A method for preparing and using a bimetallic hydroxyl compound catalyst

Abstract

The application belongs to the technical field of catalyst preparation and hydrogen peroxide synthesis, and relates to a preparation method and application of a bimetallic hydroxyl compound catalyst, in particular to a preparation method of a bimetallic hydroxyl compound catalyst and a rare earth doped bimetallic hydroxyl compound catalyst. The bimetallic hydroxyl compound catalyst is obtained through a coprecipitation reaction by taking stannate, zinc salt and rare earth salt as reactants; the molar ratio of tin in the stannate, zinc in the zinc salt and rare earth in the rare earth salt is 1:(0.8-1):(0-0.2). The ZnSn(OH)6 catalyst or the rare earth doped ZnSn(OH)6 catalyst is prepared through one-step coprecipitation under the condition of not adding or adding the rare earth salt and without adding any additive by taking water-soluble zinc salt and stannate as raw materials, the preparation method is simple, a high-pressure closed container such as a hydrothermal kettle and other morphology control agents are not needed, and the performance of the ZnSn(OH)6 catalyst in piezoelectric catalysis synthesis of hydrogen peroxide is improved through rare earth doping.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation and hydrogen peroxide synthesis technology, and more specifically relates to a method for preparing and applying a bimetallic hydroxyl compound catalyst. Background Technology

[0002] Wind and water energy are readily available and simple forms of mechanical energy in nature. Piezoelectric semiconductors can convert mechanical energy into chemical energy. Specifically, when a piezoelectric semiconductor is deformed under the action of external force (mechanical energy), the polarization electric field generated inside the semiconductor material by this deformation can cause the energy band to tilt, suppress the recombination of charge carriers, and promote the participation of charge carriers in redox reactions.

[0003] Common piezoelectric semiconductors include zinc oxide (ZnO), barium titanate (BaTiO3), sodium niobate (NaNbO3), and molybdenum disulfide (MoS2). Piezoelectric semiconductors hold promise for applications in energy harvesting, dye degradation, carbon dioxide reduction, hydrogen production, and hydrogen peroxide synthesis.

[0004] Hydrogen peroxide is a green oxidant widely used in various industrial production, environmental remediation, food industry, and biomedical fields. Currently, hydrogen peroxide is mainly produced through the anthraquinone process, but the traditional anthraquinone process has drawbacks such as high energy consumption and the emission of large amounts of toxic byproducts. Therefore, the search for a low-energy-consumption and environmentally friendly method for preparing hydrogen peroxide has attracted widespread attention. Photocatalytic synthesis of hydrogen peroxide is a green and environmentally friendly method, but this synthesis method is affected by external light conditions. Unlike photocatalytic synthesis, piezoelectric catalysis is not time-limited and can synthesize hydrogen peroxide under light-free conditions using ultrasound, ball milling, or natural vibrations. It has been found that compounds such as ZnO, ZnS, and BiOCl can synthesize hydrogen peroxide under ultrasonic excitation.

[0005] Bimetallic hydroxystannates possess advantages such as high electrical conductivity, high electron mobility, high chemical stability, high thermal stability, and good gas sensitivity, showing potential applications in optics, electronics, magnetism, and catalysis. Hydroxystannates exhibit significant photocatalytic properties, demonstrating application value in hydrogen production, carbon dioxide reduction, wastewater treatment, and air purification. Currently, bimetallic hydroxystannates are typically synthesized using hydrothermal and co-precipitation methods involving tin chloride, soluble zinc salts with pH adjustment, or soluble stannates, zinc salts with pH adjustment. These methods can control the morphology of the catalyst, generating different active sites and thus improving catalytic activity. However, hydrothermal synthesis requires high-temperature, high-pressure reaction vessels and organic morphology control agents. According to existing literature, ion-doped bimetallic hydroxystannate zinc is usually synthesized via a one-step hydrothermal method or a combination of co-precipitation and hydrothermal methods, which involve demanding process conditions. Currently, there are already reports on S... 2- Ag + Al 3+ Bi 3+ While plasma-induced hydrothermal doping of bimetallic stannates has been reported, no studies on the preparation of rare-earth ion-doped bimetallic stannates have been found, and there are no reports on the piezoelectric catalytic synthesis of hydrogen peroxide using bimetallic stannates. Therefore, finding a simple and feasible synthesis method is of great significance for the application of stannates. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing bimetallic hydroxyl compound catalysts and their applications. More specifically, this invention provides a method for preparing bimetallic hydroxyl compound catalysts and rare earth-doped bimetallic hydroxyl compound catalysts to solve the problem of harsh preparation conditions in the prior art and to simplify the preparation method of bimetallic hydroxyl compounds.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] One of the technical solutions of this invention: provides a method for preparing a bimetallic hydroxyl compound catalyst, comprising the following steps:

[0009] The bimetallic hydroxyl compound catalyst was obtained by co-precipitation reaction using stannate, zinc salt and rare earth salt as reactants.

[0010] The molar ratio of tin in the stannate, zinc in the zinc salt, and rare earth in the rare earth salt is 1:(0.8-1):(0-0.2).

[0011] When the amount of rare earth salt is 0, a bimetallic hydroxyl compound catalyst is obtained; when the amount of rare earth salt is not 0, a rare earth-doped bimetallic hydroxyl compound catalyst is obtained.

[0012] Furthermore, the stannate includes sodium stannate trihydrate (Na2SnO3·3H2O) and / or potassium stannate trihydrate (K2SnO3·3H2O).

[0013] Furthermore, the zinc salt includes at least one of zinc nitrate hexahydrate (Zn(NO3)2·6H2O), anhydrous zinc acetate (C4H6O4Zn), zinc chloride (ZnCl2), and zinc sulfate monohydrate (ZnSO4·H2O).

[0014] Furthermore, the rare earth salts include lanthanum salts and / or samarium salts.

[0015] Optionally, the lanthanum salt is lanthanum nitrate (La(NO3)3) and / or lanthanum chloride (LaCl3).

[0016] Optionally, the samarium salt is samarium nitrate (Sm(NO3)3) and / or samarium chloride (SmCl3).

[0017] Furthermore, the coprecipitation reaction is carried out at a temperature of 30-70°C for 3-5 hours.

[0018] Furthermore, in the reaction system of the coprecipitation reaction, the concentration of stannate is 0.05 mol / L, the concentration of zinc salt is 0.04-0.05 mol / L, and the concentration of rare earth salt is 0-0.01 mol / L.

[0019] In the preparation method of this invention, specific process parameters for the coprecipitation reaction are defined. When the reaction temperature is too high (above 70°C), the entropy value increases, and the system tends to be in a more symmetric phase, thus weakening the piezoelectric effect. When the reaction temperature is too low (below 30°C), the reaction kinetics performance decreases. 3+ or Sm 3+ Difficulty in incorporating into the ZHSO lattice leads to low doping efficiency; too short a reaction time results in incomplete reactions, producing undesirable products, while too long a reaction time leads to the formation of unwanted products such as La(OH)3; the concentration of each raw material in the reaction system also affects the performance of the resulting catalyst. Specifically, excessively high concentrations lead to an increase in the concentration of Zn(OH)3 ions in the solution. 2+ Sn 4 + OH - Rapid precipitation and irreversible aggregation of La 3+ or Sm 3+ Excessively high local concentrations can disrupt the charge balance of ZHS, leading to phase separation (such as the precipitation of La(OH)3). Conversely, excessively low concentrations can cause La to... 3+ or Sm 3+Insufficient doping and low defect density reduce the carrier separation rate and catalytic performance.

[0020] The second technical solution of the present invention provides a bimetallic hydroxyl compound catalyst prepared by the above preparation method.

[0021] The third technical solution of the present invention provides an application of the above-mentioned bimetallic hydroxyl compound catalyst in the preparation of hydrogen peroxide.

[0022] Furthermore, the application involves mixing the bimetallic hydroxyl compound catalyst with water, followed by a dark reaction and ultrasonic excitation to induce the synthesis of hydrogen peroxide.

[0023] The dark reaction is to allow the catalyst to be more fully adsorbed with air or water molecules, thereby obtaining better catalytic performance. The ultrasonic excitation after the dark reaction is to provide energy for the reaction, thereby initiating the catalytic reaction.

[0024] Optionally, the dark reaction is performed by allowing the mixture to stand in the dark for 30-60 minutes.

[0025] Optionally, the ultrasonic power is 100-300W, the frequency is 40kHz, and the duration is 60-120min.

[0026] The principle of piezoelectric catalytic synthesis of hydrogen peroxide includes oxygen reduction reaction and water oxidation reaction. The specific mechanism of this reaction is as follows:

[0027] Oxygen reduction phase:

[0028] O2+e - →·O2 - ;

[0029] ·O2 - +e - +2H + →H2O2;

[0030] Water oxidation stage:

[0031] 2H2O+4h + →O2+4H + ;

[0032] Water oxidation provides oxygen and hydrogen ions, which further promote the reaction.

[0033] Fourth technical solution of the present invention: A method for improving the piezoelectric catalytic synthesis of hydrogen peroxide using ZnSn(OH)6 catalyst, comprising the following steps:

[0034] A rare earth-doped ZnSn(OH)6 catalyst was obtained by co-precipitation reaction using stannate, zinc salt and rare earth salt as reactants.

[0035] The molar ratio of tin in the stannate, zinc in the zinc salt, and rare earth in the rare earth salt is 1:(0.8-1):(0-0.2), wherein the amount of rare earth salt is not zero.

[0036] Furthermore, the stannate includes sodium stannate trihydrate (Na2SnO3·3H2O) and / or potassium stannate trihydrate (K2SnO3·3H2O).

[0037] Furthermore, the zinc salt includes at least one of zinc nitrate hexahydrate (Zn(NO3)2·6H2O), anhydrous zinc acetate (C4H6O4Zn), zinc chloride (ZnCl2), and zinc sulfate monohydrate (ZnSO4·H2O).

[0038] Furthermore, the rare earth salts include lanthanum salts and / or samarium salts.

[0039] Optionally, the lanthanum salt is lanthanum nitrate (La(NO3)3) and / or lanthanum chloride (LaCl3).

[0040] Optionally, the samarium salt is samarium nitrate (Sm(NO3)3) and / or samarium chloride (SmCl3).

[0041] Furthermore, the coprecipitation reaction is carried out at a temperature of 30-70°C for 3-5 hours.

[0042] The present invention discloses the following technical effects:

[0043] This invention uses water-soluble zinc salts and stannates as raw materials to prepare ZnSn(OH)6 catalyst or rare earth-doped ZnSn(OH)6 catalyst through one-step co-precipitation without adding rare earth salts or any additives. The preparation method is simple, does not require the use of high-pressure sealed containers such as hydrothermal reactors or other morphology control agents, and improves the piezoelectric catalytic performance of ZnSn(OH)6 catalyst in the synthesis of hydrogen peroxide through rare earth doping.

[0044] The one-step co-precipitation preparation method of rare earth-doped ZnSn(OH)6 catalyst mentioned in this invention is simple. Furthermore, the piezoelectric catalytic performance of the rare earth-doped ZnSn(OH)6 catalyst in synthesizing hydrogen peroxide is significantly improved compared to pure ZnSn(OH)6. The catalyst is dispersed in a pure water system, and hydrogen peroxide is efficiently synthesized using pure water as a raw material under ultrasonic excitation. Attached Figure Description

[0045] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0046] Figure 1The XRD patterns are of the catalysts prepared in Examples 1-5.

[0047] Figure 2 The images show SEM images of the catalysts prepared in Examples 1-5, where (a) is Example 1, (b) is Example 2, (c) is Example 3, (d) is Example 4, and (e) is Example 5.

[0048] Figure 3 XPS images of the catalysts prepared in Examples 1 and 4.

[0049] Figure 4 The graph shows the yield of H2O2 synthesized by the catalysts prepared in Examples 1-5.

[0050] Figure 5 The diagram shows the cyclic performance of the catalyst prepared in Example 4 for the catalytic synthesis of H2O2.

[0051] Figure 6 The yield diagram shows the synthesis of H2O2 using different materials as catalysts.

[0052] Figure 7 This is the standard curve for hydrogen peroxide. Detailed Implementation

[0053] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0054] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0055] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0056] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0057] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0058] Piezoelectric catalysis is a catalytic technology based on the piezoelectric effect that directly converts mechanical energy (ultrasound, fluid impact, etc.) into chemical energy. An ultrasonic cleaner provides the energy source, and under the action of ultrasound, the ZnSn(OH)6 material undergoes carrier separation, thereby realizing the catalytic synthesis of hydrogen peroxide.

[0059] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0060] The raw materials and reagents used in the specific embodiments of this invention are all commercially available products. Since La 3+ or Sm 3+ Having similar electronic structures, La is used in the specific embodiments of this invention. 3+ An example is provided.

[0061] hydrogen peroxide standard curve as follows Figure 7 As shown.

[0062] Example 1

[0063] The preparation steps of ZnSn(OH)6 catalyst include:

[0064] S1. Dissolve 1 mmol of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) in 10 mL of deionized water and stir thoroughly to obtain a zinc nitrate solution.

[0065] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0066] S3. Mix the zinc nitrate solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0067] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0068] S5. Wash the solid product from step S4 three times with water and dry it in a drying oven at 60°C to obtain the ZnSn(OH)6 catalyst, denoted as ZHS.

[0069] 25 mg of the ZHS catalyst prepared in Example 1 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 minutes. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 minutes, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 145.97 μmol / L.

[0070] Example 2

[0071] The preparation steps of the 0.05La-ZnSn(OH)6 catalyst include:

[0072] S1. Dissolve 0.95 mmol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.05 mmol lanthanum nitrate (La(NO3)3) in 10 mL of deionized water and stir thoroughly to obtain a zinc nitrate-lanthanum nitrate solution.

[0073] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0074] S3. Mix the zinc nitrate-lanthanum nitrate solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0075] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0076] S5. Wash the solid product from step S4 with water three times and dry it in a drying oven at 60°C to obtain 0.05La-ZnSn(OH)6 catalyst, denoted as 0.05La-ZHS.

[0077] 25 mg of the 0.05La-ZHS catalyst prepared in Example 2 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 min. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 min. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 min, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 197.96 μmol / L.

[0078] Example 3

[0079] The preparation steps of the 0.1La-ZnSn(OH)6 catalyst include:

[0080] S1. Dissolve 0.9 mmol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.1 mmol lanthanum nitrate (La(NO3)3) in 10 mL of deionized water and stir thoroughly to obtain a zinc nitrate-lanthanum nitrate solution.

[0081] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0082] S3. Mix the zinc nitrate-lanthanum nitrate solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0083] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0084] S5. Wash the solid product from step S4 with water three times and dry it in a drying oven at 60°C to obtain 0.1La-ZnSn(OH)6 catalyst, denoted as 0.1La-ZHS.

[0085] 25 mg of the 0.1 La-ZHS catalyst prepared in Example 3 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 minutes. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 minutes, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 251.64 μmol / L.

[0086] Example 4

[0087] The preparation steps of the 0.15La-ZnSn(OH)6 catalyst include:

[0088] S1. Dissolve 0.85 mmol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.15 mmol lanthanum nitrate (La(NO3)3) in 10 mL of deionized water and stir thoroughly to obtain a zinc nitrate-lanthanum nitrate solution.

[0089] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0090] S3. Mix the zinc nitrate-lanthanum nitrate solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0091] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0092] S5. Wash the solid product from step S4 with water three times and dry it in a drying oven at 60°C to obtain a 0.15La-ZnSn(OH)6 catalyst, denoted as 0.15La-ZHS-1.

[0093] 25 mg of the 0.15La-ZHS-1 catalyst prepared in Example 4 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 min. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 min, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 295.12 μmol / L.

[0094] Example 5

[0095] The preparation steps of the 0.2La-ZnSn(OH)6 catalyst include:

[0096] S1. Dissolve 0.8 mmol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.2 mmol lanthanum nitrate (La(NO3)3) in 10 mL of deionized water and stir thoroughly to obtain a zinc nitrate-lanthanum nitrate solution.

[0097] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0098] S3. Mix the zinc nitrate-lanthanum nitrate solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0099] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0100] S5. Wash the solid product from step S4 with water three times and dry it in a drying oven at 60°C to obtain the 0.2La-ZnSn(OH)6 catalyst, denoted as 0.2La-ZHS.

[0101] 25 mg of the 0.2La-ZHS catalyst prepared in Example 5 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 minutes. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 minutes, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 263.93 μmol / L.

[0102] Example 6

[0103] The preparation steps of the 0.15La-ZnSn(OH)6 catalyst include:

[0104] S1. Dissolve 0.85 mmol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.15 mmol lanthanum nitrate (La(NO3)3) in 20 mL of deionized water and stir thoroughly to obtain a zinc nitrate-lanthanum nitrate solution.

[0105] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 20 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0106] S3. Mix the zinc nitrate-lanthanum nitrate solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0107] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0108] S5. Wash the solid product from step S4 three times with water and dry it in a drying oven at 60°C to obtain 0.15La-ZnSn(OH)6 catalyst, denoted as 0.15La-ZHS-20L.

[0109] 25 mg of the 0.15La-ZHS-20L catalyst prepared in Example 6 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 minutes. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 minutes, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 262.61 μmol / L.

[0110] Example 7

[0111] The preparation steps of the 0.15La-ZnSn(OH)6 catalyst include:

[0112] S1. Dissolve 0.85 mmol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.15 mmol lanthanum nitrate (La(NO3)3) in 10 mL of deionized water and stir thoroughly to obtain a zinc nitrate-lanthanum nitrate solution.

[0113] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0114] S3. Mix the zinc nitrate-lanthanum nitrate solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0115] S4. Place the mixed suspension from step S3 in a 50°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0116] S5. Wash the solid product from step S4 with water three times and dry it in a drying oven at 60°C to obtain 0.15La-ZnSn(OH)6 catalyst, denoted as 0.15La-ZHS-50.

[0117] 25 mg of the 0.15La-ZHS-50 catalyst prepared in Example 7 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 minutes. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 minutes, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 199.66 μmol / L.

[0118] Example 8

[0119] The preparation steps of the 0.15La-ZnSn(OH)6 catalyst include:

[0120] S1. Dissolve 0.85 mmol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.15 mmol lanthanum nitrate (La(NO3)3) in 10 mL of deionized water and stir thoroughly to obtain a zinc nitrate-lanthanum nitrate solution.

[0121] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0122] S3. Mix the zinc nitrate-lanthanum nitrate solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0123] S4. Place the mixed suspension from step S3 in a 70°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0124] S5. Wash the solid product from step S4 with water three times and dry it in a drying oven at 60°C to obtain 0.15La-ZnSn(OH)6 catalyst, denoted as 0.15La-ZHS-70.

[0125] 25 mg of the 0.15La-ZHS-70 catalyst prepared in Example 8 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 minutes. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 minutes, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 101.74 μmol / L.

[0126] Example 9

[0127] The preparation steps of the 0.15La-ZnSn(OH)6 catalyst include:

[0128] S1. Dissolve 0.85 mmol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.15 mmol lanthanum nitrate (La(NO3)3) in 10 mL of deionized water and stir thoroughly to obtain a zinc nitrate-lanthanum nitrate solution.

[0129] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0130] S3. Mix the zinc nitrate-lanthanum nitrate solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0131] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 5 hours, then centrifuge (8000 rpm) to collect the solid product.

[0132] S5. Wash the solid product from step S4 three times with water and dry it in a drying oven at 60°C to obtain 0.15La-ZnSn(OH)6 catalyst, denoted as 0.15La-ZHS-5H.

[0133] 25 mg of the 0.15La-ZHS-5H catalyst prepared in Example 9 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 minutes. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 minutes, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 278.30 μmol / L.

[0134] Example 10

[0135] The preparation steps of the 0.15La-ZnSn(OH)6 catalyst include:

[0136] S1. Dissolve 0.85 mmol of anhydrous zinc acetate (C4H6O4Zn) and 0.15 mmol of lanthanum nitrate (La(NO3)3) in 10 mL of deionized water and stir thoroughly to obtain a zinc acetate-lanthanum nitrate solution.

[0137] S2. Dissolve 1 mmol of potassium stannate trihydrate (K2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a potassium stannate solution.

[0138] S3. Mix the zinc acetate-lanthanum nitrate solution from step S1 and the potassium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0139] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0140] S5. Wash the solid product from step S4 three times with water and dry it in a drying oven at 60°C to obtain a 0.15La-ZnSn(OH)6 catalyst, denoted as 0.15La-ZHS-2.

[0141] 25 mg of the 0.15La-ZHS-2 catalyst prepared in Example 10 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 s and reacted in the dark for 60 min. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 min. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 min, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 276.60 μmol / L.

[0142] Example 11

[0143] The preparation steps of the 0.15La-ZnSn(OH)6 catalyst include:

[0144] S1. Dissolve 0.85 mmol zinc chloride (ZnCl2) and 0.15 mmol lanthanum chloride (LaCl3) in 10 mL of deionized water and stir thoroughly to obtain a zinc chloride-lanthanum chloride solution.

[0145] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0146] S3. Mix the zinc chloride-lanthanum chloride solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0147] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0148] S5. Wash the solid product from step S4 with water three times and dry it in a drying oven at 60°C to obtain a 0.15La-ZnSn(OH)6 catalyst, denoted as 0.15La-ZHS-3.

[0149] 25 mg of the 0.15La-ZHS-3 catalyst prepared in Example 11 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 minutes. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 minutes, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 280.38 μmol / L.

[0150] Example 12

[0151] The preparation steps of the 0.15La-ZnSn(OH)6 catalyst include:

[0152] S1. Dissolve 0.85 mmol zinc sulfate monohydrate (ZnSO4·H2O) and 0.15 mmol lanthanum nitrate (La(NO3)3) in 10 mL of deionized water and stir thoroughly to obtain a zinc sulfate-lanthanum nitrate solution.

[0153] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0154] S3. Mix the zinc sulfate-lanthanum nitrate solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0155] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0156] S5. Wash the solid product from step S4 three times with water and dry it in a drying oven at 60°C to obtain a 0.15La-ZnSn(OH)6 catalyst, denoted as 0.15La-ZHS-4.

[0157] 25 mg of the 0.15La-ZHS-4 catalyst prepared in Example 12 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 minutes. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 80 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 minutes, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 297.20 μmol / L.

[0158] Example 13

[0159] The preparation steps of the 0.15La-ZnSn(OH)6 catalyst include:

[0160] S1. Dissolve 0.85 mmol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.15 mmol lanthanum chloride (LaCl3) in 10 mL of deionized water and stir thoroughly to obtain a zinc nitrate-lanthanum chloride solution.

[0161] S2. Dissolve 1 mmol of potassium stannate trihydrate (K2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a potassium stannate solution.

[0162] S3. Mix the zinc nitrate-lanthanum chloride solution from step S1 and the potassium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0163] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0164] S5. Wash the solid product from step S4 with water three times and dry it in a drying oven at 60°C to obtain the 0.15La-ZnSn(OH)6 catalyst, denoted as 0.15La-ZHS-5.

[0165] 25 mg of the 0.15La-ZHS-5 catalyst prepared in Example 13 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 minutes. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 60 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 minutes, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 262.61 μmol / L.

[0166] Example 14

[0167] The preparation steps of the 0.15La-ZnSn(OH)6 catalyst include:

[0168] S1. Dissolve 0.85 mmol zinc sulfate monohydrate (ZnSO4·H2O) and 0.15 mmol lanthanum nitrate (La(NO3)3) in 10 mL of deionized water and stir thoroughly to obtain a zinc sulfate-lanthanum nitrate solution.

[0169] S2. Dissolve 1 mmol of sodium stannate trihydrate (Na2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a sodium stannate solution.

[0170] S3. Mix the zinc sulfate-lanthanum nitrate solution from step S1 and the sodium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0171] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0172] S5. Wash the solid product from step S4 with water three times and dry it in a drying oven at 60°C to obtain the 0.15La-ZnSn(OH)6 catalyst, denoted as 0.15La-ZHS-6.

[0173] 25 mg of the 0.15La-ZHS-6 catalyst prepared in Example 14 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 minutes. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 100 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 minutes, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 260.72 μmol / L.

[0174] Example 15

[0175] The preparation steps of the 0.15La-ZnSn(OH)6 catalyst include:

[0176] S1. Dissolve 0.85 mmol of anhydrous zinc acetate (C4H6O4Zn) and 0.15 mmol of lanthanum chloride (LaCl3) in 10 mL of deionized water and stir thoroughly to obtain a zinc acetate-lanthanum chloride solution.

[0177] S2. Dissolve 1 mmol of potassium stannate trihydrate (K2SnO3·3H2O) in 10 mL of deionized water and stir thoroughly to obtain a potassium stannate solution.

[0178] S3. Mix the zinc acetate-lanthanum chloride solution from step S1 and the potassium stannate solution from step S2, and stir for 5 minutes to form a uniform mixed suspension.

[0179] S4. Place the mixed suspension from step S3 in a 30°C water bath and stir for 3 hours, then centrifuge (8000 rpm) to collect the solid product.

[0180] S5. Wash the solid product from step S4 with water three times and dry it in a drying oven at 60°C to obtain 0.15La-ZnSn(OH)6 catalyst, denoted as 0.15La-ZHS-7.

[0181] 25 mg of the 0.15La-ZHS-7 catalyst prepared in Example 14 was weighed and placed in 100 mL of deionized water. It was dispersed by sonication for 3 seconds and reacted in the dark for 30 min. Then, it was reacted in a 300 W, 40 kHz digital ultrasonic cleaner for 120 minutes. After the reaction was completed, 4 mL of sample was taken. 0.5 mL of potassium iodide with a concentration of 0.4 mol / L and 0.5 mL of potassium hydrogen phthalate with a concentration of 0.1 mol / L were added to the sample solution. After standing in the dark for 30 min, the absorbance was measured at a wavelength of 350 nm. The concentration of hydrogen peroxide in the sample solution was found to be 277.35 μmol / L.

[0182] Test case

[0183] Figure 1 The XRD patterns of the catalysts prepared in Examples 1-5 are shown. As can be seen from the figures, the ZHS prepared in Example 1 and the La-doped ZHS prepared in Examples 2-5 are consistent with ZHS JCPDS card 73-2384. Since the ionic radius of La is larger than that of Zn, La doping into the ZHS lattice and substituting Zn leads to lattice expansion, an increase in the lattice constant, and a shift of the peak value to a lower angle.

[0184] Figure 2 The images show SEM images of the catalysts prepared in Examples 1-5, where (a) is Example 1, (b) is Example 2, (c) is Example 3, (d) is Example 4, and (e) is Example 5. As can be seen from the images, undoped La ZHS consisted of irregular spherical nanoparticles with a particle size of approximately 87 nm. After La doping, the ZHS transformed from irregular spherical nanoparticles into cubic nanocubes, and with increasing La doping concentration, the particle size increased, and the surface became increasingly rough.

[0185] Figure 3 XPS plots of the catalysts prepared in Examples 1 and 4 are shown. As can be seen from the plots, a 3d peak for La appears at 830-860 eV, further confirming the successful incorporation of La into ZHS.

[0186] The catalysts prepared in Examples 1-5 were weighed and subjected to piezoelectric catalytic synthesis of hydrogen peroxide performance tests. The specific steps are as follows: 25 mg of catalyst was placed in 100 mL of deionized water, ultrasonically dispersed for 3 s, reacted in the dark for 30 min, and then reacted in a 300 W, 40 kHz digitally controlled ultrasonic cleaner for 120 min. After the reaction was completed, 4 mL of sample was taken, and 0.5 mL of 0.4 mol / L potassium iodide and 0.5 mL of 0.1 mol / L potassium hydrogen phthalate were added to the sample solution. After standing in the dark for 30 min, the absorbance was measured at a wavelength of 350 nm to obtain the corresponding performance.

[0187] Figure 4 The graph shows the yield of H2O2 synthesized by the catalysts prepared in Examples 1-5. As can be seen from the graph, the yield of H2O2 synthesized by ZHS catalysis can reach 583.89 μmol / g / h; the catalytic performance gradually improves with the increase of La doping amount, and the performance of 0.15La-ZHS (0.15La-ZHS-1) is the best.

[0188] The catalyst prepared in Example 4 was weighed and subjected to a piezoelectric catalytic synthesis of hydrogen peroxide using a 0.15La-ZHS catalyst. The catalyst was collected, centrifuged, washed, and dried to obtain recycled powder. The recycled 0.15La-ZHS catalyst was then used in the next reaction, and this process was repeated five times to obtain the performance of each cycle.

[0189] Figure 5 The figure shows the cyclic performance of the catalyst prepared in Example 4 for the catalytic synthesis of H2O2. As can be seen from the figure, after five cycles, the catalytic performance for hydrogen peroxide synthesis remains at 92.2% of its original value, demonstrating the stability of the material's catalytic performance.

[0190] Figure 6 The figure shows the yield of H2O2 synthesized by different materials as catalysts. As can be seen from the figure, with the optimized doping amount (0.15La-ZSH-1), the yield of hydrogen peroxide is as high as 1180 μmol / g / h, which is significantly higher than the yield of H2O2 under piezoelectric catalysis of materials such as BiOCl (560 μmol / g / h), C-ZnO (588 μmol / g / h), and NiFe2O4 (912 μmol / g / h).

[0191] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0192] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. Use of a double metal hydroxide catalyst for the production of hydrogen peroxide, characterized in that, The application is mixing the bimetallic hydroxyl compound catalyst with water, inducing synthesis of hydrogen peroxide through ultrasonic excitation after dark reaction; The step of the bimetallic hydroxyl compound catalyst comprises: The bimetallic hydroxyl compound catalyst is obtained through co-precipitation reaction by taking stannate, zinc salt and rare earth salt as reactants; The molar ratio of tin element in the stannate, zinc element in the zinc salt and rare earth element in the rare earth salt is 1:(0.8-1):(0-0.2); The stannate comprises sodium stannate trihydrate and / or potassium stannate trihydrate; The zinc salt comprises at least one of zinc nitrate hexahydrate, zinc acetate anhydrous, zinc chloride and zinc sulfate monohydrate; The rare earth salt is lanthanum salt and / or samarium salt; The temperature of the co-precipitation reaction is 30-70℃, and the time is 3-5h; and / or, the concentration of the stannate in the reaction system of the co-precipitation reaction is 0.05 mol / L, the concentration of the zinc salt is 0.04-0.05 mol / L, and the concentration of the rare earth salt is 0-0.01 mol / L.

2. Use according to claim 1, wherein The dark reaction is standing in dark for 30-60min; and / or, the power of the ultrasonic is 100-300W, the frequency is 40kHz, and the time is 60-120min.

3. A method for improving the performance of ZnSn(OH)6 catalyst for piezoelectric catalytic synthesis of hydrogen peroxide, characterized by the steps of Comprise: The rare earth doped ZnSn(OH)6 catalyst is obtained through co-precipitation reaction by taking stannate, zinc salt and rare earth salt as reactants; The molar ratio of tin element in the stannate, zinc element in the zinc salt and rare earth element in the rare earth salt is 1:(0.8-1):(0-0.2), wherein, the amount of the rare earth salt is not 0; The rare earth salt comprises lanthanum salt and / or samarium salt.

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