A cesium iron chloride micron crystal material and its preparation method and application

Abstract

The invention discloses a cesium iron chloride micron crystalline material, a preparation method and an application thereof. The chemical expression of the cesium iron chloride micron crystalline material is, the size of the cesium iron chloride micron crystalline material is, and the morphology is a hexahedral structure. The cesium iron chloride micron crystalline material is prepared by an in-situ reduction reaction under full-spectrum illumination conditions using as a precursor. The invention uses as a precursor to prepare micron crystals by illumination in an isopropanol environment. The micron crystals have a stable structure, uniform size and regular morphology, and the preparation process is simple and advanced, and easy to operate. The prepared micron crystals are applied in photocatalytic selective reduction and toluene oxidation reactions and show excellent photocatalytic performance.

Description

Technical Field

[0001] The invention relates to the technical field of micron material preparation, and in particular to a cesium iron chloride micron crystal material and a preparation method and application thereof. Background Art

[0002] Cesium-based metal halides have been widely used in energy harvesting, light-emitting diodes, photocatalysis and other fields due to their special optical properties. (X = Cl, Br, I) has been widely used in the field of photocatalysis due to its excellent optical properties and defect tolerance. However, the toxicity of Pb limits its further commercial application. In order to overcome this defect, researchers have introduced transition metal elements such as Cu, Zn, Bi, Sn and other elements to replace toxic Pb, and further applied it to the field of photocatalysis. In recent years, researchers have reported CsPb , CsCu , Sn and Cesium-based metal halides are the most important photocatalysts In addition to Mn and Cu, there are few reports on cesium-based metal halides that replace Pb and Sn with other 3d transition metal elements; As a substitute for Pb-based cesium halides, it has the advantages of low toxicity, low cost and good thermodynamic stability; however, the current semiconductor The application in the field of photocatalysis has not yet been explored.

[0003] In recent years, some reports have been published on However, these methods have harsh reaction conditions, high requirements on equipment and technology, and the synthesis The polycrystal has irregular morphology and non-uniform size; and the method for synthesizing nanocrystals with regular morphology and uniform size has a complex synthesis procedure and has certain risks. Therefore, the present invention proposes a cesium iron chloride micron crystal material and a preparation method and application to solve the problems existing in the prior art. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a cesium iron chloride micron crystal material and a preparation method and application thereof, wherein the cesium iron chloride micron crystal material and a preparation method and application thereof are As a precursor, it was prepared by light exposure in an isopropanol environment. Micronized crystals have stable structure, uniform size and regular morphology, simple and advanced preparation process, easy operation, and can be produced Microcrystals used in photocatalysis It exhibits excellent photocatalytic performance in the selective reduction and oxidation of toluene.

[0005] To achieve the purpose of the present invention, the present invention is implemented by the following technical scheme: a cesium iron chloride micron crystal material, the chemical expression of the micron crystal material is , is a semiconductor with a regular hexahedral structure, and the size of the micron-crystalline material is , the morphology is a hexahedral structure.

[0006] A further improvement is that the micron-crystalline material is made of As the precursor, under the condition of 300W xenon lamp irradiation, the uniform size and regular morphology were obtained by in-situ photoreduction reaction. Micron crystal.

[0007] A method for preparing cesium iron chloride micron-crystalline material comprises the following steps:

[0008] Step 1: First, dissolve 324 mg of anhydrous ferric chloride in 5 ml of hydrochloric acid to prepare a mixed solution A for standby use, and then dissolve 504 mg of cesium chloride in 3 ml of hydrochloric acid to prepare a mixed solution B for standby use;

[0009] Step 2: Then slowly add the mixed solution B to the mixed solution A and stir, then naturally cool to room temperature and centrifuge, filter and wash the filtrate with ethanol three times, and then vacuum dry to obtain an orange Micron particles;

[0010] Step 3: Take 500 mg of the product obtained in step 2. The micron particles were added with 20 ml of isopropanol and then subjected to ultrasonic dispersion to obtain a mixed solvent;

[0011] Step 4: Irradiate the mixed solvent under a 300W xenon lamp, stir, centrifuge and filter, then wash the filtrate three times with isopropanol to obtain a light yellow Micron crystal.

[0012] Further improvements are: when preparing the mixed solution A in step 1, stir it for 15 minutes in a water bath at 60°C; when preparing the mixed solution B, stir it for 10 minutes in a water bath at 60°C; in step 2, the mixed solution B is added to the mixed solution A and stirred for 30 minutes in a water bath at 60°C, and the filtrate is dried under vacuum at 60°C.

[0013] Further improvements are: the ultrasonic dispersion treatment time in step three is 30 minutes; the xenon lamp irradiation stirring time in step four is 6 hours.

[0014] The invention discloses an application of cesium iron chloride micron crystal material as a photocatalytic material in carbon dioxide reduction and toluene oxidation reactions.

[0015] The beneficial effects of the present invention are: As a precursor, it was prepared by light exposure in an isopropanol environment. Micronized crystals have stable structure, uniform size and regular morphology, simple and advanced preparation process, easy operation, and can be produced Microcrystals used in photocatalysis It exhibits excellent photocatalytic performance in the selective reduction and oxidation of toluene. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 For the present invention Microcrystalline and simulated X-ray diffraction pattern of .

[0017] Figure 2 For the present invention Photocatalytic carbon dioxide reduction activity results of microcrystals.

[0018] Figure 3 For the present invention Photocatalytic toluene oxidation activity results of micron-crystals.

[0019] Figure 4 For the present invention Scanning electron micrograph of microcrystals.

[0020] Figure 5 For the present invention UV-visible diffuse reflectance absorption spectrum of micron-crystals. DETAILED DESCRIPTION

[0021] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with examples. The examples are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0022] In recent years, researchers have reported the use of CsPb , CsCu , Sn as well as Cesium-based metal halides are the most important photocatalysts The application of reduction and toluene oxidation is as follows:

[0023] The Journal of the American Chemical Society (2017, Vol. 139, pp. 5660−5663) first listed CsPb Quantum dots for photocatalysis Reduction, and further CsPb

[0024] The combination of quantum dots and graphene oxide further promotes the transport and separation of charge carriers, thereby improving photocatalysis However, for a single CsPb Quantum dots and their photocatalysis The reduction activity is about 4 mol CO is not ideal, and the toxicity of Pb also limits the use of CsPb Application of type halides in photocatalysis.

[0025] The American journal ACS Nano (ACS Nano, 2022, Vol. 16, pp. 3332−3340) reported that CsSn Nanocrystal-ZnSe composite heterostructures in photocatalysis Reduction application, low toxicity ZnSe nanorods and CsSn The nanocrystals combined to construct a type II heterojunction effectively promotes charge separation, and the photocatalytic activity of the composite material is higher than that of the original CsSn (11 mol CO) increased by 5 times. However, due to CsSn of The ions are unstable and can be easily oxidized to The catalyst needs to be maintained by inert gas, which further limits its CsSn Application of type halides in photocatalysis.

[0026] The American journal ACS Catalysis (2022, Vol. 12, pp. 2915−2926) reported Cu Quantum dots for gas-solid photocatalysis Restore, due to Cu The Lewis frustrated acid-base pairs on the surface and the d-band properties of Cu promote Cu right Strong adsorption and activation, and CO yields reached 74.81 and 148.98 respectively mol Compared with CsPb , CsSn IVA group cesium halides, composed of 3d transition metal Cu Cu It has higher activity in photocatalytic applications, and the catalyst cost is lower and more environmentally friendly.

[0027] In summary, it can be seen that the use of 3d transition metal elements to replace traditional Pb and Sn elements to construct new cesium-based halides has great prospects in photocatalytic applications.

[0028] Current Semiconductors The application in the field of photocatalysis has not yet been explored. In recent years, some literature has reported The synthesis method of the material is as follows:

[0029] The French journal Solid State Sciences (2020, Vol. 100, pp. 1293-2558) reported a sealed tube solid-phase method for synthesizing polycrystalline : Cesium chloride and ferrous chloride in a stoichiometric ratio were placed in a carbon-coated fused quartz tube and placed in an argon-filled glove box. The quartz tube containing the reaction mixture was evacuated, heated to 823 K in a muffle furnace at a heating rate of 9 K / h and annealed at this temperature for 36 h to obtain Polycrystalline powder. This method has harsh reaction conditions and high requirements on equipment and technology, and the synthesized Cs3FeCl5 polycrystalline has irregular morphology and non-uniform size.

[0030] The American Journal of Inorganic Chemistry (Inorganic Chemistry, 2022, Vol. 61, pp. 14361−14367) reported the synthesis of Nanoparticles. Although this method can obtain nanocrystals with regular morphology and uniform size, the synthesis procedure is complicated and has certain risks.

[0031] In summary, the current synthesis of regular morphology and uniform size There are still challenges in semiconductor materials.

[0032] Based on this, this embodiment provides a cesium iron chloride micron crystal material, according to Figure 1-Figure 5 As shown, the chemical expression of micron-crystalline material is , the size of micron crystal material is , the morphology is a hexahedral structure.

[0033] Microcrystalline materials are made using It is a precursor and is prepared by in situ reduction reaction under full spectrum light conditions.

[0034] The preparation method specifically comprises the following steps:

[0035] 1. Synthesis using the supersaturation method Precursor

[0036] (1) First, mix 324 mg of anhydrous ferric chloride and 5 ml of hydrochloric acid in a 60°C water bath and stir for 15 min to dissolve the anhydrous ferric chloride in the hydrochloric acid to prepare a mixed solution A for later use;

[0037] (2) Then, 504 mg of cesium chloride and 3 ml of hydrochloric acid were mixed and stirred in a 60°C water bath for 10 min to dissolve the cesium chloride in the hydrochloric acid to prepare a mixed solution B for later use;

[0038] (3) Then, the mixed solution B was slowly added to the mixed solution A and mixed and stirred for 30 min in a 60°C water bath. Then, the solution was naturally cooled to room temperature and centrifuged. After centrifugation, the solution was filtered and washed with ethanol three times. The solution was then vacuum dried at 60°C to obtain an orange solution. Micron particles;

[0039] 2. In situ photoreduction synthesis Micron particles

[0040] (1) Take 500 mg of the The micron particles were added with 20 ml of isopropanol and then subjected to ultrasonic dispersion for 30 min to obtain a mixed solvent;

[0041] (2) The mixed solvent was irradiated under a 300W xenon lamp and stirred for 6 hours, then centrifuged and filtered. The filtrate was then washed three times with isopropanol to obtain a light yellow Micron crystal.

[0042] The invention discloses an application of cesium iron chloride micron crystal material as a photocatalytic material in carbon dioxide reduction and toluene oxidation reactions.

[0043] As the instruction manual Figure 1 As shown, Compared with theoretical simulation By comparison, the X-ray diffraction pattern of The diffraction peaks of the experiment are basically consistent with those of the theoretical simulation, indicating that the It is a pure phase with no impurities.

[0044] As the instruction manual Figure 2 As shown, Photocatalytic properties of microcrystals in a solvent environment with isopropanol as dispersant and sacrificial agent Reduction performance, photocatalytic performance diagram shows Microcrystals in photocatalysis Excellent methane selectivity and yield were shown in the reduction.

[0045] As the instruction manual Figure 3 As shown, The photocatalytic performance of micron crystals in toluene as a dispersant solvent is shown in the photocatalytic performance diagram. Micronized crystals exhibited highly efficient catalytic performance in toluene oxidation reaction.

[0046] As the instruction manual Figure 4 The data shown in the figure are obtained by characterizing the samples synthesized by the synthesis scheme and the samples in the synthesis process under a scanning electron microscope (SEM). Figure 4 Indicates that the in situ photoreduction method was used to synthesize The SEM characterization picture of the micron crystal shows that the Micronized crystals have regular morphology and uniform size, with a size of approx. about.

[0047] As the instruction manual Figure 5 As shown, the prepared The UV-visible diffuse reflectance absorption spectrum of the micron-crystalline sample shows that it has good light absorption performance.

[0048] From the above, it can be seen that the samples synthesized by the method of the present invention have good photocatalytic Selective reduction in reduction reaction for , the highest yield is 2264 mol The catalytic activity is better than that of the currently reported cesium halides, and it also shows a maximum of 11.9 mmol in the photocatalytic toluene oxidation reaction. Benzaldehyde and 6.7mmol Benzyl alcohol yield. Microcrystals as photocatalysts in photocatalysis Good application prospects in reduction and oxidation of toluene.

[0049] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing cesium iron chloride micron-crystalline material, characterized in that: The following steps are involved: Step 1: First, dissolve 324 mg of anhydrous ferric chloride in 5 ml of hydrochloric acid to prepare a mixed solution A for standby use, and then dissolve 504 mg of cesium chloride in 3 ml of hydrochloric acid to prepare a mixed solution B for standby use; When preparing mixed solution A, stir it in a water bath at 60°C for 15 min; when preparing mixed solution B, stir it in a water bath at 60°C for 10 min; Step 2: Then slowly add the mixed solution B to the mixed solution A and stir, then naturally cool to room temperature and centrifuge, filter and wash the filtrate with ethanol three times, and then vacuum dry to obtain an orange Micron particles; The mixed solution B was added to the mixed solution A and stirred for 30 min in a water bath at 60°C, and the filtrate was dried under vacuum at 60°C. Step 3: Take 500 mg of the product obtained in step 2. The micron particles were added with 20 ml of isopropanol and then subjected to ultrasonic dispersion for 30 min to obtain a mixed solvent; Step 4: Irradiate the mixed solvent under a 300W xenon lamp, stir for 6 hours, centrifuge and filter, then wash the filtrate three times with isopropanol to obtain a light yellow Micron crystal.

2. Application of the micron-crystalline material prepared by the method for preparing cesium iron chloride micron-crystalline material according to claim 1, which is used as a photocatalyst material in carbon dioxide reduction and toluene oxidation reactions.

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