阅读说明：本技术 一种高稳定性有机碘化铅晶体材料及其制备方法与应用 (High-stability organic lead iodide crystal material and preparation method and application thereof ) 是由 费泓涵 宋雪玲 于 2020-06-19 设计创作，主要内容包括：本发明涉及一种高稳定性有机碘化铅晶体材料及其制备方法与应用,该晶体材料的化学式为[Pb<Sub>2</Sub>I<Sub>2</Sub>(H<Sub>2</Sub>O)<Sub>0.75</Sub>]<Sup>2+</Sup>[<Sup>–</Sup>O<Sub>2</Sub>C(CH<Sub>2</Sub>)<Sub>4</Sub>CO<Sub>2</Sub><Sup>–</Sup>],晶体结构属于单斜晶系,空间群为C2/c,晶体中[Pb<Sub>2</Sub>I<Sub>2</Sub>]无机组分呈二维层状,层与层之间通过己二酸二钠有机配体相连。与现有技术相比,本发明克服了现有杂化的有机-无机钙钛矿材料的稳定性差以及难以实现光催化全解水的缺点,结合本发明制备过程简单等优势,在光催化领域具有潜在的应用价值。(The invention relates to a high-stability organic lead iodide crystal material, a preparation method and application thereof, wherein the chemical formula of the crystal material is [ Pb ] 2 I 2 (H 2 O) 0.75 ] 2+ [ – O 2 C(CH 2 ) 4 CO 2 – ]The crystal structure belongs to a monoclinic system, the space group is C2/C, and [ Pb ] in the crystal 2 I 2 ]The inorganic components are in two-dimensional layers and pass through the layersThe adipic acid disodium salt is connected with an organic ligand. Compared with the prior art, the method overcomes the defects of poor stability and difficulty in realizing photocatalytic full hydrolysis of the existing hybrid organic-inorganic perovskite material, combines the advantages of simple preparation process and the like, and has potential application value in the field of photocatalysis.)

1. A high-stability organic lead iodide crystal material is characterized in that the chemical formula is [ Pb ] ₂I₂(H₂O)_0.75]²⁺[^–O₂C(CH₂)₄CO₂ ^–]。

2. The high-stability organic lead iodide crystal material as claimed in claim 1, wherein the crystal structure of the material belongs to monoclinic system, space group is C2/C, and [ Pb ] in the crystal₂I₂]The inorganic components are in two-dimensional layers, and the layers are connected through an adipic acid disodium organic ligand.

3. The method for preparing the high-stability organolead iodide crystalline material according to claim 1 or 2, comprising the steps of:

(1) sequentially adding lead oxide, disodium adipate, potassium iodide and concentrated hydrochloric acid into a reaction kettle filled with deionized water, uniformly stirring, and carrying out hydrothermal reaction;

(2) after the reaction is finished, cooling to room temperature, taking out a reaction product, and then filtering, washing and drying to obtain a target product.

4. The method for preparing a high-stability organic lead iodide crystalline material as claimed in claim 3, wherein in the step (1), the molar ratio of lead oxide, disodium adipate and potassium iodide is 1: (2.5-4): (3-4).

5. The method for preparing high stability organolead iodide crystalline material as claimed in claim 3, wherein in the step (1), the molar concentration of concentrated hydrochloric acid is 12mol/L, and the ratio of the added amount of concentrated hydrochloric acid to lead oxide is 230-275 μ L: 0.23 g.

6. The method for preparing a high-stability organolead iodide crystalline material according to claim 3, wherein in the step (1), the volume of the reaction vessel is 1.2 to 2 times that of deionized water used.

7. The method for preparing the high-stability organolead iodide crystalline material according to claim 3, wherein in the step (1), the hydrothermal reaction conditions are specifically: the reaction temperature is 170 ℃ and 200 ℃, and the reaction time is 50-100 hours.

8. The method for preparing a high-stability organolead iodide crystalline material according to claim 3, wherein in the step (2), the cooling rate is 3-8 ℃/hr.

9. The method for preparing high-stability organolead iodide crystalline material according to claim 3, wherein in the step (2), the washing solvent used for washing is one or both of deionized water or ethanol.

10. Use of the high-stability organolead iodide crystalline material of claim 1 or 2 for photocatalytic decomposition of water.

Technical Field

The invention belongs to the technical field of crystal materials, and relates to a high-stability organic lead iodide crystal material, and a preparation method and application thereof.

Background

With the rapid development of society, the over-exploitation and use of energy causes global energy crisis and environmental pollution problems. The construction of an effective catalytic system for the development of clean energy is one of the hot issues of global concern. Wherein a photocatalytic system is currently recognized as a simple and efficient method for converting light energy into chemical energy (H) ₂And O₂). However, designing a single-component semiconductor photocatalyst with good light energy conversion efficiency still faces a great challenge. The current photocatalyst is mainly a traditional inorganic or organic conjugated polymer, such as ultraviolet light-responsive metal oxide or visible light-responsive metal oxynitride. Only a few of these photocatalysts can be activated to achieve full-hydrolysis in one step, and thus the search for an efficient one-component full-hydrolysis catalyst remains a significant challenge.

In recent years, a class of hybrid organic-inorganic lead-calcium-titanium halide ores attracts much attention due to good optical properties, mainly because of the advantages of simple preparation method, accurate adjustment and control of band gap, high light absorption coefficient and the like. But the moisture-sensitive characteristics of the materials greatly limit the application of the materials in photocatalytic full-splitting water. The reason for this is that organic substances in the perovskite material, namely organic amines, can form hydrogen bonds with water molecules, resulting in the disintegration of the perovskite material. Recently, researchers have applied the high-concentration HI solution to realize photocatalytic hydrogen production in order to overcome the defect of humidity sensitivity. However, HI is a flammable, highly corrosive and highly photosensitive substance, which limits its application in the commercial production of hydrogen.

Based on the fact that carboxylic acid ligands and lead halide have stronger coordination capacity, the organic carboxylic acid is adopted to replace organic amine, and therefore the effective method for solving the problem of humidity sensitivity of the material is achieved. However, the response range of the materials reported at present to light is narrow, and solar energy cannot be effectively utilized, so that the application of the materials in the field of photocatalysis is limited.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a high-stability organic lead iodide crystal material, and a preparation method and application thereof.

The purpose of the invention can be realized by the following technical scheme:

one of the technical schemes of the invention provides a high-stability organic lead iodide crystal material with a chemical formula of [ Pb ]₂I₂(H₂O)_0.75]²⁺[^–O₂C(CH₂)₄CO₂ ^–]。

Furthermore, the crystal structure of the material belongs to a monoclinic system, the space group is C2/C, and [ Pb ] in the crystal₂I₂]The inorganic components are in two-dimensional layers, and the layers are connected through an adipic acid disodium organic ligand.

The second technical proposal of the invention provides a preparation method of the high-stability organic lead iodide crystal material, which is characterized by comprising the following steps:

(1) sequentially adding lead oxide, disodium adipate, potassium iodide and concentrated hydrochloric acid into a reaction kettle filled with deionized water, uniformly stirring, and carrying out hydrothermal reaction;

(2) After the reaction is finished, cooling to room temperature, taking out a reaction product, and then filtering, washing and drying to obtain a target product.

Further, in the step (1), the molar ratio of the lead oxide to the disodium adipate to the potassium iodide is 1: (2.5-4): (3-4).

Further, in the step (1), the molar concentration of concentrated hydrochloric acid is 12mol/L, and the addition amount ratio of the concentrated hydrochloric acid to the lead oxide is 230-: 0.23 g.

Further, in the step (1), the volume of the reaction kettle is 1.2-2 times of that of the deionized water used.

Further, in the step (1), the hydrothermal reaction conditions are specifically as follows: the reaction temperature is 170 ℃ and 200 ℃, and the reaction time is 50-100 hours.

Further, in the step (2), the cooling rate is 3-8 ℃/h.

Further, in the step (2), the washing solvent used for washing is one or both of deionized water and ethanol.

The material consists of a cationic two-dimensional lead iodide inorganic layer and adipate dianions for balancing charges between layers. In the preparation process, lead oxide and potassium iodide are respectively used as a lead source and an iodine source, concentrated hydrochloric acid is used as a pH regulator, and disodium adipate is used as a structure directing agent. The reasons for using lead oxide and potassium iodide instead of lead iodide are: 1) lead iodide has poor solubility in the reaction system; 2) in the process of mixing lead oxide and potassium iodide to form lead iodide, the lead iodide can be uniformly mixed with a structure directing agent, which is beneficial to the next step of hydrothermal crystal growth.

In addition, the invention also limits the addition amount of each raw material (such as adipic acid disodium, potassium iodide, concentrated hydrochloric acid and the like), specific reaction conditions (such as reaction temperature, reaction time, temperature reduction speed and the like) and the like, mainly because the conditions are key factors for successfully obtaining the high-quality organic lead iodide crystal material; if the content of the impurities is not within the range of the conditions defined in the present invention, the obtained crystalline material has many problems such as poor crystallinity, high impurity content, and even failure to obtain the target crystal.

The third technical scheme of the invention provides application of the high-stability organic lead iodide crystal material in photocatalytic decomposition of water. Can be used as a good photoresponse material for photocatalytic water decomposition.

Compared with the prior art, the invention has the following advantages:

(1) the preparation process of the material disclosed by the invention is simple and easy to operate, and the product has high crystallinity and high purity.

(2) The material obtained by the invention can resist corrosion of strong acid and strong alkali, has high tolerance to high-temperature environment, and can be heated to 200 ℃ in air atmosphere without decomposition.

(3) The light absorption range is wide, the material obtained by the invention is yellow crystal, the light absorption range can be extended to a visible light region, and the absorption band edge is 480 nanometers.

(4) The energy band meets the requirement of full water splitting, the valence band position of the material obtained by the invention is more positive than the oxidation position of water, and the conduction band position is more negative than the reduction position of water, thus meeting the energy band requirement of the full water splitting photocatalyst.

(5) The material is used for simulating catalytic total hydrolysis under sunlight, and the result shows that the catalyst can decompose water according to a stoichiometric ratio to generate H₂And O₂The aim of water decomposition of single component is fulfilled.

Drawings

FIG. 1 shows the material [ Pb ] of the present invention₂I₂(H₂O)_0.75]²⁺[^–O₂C(CH₂)₄CO₂ ^–]A schematic of the crystal structure of (a);

FIG. 2 shows the material [ Pb ] of the present invention₂I₂(H₂O)_0.75]²⁺[^–O₂C(CH₂)₄CO₂ ^–]An X-ray powder diffraction pattern after treatment in an acid-base solution;

FIG. 3 shows the material [ Pb ] of the present invention₂I₂(H₂O)_0.75]²⁺[^–O₂C(CH₂)₄CO₂ ^–]X-ray powder diffractogram after heat treatment;

FIG. 4 shows the material [ Pb ] of the present invention₂I₂(H₂O)_0.75]²⁺[^–O₂C(CH₂)₄CO₂ ^–](ii) diffuse reflectance absorption spectrum of (d);

FIG. 5 shows the material [ Pb ] of the present invention₂I₂(H₂O)_0.75]²⁺[^–O₂C(CH₂)₄CO₂ ^–]The photocatalysis effect under simulated sunlight.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

In the following examples, the molar concentration of concentrated hydrochloric acid was 12mol/L, and unless otherwise specified, it was indicated that the starting materials and the treatment techniques were conventional and commercially available in the art.