A method for preparing and applying a rhenium sulfide / cerium vanadate heterojunction photocatalyst

Abstract

This invention discloses a method for preparing a rhenium sulfide / cerium vanadate heterojunction photocatalyst and its application. The preparation method includes the following steps: 1) dissolving ammonium cerium nitrate, ascorbic acid, and ammonium metavanadate in a deionized aqueous solution of glycerol, followed by hydrothermal drying to obtain cerium vanadate; 2) dissolving thiourea and sodium perrhenate in deionized water, mixing and stirring, then adding cerium vanadate, followed by hydrothermal drying to obtain the rhenium sulfide / cerium vanadate heterojunction catalyst. In the preparation of rhenium sulfide, this invention directly adds cerium vanadate and utilizes a isothermal and pressure-controlled reaction to successfully construct a heterostructure between rhenium sulfide and cerium vanadate. By changing the rhenium sulfide content, yttrium-stabilized zirconium oxide catalysts with rhenium sulfide doping and different crystal structures can be obtained. In the photocatalytic degradation of naphthalene, by constructing an efficient photogenerated carrier transfer pathway, the separation efficiency of electron-hole pairs and the bulk charge migration efficiency are enhanced, resulting in high selectivity and long service life.

Description

Technical Field

[0001] This invention belongs to the field of photocatalysis technology, specifically relating to a method for preparing and applying a rhenium sulfide / cerium vanadate heterojunction photocatalyst. Background Technology

[0002] Naphthalene (NAP), a representative of low molecular weight polycyclic aromatic hydrocarbons (LMW-PAHs), is one of the most abundant PAHs. Its parent compound and methylated naphthalene account for approximately 95% of total PAHs. Due to its persistence, semi-volatility, and biotoxicity, NAP poses a serious threat to direct and indirect exposure in humans and animals and has been classified as a Group 2 carcinogen by the International Agency for Research on Cancer (IARC). Various processes, including the Fenton process, electrochemical oxidation, reduction, biotechnology, and photocatalytic degradation, have been used to effectively remove LMW-PAHs. Photocatalytic treatment technology, through in-situ generation of reactive oxygen species (ROS), can degrade organic pollutants into CO2, H2O, and inorganic ions without causing secondary pollution. Many semiconductor materials with good photosensitivity, environmental friendliness, and stability (such as bimetallic oxides, metal salts, and metal sulfides) are preferred photocatalyst materials. The removal of PAHs (naphthalene, anthracene, phenanthrene) by TiO2 composite nanocomposites under ultraviolet light has been extensively studied. Furthermore, the degradation of PAHs by visible light-responsive semiconductor photocatalysts has also been extensively investigated. Current research mainly focuses on BiO. X Photocatalytic materials such as Bi2O2CO3 and CeVO4 are used. However, these photocatalytic materials still suffer from poor photogenerated carrier transfer efficiency and insufficient light utilization efficiency, which limits their large-scale application in practical environments. Summary of the Invention

[0003] To address the problems existing in the prior art, the purpose of this invention is to provide a method for preparing and applying a rhenium sulfide / cerium vanadate heterojunction photocatalyst, which is specifically achieved through the following technical solution: A method for preparing a rhenium sulfide / cerium vanadate heterojunction photocatalyst includes the following steps: 1) Cerium ammonium nitrate, ascorbic acid and ammonium metavanadate are dissolved in a deionized aqueous solution of glycerol, mixed and stirred, and then the mixture is placed in a high-pressure reactor for hydrothermal reaction. The completely reacted sample is centrifuged, washed and dried to obtain cerium vanadate. 2) Thiourea and sodium perrhenate are dissolved in deionized water, mixed and stirred, and then added to the cerium vanadate mixture obtained in step 1). The mixture is placed in a high-pressure reactor for hydrothermal reaction. The completely reacted sample is centrifuged, washed, and dried to obtain the rhenium sulfide / cerium vanadate heterojunction catalyst.

[0004] Further, in step 1), the molar ratio of cerium ammonium nitrate, ascorbic acid and ammonium metavanadate is 0.5-1.5 mmol: 0.5-1.5 mmol: 0.5-1.5 mmol.

[0005] Furthermore, in step 1), the molar ratio of cerium ammonium nitrate, ascorbic acid, and ammonium metavanadate is 1 mmol: 1 mmol: 1 mmol. Further, in step 1), the amount of glycerol used in the aqueous solution of glycerol is 15-20 mL, and the amount of deionized water is 50-60 mL.

[0006] Furthermore, in step 1), the hydrothermal reaction is carried out at a temperature of 150°C for a duration of 12 hours.

[0007] Further, in step 2), the molar ratio of thiourea to sodium perrhenate is 2 mmol: 1 mmol, the amount of deionized water is 65-75 mL, and the amount of cerium vanadate added is 0.1-0.25 mmol, preferably 0.15 mmol.

[0008] Furthermore, in step 2), the hydrothermal reaction is carried out at a temperature of 200°C for a duration of 12 hours.

[0009] Application of the rhenium sulfide / cerium vanadate heterojunction catalyst prepared by any of the above preparation methods in the photocatalytic degradation of naphthalene.

[0010] The preparation method of this invention is simple, green, and controllable. During the preparation of rhenium sulfide, cerium vanadate is directly added, and a isothermal and pressure-controlled reaction is used to successfully construct a heterostructure between rhenium sulfide and cerium vanadate. In the photocatalytic degradation of naphthalene, this constructs an efficient photogenerated carrier transfer pathway, thereby enhancing the electron-hole pair separation efficiency and the bulk charge migration efficiency, exhibiting advantages such as high selectivity and long lifespan. The prepared catalyst has high efficiency and long lifespan, making it suitable for industrial production. Attached Figure Description

[0011] Figure 1 XRD patterns of CeVO4 and ReS2 / CeVO4; Figure 2 Degradation curves of naphthalene by CeVO4 and ReS2 / CeVO4 under visible light irradiation; Figure 3. Effects of different scavengers on photocatalytic activity. Detailed Implementation

[0012] The present invention will be further described below with reference to the accompanying drawings to provide a better understanding of the technical solution.

[0013] Example 1

[0014] Preparation of cerium vanadate: The specific steps include dissolving 1 mmol of cerium ammonium nitrate, 1 mmol of ascorbic acid, and 1 mmol of ammonium metavanadate in a glycerol / deionized water mixture consisting of 18 mL of glycerol and 54 mL of deionized water, and stirring continuously for 1 hour. Then, the mixture is placed in a 100 mL high-pressure reactor and maintained at 150 °C for 12 hours. Subsequently, it is washed three times each with deionized water and ethanol, and dried under vacuum at 80 °C to obtain cerium vanadate.

[0015] Example 2

[0016] Preparation of rhenium sulfide / cerium vanadate heterojunction catalyst: The specific steps for preparing the rhenium sulfide / cerium vanadate catalyst include dissolving 2 mmol of thiourea and 1 mmol of sodium perrhenate in 70 mL of deionized water, stirring continuously for 30 minutes, and then adding 0.1 mmol of cerium vanadate. The mixture is then placed in a 100 mL high-pressure reactor and maintained at 200 °C for 12 hours. Subsequently, it is washed three times with deionized water and ethanol respectively, and dried under vacuum at 80 °C to obtain the rhenium sulfide / cerium vanadate heterojunction catalyst, denoted as ReS / CeV-10.

[0017] Example 3

[0018] The steps are basically the same as in Example 2, except that the amount of cerium vanadate added is 0.15 mmol, denoted as ReS / CeV-15.

[0019] Example 4

[0020] The steps are basically the same as in Example 2, except that the amount of cerium vanadate added is 0.20 mmol, denoted as ReS / CeV-20.

[0021] Example 5

[0022] The steps are basically the same as in Example 2, except that the amount of cerium vanadate added is 0.25 mmol, denoted as ReS / CeV-25.

[0023] Verification Example 1 The XRD patterns of the heterojunction catalysts prepared in Examples 2-5 above are shown below. Figure 1 As shown, from Figure 1As can be seen from the data, the characteristic peaks at 18.2°, 24.0°, 32.4°, and 47.9° in the rhenium sulfide / cerium vanadate heterojunction catalyst correspond to the (1 0 1), (2 0 0), (1 1 2), and (3 1 2) crystal planes of cerium vanadate (PDF#12-0757), respectively. Meanwhile, the characteristic peaks at 14.5°, 33.3°, and 29.4° of ReS / CeV-10, ReS / CeV-15, ReS / CeV-20, and ReS / CeV-25 are consistent with the (0 0 1), (-2 0 1), and (-2 0 2) crystal planes of rhenium sulfide (PDF#27-0502), confirming the successful synthesis of the rhenium sulfide / cerium vanadate heterojunction.

[0024] Verification Example 2 The photocatalytic degradation of the pollutant naphthalene by the heterojunction catalysts prepared in Examples 2-5 above was tested. 30 mg of the aforementioned rhenium sulfide / cerium vanadate heterojunction catalyst was added to 100 mL of a 30 mg / L naphthalene pollutant solution. The experiment consisted of two parts: a dark reaction and a light reaction. The dark reaction was conducted without a light source. The dark reaction was maintained for 40 minutes to achieve adsorption-desorption equilibrium of the pollutant. The light reaction was maintained for 120 minutes, and the degradation of the pollutant was observed. During the experiment, 3 mL of sample was taken every 20 minutes, filtered through a 0.45 μm filter needle, and then placed in a UV-Vis spectrophotometer to detect the concentration change. The results are as follows: Figure 2 As shown in the figure, the experiment shows that ReS / CeV-15 has the best degradation efficiency for naphthalene after 120 minutes of light irradiation, reaching 91.7%, which demonstrates the excellent performance of the rhenium sulfide / cerium vanadate heterojunction catalyst for the pollutant naphthalene.

[0025] Verification Example 3 like Figure 3 As shown, different scavengers were used to target O2 during the photocatalytic process. - h + The efficiency of ·OH radical degradation was investigated. The results showed that the introduction of IPA and BQ significantly reduced the degradation efficiency of NAP, indicating that ·O2... - ·OH and ·OH are the main factors affecting free radicals.

[0026] The preparation method of this invention utilizes a hydrothermal reaction under constant temperature and pressure conditions to construct an efficient built-in electric field charge transfer path by using the staggered band structure of rhenium sulfide and cerium vanadate. This suppresses the internal recombination of photogenerated electron-hole pairs, enhances the charge transfer rate in the bulk phase, increases the yield of reactive oxygen species (ROS), and utilizes the interaction mechanism between ROS and pollutant molecules to achieve efficient degradation.

Claims

1. A method for preparing a rhenium sulfide / cerium vanadate heterojunction photocatalyst, characterized by Includes the following steps: 1) Cerium ammonium nitrate, ascorbic acid and ammonium metavanadate are dissolved in a deionized aqueous solution of glycerol, mixed and stirred, and then the mixture is placed in a high-pressure reactor for hydrothermal reaction. The completely reacted sample is centrifuged, washed and dried to obtain cerium vanadate. 2) Thiourea and sodium perrhenate are dissolved in deionized water, mixed and stirred, and then added to the cerium vanadate mixture obtained in step 1). The mixture is placed in a high-pressure reactor for hydrothermal reaction. The completely reacted sample is centrifuged, washed, and dried to obtain the rhenium sulfide / cerium vanadate heterojunction catalyst. The molar ratio of thiourea to sodium perrhenate is 2 mmol:1 mmol, and the amount of cerium vanadate added is 0.1-0.25 mmol.

2. The method for preparing a rhenium sulfide / cerium vanadate heterojunction photocatalyst according to claim 1, characterized in that In step 1), the molar ratio of cerium ammonium nitrate, ascorbic acid, and ammonium metavanadate is 0.5-1.5 mmol: 0.5-1.5 mmol: 0.5-1.5 mmol.

3. The preparation method of a rhenium sulfide / cerium vanadate heterojunction photocatalyst as described in claim 2, characterized in that... In step 1), the molar ratio of cerium ammonium nitrate, ascorbic acid, and ammonium metavanadate is 1 mmol: 1 mmol: 1 mmol.

4. The preparation method of a rhenium sulfide / cerium vanadate heterojunction photocatalyst as described in claim 1, characterized in that... In step 1), the amount of glycerol used in the aqueous solution is 15-20 mL, and the amount of deionized water is 50-60 mL.

5. The preparation method of a rhenium sulfide / cerium vanadate heterojunction photocatalyst as described in claim 1, characterized in that... In step 1), the hydrothermal reaction is carried out at a temperature of 150°C for a duration of 12 hours.

6. The preparation method of a rhenium sulfide / cerium vanadate heterojunction photocatalyst as described in claim 1, characterized in that... In step 2), the amount of deionized water used is 65-75 mL.

7. The preparation method of a rhenium sulfide / cerium vanadate heterojunction photocatalyst as described in claim 6, characterized in that... The amount of cerium vanadate added was 0.15 mmol.

8. The method for preparing a rhenium sulfide / cerium vanadate heterojunction photocatalyst as described in claim 1, characterized in that... In step 2), the hydrothermal reaction is carried out at a temperature of 200°C for a duration of 12 hours.

9. The application of the rhenium sulfide / cerium vanadate heterojunction catalyst prepared by any one of the preparation methods described in claims 1-8 in the photocatalytic degradation of naphthalene.

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