A CO2 reduction CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst and a preparation method thereof

Abstract

The present application relates to a kind of for CO2 reduction CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst and its preparation method, the preparation method has the following steps: with bismuth oxychloride and lead nitrate is added to aqueous solution, freeze-drying after ultrasonic, by muffle furnace calcination, obtain precursor material;CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst is obtained by two-step calcination method again by adding cesium bromide and potassium bromide, dissolving, ultrasonic, freeze-drying, by muffle furnace calcination its feature is.CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst prepared has excellent performance and good cycle stability.The drug used in preparation is easily obtained and low in price, and preparation is simple and short in time.CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst prepared can be successfully applied in the field of photocatalytic CO2 reduction.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation technology, specifically relating to a photocatalyst for CO2 reduction of CsPbBr3 quantum dot / BiOCl heterojunction and its preparation method. Background Technology

[0002] The excessive consumption of fossil fuels and increased carbon dioxide emissions have exacerbated the energy crisis and global warming. Driving artificial photosynthesis with solar energy can not only reduce atmospheric CO2 levels but also produce valuable chemical fuels such as CO, CH4, and CH3OH. This provides an effective strategy for addressing the pressing energy shortage and severe global warming problems. Currently, design strategies for catalysts with high catalytic performance have been developed, such as single-atom design, facet control, defect engineering, and the construction of heterojunctions. Despite these excellent results, the low catalytic efficiency and poor selectivity of target products of these materials are far from meeting the requirements for practical industrial applications. Therefore, to achieve efficient CO2 conversion, it is essential to design a photocatalyst with high visible light capture capability and high catalytic activity.

[0003] CsPbBr3 quantum dots (QDs) have attracted widespread attention from researchers due to their excellent luminescent properties, simple preparation, and low cost. However, QDs suffer from severe charge recombination, resulting in poor conversion efficiency in CO2 photoreduction. This problem can be effectively solved by constructing heterojunctions to suppress charge recombination and promote charge separation. To date, various cocatalysts have been used to couple with QDs to construct heterojunctions, mainly including carbon materials, g-C3N4, noble metals, metal complexes, metal-organic frameworks, Mxenes, and conductive polymers. Cocatalysts have two functions: firstly, they provide additional channels for charge transfer to promote it; secondly, they can extract photogenerated electrons from QDs, which also suppresses carrier recombination to some extent. Although electron-hole pairs are separated in these heterojunctions, highly reducing electrons in the QDs are still sacrificed during the reaction, a phenomenon that is detrimental to the photocatalytic CO2 reduction reaction. Furthermore, current methods for preparing QDs-based heterostructures still suffer from drawbacks such as complex fabrication processes and high costs, hindering their practical applications. Therefore, designing highly efficient QDs-based heterojunction photocatalysts that simultaneously possess high charge separation efficiency and strong redox capabilities remains a pressing challenge. Summary of the Invention

[0004] To avoid the shortcomings of existing technologies, this invention provides a photocatalyst for CO2 reduction of CsPbBr3 quantum dot / BiOCl heterojunction and its preparation method.

[0005] One of the objectives of this invention is to provide a suitable semiconductor material.

[0006] The second objective of this invention is to provide a simple and easy-to-implement two-step calcination method.

[0007] The third objective of this invention is to provide a photocatalyst for CO2 reduction of CsPbBr3 quantum dot / BiOCl heterojunction.

[0008] The photocatalyst for CO2 reduction of CsPbBr3 quantum dot / BiOCl heterojunction prepared in this invention is prepared by a two-step calcination method using bismuth oxychloride, cesium bromide, potassium bromide, and lead nitrate as raw materials. The preparation process includes the following specific steps:

[0009] 1. First, add 0.1-0.5 g of bismuth oxychloride and 5-10 mg of lead nitrate to 1 mL of deionized water, sonicate for 1-3 h, mix thoroughly, and freeze-dry for 10-20 h to obtain a white powder;

[0010] 2. Place the obtained white powder in a covered crucible and calcine it in a muffle furnace at 450-650℃ for 1-3 hours to obtain a yellow powder;

[0011] 3. Add the yellow powder obtained in step 1, 1-5 mg of potassium bromide and 1-5 mg of cesium bromide to 1 mL of deionized water, sonicate for 1-3 h, mix thoroughly, freeze dry for 10-20 h to obtain the yellow powder;

[0012] 4. Place the obtained yellow powder in a covered crucible and calcine it in a muffle furnace at 450-650℃ for 1-3 h to obtain a CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst.

[0013] The beneficial effects of this invention are:

[0014] 1. This invention provides a photocatalyst for CO2 reduction of CsPbBr3 quantum dot / BiOCl heterojunction and its preparation method. It is characterized by using bismuth oxychloride, cesium bromide, potassium bromide and lead oxide as raw materials, and preparing it through a two-step calcination method. It only requires common laboratory equipment and does not require special equipment. The process is simple and easy to operate.

[0015] 2. This method provides a novel matrix—bismuth oxychloride—for preparing a photocatalyst for CO2 reduction of CsPbBr3 quantum dot / BiOCl heterojunction.

[0016] 3. The CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst obtained by this method exhibits good cycle stability;

[0017] 4. The drugs used in this invention are inexpensive, simple to prepare, and quick to prepare. After preparation, no complicated or tedious steps are required, making it particularly suitable for batch and low-cost preparation, and suitable for industrial-scale production and commercial applications.

[0018] 5. The CsPbBr3 quantum dot / BiOCl heterojunction catalyst provided by this invention can be successfully applied to the field of photocatalytic CO2 reduction. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings will be briefly introduced in the description of the embodiments or the prior art below. However, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 Transmission electron microscopy (TEM) of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst prepared in Example 1 of this invention.

[0021] Figure 2 The image shows the X-ray diffraction (XRD) pattern of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst prepared in Example 1 of this invention.

[0022] Figure 3 The absorption spectrum of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst prepared in Example 1 of this invention is shown.

[0023] Figure 4 Performance testing of CsPbBr3 quantum dot / BiOCl heterojunction photocatalytic CO2 reduction prepared in Examples 1-3 and Comparative Example 1 of this invention.

[0024] Figure 5 Stability test of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalytic CO2 reduction prepared in Example 1 of this invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0027] Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0028] Example 1:

[0029] First, 0.1 g of bismuth oxychloride and 5 mg of lead nitrate were added to 1 mL of deionized water, sonicated for 1 h, thoroughly mixed, and freeze-dried for 10 h to obtain a white powder. The white powder was then placed in a covered crucible and calcined in a muffle furnace at 450 °C for 1 h to obtain a yellow powder. The obtained yellow powder, 1 mg of potassium bromide, and 1 mg of cesium bromide were added to 1 mL of deionized water, sonicated for 1 h, thoroughly mixed, and freeze-dried for 10 h to obtain another yellow powder. The yellow powder was then placed in a covered crucible and calcined in a muffle furnace at 450 °C for 1 h to obtain a CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst.

[0030] Example 2:

[0031] First, 0.2 g of bismuth oxychloride and 7 mg of lead nitrate were added to 1 mL of deionized water, sonicated for 2 h, thoroughly mixed, and freeze-dried for 15 h to obtain a white powder. The white powder was then placed in a covered crucible and calcined in a muffle furnace at 500 °C for 2 h to obtain a yellow powder. The obtained yellow powder, 3 mg of potassium bromide, and 3 mg of cesium bromide were added to 1 mL of deionized water, sonicated for 2 h, thoroughly mixed, and freeze-dried for 15 h to obtain another yellow powder. The yellow powder was then placed in a covered crucible and calcined in a muffle furnace at 500 °C for 2 h to obtain a CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst.

[0032] Example 3:

[0033] First, 0.3 g of bismuth oxychloride and 10 mg of lead nitrate were added to 1 mL of deionized water, sonicated for 3 h, thoroughly mixed, and freeze-dried for 20 h to obtain a white powder. The white powder was then placed in a covered crucible and calcined in a muffle furnace at 550 °C for 3 h to obtain a yellow powder. The obtained yellow powder, 5 mg of potassium bromide, and 5 mg of cesium bromide were added to 1 mL of deionized water, sonicated for 3 h, thoroughly mixed, and freeze-dried for 20 h to obtain another yellow powder. The yellow powder was then placed in a covered crucible and calcined in a muffle furnace at 450 °C for 1 h to obtain a CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst.

[0034] Comparative Example 1:

[0035] 0.1 g of bismuth oxychloride, 5 mg of lead nitrate, 1 mg of potassium bromide and 1 mg of cesium bromide were added to 1 mL of deionized water, sonicated for 1 h, thoroughly mixed, and freeze-dried for 10 h to obtain a white powder. The obtained white powder was placed in a covered crucible and calcined in a muffle furnace at 450 °C for 1 h to obtain a CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst.

[0036] Figure 1 TEM images of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst prepared in Example 1, from... Figure 1 It can be seen that CsPbBr3 quantum dots are uniformly distributed in BiOCl nanosheets.

[0037] Figure 2 XRD analysis of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst prepared in Example 1, from... Figure 2 It can be seen that all the diffraction peaks point to the characteristic peaks of CsPbBr3 and BiOCl.

[0038] Figure 3 The absorption spectrum of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst prepared in Example 1 is shown below. Figure 3 It can be seen that its absorption cutoff edge is around 460nm.

[0039] Figure 4 Performance testing of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalytic CO2 reduction prepared in Examples 1-3 and Comparative Example 1 of this invention. Figure 4 It can be seen that the CsPbBr3 quantum dot / BiOCl heterojunction photocatalytic CO2 reduction performance prepared in Example 1 is much higher than that prepared in Examples 2, 3 and Comparative Example 1.

[0040] Figure 5 The stability of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalytic CO2 reduction prepared in Example 1 of this invention was tested. Figure 5 It can be seen that the CsPbBr3 quantum dot / BiOCl heterojunction prepared in Example 1 exhibits good stability in photocatalytic CO2 reduction.

Claims

1. A method for preparing a CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst for CO2 reduction, comprising the following steps: First, add 0.1-0.5g of bismuth oxychloride and 0.005-0.010g of lead nitrate to 1mL of deionized water, sonicate for 1-3 hours to mix thoroughly, and freeze-dry for 10-20 hours to obtain a white powder. Place the white powder in a covered crucible and calcine it in a muffle furnace at 450-650℃ for 1-3 hours to obtain a yellow powder. Add the obtained yellow powder, 0.001-0.005g of potassium bromide, and 0.001-0.005g of cesium bromide to 1mL of deionized water, sonicate for 1-3 hours to mix thoroughly, and freeze-dry for 10-20 hours to obtain a yellow powder. Place the obtained yellow powder in a covered crucible and calcine it in a muffle furnace at 450-650℃ for 1-3 hours to obtain a CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst.

2. The preparation method of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst according to claim 1, characterized in that, The amount of bismuth oxychloride used is 0.1 g, and the amount of lead nitrate used is 0.005 g.

3. The preparation method of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst according to claim 1, characterized in that, The amount of potassium bromide used is 0.001 g, and the amount of cesium bromide used is 0.001 g.

4. The application of the CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst prepared by the method according to claim 1, characterized in that, The CsPbBr3 quantum dot / BiOCl heterojunction photocatalyst is used for photocatalytic CO2 reduction.

Images