°C to 500°C, and the second weight loss is the decomposition stage of graphene oxide. It can be seen that graphene oxide is basically completely decomposed after 550°C. From the DTA curve, a sharp exothermic peak appears at about 220°C, and the weight of the catalyst decreases rapidly, which may be due to the combustion of graphene oxide at 220°C, causing the structure of the catalyst to collapse rapidly and causing mass loss. A small and sharp endothermic peak appears at about 450°C, which is due to the combustion and decomposition of graphene oxide structure at 450°C under air conditions. By comparing the catalyst AgPd@GO with AgPd@4-tert-BzA / GO, it can be found that compared with AgPd@GO, the second stage melting weight loss temperature of AgPd@4-tert-BzA / GO increases from 420°C to 450°C, and the complete decomposition temperature increases from 470°C to 500°C. This phenomenon can be attributed to the introduction of metal palladium, which makes the structure of the material more stable due to the coordination between metal palladium and the surface of graphene oxide. The thermal analysis curve of the catalyst Pd@4-tert-BzA / GO further proves that there is a certain interaction between metal palladium and the functionalized intercalated graphene oxide material, which improves the thermal stability of the catalyst.

[0080] The specific surface area and pore structure of Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and AgPd@4-tert-BzA / GO were tested, and the specific surface area and pore structure test results of different materials are shown in Table 2. As can be seen from Table 2, the specific surface areas of the catalysts AgPd@4-tert-BzA / GO, Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO and AgPd@GO are 2.5176 m 2 / g, 8.2991 m 2 / g, 9.0085 m 2 / g, 16.0779 m 2nm, 4.4122 nm, 9.2816 nm. It can be found from the results that the pore size of the catalyst AgPd@4-tert-BzA / GO is the largest, which may be due to the fact that after the functionalization and modification of graphene oxide with p-tert-butylaniline, the interlayer spacing of graphene oxide is increased, and the electronic interaction between the bimetallic nanoparticles and the graphene oxide material has a certain supporting effect on the interlayer spacing of the graphene oxide material, thus having a larger pore size. This result can correspond to the characterization results of XRD.

[0081] Table 2 Specific surface area and pore structure test results of different materials

[0082] Catalyst Pore size (nm) Pore volume (cm3 / g) 3 / g) Specific surface area (m 2 / g)]]> Ag@4-tert-BzA / GO 4.9551 0.010364 8.2991 Pd@4-tert-BzA / GO 4.4122 0.009937 9.0085 AgPd@GO 9.2816 0.037307 16.0779 AgPd@4-tert-BzA / GO 11.6358 0.007324 2.5176

[0083] UV-visible absorption spectra, band gap width and valence band position analysis were performed on GO, Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and AgPd@4-tert-BzA / GO, and the light absorption performance diagrams of different materials were obtained, as shown in Figure 9 Figure 9 Among them, (a) is the UV-vis diffuse reflectance spectrum of different materials, (b) is the band gap width curve of different materials, and (c) is the valence band position diagram of different materials.

[0084] From Figure 9 (a), it can be observed that there is a sharp main peak at 223 nm, and there are shoulder peaks around 300-500 nm, which can be attributed to the π-π* transition of the aromatic C=C bond and the n-π* transition of the C=O bond on the graphene oxide. Compared with graphene oxide, the loaded metal also shows two groups of absorption peaks at 223 nm and 300-500 nm, but the absorption peak at 223 nm has a red shift, which is due to the fact that after the functionalization and modification of graphene oxide with p-tert-butylaniline, a part of the oxygen-containing functional groups on the graphene oxide are reduced, and the plasmonic surface resonance effect of silver metal leads to the red shift. From Figure 9 (a), it can be found that after introducing metal into the graphene oxide support material, the absorption light region of the catalyst shifts to the visible light, and there is a strong absorption in the entire ultraviolet-visible light region, which makes the visible light catalytic performance of the catalyst enhanced. This is because the metal silver nanoparticles have a synergistic effect with the support material, which can strongly absorb visible light, broaden the light response range, and improve the utilization rate of visible light (400-800 nm).

[0085] According to the formula TauePlot ((ahv) 1 / n = A (hv - E g ​), a is the absorbance index, h is the Planck constant (6.6*10 -34 Js), v is the frequency, A is the absorbance constant, n is related to the type of semiconductor, and the sample is an indirect band gap semiconductor, so n = 2) to calculate the band gap width of different materials, from Figure 9 As can be seen in (b), the band gaps of AgPd@4-tert-BzA / GO, Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and GO are 1.15eV, 1.25eV, 1.35eV, 1.38eV and 1.52eV, respectively. The band gap of the catalyst AgPd@4-tert-BzA / GO is the narrowest, indicating that the material has the highest light absorption capacity.

[0086] From Figure 9 As can be seen in (c), the valence bands of AgPd@4-tert-BzA / GO, Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO and AgPd@GO are 2.30eV, 1.01eV, 2.43eV and 1.50eV, respectively. Compared with the catalyst AgPd@4-tert-BzA / GO and AgPd@GO, the valence band of the catalyst AgPd@4-tert-BzA / GO increases by 0.8eV, and the valence band is more correct, indicating that the oxidation capacity of the catalyst AgPd@4-tert-BzA / GO is stronger, and more photoelectrons can be generated. In summary, the catalyst AgPd@4-tert-BzA / GO has a wider light absorption capacity and a narrower valence band, and therefore has better photocatalytic performance.

[0087] The electrochemical performance of Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and AgPd@4-tert-BzA / GO was tested, and the electrochemical cyclic voltammetry curve was tested in a 0.1 mol / L saturated anhydrous sodium sulfate solution. The double-layer capacitance (EDLC) represented by the cyclic voltammetry curve was further analyzed to analyze the electrochemical surface area of the catalyst. First, calculate the half of the positive and negative current density difference of the potential center of the CV curve, use the value and the corresponding scan speed to plot, and finally get the relative size of the electrochemical specific surface area by fitting the slope of the curve, and get the electrochemical performance graph of different materials, as shown in Figure 10 Figure 10 ​In the figure, (a) is the electrochemical cyclic voltammetry curve of Ag@4-tert-BzA / GO, (b) is the electrochemical cyclic voltammetry curve of Pd@4-tert-BzA / GO, (c) is the electrochemical cyclic voltammetry curve of AgPd@GO, (d) is the electrochemical cyclic voltammetry curve of AgPd@4-tert-BzA / GO, and (e) is the comparison diagram of electrochemical active surface area of different materials.

[0088] From Figure 10 It can be seen from the figure that the curve slopes of AgPd@4-tert-BzA / GO, Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO and AgPd@GO are 5.39 mF / cm 2 , 4.18 mF / cm 2 , 3.13 mF / cm 2 and 4.47 mF / cm 2 , respectively. The electrochemical surface area of the catalyst AgPd@4-tert-BzA / GO is the largest, because the interlayer spacing of 4-tert-BzA / GO is larger during the synthesis of the catalyst, the dispersion of AgPd bimetallic nanoparticles is better, which corresponds to the particle size distribution data of the HR-TEM image of the catalyst, and the functionalized graphene oxide has more defect structures, so that the metal nanoparticles are coordinated with it, thereby having higher activity.

[0089] The electrochemical impedance and visible light transient photocurrent response of GO, Ag@4-tert-BzA / GO, Pd@4-tert-BzA / GO, AgPd@GO and AgPd@4-tert-BzA / GO were tested, and the electrochemical impedance spectrum and transient photocurrent response analysis diagram of different materials were obtained, as shown in Figure 11 . Figure 11 In the figure, (a) is the electrochemical impedance spectrum diagram of different materials, and (b) is the transient photocurrent response analysis diagram of different materials.

[0090] In the electrochemical impedance spectrum, the size of the arc radius is related to the impedance value of the material. The smaller the radius, the smaller the resistance value of the material, and the better the conductivity. From Figure 11 It can be seen from (a) that the radius of the catalyst AgPd@4-tert-BzA / GO is the smallest, and the conductivity is the strongest, which is most conducive to the migration and transmission of carriers. From Figure 11 (b), it can be seen that the catalyst AgPd@4-tert-BzA / GO shows stronger photocurrent. The enhancement of photocurrent is due to the coordination bond between the metal and the graphene oxide carrier material, which can improve the separation efficiency of photo-generated carriers, thereby greatly improving the visible light photocatalytic activity.

[0091] Example 2

[0092] Mix 170 mg of graphene oxide and 18 mL of ethanol at a temperature of 28°C and a frequency of 90 Hz until the graphene oxide is completely dispersed, then add 33 mg of azobisisobutyronitrile and 9.8 mmol of 4-tert-butyl aniline, and react at an ultrasonic frequency of 90 Hz and a temperature of 35°C for 2.5 h. After the reaction is completed, the obtained system is allowed to stand at 27°C for 1.7 h, then centrifuged at a speed of 11000 r / min for 8 min, the product is collected, washed with dimethylformamide for 4 times, anhydrous ethanol for 4 times, and water for 4 times in sequence, and finally freeze-dried at -85°C for 18 h to obtain the functionalized intercalated graphene oxide material;

[0093] Mix 53 mg of the functionalized intercalated graphene oxide material and 13 mL of ethanol at a temperature of 28°C and a frequency of 90 Hz until the functionalized intercalated graphene oxide material is completely dispersed, then add 1.5 mL of a silver nitrate solution with a mass concentration of 1.3 mg / mL dropwise (the dropwise adding time is 25 min), and react under 330w xenon lamp irradiation for 0.8 h to obtain an intermediate product. Add 1.3 mL of a palladium acetate solution with a mass concentration of 1.3 mg / mL dropwise to the intermediate product (the dropwise adding time is 25 min), and continue to react under 330w xenon lamp irradiation for 9 h. After the reaction is completed, centrifuge at a speed of 11000 r / min for 8 min, collect the product, wash with anhydrous ethanol for 2 times, and water for 3 times in sequence, and finally vacuum dry at a vacuum degree of 10000 Pa and a temperature of 65°C for 7 h to obtain the silver-palladium-based catalyst.

[0094] Example 3

[0095] Mix 130 mg of graphene oxide and 12 mL of ethanol at a temperature of 22°C and a frequency of 75 Hz until the graphene oxide is completely dispersed, then add 25 mg of azobisisobutyronitrile and 9.2 mmol of 4-tert-butyl aniline, and react at an ultrasonic frequency of 75 Hz and a temperature of 25°C for 3.5 h. After the reaction is completed, the obtained system is allowed to stand at 20°C for 2.5 h, then centrifuged at a speed of 9000 r / min for 12 min, the product is collected, washed with dimethylformamide for 2 times, anhydrous ethanol for 3 times, and water for 3 times in sequence, and finally freeze-dried at -75°C for 26 h to obtain the functionalized intercalated graphene oxide material;

[0096] The functional intercalated graphene oxide material 47 mg and 7 mL of ethanol are mixed at a temperature of 22 DEG C and a frequency of 75 Hz until the functional intercalated graphene oxide material is completely dispersed, and then 0.8 mL of silver nitrate solution with a mass concentration of 0.7 mg / mL is added dropwise (the dropwise adding time is 15 min), and the intermediate product is obtained by reacting under the irradiation of a 280 w xenon lamp for 1.3 h; 1 mL of palladium acetate solution with a mass concentration of 0.7 mg / mL is added dropwise into the intermediate product (the dropwise adding time is 15 min), and the reaction is continued under the irradiation of a 280 w xenon lamp for 11 h; after the reaction is completed, the product is collected by centrifugation at a speed of 9000 r / min for 12 min, washed with anhydrous ethanol for 3 times and water for 2 times in sequence, and finally dried under vacuum at a vacuum degree of 10000 Pa and a temperature of 55 DEG C for 9 h to obtain the silver-palladium-based catalyst.

[0097] It can be known from the above embodiment that the application provides a preparation method of a silver-palladium-based catalyst, the functional groups and oxygen defects on the functional intercalated graphene oxide material and the introduced benzamide structure provide more coordination sites, so that firm adhesion and coordination assembly between metal nanoparticles and graphene oxide are caused, and the AgPd bimetallic nano-alloy structure mainly exists in the form of coordination in the functional intercalated graphene oxide material. In addition, the high specific surface area of the functional intercalated graphene oxide material can provide more active sites to absorb reactant molecules, which is beneficial to inhibit the recombination of photo-generated holes and electrons and improve the catalytic performance.

[0098] The application uses the functional intercalated graphene oxide material with a high surface area to load AgPd bimetal, and a composite catalyst AgPd@4-tert-BzA / GO with good dispersion, large pore size, high thermal stability and excellent light absorption and photocatalytic performance is prepared.

[0099] The above only describes the preferred embodiments of the application, and it should be noted that some improvements and refinements can be made by those skilled in the art without departing from the principles of the application, and these improvements and refinements should also be regarded as the protection scope of the application.

Claims

1. A method for preparing a silver-palladium-based catalyst, characterized in that, The preparation method comprises the following steps: (1) mixing graphene oxide, ethanol, azobisisobutyronitrile and 4-tert-butyl aniline to obtain a functional intercalation graphene oxide material; (2) mixing the functional intercalation graphene oxide material, ethanol and silver nitrate solution to obtain an intermediate product by reducing silver to silver nanoparticles under xenon lamp irradiation; (3) mixing the intermediate product and palladium acetate solution to obtain the silver-palladium-based catalyst by reducing palladium to palladium nanoparticles under xenon lamp irradiation.

2. The production method according to claim 1, wherein In step (1), the mass-volume ratio of graphene oxide, ethanol and azobisisobutyronitrile is 120-180 mg: 10-20 mL: 25-35 mg. The mass-mole ratio of azobisisobutyronitrile and 4-tert-butyl aniline is 25-35 mg: 9-10 mmol.

3. The production method according to claim 1 or 2, characterized by, In step (1), the reaction temperature is 20-35℃, and the reaction time is 2.5-3.5 h.

4. The production method according to claim 3, wherein In step (2), the mass concentration of silver nitrate solution is 0.5-1.5 mg / mL.

5. The production method according to claim 4, wherein In step (2), the mass-volume ratio of functional intercalation graphene oxide material, ethanol and silver nitrate solution is 45-55 mg: 5-15 mL: 0.5-1.5 mL.

6. The production method according to claim 5, wherein In step (2), the xenon lamp power of the reaction is 250-350 w, and the reaction time is 0.5-1.5 h.

7. The production method according to claim 6, wherein In step (3), the mass concentration of palladium acetate solution is 0.5-1.5 mg / mL.

8. The production method according to claim 7, wherein In step (2), the volume ratio of silver nitrate solution to step (3) palladium acetate solution is 0.5-1.5: 0.5-1.

5.

9. The production method according to claim 8, wherein In step (3), the xenon lamp power of the reaction is 250-350 w, and the reaction time is 8-12 h.

10. The silver-palladium-based catalyst prepared by the preparation method of any one of claims 1-9.

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