A nickel-doped Cs2AgBiCl6 composite material, its preparation method and application

Abstract

The application discloses a kind of nickel-doped Cs2AgBiCl6 Composite material and its preparation method and application.Belongs to photocatalytic material technical field, in the nickel-doped Cs2AgBiCl6 Composite material, 10% by mole percentage, contain 50% nickel chloride.Preparation method includes: cesium chloride, bismuth chloride, silver chloride and nickel chloride are placed in agate mortar and mixed.Mix the mixture, then continuously grind at room temperature, air environment, then put into muffle furnace and calcine, obtain target product.Compared with existing photocatalyst, the nickel-doped Cs2AgBiCl6 Composite material photocatalyst of the application improves the photocatalytic CO2 photoreduction efficiency, wherein doping can modify semiconductor photocatalytic material, to accelerate the separation and transfer of carrier, to improve the purpose of photocatalytic activity.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to a nickel-doped Cs2AgBiCl6 composite material, its preparation method, and its application. Background Technology

[0002] Photocatalysis technology can use solar energy to drive catalytic reactions, directly converting carbon dioxide gas into hydrocarbon solar fuels, which is a feasible method to solve the ecological environment and energy crisis.

[0003] Halide double perovskite materials have become a research hotspot in novel photocatalytic materials due to their excellent optical properties, tunable band structure, good chemical stability, and lead-free and environmentally friendly characteristics. Among them, cesium silver bismuth chloride (Cs₂AgBiCl₆) double perovskite materials possess suitable band gaps, excellent light absorption performance, and good structural stability. Compared with traditional titanium-based and bismuth-based photocatalytic materials, they have stronger visible light harvesting capabilities, showing great application potential in the field of photocatalysis. However, pure-phase Cs₂AgBiCl₆ materials have fast electron-hole recombination rates, limited visible light response range, and low solar energy utilization.

[0004] Metal ion doping is an effective method for modifying semiconductor photocatalytic materials. It can control the band structure of the material, suppress carrier recombination, and broaden the photoresponse range through lattice doping. Therefore, doping can be used to improve the photocatalytic performance of Cs₂AgBiCl₆ materials.

[0005] Currently, there are no reports on the preparation process and application of nickel-doped Cs2AgBiCl6 photocatalysts for CO2 reduction. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a nickel-doped Cs₂AgBiCl₆ composite material, its preparation method, and its applications. This invention improves the photocatalytic CO₂ photoreduction efficiency through metal doping.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows.

[0008] A method for preparing a nickel-doped Cs2AgBiCl6 composite material includes the following steps.

[0009] 1) Mix cesium chloride, bismuth chloride, silver chloride and nickel chloride evenly, and then grind them at room temperature and in air.

[0010] 2) After grinding, the material is placed in a muffle furnace for calcination to obtain Ni-Cs2AgBiCl6 photocatalyst.

[0011] Furthermore, in molar ratio, cesium chloride:silver chloride:bismuth chloride:nickel chloride = 2:(0.5-1):1:(0.1-1).

[0012] Further, in step 1), cesium chloride, bismuth chloride, silver chloride and nickel chloride are placed in an agate grinding medium and mixed evenly, and the grinding time is 1 hour.

[0013] Furthermore, in step 2), the calcination temperature is 300-400℃, the calcination time is 3-5h, and the heating rate is 5℃ / min.

[0014] This invention provides an application of nickel-doped Cs2AgBiCl6 composite material in the photocatalytic reduction of carbon dioxide.

[0015] Further, the method is as follows: under visible light irradiation, the nickel-doped Cs2AgBiCl6 composite material is placed in a sealed container filled with carbon dioxide gas to reduce CO2 to CO.

[0016] The beneficial effects of this invention are as follows.

[0017] 1. The nickel-doped Cs₂AgBiCl₆ composite photocatalyst prepared in this invention improves carrier separation efficiency. Compared with pure Cs₂AgBiCl₆ photocatalyst, the photocatalytic activity is increased by 2 to 3 times.

[0018] 2. The nickel-doped Cs2AgBiCl6 composite photocatalyst prepared by this invention has a particulate structure, which increases the specific surface area and provides more surface active sites.

[0019] 3. The nickel-doped Cs2AgBiCl6 composite photocatalyst prepared by this invention has good photocatalytic reduction performance of carbon dioxide. Moreover, the method is simple, convenient, lead-free, green and environmentally friendly, and will not cause secondary pollution, which is conducive to large-scale production. Attached Figure Description

[0020] Figure 1 X-ray diffraction (XRD) patterns of CABC, 10Ni-CABC, 20Ni-CABC, 30Ni-CABC, and 50Ni-CABC are shown, where (a) is the overall XRD pattern and (b) is an enlarged view of the dashed area in (a).

[0021] Figure 2 This is a scanning electron microscope (SEM) image of CABC.

[0022] Figure 3 This is a scanning electron microscope (SEM) image of 30Ni-CABC.

[0023] Figure 4EDS plot of elemental mapping for 30Ni-CABC.

[0024] Figure 5 Photoluminescence (PL) patterns of CABC, 10Ni-CABC, 20Ni-CABC, 30Ni-CABC, and 50Ni-CABC.

[0025] Figure 6 Comparison of photocatalytic reduction of carbon dioxide reactions for CABC, 10Ni-CABC, 20Ni-CABC, 30Ni-CABC, and 50Ni-CABC.

[0026] Figure 7 A comparison chart of the photocatalytic reduction activities of CABC, 10Ni-CABC, 20Ni-CABC, 30Ni-CABC, and 50Ni-CABC. Detailed Implementation

[0027] Example 1: Nickel-doped Cs2AgBiCl6 composite material.

[0028] (a) Preparation method of CABC.

[0029] Cesium chloride (2 mmol), bismuth chloride (1 mmol), and silver chloride (1 mmol) were mixed in an agate mortar. The mixture was thoroughly mixed and then ground continuously at room temperature and in air for 1 h. The ground sample was calcined at 350 °C for 4 h at a temperature rate of 5 °C / min to obtain Cs₂AgBiCl₆, denoted as CABC.

[0030] (ii) Preparation method of 10Ni-CABC.

[0031] Cesium chloride (2 mmol), bismuth chloride (1 mmol), silver chloride (0.9 mmol), and nickel chloride (0.1 mmol) were mixed in an agate mortar. The mixture was thoroughly mixed and then ground continuously for 1 hour at room temperature and in air. The ground sample was calcined at 350 °C for 4 hours at a temperature rate of 5 °C / min to obtain a nickel-doped Cs₂AgBiCl₆ photocatalyst. Based on the molar percentage of nickel chloride to silver chloride and nickel chloride, it contained 10% nickel chloride and was denoted as 10Ni-CABC.

[0032] (ii) Preparation method of 20Ni-CABC.

[0033] Cesium chloride (2 mmol), bismuth chloride (1 mmol), silver chloride (0.8 mmol), and nickel chloride (0.2 mmol) were mixed in an agate mortar. The mixture was thoroughly mixed and then ground continuously at room temperature and in air for 1 h. The ground sample was calcined at 350 °C for 4 h at a temperature rate of 5 °C / min to obtain a nickel-doped Cs₂AgBiCl₆ photocatalyst containing 20% ​​nickel chloride, denoted as 20Ni-CABC.

[0034] (III) Preparation method of 30Ni-CABC.

[0035] Cesium chloride (2 mmol), bismuth chloride (1 mmol), silver chloride (0.7 mmol), and nickel chloride (0.3 mmol) were mixed in an agate mortar. The mixture was thoroughly mixed and then ground continuously for 1 hour at room temperature and in air. The ground sample was calcined at 350 °C for 4 hours at a temperature rate of 5 °C / min to obtain a nickel-doped Cs₂AgBiCl₆ photocatalyst. Based on the molar percentage of nickel chloride to silver chloride and nickel chloride, it contained 30% nickel chloride and was denoted as 30Ni-CABC.

[0036] (iv) Preparation method of 50Ni-CABC.

[0037] Cesium chloride (2 mmol), bismuth chloride (1 mmol), silver chloride (0.5 mmol), and nickel chloride (0.5 mmol) were mixed in an agate mortar. The mixture was thoroughly mixed and then ground continuously at room temperature and in air for 1 h. The ground sample was calcined at 350 °C for 4 h at a temperature rate of 5 °C / min to obtain a nickel-doped Cs₂AgBiCl₆ photocatalyst. Based on the molar percentage of nickel chloride to silver chloride and nickel chloride, it contained 50% nickel chloride and was denoted as 50Ni-CABC.

[0038] (v) Characterization.

[0039] XRD tests were performed on CABC, 10Ni-CABC, 20Ni-CABC, 30Ni-CABC, and 50Ni-CABC. The test results are as follows. Figure 1 As shown, from Figure 1 The diffraction peaks of nickel-doped Cs2AgBiCl6 are slightly shifted compared to the diffraction peaks of pure-phase CABC, indicating the successful preparation of the composite sample Ni-CABC.

[0040] Figure 2 , Figure 3 The images show SEM images of CABC and 30Ni-CABC, respectively. As can be seen from the images, pure-phase CABC has a bulk structure, while the nickel-doped Cs₂AgBiCl₆ photocatalyst has a particulate structure. Figure 4 The EDS diagram of 30Ni-CABC shows that Ni, Cs, Ag, Bi and Cl elements are present simultaneously and uniformly distributed, indicating that the photocatalyst was successfully prepared.

[0041] Figure 5 The PL spectra of CABC, 10Ni-CABC, 20Ni-CABC, 30Ni-CABC, and 50Ni-CABC are shown in the figure. It can be seen from the figure that the pure-phase Cs₂AgBiCl₆ sample has the highest emission peak, indicating that photogenerated electrons and holes recombine readily. After nickel doping modification, the fluorescence intensity of the samples decreased significantly, and the 30Ni-CABC sample exhibited the lowest PL emission peak. This indicates that 30Ni-CABC has a higher separation efficiency for photogenerated electrons and holes.

[0042] Example 2: Application of nickel-doped Cs2AgBiCl6 photocatalyst in photocatalytic reduction of carbon dioxide.

[0043] Using a 300W xenon lamp as the light source, 10 mg each of CABC, 10Ni-CABC, 20Ni-CABC, 30Ni-CABC, 50Ni-CABC, and pure-phase CABC were evenly spread on a porcelain boat, and 1 mL of water was added before placing the boat into a sealed reaction vessel. The sealed reaction vessel was evacuated using a vacuum pump, and carbon dioxide gas was passed through repeatedly. The gas was then continuously tested for 2 hours using a gas chromatograph. The test results are shown below. Figure 6 and Figure 7 .

[0044] like Figure 6 As shown, CO production gradually increases over time, indicating that the sample has high stability. The results also show that 30Ni-CABC exhibits the highest photocatalytic performance; therefore, metal-doped lead-free halide perovskite materials are an effective way to promote photocatalytic reactions.

[0045] like Figure 7 As shown, the nickel-doped Cs₂AgBiCl₆ photocatalyst prepared in this invention exhibits excellent photocatalytic activity, with a carbon monoxide generation rate of 9 μmol·h⁻¹ in 10Ni-CABC. -1 ·g -1 The carbon monoxide formation rate of 20Ni-CABC reached 10.91 μmol·h⁻¹. -1 ·g -1 The carbon monoxide formation rate of 30Ni-CABC reached 13.7 μmol·h⁻¹. -1 ·g -1 The carbon monoxide formation rate of 50Ni-CABC reached 9.9 μmol·h⁻¹. -1 ·g -1 The carbon monoxide formation rate of pure-phase CABC is only 4.9 μmol·h⁻¹.-1 ·g -1 。

Claims

1. A method for preparing a nickel-doped Cs₂AgBiCl₆ composite material, characterized in that, Includes the following steps: 1) Mix cesium chloride, bismuth chloride, silver chloride and nickel chloride evenly, and then grind them at room temperature and in air. 2) After grinding, the material is placed in a muffle furnace for calcination to obtain Ni-Cs2AgBiCl6 photocatalyst.

2. The method for preparing a nickel-doped Cs₂AgBiCl₆ composite material according to claim 1, characterized in that, In step 1), the molar ratio is cesium chloride:silver chloride:bismuth chloride:nickel chloride = 2:(0.5-1):1:(0.1-1).

3. The method for preparing a nickel-doped Cs₂AgBiCl₆ composite material according to claim 1, characterized in that, In step 1), cesium chloride, bismuth chloride, silver chloride and nickel chloride are placed in an agate grinding medium and mixed evenly for 1 hour.

4. The method for preparing a nickel-doped Cs₂AgBiCl₆ composite material according to claim 1, characterized in that, In step 2), the calcination temperature is 300-400℃, the calcination time is 3-5h, and the heating rate is 5℃ / min.

5. A nickel-doped Cs2AgBiCl6 composite material prepared according to the preparation method of any one of claims 1-4.

6. The application of the nickel-doped Cs2AgBiCl6 composite material of claim 5 in the photocatalytic reduction of carbon dioxide.

7. The application of the nickel-doped Cs₂AgBiCl₆ composite material according to claim 6 in the photocatalytic reduction of carbon dioxide, characterized in that, The method is as follows: Under visible light irradiation, the nickel-doped Cs2AgBiCl6 composite material is placed in a sealed container filled with carbon dioxide gas to reduce CO2 to CO.

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