Ni-doped Cs2NaBiCl6 photocatalyst, preparation method thereof and application thereof in photocatalytic reduction of carbon dioxide

Abstract

The application discloses a Ni-doped Cs2NaBiCl6 photocatalyst, a preparation method thereof and application of the photocatalyst in photocatalytic reduction of carbon dioxide, and belongs to the technical field of photocatalytic material for preventing and treating air pollution. The preparation method comprises the following steps: dissolving sodium chloride, bismuth chloride and nickel chloride in hydrochloric acid, and reacting under the condition of heating and stirring; adding cesium chloride, immediately generating white precipitate, and after the reaction is completed, centrifuging, washing and drying to obtain Cs2Na 1‑x Ni x BiCl6, and x is 0.1-0.5. The nickel-doped Cs2NaBiCl6 double perovskite photocatalyst has stronger photocatalytic reduction capacity, can greatly improve the activity of the nickel-doped Cs2NaBiCl6 double perovskite photocatalyst in photocatalytic reduction of carbon dioxide, and the generation rate of carbon monoxide reaches 12.71 mu mol per hour ‑1 ·g ‑1 .

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic materials for the prevention and control of air pollution, specifically relating to a Ni-doped Cs2NaBiCl6 photocatalyst, its preparation method, and its application in the photocatalytic reduction of carbon dioxide. 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, utilizing inexhaustible solar energy, can directly convert carbon dioxide gas into hydrocarbon solar fuels, representing a feasible method to simultaneously address the energy crisis and environmental pollution. Therefore, halide perovskites, as a new class of semiconductor photocatalysts, have attracted significant research interest in this field. Among them, the all-inorganic metal halide double perovskite Cs₂NaBiCl₆ has become a highly promising photocatalyst candidate material in recent years due to its high extinction coefficient, low exciton binding energy, tunable band structure, and good stability to light, heat, and moisture. Furthermore, Bi in Cs₂NaBiCl₆ is known to serve as a catalytic site for CO₂ reduction. However, the photocatalytic performance of Cs₂NaBiCl₆ is largely limited by severe charge recombination. To overcome these limitations, various strategies have been developed, including morphology modulation, heterostructure, and bandgap tuning, to enhance its photocatalytic performance. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a Ni-doped Cs₂NaBiCl₆ photocatalyst, its preparation method, and its application in the photocatalytic reduction of carbon dioxide. This invention utilizes an acid precipitation method to construct a nickel-doped cesium sodium bismuth chloride perovskite, which enhances carrier separation efficiency, thereby improving the photocatalytic reduction activity of carbon dioxide.

[0004] The technical solution adopted in this invention is: a method for preparing Ni-doped Cs₂NaBiCl₆ photocatalyst, comprising the following steps: dissolving sodium chloride, bismuth chloride, and nickel chloride in hydrochloric acid and reacting them; adding cesium chloride, which immediately forms a white precipitate; after the reaction is completed, centrifuging, washing, and drying to obtain the nickel-doped cesium sodium bismuth chloride perovskite photocatalyst Cs₂Na 1-x Ni x BiCl6, x is 0.1-0.5.

[0005] Furthermore, the ratio of cesium chloride:sodium chloride:bismuth chloride:nickel chloride is 2:0.5-1:1:0.1-0.5.

[0006] Furthermore, the reaction is carried out at 50-100°C under stirring conditions for 0.5-5 hours.

[0007] Furthermore, the ratio of bismuth chloride to hydrochloric acid is 1 mmol: 5 mL - 20 mL.

[0008] A Ni-doped Cs2NaBiCl6 photocatalyst prepared according to the above preparation method.

[0009] Application of the above-mentioned Ni-doped Cs2NaBiCl6 photocatalyst in the photocatalytic reduction of carbon dioxide.

[0010] Further, the method is as follows: Under visible light irradiation, the Ni-doped Cs2NaBiCl6 photocatalyst is placed in a closed space filled with carbon dioxide gas, and the carbon dioxide gas is reduced to carbon monoxide gas.

[0011] The beneficial effects of this invention are as follows.

[0012] 1. This invention utilizes an acid precipitation method to prepare a nickel-doped cesium sodium bismuth chloride perovskite photocatalyst, namely a Ni-doped Cs2NaBiCl6 photocatalyst. Orbital hybridization introduces impurity intermediate energy levels, significantly reducing the intrinsic band gap of the material, thereby achieving the purpose of improving the photocatalytic reduction activity of carbon dioxide.

[0013] 2. This invention utilizes an acid precipitation method to prepare a nickel-doped cesium sodium bismuth chloride perovskite photocatalyst. The impurity energy level can act as a stepping stone for electron transitions, thereby improving photon utilization and achieving the goal of enhancing the photocatalytic reduction of carbon dioxide.

[0014] 3. The nickel-doped cesium sodium bismuth chloride double perovskite photocatalyst prepared by this invention has stronger photocatalytic reduction ability, participates in catalytic reactions, 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

[0015] Figure 1 Cs2NaBiCl6, Cs2Na 0.9 Ni 0.1 BiCl6, Cs2Na 0.8 Ni 0.2 BiCl6, Cs2Na 0.7 Ni 0.3 BiCl6 and Cs2Na 0.5 Ni 0.5 XRD pattern of BiCl6.

[0016] Figure 2 Cs2NaBiCl6, Cs2Na 0.9 Ni 0.1 BiCl6, Cs2Na 0.8 Ni 0.2 BiCl6, Cs2Na 0.7 Ni0.3 BiCl6 and Cs2Na 0.5 Ni 0.5 PL diagram of BiCl6.

[0017] Figure 3 Cs2NaBiCl6 and Cs2Na 0.8 Ni 0.2 SEM images of BiCl6 and Cs2Na 0.8 Ni 0.2 Energy dispersive X-ray spectroscopy (EDS) of BiCl6; where (a) is the SEM image of Cs2NaBiCl6, and (b) is the SEM image of Cs2NaBiCl6. 0.8 Ni 0.2 SEM image of BiCl6, (c) is Cs2Na 0.8 Ni 0.2 Energy spectrum of BiCl6.

[0018] Figure 4 Cs2NaBiCl6, Cs2Na 0.9 Ni 0.1 BiCl6, Cs2Na 0.8 Ni 0.2 BiCl6, Cs2Na 0.7 Ni 0.3 BiCl6 and Cs2Na 0.5 Ni 0.5 Comparison chart of BiCl6 photocatalytic reduction performance of carbon dioxide to carbon monoxide.

[0019] Figure 5 Cs2NaBiCl6, Cs2Na 0.9 Ni 0.1 BiCl6, Cs2Na 0.8 Ni 0.2 BiCl6, Cs2Na 0.7 Ni 0.3 BiCl6 and Cs2Na 0.5 Ni 0.5 Comparison chart of the photocatalytic reduction rate of carbon dioxide to carbon monoxide by BiCl6. Detailed Implementation

[0020] Comparative Example 1: A Cs2NaBiCl6 photocatalyst (Cs2NaBiCl6).

[0021] Dissolve 1.0 mmol sodium chloride and 1.0 mmol bismuth chloride in 10 mL of 36% hydrochloric acid and react with constant stirring and controlled heating to 80°C.

[0022] Then, 2.0 mmol of cesium chloride was added to the mixture, and a white precipitate immediately formed. The mixture was stirred vigorously for 30 min. Finally, the precipitate was centrifuged with isopropanol, washed until hydrochloric acid was completely removed, and then dried to obtain Cs₂NaBiCl₆.

[0023] Example 1: A Ni-doped Cs₂NaBiCl₆ photocatalyst (Cs₂Na 0.9 Ni 0.1 BiCl6).

[0024] (a) Preparation method.

[0025] 0.9 mmol sodium chloride, 0.1 mmol nickel chloride and 1.0 mmol bismuth chloride were dissolved in 10 mL of 36% hydrochloric acid and the reaction was carried out with constant stirring and controlled heating to 80°C.

[0026] Then, 2.0 mmol of cesium chloride was added to the mixture, and a white precipitate immediately formed. The mixture was stirred vigorously for 30 min. Finally, the precipitate was centrifuged with isopropanol, washed until hydrochloric acid was completely removed, and then dried to obtain Cs₂Na. 0.9 Ni 0.1 BiCl6.

[0027] (ii) Characterization.

[0028] The Cs₂NaBiCl₆ prepared in Comparative Example 1 and the Cs₂Na prepared in this example were compared. 0.9 Ni 0.1 BiCl6 was subjected to XRD testing, and the results are as follows: Figure 1 .from Figure 1 As can be seen from Cs2Na 0.9 Ni 0.1 The characteristic peak intensity of BiCl6 is lower than that of Cs2NaBiCl6, indicating that Cs2Na was successfully prepared. 0.9 Ni 0.1 BiCl6.

[0029] The Cs₂NaBiCl₆ prepared in Comparative Example 1 and the Cs₂Na prepared in this example were compared. 0.9 Ni 0.1 BiCl6 was subjected to PL testing, and the results are as follows: Figure 2 .from Figure 2 As can be seen from Cs2Na 0.9 Ni 0.1 The PL emission peak of BiCl6 is lower than that of Cs2NaBiCl6, indicating that the introduction of Ni ions can effectively improve the separation efficiency of photogenerated carriers, thereby improving photocatalytic performance.

[0030] Example 2: A Ni-doped Cs₂NaBiCl₆ photocatalyst (Cs₂Na 0.8 Ni 0.2 BiCl6).

[0031] (a) Preparation method.

[0032] 0.8 mmol sodium chloride, 0.2 mmol nickel chloride and 1.0 mmol bismuth chloride were dissolved in 10 mL of 36% hydrochloric acid and the reaction was carried out with constant stirring and controlled heating to 80 °C.

[0033] Then, 2.0 mmol of cesium chloride was added to the mixture, and a white precipitate immediately formed. The mixture was stirred vigorously for 30 min. Finally, the precipitate was centrifuged with isopropanol, washed until hydrochloric acid was completely removed, and then dried to obtain Cs₂Na. 0.8 Ni 0.2 BiCl6.

[0034] (ii) Characterization.

[0035] The Cs₂NaBiCl₆ prepared in Comparative Example 1 and the Cs₂Na prepared in this example were compared. 0.8 Ni 0.2 BiCl6 was subjected to XRD testing, and the results are as follows: Figure 1 .from Figure 1 As can be seen from Cs2Na 0.8 Ni 0.2 The characteristic peak intensity of BiCl6 is lower than that of Cs2NaBiCl6, indicating that Cs2Na was successfully prepared. 0.8 Ni 0.2 BiCl6.

[0036] The Cs₂NaBiCl₆ prepared in Comparative Example 1 and the Cs₂Na prepared in this example were compared. 0.8 Ni 0.2 BiCl6 was subjected to PL testing, and the results are as follows: Figure 2 .from Figure 2 As can be seen from Cs2Na 0.8 Ni 0.2 The PL emission peak of BiCl6 is lower than that of Cs2NaBiCl6, indicating that the introduction of Ni ions can effectively improve the separation efficiency of photogenerated carriers, thereby improving photocatalytic performance.

[0037] The Cs₂NaBiCl₆ prepared in Comparative Example 1 and the Cs₂Na prepared in this example were compared. 0.8 Ni 0.2 BiCl6 was tested using SEM, and the results are as follows: Figure 3 .from Figure 3 As can be seen from (a) and (b), Cs2Na0.8 Ni 0.2 The BiCl6 composite sample is larger in size than the Cs2NaBiCl6 sample, and Figure 3 The presence of Ni can be clearly observed in the EDS energy spectrum image in (c), indicating that Cs2Na 0.8 Ni 0.2 Successful synthesis of BiCl6.

[0038] Example 3: A Ni-doped Cs₂NaBiCl₆ photocatalyst (Cs₂Na 0.7 Ni 0.3 BiCl6).

[0039] (a) Preparation method.

[0040] 0.7 mmol sodium chloride, 0.3 mmol nickel chloride and 1.0 mmol bismuth chloride were dissolved in 10 mL of 36% hydrochloric acid and the reaction was carried out with constant stirring and controlled heating to 80°C.

[0041] Then, 2.0 mmol of cesium chloride was added to the mixture, and a white precipitate immediately formed. The mixture was stirred vigorously for 30 min. Finally, the precipitate was centrifuged with isopropanol, washed until hydrochloric acid was completely removed, and then dried to obtain Cs₂Na. 0.7 Ni 0.3 BiCl6.

[0042] (ii) Characterization.

[0043] The Cs₂NaBiCl₆ prepared in Comparative Example 1 and the Cs₂Na prepared in this example were compared. 0.7 Ni 0.3 BiCl6 was subjected to XRD testing, and the results are as follows: Figure 1 .from Figure 1 As can be seen from Cs2Na 0.7 Ni 0.3 The characteristic peak intensity of BiCl6 is lower than that of Cs2NaBiCl6, indicating that Cs2Na was successfully prepared. 0.7 Ni 0.3 BiCl6.

[0044] The Cs₂NaBiCl₆ prepared in Comparative Example 1 and the Cs₂Na prepared in this example were compared. 0.7 Ni 0.3 BiCl6 was subjected to PL testing, and the results are as follows: Figure 2 .from Figure 2 As can be seen from Cs2Na 0.7 Ni 0.3The PL emission peak of BiCl6 is lower than that of Cs2NaBiCl6, indicating that the introduction of Ni ions can effectively improve the separation efficiency of photogenerated carriers, thereby improving photocatalytic performance.

[0045] Example 4: A Ni-doped Cs₂NaBiCl₆ photocatalyst (Cs₂Na 0.5 Ni 0.5 BiCl6).

[0046] (a) Preparation method.

[0047] 0.5 mmol sodium chloride, 0.5 mmol nickel chloride and 1.0 mmol bismuth chloride were dissolved in 10 mL of 36% hydrochloric acid and the reaction was carried out with constant stirring and controlled heating to 80°C.

[0048] Then, 2.0 mmol of cesium chloride was added to the mixture, and a white precipitate immediately formed. The mixture was stirred vigorously for 30 min. Finally, the precipitate was centrifuged with isopropanol, washed until hydrochloric acid was completely removed, and then dried to obtain Cs₂Na. 0.5 Ni 0.5 BiCl6.

[0049] (ii) Characterization.

[0050] The Cs₂NaBiCl₆ prepared in Comparative Example 1 and the Cs₂Na prepared in this example were compared. 0.5 Ni 0.5 BiCl6 was subjected to XRD testing, and the results are as follows: Figure 1 .from Figure 1 As can be seen from Cs2Na 0.5 Ni 0.5 The characteristic peak intensity of BiCl6 is lower than that of Cs2NaBiCl6, indicating that Cs2Na was successfully prepared. 0.5 Ni 0.5 BiCl6.

[0051] The Cs₂NaBiCl₆ prepared in Comparative Example 1 and the Cs₂Na prepared in this example were compared. 0.5 Ni 0.5 BiCl6 was subjected to PL testing, and the results are as follows: Figure 2 .from Figure 2 As can be seen from Cs2Na 0.5 Ni 0.5 The PL emission peak of BiCl6 is lower than that of Cs2NaBiCl6, indicating that the introduction of Ni ions can effectively improve the separation efficiency of photogenerated carriers, thereby improving photocatalytic performance.

[0052] Example 5: Application of Ni-doped Cs2NaBiCl6 photocatalyst in photocatalytic reduction of carbon dioxide.

[0053] I. Methods.

[0054] Using a 300W xenon lamp as the light source, 0.03g of Cs₂NaBiCl₆ and Cs₂Na were respectively... 0.9 Ni 0.1 BiCl6, Cs2Na 0.8 Ni 0.2 BiCl6, Cs2Na 0.7 Ni 0.3 BiCl6 or Cs2Na 0.5 Ni 0.5 BiCl6 and 1 mL of deionized water were placed in a sealed reaction vessel. The sealed vessel was evacuated using a vacuum pump, and carbon dioxide gas was passed through it. This process was repeated three times, and then the carbon dioxide was reduced under visible light irradiation.

[0055] Depend on Figure 4 It can be seen that the nickel-doped cesium sodium bismuth chloride double perovskite photocatalyst prepared in this invention exhibits good photocatalytic activity and stability. After 2 hours of irradiation, the Cs₂Na₂O₃ prepared in Example 1 showed good photocatalytic activity and stability. 0.9 Ni 0.1 The yield of carbon monoxide from BiCl6 reached 15.41 μmol·g. -1 Cs2Na prepared in Example 2 0.8 Ni 0.2 The yield of carbon monoxide from BiCl6 reached 25.42 μmol·g. -1 Cs2Na prepared in Example 3 0.7 Ni 0.3 The yield of carbon monoxide from BiCl6 reached 21.09 μmol·g. -1 Cs2Na prepared in Example 4 0.5 Ni 0.5 The yield of carbon monoxide from BiCl6 reached 16.38 μmol·g. -1 The yield of carbon monoxide from Cs₂NaBiCl₆ was only 10.62 μmol·g⁻¹. -1 .

[0056] Depend on Figure 5 It can be seen that the Cs2Na prepared in Example 1 0.9 Ni 0.1 The carbon monoxide formation rate of BiCl6 reached 7.7 μmol·h⁻¹. -1 ·g -1 Cs2Na prepared in Example 2 0.8 Ni 0.2 The carbon monoxide formation rate of BiCl6 reached 12.71 μmol·h⁻¹. -1 ·g -1 Cs2Na prepared in Example 30.7 Ni 0.3 The carbon monoxide formation rate of BiCl6 reached 10.55 μmol·h⁻¹. -1 ·g -1 Cs2Na prepared in Example 4 0.5 Ni 0.5 The carbon monoxide formation rate of BiCl6 reached 8.19 μmol·h⁻¹. -1 ·g -1 The formation rate of carbon monoxide from Cs₂NaBiCl₆ is only 5.31 μmol·h⁻¹. -1 ·g -1 .

Claims

1. A method for preparing a Ni-doped Cs₂NaBiCl₆ photocatalyst, characterized in that, The process includes the following steps: dissolving sodium chloride, bismuth chloride, and nickel chloride in hydrochloric acid and reacting them; adding cesium chloride, which immediately forms a white precipitate; centrifuging, washing, and drying after the reaction to obtain the nickel-doped cesium sodium bismuth chloride perovskite photocatalyst Cs₂Na. 1-x Ni x BiCl6, x is 0.1-0.

5.

2. The method for preparing a Ni-doped Cs₂NaBiCl₆ photocatalyst according to claim 1, characterized in that, The molar ratio of cesium chloride:sodium chloride:bismuth chloride:nickel chloride is 2:0.5-1:1:0.1-0.

5.

3. The method for preparing a Ni-doped Cs₂NaBiCl₆ photocatalyst according to claim 1, characterized in that, The reaction was carried out at 50-100℃ under stirring conditions for 0.5-5 hours.

4. The method for preparing a Ni-doped Cs₂NaBiCl₆ photocatalyst according to claim 1, characterized in that, Bismuth chloride: 1 mmol of hydrochloric acid is used to make 5 mL to 20 mL of hydrochloric acid.

5. A Ni-doped Cs2NaBiCl6 photocatalyst prepared according to any one of claims 1-4.

6. The application of the Ni-doped Cs2NaBiCl6 photocatalyst according to claim 5 in the photocatalytic reduction of carbon dioxide.

7. The application of the Ni-doped Cs₂NaBiCl₆ photocatalyst according to claim 6 in the photocatalytic reduction of carbon dioxide, characterized in that, The method is as follows: Under visible light irradiation, the Ni-doped Cs2NaBiCl6 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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