Preparation method of BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst for CO2 reduction
A cost-effective in-situ synthesis method for BiOCl/BaTiO3 heterojunction catalysts addresses the complexity and cost issues of existing BaTiO3-based methods, providing a stable and efficient catalyst for CO2 reduction.
Patent Information
- Application Number
- CN202510513681.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-23
- Publication Date
- 2025-07-15
Smart Images
Figure CN120305991A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of nanomaterial preparation, and particularly relates to a preparation method of a BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst for CO2 reduction. Background Art
[0002] Converting carbon dioxide into solar fuels or other high-value chemicals by harnessing the inexhaustible solar energy provides a promising solution to the impending energy shortage and stringent global warming. Limited by the chemical inertness of carbon dioxide molecules, the slow kinetics of multi-electron reactions, and the high recombination rate of photoinduced carriers in semiconductor photocatalysts, many design strategies aimed at developing efficient photocatalysts have been explored, such as single-atom design, facet control, defect engineering, and heterostructure construction. Despite these significant achievements, the low conversion efficiency and low selectivity of target products are still far from meeting the standards of practical industrial applications. From the perspective of carrier dynamics, further regulating carrier transfer to achieve specific migration paths, prolonging carrier lifetimes, and improving the utilization efficiency of photoinduced carriers in these efficient photocatalysts are crucial for further enhancing performance. Therefore, to achieve efficient CO2 conversion, it is highly necessary to design a photocatalyst with high visible light capture ability and high catalytic activity.
[0003] Adding piezoelectric nanomaterials to heterojunction photocatalysts is an effective method to promote the separation of photo-generated carriers. Barium titanate (BaTiO3) is a traditional piezoelectric material that exhibits excellent piezocatalytic performance and has been widely used in the field of piezophotocatalysis in recent years. Generally, the piezoelectric lattice deformation caused by external mechanical forces generates a piezoelectric polarization field, with negative and positive charges on its two opposite sides respectively, which guides the separation of photoelectrons and holes in opposite directions. Therefore, when simultaneously excited by ultrasonic vibration and light irradiation, piezoelectric-involved heterostructures, such as BaTiO3 / Ag2O, BaTiO3 / ZnO, BaTiO3 / TiO2, PbTiO3 / CdS, BiFeO3 / TiO2, and BiFeO3 / TpPa-1-COF, etc., the internal electric field caused by the piezoelectric response and the interfacial electric field at the heterojunction interface, along with appropriate band alignments, can synergistically promote the charge transfer process, thus effectively enhancing the carrier separation efficiency and achieving significantly improved piezophotocatalytic activity.
[0004] Currently, the reported methods for preparing BaTiO3-based heterojunction piezoelectric materials still have disadvantages such as complex preparation processes and high costs, which are not conducive to practical applications. In addition, it is necessary to select suitable semiconductor materials for coupling with it and prepare heteromaterials with high-efficiency piezophotocatalytic performance through simple preparation methods. Summary of the Invention
[0005] To avoid the deficiencies of the prior art, the present invention provides a preparation method for a BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst for CO2 reduction.
[0006] One of the objectives of the present invention is to provide a semiconductor material with suitable energy bands.
[0007] Another objective of the present invention is to provide a simple and feasible in-situ synthesis method.
[0008] A further objective of the present invention is to provide a BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst for CO2 reduction.
[0009] The BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst prepared by the present invention is prepared by an in-situ synthesis method using barium titanate, bismuth nitrate pentahydrate, sodium chloride, deionized water, and absolute ethanol as raw materials. The preparation process includes the following specific steps: 1. First, add 0.01 - 0.10 g of sodium chloride to 15 mL of deionized water, and reflux and heat in a three-necked flask to 100 - 150 °C; 2. Then, disperse 0.1 - 0.5 g of bismuth nitrate pentahydrate and 0.1 - 0.5 g of barium titanate in 20 mL of ethanol under ultrasonic treatment to obtain a suspension; 3. Drop the suspension obtained in step two into the sodium chloride solution in step one. Keep it at 100 - 150 °C for 3 - 5 h and then naturally cool to room temperature. Wash it several times with deionized water and absolute ethanol, and dry it in vacuum at 40 °C for 10 h to obtain the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst.
[0010] Advantages of the present invention: 1. The present invention provides a preparation method for a BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst for CO2 reduction, which is characterized by using barium titanate, bismuth nitrate pentahydrate, sodium chloride, deionized water, and absolute ethanol as raw materials and being prepared by an in-situ synthesis method. It only requires ordinary equipment commonly used in laboratories and does not require special equipment. Its process is simple and easy to operate; 2. This method provides a novel matrix - bismuth oxychloride, for preparing the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst for CO2 reduction; 3. The BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst obtained by this method has good cycle stability; 4. The drugs used in the present invention are inexpensive, the preparation is simple and takes a short time, and there is no need for complex and cumbersome steps after preparation. It is especially suitable for batch and low-cost preparation, and is suitable for industrial-scale production and commercial applications; 5. The BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst provided by the present invention can be successfully applied to fields such as piezoelectric photocatalytic CO2 reduction. Description of the Drawings
[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings in the description of the embodiments or the prior art. However, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0012] Figure 1 Transmission electron microscope (TEM) of the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst prepared in Example 1 of the present invention.
[0013] Figure 2 X-ray diffraction (XRD) pattern of the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst prepared in Example 1 of the present invention.
[0014] Figure 3 Absorption spectrum of the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst prepared in Example 1 of the present invention.
[0015] Figure 4 Yield and stability tests of piezoelectric photocatalytic CO2 reduction of the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst prepared in Example 1 of the present invention. Detailed Embodiments
[0016] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0017] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.
[0018] Unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods; unless otherwise specified, the reagents and materials can all be obtained in the market.
[0019] Example 1: First, 0.01 g of sodium chloride was added to 15 mL of deionized water, and the mixture was refluxed and heated to 100 °C in a three-necked flask; then, 0.1 g of bismuth nitrate pentahydrate and 0.1 g of barium titanate were dispersed in 20 mL of ethanol under ultrasound to obtain a suspension; the obtained suspension was dropped into the sodium chloride solution. After maintaining at 100 °C for 3 h, it was naturally cooled to room temperature, washed several times with deionized water and absolute ethanol, and dried in vacuo at 40 °C for 10 h to obtain the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst.
[0020] Example 2: First, 0.05 g of sodium chloride was added to 15 mL of deionized water, and the mixture was refluxed and heated to 120 °C in a three-necked flask; then, 0.2 g of bismuth nitrate pentahydrate and 0.2 g of barium titanate were dispersed in 20 mL of ethanol under ultrasound to obtain a suspension; the obtained suspension was dropped into the sodium chloride solution. After maintaining at 120 °C for 4 h, it was naturally cooled to room temperature, washed several times with deionized water and absolute ethanol, and dried in vacuo at 40 °C for 10 h to obtain the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst.
[0021] Example 3: First, 0.10 g of sodium chloride was added to 15 mL of deionized water, and the mixture was refluxed and heated to 150 °C in a three-necked flask; then, 0.5 g of bismuth nitrate pentahydrate and 0.5 g of barium titanate were dispersed in 20 mL of ethanol under ultrasound to obtain a suspension; the obtained suspension was dropped into the sodium chloride solution. After maintaining at 150 °C for 5 h, it was naturally cooled to room temperature, washed several times with deionized water and absolute ethanol, and dried in vacuo at 40 °C for 10 h to obtain the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst.
[0022] Comparative Example 1: First, 0.01 g of sodium chloride was added to 15 mL of deionized water, and the mixture was refluxed and heated to 50 °C in a three-necked flask; then, 0.1 g of bismuth nitrate pentahydrate and 0.1 g of barium titanate were dispersed in 20 mL of ethanol under ultrasound to obtain a suspension; the obtained suspension was dropped into the sodium chloride solution. After maintaining at 50 °C for 3 h, it was naturally cooled to room temperature, washed several times with deionized water and absolute ethanol, and dried in vacuo at 40 °C for 10 h to obtain the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst.
[0023] Comparative Example 2: First, 15 mL of deionized water was refluxed and heated to 150 °C in a three-necked flask. Then, 0.5 g of bismuth nitrate pentahydrate and 0.5 g of barium titanate were dispersed in 20 mL of ethanol under ultrasound to obtain a suspension. The obtained suspension was dropped into a sodium chloride solution. After maintaining at 150 °C for 5 h, it was naturally cooled to room temperature, washed several times with deionized water and absolute ethanol, and dried in vacuum at 40 °C for 10 h to obtain the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst.
[0024] Figure 1 TEM of the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst prepared in Example 1. From Figure 1 it can be seen that BaTiO3 is uniformly distributed on the BiOCl nanosheets.
[0025] Figure 2 XRD of the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst prepared in Example 1. From Figure 2 it can be seen that all the diffraction peaks point to the characteristic peaks of BaTiO3 and BiOCl.
[0026] Figure 3 Absorption spectrum of the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst prepared in Example 1. From Figure 3 it can be seen that its absorption cut-off edge is around 430 nm.
[0027] Figure 4 Performance test of the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst prepared in Example 1 for piezoelectric photocatalytic CO2 reduction. From Figure 4 it can be seen that the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst has excellent performance in piezoelectric photocatalytic CO2 reduction and good cycle stability. The results show that the prepared BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst is successfully used in the field of piezoelectric photocatalytic CO2 reduction.
Claims
1. A preparation method for a BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst for CO2 reduction, comprising the following steps: First, add 0.01 - 0.10 g of sodium chloride to 15 mL of deionized water, and reflux and heat in a three-necked flask to 100 - 150 °C; then disperse 0.1 - 0.5 g of bismuth nitrate pentahydrate and 0.1 - 0.5 g of barium titanate in 20 mL of ethanol under ultrasound to obtain a suspension; add the obtained suspension dropwise to the sodium chloride solution. After maintaining at 100 - 150 °C for 3 - 5 h, naturally cool to room temperature, wash several times with deionized water and absolute ethanol, and vacuum dry at 40 °C for 10 h to obtain the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst.
2. The preparation method of the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst according to claim 1, wherein The dosage of sodium chloride is 0.01 g, and the dosage of barium titanate is 0.1 g.
3. The preparation method of the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst according to claim 1, characterized in that, The dosage of bismuth nitrate pentahydrate is 0.1 g.
4. Application of the BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst prepared by the preparation method according to claim 1, characterized in that, The BiOCl / BaTiO3 heterojunction piezoelectric photocatalyst is applied to photocatalytic CO2 reduction.