Efficient and stable ozone normal-temperature decomposition copper oxide catalyst and preparation method thereof

Abstract

The invention discloses an efficient and stable ozone normal temperature decomposition copper oxide catalyst and a preparation method thereof, and belongs to the technical field of catalyst preparation and environmental protection, the preparation method of the copper oxide catalyst comprises the following steps: (1) adding a copper salt into an alcohol solvent, and stirring until the copper salt is completely dissolved to obtain a precursor solution; (2) dropwise adding the precursor solution into a stirred strong alkali solution, and completely dropwise adding to obtain black slurry; and (3) directly carrying out aging treatment on the black slurry, or continuously stirring the black slurry and then carrying out aging treatment, then carrying out suction filtration, washing for several times, and drying to obtain the efficient and stable ozone normal-temperature decomposition copper oxide catalyst. According to the method, raw materials are easy to obtain, preparation conditions are mild, large-scale preparation is easy, and the prepared copper oxide catalyst is good in environmental adaptability, capable of rapidly achieving high-humidity and high-airspeed ozone decomposition, high in activity, stable and good in reusability.

Description

Technical Field

[0001] The invention relates to the technical field of catalyst preparation and environmental protection, and in particular to a highly efficient and stable ozone room-temperature decomposition copper oxide catalyst and a preparation method thereof. Background Art

[0002] Ozone in the stratosphere protects life on Earth from strong ultraviolet radiation, but excessive ozone concentration near the ground will cause ozone pollution. Ozone pollution has obvious seasonality, mainly concentrated in late spring, summer and early autumn. Ozone pollution can cause harm to the ecosystem and environment and affect human health, such as damaging the skin barrier function and inducing respiratory, cardiovascular and immune system diseases. In daily production and life, ozone is widely used in water treatment, chemical oxidation, food processing and preservation, and medical technology due to its strong oxidizing properties. It is an effective means to achieve the purposes of sterilization, removal of pollutants, decolorization, and preservation. Therefore, the application and development of ozone control technology is becoming increasingly important.

[0003] At present, the main ozone control technologies include thermal decomposition, catalytic decomposition, activated carbon adsorption, and liquid absorption. Among them, the catalytic decomposition method has the characteristics of low energy consumption, good safety, rapid reaction, high treatment efficiency, and less secondary pollution. It is the most advantageous ozone control technology. The core of the catalytic decomposition method lies in the catalyst, and an efficient catalyst is the key to achieving efficient ozone control. Precious metal catalysts have high activity, but their high price is not conducive to widespread use. Therefore, it is necessary to innovate and optimize the catalyst in order to promote the further development of ozone control technology.

[0004] Copper oxide is a cheap and readily available catalytic material with broad application prospects in the fields of energy, environment and chemical synthesis due to its unique physical and chemical properties. However, in the field of catalytic ozone decomposition, most of the catalysts currently developed are manganese oxides. Based on the test results of different metal oxides catalytic decomposition of ozone reported by Dhandapani and Oyama (B. Dhandapani, STOyama, Gas phase ozone decomposition catalysts, Applied Catalysis B: Environmental, Volume 11, Issue 2, 1997, Pages 129-166): MnO2 (42%) > Co3O4 (39%) > NiO (35%) > Fe2O3 (24%) > Ag2O (21%) > Cr2O3 (18%) > CeO2 (11%) > MgO (8%) > V2O5 (8%) > CuO (5%). Researchers prefer to research and develop manganese oxides. Copper oxide has long been considered an ideal catalytic ozone decomposition material. It is mostly used as a doping component to improve the activity and stability of manganese oxides. For example, the Chinese patent document with publication number CN112473728A discloses a highly efficient moisture-resistant ozone decomposition catalyst with a separation The active components of the medium-temperature hydrophobic ozone decomposition catalyst in the Chinese patent document with publication number CN109012690A are mainly composed of manganese and copper oxides; the high-efficiency moisture-resistant ozone decomposition catalyst in the Chinese patent document with publication number CN106824218A uses manganese, copper, nickel and cobalt oxides as active components; the manganese-based composite oxide catalyst for catalytic decomposition of ozone in the Chinese patent document with publication number CN102600861A includes manganese oxide and at least one transition metal oxide (which can be selected from CuO x ).

[0005] Furthermore, a Chinese patent document with publication number CN107983348A discloses a highly efficient ozone decomposition catalyst, the main active ingredient of which is cuprous oxide, which is obtained by reducing a copper salt aqueous solution in an alkaline environment using a reducing agent such as ascorbic acid and formaldehyde. The cuprous oxide ozone decomposition catalyst can completely decompose hundreds of ppm of ozone at room temperature or even at zero degrees. However, formaldehyde is highly toxic, and an alkaline environment requires a high concentration of alkaline environment, which is a relatively harsh condition.

[0006] In summary, in order to enrich the types of catalysts for room-temperature ozone decomposition, promote the development of ozone control technology, improve the quality of the atmospheric environment, and protect human health, it is necessary to explore and innovate copper oxide catalysts. Summary of the invention

[0007] In order to solve the shortcomings of the prior art, the present invention provides a method for preparing an efficient and stable ozone decomposition copper oxide catalyst at room temperature. The raw materials are easy to obtain, the preparation conditions are mild, and it is easy to prepare on a large scale. The prepared copper oxide catalyst has good environmental adaptability, can quickly realize the decomposition of high-humidity and high-space-velocity ozone, and is highly active and stable.

[0008] The specific technical solutions adopted are as follows:

[0009] The present invention provides a method for preparing an efficient and stable catalyst for decomposing copper oxide by ozone at room temperature, comprising the following steps:

[0010] (1) adding copper salt to an alcohol solvent and stirring until the copper salt is completely dissolved to obtain a precursor solution;

[0011] (2) dripping the precursor solution obtained in step (1) into the stirred strong alkaline solution drop by drop, and obtaining a black slurry after all the precursor solution is dripped in;

[0012] (3) directly subjecting the black slurry obtained in step (2) to an aging treatment, or continuing to stir the black slurry obtained in step (2) and then subjecting it to an aging treatment, followed by suction filtration, washing several times, and drying to obtain the highly efficient and stable ozone decomposition copper oxide catalyst at room temperature.

[0013] The present invention uses alcohol solvents to dissolve copper salts, and its purpose is to induce the formation of stable and efficient active structures, and the effects are as follows: ① alcohol and copper ions can form complexes, and copper is regularly complexed and distributed in the skeleton with high dispersion; ② the surface tension of alcohol is low, and when the precursor solution is added to the strong alkali solution, the surface tension of the strong alkali solution can be significantly reduced. Under this change, the reaction product of the precursor substance and the strong alkali is rapidly nucleated, and under the wrapping effect of the alcohol, the copper oxide generated during the aging process can be prevented from agglomerating, thereby exposing more active sites; ③ during the aging process, the alcohol will be oxidized, causing the copper oxide to be hydroxylated, thereby forming more active sites on the surface of the copper oxide. It is precisely because of these specific effects that a stable, efficient and stable ozone room temperature decomposition copper oxide catalyst can be finally regulated.

[0014] Preferably, the copper salt is selected from inorganic or organic copper salts such as copper sulfate, copper nitrate, copper chloride or copper acetate; and the alcohol solvent is ethanol, ethylene glycol or propanol.

[0015] Further preferably, in the precursor solution, the ratio of the copper salt to the alcohol solvent is 1 mmol:1-10 mL, calculated on the molar number of the copper element.

[0016] Optionally, the strong base is sodium hydroxide, potassium hydroxide or lithium hydroxide, and the concentration of the strong base solution is 1 to 10 mmol / mL.

[0017] Preferably, the molar ratio of the copper salt to the strong base is 1:1-20.

[0018] Further preferably, in step (2), the dropping speed is 0.1-1 mL / min, the stirring temperature is room temperature, and the rotation speed is 100-1000 rpm. If the dropping speed is too fast, the local concentration will be too high, affecting the uniform dispersion of the active component formed, and the rapid precipitation will cause the particles to grow and agglomerate, and the specific surface area will be reduced, affecting the activity; if the dropping speed is too slow, the concentration of the reactants will be too low, affecting the formation of the active structure, and the dropping time will be too long, increasing the complexity of the operation.

[0019] In step (3), stirring is continued for 5 to 30 minutes; the aging treatment parameters are 25 to 100° C., 1 to 12 hours, suction filtration and washing until the filtrate is neutral, and drying to obtain the highly efficient and stable ozone decomposition of copper oxide at room temperature.

[0020] Furthermore, the drying temperature is 25 to 120° C., and the drying time is 1 to 72 hours.

[0021] The present invention also provides a highly efficient and stable catalyst for decomposing copper oxide by ozone at room temperature, which is prepared by the method for preparing the highly efficient and stable catalyst for decomposing copper oxide by ozone at room temperature.

[0022] The present invention also provides an ozone decomposition catalyst at room temperature, comprising a catalyst carrier and the highly efficient and stable ozone decomposition copper oxide catalyst loaded thereon.

[0023] Furthermore, the catalyst carrier is activated carbon, molecular sieve, alumina or cordierite, etc., and the highly efficient and stable ozone decomposition copper oxide catalyst at room temperature is ground into a slurry and coated on the carrier.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The method of the present invention has a simple process, uses a small number of raw materials that are cheap and easily available, and has mild and undemanding preparation conditions, thus being suitable for large-scale industrial production.

[0026] (2) The method of the present invention can obtain a highly efficient and stable ozone decomposition catalyst at room temperature, which is a preparation method that is very consistent with energy conservation and emission reduction.

[0027] (3) The present invention uses the action of alcohol solvents and combines a specific preparation method to obtain a copper oxide catalyst having an active structure that can efficiently and stably catalyze ozone decomposition, and still exhibits excellent catalytic performance under extreme environments of high humidity and high flux. The copper oxide catalyst enriches the application field of copper oxides and provides a new choice for the production industry of ozone decomposition catalysts at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a SEM picture of the highly efficient and stable ozone decomposition copper oxide catalyst at room temperature obtained in Example 1-4.

[0029] Figure 2 It is the XRD diagram of the highly efficient and stable ozone decomposition copper oxide catalyst at room temperature prepared in Example 1-4.

[0030] Figure 3 It is the activity diagram of the highly efficient and stable ozone decomposition copper oxide catalyst at room temperature prepared in Examples 1-4 and the samples of Comparative Examples 1 and 2. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the examples and accompanying drawings. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The operating methods of the following examples that do not specify specific conditions are usually performed under normal conditions or under conditions recommended by the manufacturer. The content that is not described in detail in this specification sheet belongs to the prior art known to professionals in the field. The experimental materials used in the following examples, if not otherwise specified, can be purchased by conventional biochemical reagent companies.

[0032] Example 1

[0033] 1 g of copper sulfate was added to 6.25 ml of ethanol and stirred until the copper sulfate was completely dissolved to obtain a precursor solution; 0.25 g of sodium hydroxide was dissolved in 6.25 ml of deionized water to obtain a strong alkaline solution, and the precursor solution obtained in the above step was dripped dropwise at a rate of 0.1 ml / min into the stirred sodium hydroxide solution (the stirring temperature was room temperature and the rotation speed was 100 rpm) until a black slurry was obtained after all the slurry was dripped in, and the obtained black slurry was directly aged at 25° C. for 12 h, then filtered and washed until the filtrate was neutral, and the obtained solid product was dried at room temperature for 72 h to obtain the said efficient and stable ozone decomposition of copper oxide at room temperature catalyst.

[0034] Example 2

[0035] 1 g of copper nitrate is added to 41.3 ml of ethylene glycol and stirred until the copper nitrate is completely dissolved to obtain a precursor solution; 4.62 g of potassium hydroxide is dissolved in 8.25 ml of deionized water to obtain a strong alkaline solution, and the precursor solution obtained in the above step is dripped dropwise at a rate of 1 ml / min into the stirred potassium hydroxide solution (the stirring temperature is room temperature and the rotation speed is 1000 rpm) until all the precursor solution is dripped in to obtain a black slurry, and the black slurry is stirred for 30 minutes, aged at 100° C. for 1 hour, cooled to room temperature, filtered, washed until the filtrate is neutral, and the obtained solid product is dried at 120° C. for 1 hour to obtain the said efficient and stable ozone decomposition of copper oxide at room temperature catalyst.

[0036] Example 3

[0037] 1 g of copper chloride is added to 10 ml of propanol and stirred until the copper chloride is completely dissolved to obtain a precursor solution; 1.79 g of lithium hydroxide is dissolved in 15 ml of deionized water to obtain a strong alkaline solution, and the precursor solution obtained in the above step is dripped dropwise at a rate of 0.5 ml / min into the stirred (stirring temperature is room temperature, rotation speed is 800 rpm) lithium hydroxide solution until all the solution is dripped in to obtain a black slurry, and the black slurry is stirred for 10 min, aged at 60° C. for 5 h, cooled to room temperature, filtered, washed until the filtrate is neutral, and the obtained solid product is dried at 100° C. for 2 h to obtain the said efficient and stable ozone decomposition of copper oxide at room temperature catalyst.

[0038] Example 4

[0039] 1 g of copper acetate is added to 10 ml of ethanol and stirred until the copper acetate is completely dissolved to obtain a precursor solution; 1.6 g of sodium hydroxide is dissolved in 10 ml of deionized water to obtain a strong alkaline solution, and the precursor solution obtained in the above step is dripped dropwise at a rate of 0.3 ml / min into the stirring (stirring temperature is room temperature, rotation speed is 500 rpm) sodium hydroxide solution until all the precursor solution is dripped into the solution to obtain a black slurry, and the black slurry is stirred for 20 minutes, aged at 25° C. for 2 hours, cooled to room temperature, filtered, washed until the filtrate is neutral, and the obtained solid product is dried at 60° C. for 5 hours to obtain the highly efficient and stable ozone decomposition of copper oxide at room temperature.

[0040] Comparative Example 1

[0041] 1 g of copper acetate was added to 10 ml of deionized water and stirred until the copper acetate was completely dissolved to obtain a precursor solution; 1.6 g of sodium hydroxide was dissolved in 10 ml of deionized water to obtain a strong alkaline solution, and the precursor solution obtained in the previous step was dripped dropwise at a rate of 0.3 ml / min into the stirred sodium hydroxide solution (stirring temperature was room temperature and rotation speed was 500 rpm) until all the solution was dripped in to obtain a slurry, and the slurry was stirred for 20 min, aged at 25° C. for 2 h, cooled to room temperature, filtered, washed until the filtrate was neutral, and the obtained solid product was dried at 60° C. for 5 h to obtain a copper oxide material.

[0042] Comparative Example 2

[0043] Commercially available copper oxide (CAS No.: 1317-38-0).

[0044] Sample analysis

[0045] The SEM images of the highly efficient and stable ozone decomposition copper oxide catalysts prepared in Examples 1-4 are as follows: Figure 1 As shown;

[0046] The XRD patterns of the highly efficient and stable ozone decomposition copper oxide catalysts prepared in Examples 1-4 are as follows: Figure 2 As shown, the peaks at diffraction angles of 32.5°, 35.5°, 38.7°, 48.7°, 53.5°, 58.3°, 61.5°, 66.2°, 68.0°, and 75.2° prove that the synthesized copper oxide is tenorite-type CuO.

[0047] The highly efficient and stable ozone decomposition copper oxide catalysts prepared in Examples 1-4 and the copper oxide material obtained in Comparative Example 1 were placed in a fixed bed reactor for activity evaluation. The total flow rate of the simulated gas was 1.2 L / min, 50 ppm O3, relative humidity RH = 70%, the amount of each catalyst was 0.06 g, the reaction space velocity was 1200 L / g / h, the test temperature was 25 ° C, and the reaction temperature was 15 ° C. Figure 3 As shown, after 4 hours of testing, the ozone decomposition rates of the catalyst materials of Examples 1-4 were all above 75%, among which the sample with the highest ozone decomposition rate was the sample of Example 4, which reached 97%; the sample in Example 4 was further tested five times, each time for 12 hours, and the ozone decomposition rate was about 97%, indicating that the catalyst had good stability and reusability (reusability test: each time the test was 12 hours, then stopped for 2 hours and then tested again, and the test was repeated 5 times). The ozone decomposition rate of the sample in Comparative Example 1 was about 20%, and the commercially available copper oxide in Comparative Example 2 could hardly achieve effective catalytic decomposition of ozone.

[0048] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an efficient and stable ozone decomposition copper oxide catalyst at room temperature, characterized in that: The following steps are involved: (1) adding a copper salt to an alcohol solvent and stirring until the copper salt is completely dissolved to obtain a precursor solution; the copper salt includes copper sulfate, copper nitrate, copper chloride or copper acetate; the alcohol solvent is ethanol, ethylene glycol or propanol; (2) dripping the precursor solution obtained in step (1) into the stirred strong alkaline solution drop by drop, and obtaining a black slurry after all the precursor solution is dripped in; (3) directly subjecting the black slurry obtained in step (2) to an aging treatment, or continuing to stir the black slurry obtained in step (2) and then subjecting it to an aging treatment, followed by suction filtration, washing several times, and drying to obtain the highly efficient and stable ozone decomposition copper oxide catalyst at room temperature.

2. The method for preparing a highly efficient and stable ozone decomposition copper oxide catalyst at room temperature according to claim 1, characterized in that: In the precursor solution, the ratio of copper salt to alcohol solvent is 1mmol:1-10mL based on the molar number of copper element.

3. The method for preparing a highly efficient and stable ozone decomposition copper oxide catalyst at room temperature according to claim 1, characterized in that: The strong base is sodium hydroxide, potassium hydroxide or lithium hydroxide, and the concentration of the strong base solution is 1-10 mmol / mL.

4. The method for preparing a highly efficient and stable ozone decomposition copper oxide catalyst at room temperature according to claim 3, characterized in that: The molar ratio of the copper salt to the strong base is 1:1-20.

5. The method for preparing a highly efficient and stable ozone decomposition copper oxide catalyst at room temperature according to claim 1, characterized in that: In step (2), the dropping speed is 0.1-1 mL / min, the stirring temperature is room temperature, and the rotation speed is 100-1000 rpm.

6. The method for preparing a highly efficient and stable ozone decomposition copper oxide catalyst at room temperature according to claim 1, characterized in that: In step (3), stirring is continued for 5 to 30 minutes; the aging treatment parameters are 25 to 100° C., 1 to 12 hours, suction filtration and washing until the filtrate is neutral, and drying to obtain the highly efficient and stable ozone decomposition of copper oxide at room temperature.

7. A highly efficient and stable copper oxide catalyst for decomposing ozone at room temperature obtained according to the method for preparing a highly efficient and stable copper oxide catalyst for decomposing ozone at room temperature according to any one of claims 1 to 6.

8. An ozone decomposition catalyst at room temperature, characterized in that: The invention comprises a catalyst carrier and a catalyst carrier loaded thereon and the highly efficient and stable ozone decomposition copper oxide catalyst at room temperature as described in claim 7.

9. The ozone room temperature decomposition catalyst according to claim 8, characterized in that: The catalyst carrier is activated carbon, molecular sieve, alumina or cordierite.

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