An organic-inorganic hybrid double perovskite material, and a preparation method and application thereof

Abstract

The application discloses an organic-inorganic hybrid double perovskite material and a preparation method and application thereof. The molecular formula of the organic-inorganic hybrid double perovskite material is (NH3CH2CH2CH2NH3)2AgBiX8, wherein X is Cl, Br or I. The application forms the organic-inorganic hybrid double perovskite material by taking 1,3-propanediamine as a spacer cation, monovalent silver ions and trivalent bismuth ions as metal cations and halogen ions as anions, and the organic-inorganic hybrid double perovskite material shows a more dispersed charge layout, has excellent carrier migration rate and shows excellent photocatalytic activity and stability in selective oxidation of toluene by photocatalysis.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nanomaterial preparation and photoelectrocatalysis, and particularly relates to an organic-inorganic hybrid double perovskite material, a preparation method thereof and application thereof in photo-catalytic C(sp 3 -H bond activation. BACKGROUND

[0002] As a new type of ionic semiconductor material, full-metal halide perovskite, especially CsPbBr3 and CsPbI3, has become a hot material in the field of optoelectronics in recent years due to its excellent light absorption, suitable band gap and high carrier mobility. In addition to the great achievements of perovskite solar cells, the application in photocatalytic hydrogen, carbon dioxide reduction and organic conversion has also attracted widespread research interest. However, due to the instability under light, heat and humidity conditions, and the serious lead toxicity, the application of this kind of material in the field of photoelectrocatalysis is severely restricted. An effective strategy to improve the stability of perovskite is to add organic amine ligands to separate the inorganic octahedral layer, thereby converting the perovskite from a three-dimensional (3D) framework to a low-dimensional layered structure. Low-dimensional perovskite, especially two-dimensional Ruddlesden-Popper (RP) organic-inorganic hybrid perovskite material, has attracted a lot of attention due to its high environmental stability. The general formula of RP phase perovskite is R2An-1BnX(3n+1), where R is a large-size organic cation (such as a lipid or aromatic alkyl ammonium salt), mainly as a separation layer in the two-dimensional perovskite structure; A, B and X are organic cations, divalent metal cations and halide ions, respectively; n is the number of inorganic layers. The interlayer organic molecules in this two-dimensional perovskite structure are affected by van der Waals forces. The hydrophobic lipid or aromatic alkyl ammonium salt can improve the humidity stability of the two-dimensional perovskite. Although the stability of the RP type perovskite has been significantly improved compared with the three-dimensional perovskite, there is still a problem of large van der Waals band gap, and the interlayer van der Waals force is still unstable under relatively harsh environments, resulting in problems in stability. n-1 B n X 3n+1 However, due to the instability under light, heat and humidity conditions, and the serious lead toxicity, the application of this kind of material in the field of photoelectrocatalysis is severely restricted. An effective strategy to improve the stability of perovskite is to add organic amine ligands to separate the inorganic octahedral layer, thereby converting the perovskite from a three-dimensional (3D) framework to a low-dimensional layered structure. Low-dimensional perovskite, especially two-dimensional Ruddlesden-Popper (RP) organic-inorganic hybrid perovskite material, has attracted a lot of attention due to its high environmental stability. The general formula of RP phase perovskite is R2An-1BnX(3n+1), where R is a large-size organic cation (such as a lipid or aromatic alkyl ammonium salt), mainly as a separation layer in the two-dimensional perovskite structure; A, B and X are organic cations, divalent metal cations and halide ions, respectively; n is the number of inorganic layers. The interlayer organic molecules in this two-dimensional perovskite structure are affected by van der Waals forces. The hydrophobic lipid or aromatic alkyl ammonium salt can improve the humidity stability of the two-dimensional perovskite. Although the stability of the RP type perovskite has been significantly improved compared with the three-dimensional perovskite, there is still a problem of large van der Waals band gap, and the interlayer van der Waals force is still unstable under relatively harsh environments, resulting in problems in stability. SUMMARY

[0003] In order to solve the problems existing in the prior art, the purpose of the present application is to provide an organic-inorganic hybrid double perovskite material and a preparation method and application thereof. The molecular formula of the organic-inorganic hybrid double perovskite material is (NH3CH2CH2CH2NH3)2AgBiX8 (X = Cl, Br, I), which uses 1,3-propanediamine as a spacer cation, monovalent silver ions and trivalent bismuth ions as metal cations, and halide ions as anions to form an organic-inorganic hybrid double perovskite material, which shows more dispersed charge distribution, has excellent carrier migration rate, and shows excellent photocatalytic activity and stability in the selective oxidation of toluene in photocatalysis.

[0004] In order to achieve the above technical purposes, the present application adopts the following technical solutions:

[0005] An organic-inorganic hybrid double perovskite material has a molecular formula of (NH3CH2CH2CH2NH3)2AgBiX8, wherein X=Cl, Br or I.

[0006] The present application also provides a preparation method of the above organic-inorganic hybrid double perovskite material. First, a bismuth compound, a silver compound and 1,3-propanediamine are added into an HX solution, heated and stirred to dissolve them, and a transparent liquid is formed. Then, isopropanol is added into the transparent liquid, heating is stopped, and the organic-inorganic hybrid double perovskite material is formed by nucleation and crystallization under stirring.

[0007] Preferably, the bismuth compound is a nitrate, an oxide or a halide of bismuth; and the silver compound is a nitrate, an oxide or a halide of silver.

[0008] Preferably, the molar ratio of 1,3-propanediamine, bismuth and silver is 2:1:1, the concentration of bismuth in the HX solution is 0.4-0.1 mol / L, and the mass fraction of the HX solution is 45-50 wt%.

[0009] Preferably, the heating temperature is 90-110℃.

[0010] Preferably, the volume ratio of isopropanol to the HX solution is 2.5-10.

[0011] The present application also provides an application of the above organic-inorganic hybrid double perovskite material. The material is used as a photocatalyst for photocatalytic C(sp 3 )-H bond activation reaction.

[0012] Compared with the prior art, the present application has the following advantages:

[0013] The present application synthesizes the organic-inorganic hybrid double perovskite material by a heat-assisted-anti-solvent method. The introduction of 1,3-propanediamine not only improves the hydrophobicity of the material, but also is beneficial to the adsorption of toluene and the desorption of benzaldehyde. The 1,3-propanediamine is a spacer cation, and the charge distribution of the perovskite is more dispersed, so the carrier migration rate is excellent. Therefore, the perovskite with 1,3-propanediamine as a spacer cation shows excellent photocatalytic toluene activity and stability, and the photocatalytic toluene activity is significantly higher than that of other short-chain double-side alkylamine double perovskites and Cs2AgBiBr6 with a 3D structure, and the stability is significantly improved compared with Cs2AgBiBr6. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 Cs2AgBiBr6(a) prepared for Comparative Example 2, (NH3CH2CH2NH3)4AgBiBr6(b) prepared for Comparative Example 312 (b) XRD patterns of Cs2AgBiBr6(a) prepared for Comparative Example 2, (NH3CH2CH2NH3)4AgBiBr6(b) prepared for Comparative Example 3, (NH3CH2CH2CH2NH3)2AgBiBr8(c) prepared for Example 1, and (NH3CH2CH2CH2CH2NH3)2AgBiBr8(d) prepared for Comparative Example 4;

[0015] Figure 2 (b) XRD patterns of Cs2AgBiBr6(a) prepared for Comparative Example 2, (NH3CH2CH2NH3)4AgBiBr6(b) prepared for Comparative Example 3, (NH3CH2CH2CH2NH3)2AgBiBr8(c) prepared for Example 1, and (NH3CH2CH2CH2CH2NH3)2AgBiBr8(d) prepared for Comparative Example 4; 12 (b) SEM images of Cs2AgBiBr6(a) prepared for Comparative Example 2, (NH3CH2CH2NH3)4AgBiBr6(b) prepared for Comparative Example 3, (NH3CH2CH2CH2NH3)2AgBiBr8(c) prepared for Example 1, and (NH3CH2CH2CH2CH2NH3)2AgBiBr8(d) prepared for Comparative Example 4.

[0016] Figure 3 (b) XRD patterns of Cs2AgBiBr6(a) prepared for Comparative Example 2, (NH3CH2CH2NH3)4AgBiBr6(b) prepared for Comparative Example 3, (NH3CH2CH2CH2NH3)2AgBiBr8(c) prepared for Example 1, and (NH3CH2CH2CH2CH2NH3)2AgBiBr8(d) prepared for Comparative Example 4; 12 (b) Charge distribution diagrams of (NH3CH2CH2CH2NH3)2AgBiBr8(c) prepared for Example 1 and (NH3CH2CH2CH2CH2NH3)2AgBiBr8(d) prepared for Comparative Example 4 in the CBM (001) plane; and (NH3CH2CH2NH3)4AgBiBr6(e) prepared for Comparative Example 2 and (NH3CH2CH2CH2NH3)2AgBiBr8(f) prepared for Comparative Example 3 in the VBM (001) plane. 12 (f) Charge distribution diagrams of (NH3CH2CH2CH2NH3)2AgBiBr8(g) prepared for Example 1 and (NH3CH2CH2CH2CH2NH3)2AgBiBr8(h) prepared for Comparative Example 4 in the VBM (001) plane. DETAILED DESCRIPTION

[0017] The present application will be further described in conjunction with the following examples, but the scope of the present application is not limited to these examples.

[0018] The present application evaluates the performance of the synthesized organic-inorganic hybrid double perovskite material by photocatalytic C(sp 3 The solvent used is acetonitrile; the light source is a 300W xenon lamp equipped with a 420nm filter. Benzaldehyde and benzyl alcohol produced in the reaction are quantified by gas chromatography.

[0019] Example 1

[0020] Preparation of (NH3CH2CH2CH2NH3)2AgBiBr8:

[0021] To 5 mL of HBr (48 wt%) was added 0.5 mmol of BiBr3, 0.5 mmol of AgBr and 1 mmol of NH2CH2CH2CH2NH2. The mixture was heated to 100 °C with magnetic stirring. After dissolution, 25 mL of isopropanol was quickly added, the heating was turned off and stirring was continued for 1 h. Washing with ethyl acetate and drying under vacuum gave the (NH3CH2CH2CH2NH3)2AgBiBr8 material, noted PABB.

[0022] Comparative Example 1

[0023] Preparation of Cs3Bi2Br9:

[0024] To 5 mL of HBr (48 wt%) was added 1 mmol of BiBr3and 1.5 mmol of CsBr. The mixture was heated to 100 °C with magnetic stirring. After dissolution, 25 mL of isopropanol was quickly added, the heating was turned off and stirring was continued for 1 h. Washing with ethyl acetate and drying under vacuum gave the Cs3Bi2Br9 material.

[0025] Comparative Example 2

[0026] Preparation of Cs2AgBiBr6:

[0027] To 5 mL of HBr (48 wt%) was added 0.5 mmol of BiBr3, 0.5 mmol of AgBr and 1 mmol of CsBr. The mixture was heated to 100 °C with magnetic stirring. After dissolution, 25 mL of isopropanol was quickly added, the heating was turned off and stirring was continued for 1 h. Washing with ethyl acetate and drying under vacuum gave the Cs2AgBiBr6 material, noted CABB.

[0028] Comparative Example 3

[0029] Preparation of (NH3CH2CH2NH3)4AgBiBr: 12

[0030] To 5 mL of HBr (48 wt%) was added 0.5 mmol of BiBr3, 0.5 mmol of AgBr and 2 mmol of NH2CH2CH2NH2. The mixture was heated to 100 °C with magnetic stirring. After dissolution, 25 mL of isopropanol was quickly added, the heating was turned off and stirring was continued for 1 h. Washing with ethyl acetate and drying under vacuum gave the (NH3CH2CH2NH3)4AgBiBr 12 material, noted EABB.

[0031] Comparative Example 4

[0032] Preparation of (NH3CH2CH2CH2CH2NH3)2AgBiBr8: ​

[0033] Into 5 mL of HBr (48 wt%) was added 0.5 mmol of BiBr3, 0.5 mmol of AgBr and 1 mmol of NH2CH2CH2CH2CH2NH2. The mixture was heated to 100 °C with magnetic stirring. After dissolution, 25 mL of isopropanol was added quickly, the heating was turned off and the stirring was continued for 1 h. The (NH3CH2CH2CH2CH2NH3)2AgBiBr8 material, denoted as BABB, was obtained by washing with ethyl acetate and drying in vacuum.

[0034] Single crystal data of the samples prepared in Example 1 and Comparative Examples 2-4

[0035]

[0036] As shown in FIG. 1, the powder XRD data matched well with the XRD simulated from the single crystal structure calculation, proving the successful preparation of the double perovskite materials of Example 1 and Comparative Examples 2-4. Figure 1 As shown in FIG. 2, CABB exhibited an octahedral morphology, and EABB exhibited a cubic-like morphology. PABB and BABB exhibited a plate-like morphology, and the lateral size of PABB was larger than that of BABB.

[0037] Figure 2 As shown in FIG. 3, the charge distribution of PABB in the 001 direction was more dispersed, whether in the conduction band or in the valence band, proving that PABB had an excellent charge migration rate.

[0038] As shown in FIG. 4, the charge distribution of PABB in the 001 direction was more dispersed, whether in the conduction band or in the valence band, proving that PABB had an excellent charge migration rate. Figure 3 Performance evaluation:

[0039] The photocatalytic C(sp 3 )-H bond activation was used as a model reaction to investigate the catalytic activity of the prepared samples:

[0040] The solvent used was 2 mL of acetonitrile, 5 mg of catalyst, and the amount of reaction substrate was 50 μmol. The light source was a 300 W xenon lamp equipped with a λ≥400 nm filter. The amount of reactant and product was determined by the internal standard method using n-decane as an internal standard. Quantification was performed on a Shimadzu GC2010 Plus chromatograph equipped with an FID detector and a WAX capillary column (30 m x 0.25 mm x 0.25 μm).

[0041] The results of the photocatalytic oxidation of toluene reaction of the samples prepared in Example 1 and Comparative Examples 1-4 are shown in Table 2:

[0042] Table 2. Results of photocatalytic oxidation of toluene reaction of the samples prepared in Example 1 and Comparative Examples 1-4

[0043]

[0044] ​​

[0045] Table 3 Photocatalytic cycle stability of samples prepared in Example 1 and Comparative Example 2

[0046]

[0047] Note: During the recycling process, the reaction solution was centrifuged after each reaction, the catalyst was recovered, and then reused after vacuum drying at 60°C.

[0048] As can be seen from Table 3, the photocatalytic stability of toluene of (NH3CH2CH2CH2NH3)2AgBiBr8 is significantly improved compared to Cs2AgBiBr6.

Claims

1. An organic-inorganic hybrid double perovskite material, characterized in that: The molecular formula of the organic-inorganic hybrid double perovskite material is (NH3CH2CH2CH2NH3)2AgBiBr8.

2. The method for preparing the organic-inorganic hybrid double perovskite material according to claim 1, characterized in that: First, bismuth compound, silver compound and 1,3-propanediamine are added to HBr solution, heated and stirred to dissolve them and form a transparent liquid; then isopropanol is added to the transparent liquid, heating is stopped, and nucleation and crystallization are carried out under stirring to form an organic-inorganic hybrid double perovskite material.

3. The preparation method according to claim 2, characterized in that: Bismuth compounds are bismuth nitrates, oxides, or halides; silver compounds are silver nitrates, oxides, or halides.

4. The preparation method according to claim 2, characterized in that: The molar ratio of bismuth in 1,3-propanediamine and bismuth in the bismuth compound to silver in the silver compound is 2:1:

1. The concentration of bismuth in the bismuth compound in HBr is 0.4–0.1 mol / L, and the mass fraction of the HBr solution is 45–50 wt%.

5. The preparation method according to claim 2, characterized in that: The heating temperature is 90-110℃.

6. The preparation method according to claim 2, characterized in that: The volume ratio of isopropanol to HBr solution is 2.5–10.

7. The application of the organic-inorganic hybrid double perovskite material according to claim 1 or the organic-inorganic hybrid double perovskite material prepared by the preparation method according to any one of claims 2-6, characterized in that: It was used as a photocatalyst for the selective oxidation of toluene to benzaldehyde.

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