Cesium zirconium chloride / acid modified carbon nitride heterojunction photocatalyst as well as preparation method and application thereof

Abstract

The invention discloses a cesium zirconium chloride / acid modified carbon nitride heterojunction photocatalyst as well as a preparation method and application thereof. Belongs to the technical field of photocatalytic materials, and the cesium zirconium chloride / acid modified carbon nitride heterojunction photocatalyst contains 10-50% by mole of cesium zirconium chloride. The preparation method comprises the following steps: adding zirconium chloride and tubular graphite phase carbon nitride into hydrochloric acid, and uniformly mixing to obtain a precursor A; dissolving cesium chloride in hydrochloric acid to prepare a precursor B; and rapidly injecting the precursor B into the precursor A to rapidly generate a precipitate, and purifying with methanol to obtain a target product. According to the invention, the acid-modified carbon nitride is introduced to be compounded with the cesium zirconium chloride to construct a heterojunction structure, so that the photocatalytic CO2 photoreduction efficiency is improved. The tubular g-C3N4 can increase the specific surface area of the material and provide more surface active sites; the surface protonation of the acid-modified g-C3N4 can improve the polarization degree of the g-C3N4, so that the photocatalytic performance is remarkably improved, and the purpose of improving the photocatalytic activity of the composite material is achieved.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst, its preparation method, and its application. Background Technology

[0002] In recent years, massive carbon dioxide emissions have exacerbated the global greenhouse effect, leading to a series of environmental and social problems. Photocatalytic carbon dioxide reduction uses inexhaustible solar energy to directly convert carbon dioxide gas into hydrocarbon solar fuels, making it a feasible method to simultaneously address the energy crisis and environmental pollution.

[0003] In recent years, lead halide perovskites ABX3 (A=Cs, MA, FA; X=Cl, Br, I) have attracted considerable interest due to their unique optical properties. Lead halide perovskites are considered ideal candidate materials for photocatalysts. However, due to problems such as insufficient surface active sites, low CO2 photoreduction efficiency, and excessively fast electron-hole recombination rates, single photocatalysts cannot meet practical requirements.

[0004] Graphitic carbon nitride (g-C3N4) has become one of the most promising photocatalysts for carbon dioxide reduction due to its non-toxicity, simple synthesis, and high chemical stability. However, g-C3N4 also has obvious drawbacks, such as small specific surface area, rapid recombination of photogenerated carriers, and poor adsorption capacity for carbon dioxide. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a cesium zirconate chloride / acid-modified carbon nitride photocatalyst, its preparation method, and its application in the photocatalytic reduction of carbon dioxide. This invention improves the photocatalytic CO2 reduction efficiency by introducing an acid-modified carbon nitride and cesium zirconate chloride composite to construct a heterojunction structure. Constructing tubular g-C3N4 increases the specific surface area of ​​the material, providing more surface active sites; the surface protonation of acid-modified g-C3N4 increases its polarization, thereby significantly improving photocatalytic performance and achieving the goal of enhancing the photocatalytic activity of the composite material.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is: a cesium zirconate chloride / acid-modified carbon nitride heterojunction photocatalyst, containing 10%-50% cesium zirconate chloride by molar percentage.

[0007] A method for preparing a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst, the method comprising the following steps:

[0008] 1) Zirconium chloride (ZrCl4) and tubular graphitic carbon nitride (g-C3N4) were added to hydrochloric acid and mixed evenly to obtain precursor A;

[0009] 2) Cesium chloride (CsCl) was dissolved in hydrochloric acid to prepare precursor B;

[0010] 3) Precursor B is rapidly injected into precursor A to generate a precipitate, which is then washed with methanol to obtain a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst.

[0011] Furthermore, in molar ratio, zirconium chloride: cesium chloride: tubular graphitic carbon nitride = 1: (1.5-2.5): (1-10).

[0012] Further, in step 1), the amount of hydrochloric acid added is based on the material-to-liquid ratio: zirconium chloride: hydrochloric acid = 1 mmol: (3 mL - 5 mL).

[0013] Further, in step 2), the amount of hydrochloric acid added is based on the material-to-liquid ratio: cesium chloride: hydrochloric acid = 1 mmol: (1 mL - 3 mL).

[0014] Furthermore, the method for preparing the tubular graphitic carbon nitride includes the following steps: dissolving melamine in water at 60℃-100℃, obtaining the precursor by hydrothermal method, and obtaining tubular graphitic carbon nitride by calcination.

[0015] Furthermore, the hydrothermal method is characterized by a hydrothermal reaction temperature of 160℃-200℃ and a hydrothermal reaction time of 18h-30h.

[0016] Furthermore, the calcination is carried out at a temperature of 500℃-600℃ for a duration of 4h-6h.

[0017] This invention provides the application of a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst in the photocatalytic reduction of carbon dioxide.

[0018] Further, the method is as follows: under visible light irradiation, the cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst is placed in a closed space filled with carbon dioxide gas, and the carbon dioxide gas is reduced to carbon monoxide gas.

[0019] The beneficial effects of this invention are:

[0020] 1. This invention utilizes an in-situ generation method to prepare a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst. The heterojunction structure can improve the carrier separation efficiency, thereby achieving the purpose of improving photocatalytic activity.

[0021] 2. The present invention utilizes an in-situ generation method to construct a cesium zirconate chloride / acid-modified carbon nitride heterojunction photocatalyst. The use of tubular g-C3N4 can increase the specific surface area of ​​the material and provide more surface active sites. The surface protonation of acid-modified g-C3N4 can improve the polarization degree of g-C3N4, thereby significantly improving the photocatalytic performance and achieving the purpose of improving the photocatalytic activity of the composite material.

[0022] 3. The cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst constructed by the in-situ generation method of this invention has stronger photocatalytic reduction ability, participates in catalytic reaction, and has good photocatalytic reduction performance of carbon dioxide. Moreover, the method is simple, convenient, low-cost, mild and conducive to large-scale production. Attached Figure Description

[0023] Figure 1 XRD patterns for CN, CN-H, CZC, 10CZC / CN, 20CZC / CN, 30CZC / CN, and 50CZC / CN.

[0024] Figure 2 This is the SEM image of CZC.

[0025] Figure 3 This is a SEM image of CN-H.

[0026] Figure 4 This is a SEM image of 20CZC / CN.

[0027] Figure 5 Comparison of photocatalytic reduction of carbon dioxide reactions for CN, CN-H, CZC, 10CZC / CN, 20CZC / CN, 30CZC / CN, and 50CZC / CN.

[0028] Figure 6 Comparison of photocatalytic reduction activities of carbon dioxide for CN, CN-H, CZC, 10CZC / CN, 20CZC / CN, 30CZC / CN and 50CZC / CN. Detailed Implementation

[0029] Example 1: A cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst (10CZC / CN)

[0030] (I) Preparation method of 10CZC / CN

[0031] 1) Preparation of tubular graphitic carbon nitride (g-C3N4): Melamine (1g) was dissolved in 60mL of deionized water and stirred at 90℃ until a clear solution was obtained. The prepared solution was placed in a 100mL high-temperature reactor and heated at 180℃ for 24h to obtain a melamine-triuric acid precursor. Under nitrogen atmosphere, the precursor was calcined at 550℃ for 4h at a temperature rate of 5℃ / min, and then cooled to ambient temperature to obtain g-C3N4 nanotubes, labeled CN.

[0032] 2) Add ZrCl4 (1 mmol) and g-C3N4 nanotubes (9 mmol) to 4 mL HCl and stir at 80 °C for 30 min to obtain precursor A.

[0033] 3) Dissolve CsCl (2 mmol) in 4 mL HCl to prepare precursor B.

[0034] 4) Precursor B was rapidly injected into precursor A, which quickly generated a precipitate. The precipitate was washed three times with methanol and dried at 100°C for 12 hours to obtain a cesium zirconate chloride / acid-modified carbon nitride heterojunction photocatalyst containing 10% cesium zirconate chloride by molar percentage, labeled as 10CZC / CN.

[0035] (ii) Comparative Example

[0036] 1. Comparative Example 1 – Preparation of Acid-Modified Tubular Graphitic Carbon Nitride (g-C3N4)

[0037] g-C3N4 nanotubes were added to 10 mL of HCl, stirred at 80 °C for 30 min, filtered, and dried at 100 °C for 12 h to obtain acid-modified g-C3N4 nanotubes, labeled CN-H.

[0038] 2. Comparative Example 2 – Preparation of Chlorinated Cesium Zirconate (Cs₂ZrCl₆)

[0039] ZrCl4 (1 mmol) was added to 4 mL of HCl and stirred at 80 °C for 30 min to prepare precursor A. CsCl (2 mmol) was dissolved in 4 mL of HCl to prepare precursor B. Precursor B was rapidly injected into precursor A, and a precipitate was rapidly formed. The precipitate was washed three times with methanol and dried at 100 °C for 12 h to obtain cesium zirconate chloride, labeled CZC.

[0040] (iii) Characterization

[0041] XRD tests were performed on CN, CN-H, CZC, and 10CZC / CN, and the test results are as follows: Figure 1 As shown, from Figure 1 The results show that typical characteristic peaks of CN-H and CZC were detected in 10CZC / CN, indicating the successful preparation of 10CZC / CN.

[0042] Example 2: A cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst (20CZC / CN)

[0043] (I) Preparation method of 20CZC / CN

[0044] 1) Preparation of tubular graphitic carbon nitride (g-C3N4): Same as in Example 1.

[0045] 2) Add ZrCl4 (1 mmol) and g-C3N4 nanotubes (4 mmol) to 4 mL HCl and stir at 80 °C for 30 min to obtain precursor A.

[0046] 3) Dissolve CsCl (2 mmol) in 4 mL HCl to prepare precursor B.

[0047] 4) Precursor B was rapidly injected into precursor A, which quickly generated a precipitate. The precipitate was washed three times with methanol and dried at 100°C for 12 hours to obtain a cesium zirconate chloride / acid-modified carbon nitride heterojunction photocatalyst containing 20% ​​cesium zirconate chloride by molar percentage, labeled as 20CZC / CN.

[0048] (ii) Characterization

[0049] XRD tests were performed on CN, CN-H, CZC, and 20CZC / CN, and the test results are as follows: Figure 1 As shown, from Figure 1 The results show that typical characteristic peaks of CN-H and CZC were detected in 20CZC / CN, indicating the successful preparation of 20CZC / CN.

[0050] Figure 2 This is the SEM image of CZC. Figure 3 The image shows a SEM image of CN-H. The prepared 20CZC / CN was then subjected to SEM testing, as shown below. Figure 4 As shown, CZC grows on the CN-H surface, indicating the successful synthesis of 20CZC / CN.

[0051] Example 3: A cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst (30CZC / CN)

[0052] (I) Preparation method of 30CZC / CN

[0053] 1) Preparation of tubular graphitic carbon nitride (g-C3N4): Same as in Example 1.

[0054] 2) Add ZrCl4 (1 mmol) and g-C3N4 nanotubes (2 mmol) to 4 mL HCl and stir at 80 °C for 30 min to obtain precursor A.

[0055] 3) Dissolve CsCl (2 mmol) in 4 mL HCl to prepare precursor B.

[0056] 4) Precursor B was rapidly injected into precursor A, which quickly generated a precipitate. The precipitate was washed three times with methanol and dried at 100°C for 12 hours to obtain a cesium zirconate chloride / acid-modified carbon nitride heterojunction photocatalyst containing 30% cesium zirconate chloride by molar percentage, labeled as 30CZC / CN.

[0057] (ii) Characterization

[0058] XRD tests were performed on CN, CN-H, CZC, and 30CZC / CN, and the test results are as follows: Figure 1 As shown, from Figure 1 The results show that typical characteristic peaks of CN-H and CZC were detected in 30CZC / CN, indicating the successful preparation of 30CZC / CN.

[0059] Example 4: A cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst (50CZC / CN)

[0060] (I) Preparation method of 50CZC / CN

[0061] 1) Preparation of tubular graphitic carbon nitride (g-C3N4): Same as in Example 1.

[0062] 2) Add ZrCl4 (1 mmol) and g-C3N4 nanotubes (1 mmol) to 4 mL HCl and stir at 80 °C for 30 min to obtain precursor A.

[0063] 3) Dissolve CsCl (2 mmol) in 4 mL HCl to prepare precursor B.

[0064] 4) Precursor B was rapidly injected into precursor A, which quickly generated a precipitate. The precipitate was washed three times with methanol and dried at 100°C for 12 hours to obtain a cesium zirconate chloride / acid-modified carbon nitride heterojunction photocatalyst containing 50% cesium zirconate chloride by molar percentage, labeled as 50CZC / CN.

[0065] (ii) Characterization

[0066] XRD tests were performed on CN, CN-H, CZC, and 50CZC / CN, and the test results are as follows: Figure 1 As shown, from Figure 1 The results show that typical characteristic peaks of CN-H and CZC were detected in 50CZC / CN, indicating the successful preparation of 50CZC / CN.

[0067] Example 5: Application of cesium zirconate chloride / acid-modified carbon nitride heterojunction photocatalyst in photocatalytic reduction of carbon dioxide.

[0068] The method is as follows: Using a 300W xenon lamp as the light source, 0.03g of the catalysts 10CZC / CN, 20CZC / CN, 30CZC / CN, and 50CZC / CN prepared in Examples 1-4, and the catalysts CN, CN-H, and CZC prepared in the comparative examples, were respectively placed in 1mL of deionized water and placed into sealed reaction containers. A vacuum pump was used to evacuate the sealed reaction containers, and carbon dioxide gas was introduced through the system for three cycles. Then, carbon dioxide was reduced under visible light irradiation for 120 minutes. The results are as follows: Figure 5 and Figure 6 .

[0069] like Figure 5 As shown, CO production gradually increases over time, indicating that the sample has high stability. The results show that 20CZC / CN exhibits the highest photocatalytic performance; therefore, constructing a cesium zirconate chloride / acid-modified carbon nitride heterojunction structure is an effective way to promote photocatalytic reactions.

[0070] like Figure 6 As shown, the cesium zirconate chloride / acid-modified carbon nitride photocatalyst prepared in this invention exhibits excellent photocatalytic activity, with a carbon monoxide generation rate of 34.21 μmol·h⁻¹ in 10CZC / CN. -1 ·g -1 The carbon monoxide formation rate of 20CZC / CN reached 51.83 μmol·h⁻¹. -1 ·g -1 The carbon monoxide formation rate of 30CZC / CN reached 42.87 μmol·h⁻¹. -1 ·g -1 The carbon monoxide formation rate at a 50CZC / CN ratio reached 31.04 μmol·h⁻¹. -1 ·g -1 The carbon monoxide formation rate of CN is only 3.09 μmol·h⁻¹. -1 ·g -1 .

Claims

1. A cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst, characterized in that, The cesium zirconate chloride / acid-modified carbon nitride heterojunction photocatalyst contains 10%-50% cesium zirconate chloride by molar percentage.

2. The preparation method of the cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst according to claim 1, characterized in that, The preparation method includes the following steps: 1) Zirconium chloride and tubular graphitic carbon nitride were added to hydrochloric acid and mixed evenly to obtain precursor A; 2) Cesium chloride was dissolved in hydrochloric acid to prepare precursor B; 3) Precursor B is rapidly injected into precursor A to generate a precipitate, which is then washed with methanol to obtain a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst.

3. The method for preparing a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst according to claim 2, characterized in that, The molar ratio is zirconium chloride: cesium chloride: tubular graphitic carbon nitride = 1: (1.5-2.5): (1-10).

4. The preparation method of a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst according to claim 2, characterized in that, In step 1), the amount of hydrochloric acid added is based on the material-liquid ratio of zirconium chloride:hydrochloric acid = 1 mmol:(3 mL - 5 mL).

5. The method for preparing a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst according to claim 2, characterized in that, In step 2), the amount of hydrochloric acid added is based on the material-to-liquid ratio: cesium chloride: hydrochloric acid = 1 mmol: (1 mL - 3 mL).

6. The method for preparing a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst according to claim 2, characterized in that, The method for preparing tubular graphitic carbon nitride includes the following steps: dissolving melamine in water at 60℃-100℃, obtaining a precursor by hydrothermal method, and obtaining tubular graphitic carbon nitride by calcination.

7. The method for preparing a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst according to claim 6, characterized in that, The hydrothermal method is as follows: the hydrothermal reaction temperature is 160℃-200℃, and the hydrothermal reaction time is 18h-30h.

8. The method for preparing a cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst according to claim 6, characterized in that, The calcination is carried out at a temperature of 500℃-600℃ for a time of 4h-6h.

9. The application of the cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst according to claim 1 in the photocatalytic reduction of carbon dioxide.

10. The application according to claim 9, characterized in that, The method is as follows: Under visible light irradiation, the cesium zirconate chloride / acid modified carbon nitride heterojunction photocatalyst is placed in a closed space filled with carbon dioxide gas, and the carbon dioxide gas is reduced to carbon monoxide gas.

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