Preparation of CeO2 / Zn-SA and application of CeO2 / Zn-SA in photocatalytic degradation of phenol

Abstract

The invention discloses a preparation method of a monatomic zinc catalyst and application of the monatomic zinc catalyst in photocatalytic degradation of phenol. During preparation, cerium oxide is taken as a carrier, and a metal zinc source is successfully loaded in a monatomic form by adopting a surface oxidation-reduction method. The synthesis method conforms to the green chemistry concept, is pollution-free, simple to operate, low in cost and easy to popularize, and can effectively control the loading capacity of single atoms. The monatomic zinc catalyst disclosed by the invention can be used for photocatalytic degradation of phenol, has high activity, is easy to recover, and has good catalytic activity and long catalytic life.

Description

Technical Field

[0001] The present disclosure belongs to the field of catalytic technology, and particularly relates to a preparation method of a single-atom zinc catalyst and its application in photocatalytic degradation of phenol. Background Art

[0002] The statements herein merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] Dyes and phenolic compounds are the main culprits of water pollution. Phenolic compounds and their derivatives are used as raw materials in various manufacturing industries and the petrochemical industry. Phenols contained in industrial waste are considered a major source of environmental pollution and are known for their low visibility and high stability. Phenolic substances often appear in the emissions of various industries, such as the manufacture of petrochemical products, resins, paper, paint, plastics, wood products, pesticides, insecticides, herbicides, and detergents. All of these are listed as priority pollutants due to their high toxicity and carcinogenic, mutagenic, and teratogenic properties. Long-term exposure to such pollutants can cause irritation to the gastrointestinal and central nervous systems, liver, kidneys, and cardiovascular tissues.

[0004] Among them, phenol, as a carcinogenic compound, poses a high risk to human health even at low concentrations and disrupts the aquatic ecosystem. Therefore, the World Health Organization has set the limit concentration of phenol in drinking water at 1 μg·L -1 . In addition, as a non-biodegradable pollutant, it tends to accumulate in organisms and form different toxic aromatic intermediates, thus becoming a serious threat.

[0005] To achieve effective wastewater treatment, various strategies have been implemented, including adsorption using activated carbon, biological treatment, and solvent extraction. In this process, the most commonly used adsorbent is activated carbon. However, its cost is relatively high, and its regeneration means a loss of adsorption capacity. Biological treatment is also considered more economical. However, this process is ineffective in high-concentration phenol due to the inactivation of microorganisms. The solvent extraction method allows the recovery of phenol from concentrated wastewater. However, it can only barely meet the requirements set by the World Health Organization.

[0006] Therefore, a photocatalytic method has been developed as an alternative method, and it has great promise to use semiconductor materials with the potential to reduce pollutants. Cerium oxide (CeO2) is a semiconductor material that has a wide range of applications in environmental governance and clean energy production, such as in the degradation of organic compounds and hydrogen production.

[0007] The application of the photocatalytic process has been proven to be one of the most effective, simplest, most ecological, most profitable, and most innovative methods for degrading phenolic compounds in water. Among them, single-atom catalysts (SACs) are more efficient and economical catalysts in this process. Summary of the Invention

[0008] The object of the present disclosure is to provide a preparation method of a single-atom zinc catalyst and its application in photocatalytic degradation of phenol. The reaction has mild reaction conditions, the catalyst is easy to separate, can be recycled, and has excellent cycle stability.

[0009] The technical solution adopted by the present disclosure to solve the above problems is as follows: A preparation method of a single-atom zinc catalyst for photocatalytic degradation of phenol, comprising the following steps:

[0010] 1) Disperse the cerium oxide support in deionized water to form a mixed solution, and then add a zinc source to the mixed solution to react the Ce on the surface of CeO2 with the zinc source. 4+ with the zinc source.

[0011] 2) After reacting for a period of time, separate the metal zinc source from the mixed solution, and obtain CeO2 / Zn-SA after evaporating the solvent.

[0012] Preferably, the zinc source in step 1) is elemental zinc.

[0013] Preferably, the reaction method in step 1) is not limited to stirring, ultrasonic and oscillation.

[0014] Preferably, the separation method of the single-atom zinc catalyst after reaction in step 2) is not limited, and any method that can separate the product can be applied.

[0015] More preferably, the loading amount of single-atom zinc on the CeO2 / Zn-SA catalyst is 1 wt% - 40 wt%.

[0016] Another object of the present disclosure is to provide an application of photocatalytic degradation of phenol catalyzed by a single-atom zinc catalyst. Using CeO2 / Zn-SA as a photocatalyst, add a phenol solution to explore the photocatalytic degradation efficiency under normal temperature and pressure conditions.

[0017] Specifically, it includes the following steps:

[0018] 1) Add the CeO2 / Zn-SA catalyst and the phenol solution into a quartz bottle.

[0019] 2) Carry out photocatalytic degradation under normal temperature and pressure conditions.

[0020] 3) After the reaction, collect the CeO2 / Zn-SA catalyst, wash and dry it, and it can be used continuously.

[0021] Compared with the prior art, the advantages of the present disclosure are as follows:

[0022] (1) The single-atom zinc catalyst of the present disclosure can solve the problem that it is difficult to separate homogeneous catalysts from raw materials and products. The preparation method of the present disclosure is a brand-new method, which conforms to the concept of green chemistry, is pollution-free, simple to operate, can be prepared in gram scale, can effectively control the loading amount of single atoms, has low cost and is easy to promote.

[0023] (2) When the single-atom zinc catalyst of the present disclosure is used for photocatalytic degradation of phenol, the conditions are mild. Photodegradation is carried out under normal temperature and pressure conditions. The catalyst is easy to recycle and still maintains good catalytic effect after being used multiple times. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The specification drawings forming a part of the present disclosure are used to provide a further understanding of the present disclosure. The schematic embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation to the present disclosure.

[0025] Figure 1 It is the aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC-HAADF-STEM) image of CeO2 / Zn-SA prepared in Example 1 of the present disclosure.

[0026] Figure 2 It is the EXAFS characterization of CeO2 / Zn-SA prepared in Example 1 of the present disclosure.

[0027] Figure 3 It is the data graph of catalytic degradation of phenol by CeO2 / Zn-SA catalysts with different loadings described in Application Example 1 of the present disclosure.

[0028] Figure 4 It is the cyclic data graph of catalytic degradation of phenol by the CeO2 / Zn-SA catalyst with a loading of 6 wt% described in Application Example 1 of the present disclosure. MODE OF IMPLEMENTATION

[0029] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present disclosure belongs.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0031] Example 1: Synthesis of CeO2 / Zn-SA catalyst with a loading of 4 wt%

[0032] (1) Weigh 100 mg of CeO₂ in a beaker, add 50 mL of deionized water, and perform ultrasonic dispersion.

[0033] (2) Under ultrasonic conditions, the uniformly dispersed CeO₂ solution reacts with the zinc sheet.

[0034] (3) After reacting for 1 h, separate the solution from the zinc sheet to obtain CeO₂ / Zn-SA with a loading of 4 wt%.

[0035] Example 2: Synthesis of CeO₂ / Zn-SA catalyst with a loading of 6 wt%

[0036] (1) Weigh 150 mg of CeO₂ in a beaker, add 80 mL of deionized water, and perform ultrasonic dispersion.

[0037] (2) Under stirring conditions, the uniformly dispersed CeO₂ solution reacts with the zinc sheet.

[0038] (3) After reacting for 12 h, separate the solution from the zinc sheet to obtain CeO₂ / Zn-SA with a loading of 6 wt%.

[0039] Example 3: Synthesis of CeO₂ / Zn-SA catalyst with a loading of 9 wt%

[0040] (1) Weigh 200 mg of CeO₂ in a beaker, add 100 mL of deionized water, and perform ultrasonic dispersion.

[0041] (2) Under oscillating conditions, the uniformly dispersed CeO₂ solution reacts with the zinc sheet.

[0042] (3) After reacting for 24 h, separate the solution from the zinc sheet to obtain CeO₂ / Zn-SA with a loading of 9 wt%.

[0043] Application Example 1:

[0044] Apply CeO₂ / Zn-SA catalysts with different loadings to the photocatalytic degradation of phenol reaction to detect the catalytic performance of the CeO₂ / Zn-SA catalysts. Specifically:

[0045] Apply the catalysts prepared in Examples 1 - 3 to the photocatalytic degradation of phenol reaction. The specific process is as follows:

[0046] Add 20 mg of CeO2 / Zn-SA catalyst and 40 mL of phenol solution into a quartz bottle and disperse them evenly by ultrasonic wave. First, conduct dark treatment, that is, stir for 30 min under dark conditions to achieve adsorption-desorption equilibrium, and set the rotation speed to 180 r. Then, turn on the light source (adjust the light source intensity to 100%, keep the rotation speed unchanged, and the light source conversion time is 1 s) for degradation. The total degradation time is 150 min, and samples are taken every 30 min for testing using a UV spectrophotometer (UV-2700).

[0047] The foregoing are only the preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent substitution on some of the technical features. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

1. A single-atom zinc catalyst for photocatalytic degradation of phenol, which can be represented as CeO2 / Zn-SA (SA represents single atom).

2. A preparation method of a single-atom zinc catalyst for photocatalytic degradation of phenol, characterized in that First, CeO2 is dispersed in water to form a mixed solution, and then a zinc source is added to CeO2 for reaction. After the reaction, the zinc source is separated to obtain CeO2 / Zn-SA.

3. The preparation method of a single-atom zinc catalyst for photocatalytic degradation of phenol according to claim 2, characterized in that The zinc source is elemental zinc.

4. The preparation method of a single-atom zinc catalyst for photocatalytic degradation of phenol according to claim 2, characterized in that The reaction methods between CeO2 and zinc include but are not limited to mechanical stirring, ultrasonic treatment, and oscillation.

5. The preparation method of a single-atom zinc catalyst for photocatalytic degradation of phenol according to claim 2, characterized in that The separation method of the single-atom zinc catalyst after the reaction is not limited, and any method that can separate the product can be applied.

6. The single-atom zinc catalyst for photocatalytic degradation of phenol according to claim 2, characterized in that The loading amount of zinc in the single-atom zinc catalyst is 1 wt% - 40 wt%.

7. An application of a single-atom zinc catalyst for photocatalytic degradation of phenol, characterized in that CeO2 / Zn-SA is used as a photocatalyst.

8. The application of a single-atom zinc catalyst for photocatalytic degradation of phenol according to claim 7, characterized in that The photocatalytic degradation of phenol is carried out at room temperature and atmospheric pressure.

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