Preparation method and application of BiOBr for electrocatalytic reduction of oxygen

Abstract

The invention discloses a preparation method and application of BiOBr for electrocatalytic reduction of oxygen, and the method comprises the following steps: adding a Bi precursor and a surfactant into a solution to obtain a mixed solution; adding a Br precursor into the mixed solution to obtain a mixture, transferring the mixture into a polytetrafluoroethylene lining, and putting the polytetrafluoroethylene lining into a stainless steel shell; the polytetrafluoroethylene lining and the stainless steel shell react in a blast oven, after the reaction is finished, reaction liquid is poured out, the reaction liquid is centrifuged to obtain sediment, the sediment is repeatedly washed with deionized water and ethyl alcohol for multiple times, and BiOBr is obtained; the BiOBr is applied to a reaction for reducing oxygen 2e <-> into H2O2 through electro-catalysis. The preparation method has the beneficial effects that the operation is simple, the raw materials in the method are safe, the cost is low, and the selectivity is high; biOBr has high catalytic property in an alkaline solution, so that oxygen is converted into H2O2 in a 2e-path.

Description

Technical Field

[0001] The present invention relates to the field of electrocatalysis technology, and in particular to a preparation method and application of BiOBr for electrocatalytic reduction of oxygen. Background Art

[0002] As a common compound, hydrogen peroxide is widely used in textile bleaching, papermaking, wastewater treatment, medical disinfection and chemical synthesis, so it has a great market demand. At present, the industrial production of H2O2 still relies on the traditional anthraquinone method, which has the disadvantages of low yield, high energy consumption and serious pollution. Electrocatalytic oxygen reduction can directly produce H2O2, and the process is green and efficient, so it has great application prospects.

[0003] BiOBr is a common bismuth oxyhalide material. 2+ and [Br] - They are intertwined and arranged to form [-Br-Bi-OO-Bi-Br-] layers along the c-axis, thus forming a built-in electric field inside them, which promotes the separation of photogenerated electrons and holes. They are widely used in the degradation of organic matter, but there is no application in the electrocatalytic reduction of oxygen 2e- to H2O2.

[0004] Therefore, it is very necessary to propose a simple, raw material-safe, non-toxic, pollution-free, low-cost, and highly selective BiOBr preparation method, and to apply the prepared product to the electrocatalytic reduction of oxygen 2e- to H2O2. Summary of the invention

[0005] In order to solve the above problems, especially to address the deficiencies in the prior art, the present invention provides a method for preparing BiOBr for electrocatalytic reduction of oxygen and its application, which can solve the above problems.

[0006] To achieve the above purpose, the present invention adopts the following technical means:

[0007] A method for preparing BiOBr for electrocatalytic reduction of oxygen, the method comprising the following steps:

[0008] (1) Adding Bi precursor and surfactant into the solution and stirring evenly to obtain a mixed solution;

[0009] (2) adding a Br precursor to the mixed solution of step (1), stirring evenly to obtain a mixture, transferring the mixture to a polytetrafluoroethylene liner, and placing the polytetrafluoroethylene liner in a stainless steel housing;

[0010] (3) reacting the polytetrafluoroethylene liner in step (2) together with the stainless steel shell in a blast oven at a temperature of 130-150° C. for a reaction time of 2-4 h. After the reaction is completed, cool to room temperature, remove the polytetrafluoroethylene liner, pour out the reaction solution, centrifuge the reaction solution to obtain a precipitate, wash the precipitate repeatedly with deionized water and ethanol for several times, and dry at 55-65° C. for 12-24 h to obtain BiOBr.

[0011] A further solution of the present invention is that the Bi precursor is a soluble metal compound Bi(NO3)3·5H2O; the surfactant is polyvinyl pyrrolidone; and the solution is a mixed solution of deionized water and ethylene glycol, with a volume ratio of 1:5.

[0012] A further embodiment of the present invention is that the stirring time in step (1) is 30-60 min; and the stirring time in step (2) is 10-30 min.

[0013] A further embodiment of the present invention is that the Br precursor is a soluble bromide salt, and the bromide salt includes any one of potassium bromide and 1-butyl-3-methylimidazolium bromide.

[0014] A further embodiment of the present invention is that the molar ratio of the Bi precursor to the Br precursor is 1:1 to 1:1.2.

[0015] A further solution of the present invention is to react the polytetrafluoroethylene liner in step (2) together with the stainless steel shell in a blast oven, the temperature of the blast oven is 140° C., the reaction time is 3 h, after the reaction is completed, the polytetrafluoroethylene liner is taken out after cooling to room temperature, the reaction liquid is poured out, the reaction liquid is centrifuged to obtain a precipitate, the precipitate is repeatedly washed with deionized water and ethanol for 6 times, and dried at 65° C. for 12 h to obtain BiOBr.

[0016] A further solution of the present invention is that the BiOBr is in a flower-like structure, and the flower-like structure is self-assembled from a plurality of BiOBr nanosheets.

[0017] Another object of the present invention is to provide BiOBr prepared by a method for preparing BiOBr for electrocatalytic reduction of oxygen.

[0018] Another object of the present invention is to provide an application of BiOBr of the present invention, wherein the BiOBr is used in electrocatalytic oxidation of oxygen 2e - The application of the reduction reaction to H2O2 is as follows: the prepared BiOBr is mixed with XC-72R in a mass ratio of 3:2, and the mixture is prepared into ink and coated on a glassy carbon electrode. After drying, the ink is used as a working electrode in an oxygen-saturated 0.1M KOH solution to test the performance of the electrocatalytic reduction of oxygen to hydrogen peroxide.

[0019] Beneficial effects of the present invention:

[0020] The present invention provides a preparation method of BiOBr, which is simple to operate, has safe raw materials, low cost and high selectivity; the BiOBr prepared by the present invention has high catalytic activity in alkaline solution, and can convert oxygen into 2e - Pathway converted to H2O2. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the X-ray diffraction pattern (XRD) of BiOBr of the present invention;

[0022] Figure 2 is a scanning electron microscope image (SEM) of the BiOBr of the present invention;

[0023] Figure 3 Graph showing the selectivity of the electrocatalytic reduction of oxygen to produce H2O2 by BiOBr of the present invention;

[0024] Figure 4 This is a disk-ring electrode current density diagram of the electrocatalytic reduction of oxygen to generate H2O2 by BiOBr of the present invention;

[0025] Figure 5 Figure 2 is a diagram of the number of transferred electrons during the electrocatalytic reduction of oxygen to produce H2O2 by BiOBr of the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1

[0028] A method for preparing BiOBr for electrocatalytic reduction of oxygen, the method comprising the following steps:

[0029] (1) Adding a Bi precursor and a surfactant into a solution, wherein the Bi precursor is a soluble metal compound Bi(NO3)3·5H2O, the surfactant is polyvinyl pyrrolidone, and the solution is a mixed solution of deionized water and ethylene glycol, the volume ratio of the two being 1:5, stirring evenly for 30-60 min to obtain a mixed solution;

[0030] (2) Adding a Br precursor to the mixed solution of step (1), wherein the molar ratio of the Bi precursor to the Br precursor is 1:1 to 1:1.2, wherein the Br precursor is a soluble bromine salt, wherein the bromine salt includes any one of potassium bromide and 1-butyl-3-methylimidazolium bromide, stirring evenly for 10-30 min to obtain a mixture, transferring the mixture to a polytetrafluoroethylene liner, and placing the polytetrafluoroethylene liner in a stainless steel housing;

[0031] (3) reacting the polytetrafluoroethylene liner in step (2) together with the stainless steel shell in a blast oven at a temperature of 130-150° C. for a reaction time of 2-4 h. After the reaction is completed, the polytetrafluoroethylene liner is removed after cooling to room temperature, the reaction solution is poured out, and the reaction solution is centrifuged to obtain a precipitate. The precipitate is repeatedly washed with deionized water and ethanol for several times, and dried at 55-65° C. for 12-24 h to obtain BiOBr. The BiOBr has a flower-like structure, and the flower-like structure is self-assembled by multiple BiOBr nanosheets.

[0032] A method for preparing BiOBr for electrocatalytic reduction of oxygen to obtain BiOBr. - The application of the reduction reaction to H2O2 is as follows: the prepared BiOBr is mixed with XC-72R in a mass ratio of 3:2, and the mixture is prepared into ink and coated on a glassy carbon electrode. After drying, the ink is used as a working electrode in an oxygen-saturated 0.1M KOH solution to test the performance of the electrocatalytic reduction of oxygen to hydrogen peroxide.

[0033] Example 2

[0034] 0.97 g Bi(NO3)3·5H2O and 0.8 g polyvinyl pyrrolidone were added to a mixed solution of 10 ml deionized water and 50 ml ethylene glycol, and the mixture was stirred for 30 min. Then, 0.25 g KBr was added and the mixture was stirred for 10 min. The mixture was transferred to a polytetrafluoroethylene liner, and the polytetrafluoroethylene liner was placed in a stainless steel shell. The polytetrafluoroethylene liner and the stainless steel shell were reacted in a blast oven at 140°C for 3 h. After the reaction, the liner was taken out, the reaction solution was poured out, and the mixture was centrifuged. The precipitate was repeatedly washed with deionized water and ethanol for 6 times, and dried at 65°C for 12 h to obtain BiOBr.

[0035] Example 3

[0036] 0.97 g Bi(NO3)3·5H2O and 0.8 g polyvinyl pyrrolidone were added to a mixed solution of 10 ml deionized water and 50 ml ethylene glycol, and the mixture was stirred for 30 min. Then, 0.48 g 1-butyl-3-methylimidazolium bromide was added and the mixture was stirred for 10 min. The mixture was transferred to a polytetrafluoroethylene liner, and the polytetrafluoroethylene liner was placed in a stainless steel shell. The polytetrafluoroethylene liner and the stainless steel shell were reacted in a blast oven at 140°C for 3 h. After the reaction was completed, the liner was taken out, the reaction solution was poured out, and the mixture was centrifuged. The precipitate was repeatedly washed with deionized water and ethanol for 6 times, and dried at 65°C for 12 h to obtain BiOBr.

[0037] The obtained product was subjected to X-ray diffraction, and its spectrum was consistent with the standard card JCPDS:, and the obtained product was BiOBr crystal, such as Figure 1 shown.

[0038] The prepared product was photographed under a scanning electron microscope. Figure 2 As shown, the product has a flower-like structure with a diameter of 500-700nm and a thickness of 10-20nm for the nanosheets.

[0039] The prepared BiOBr was mixed with XC-72R in a mass ratio of 3:2, and dispersed in a mixed solution of isopropanol, water, and Nafion at 5 mg / ml. After ultrasonication at 20% power for 10 minutes in an ultrasonic crusher, a uniformly mixed ink was obtained. An appropriate amount was dropped on the glassy carbon electrode and used as the working electrode after natural drying. The test system was a three-electrode system, with the Ag / AgCl electrode as the reference electrode, the platinum mesh as the counter electrode, and the glassy carbon electrode as the working electrode; the test environment was an oxygen-saturated 0.1M KOH solution, the potential scanning range was 1.0-0V relative to the reversible hydrogen electrode, the potential scanning speed was 5mV / s, and the rotating disk speed was 1600rpm. The test results are as follows Figure 3 , Figure 4 , Figure 5 shown.

[0040] The examples given in the present invention are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here, and the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for preparing BiOBr for electrocatalytic reduction of oxygen, characterized in that: The method comprises the following steps: (1) Adding Bi precursor and surfactant into the solution and stirring evenly to obtain a mixed solution; (2) adding a Br precursor to the mixed solution of step (1), stirring evenly to obtain a mixture, transferring the mixture to a polytetrafluoroethylene liner, and placing the polytetrafluoroethylene liner in a stainless steel housing; (3) reacting the polytetrafluoroethylene liner in step (2) together with the stainless steel shell in a blast oven at a temperature of 130-150° C. for a reaction time of 2-4 h. After the reaction is completed, cool to room temperature, remove the polytetrafluoroethylene liner, pour out the reaction solution, centrifuge the reaction solution to obtain a precipitate, wash the precipitate repeatedly with deionized water and ethanol for several times, and dry at 55-65° C. for 12-24 h to obtain BiOBr.

2. The method for preparing a catalytic material in which single atoms and nanoparticles coexist according to claim 1, characterized in that: The Bi precursor is a soluble metal compound Bi(NO3)3·5H2O; the surfactant is polyvinyl pyrrolidone; and the solution is a mixed solution of deionized water and ethylene glycol, with a volume ratio of 1:

5.

3. The method for preparing BiOBr for electrocatalytic reduction of oxygen according to claim 1, characterized in that: The stirring time in step (1) is 30-60 min; the stirring time in step (2) is 10-30 min.

4. The method for preparing BiOBr for electrocatalytic reduction of oxygen according to claim 1, characterized in that: The Br precursor is a soluble bromide salt, and the bromide salt includes any one of potassium bromide and 1-butyl-3-methylimidazolium bromide.

5. The method for preparing BiOBr for electrocatalytic reduction of oxygen according to claim 1, characterized in that: The molar ratio of the Bi precursor to the Br precursor is 1:1 to 1:1.

2.

6. The method for preparing BiOBr for electrocatalytic reduction of oxygen according to claim 1, characterized in that: The polytetrafluoroethylene liner in step (2) and the stainless steel shell are reacted in a blast oven at a temperature of 140°C for a reaction time of 3 hours. After the reaction is completed, the polytetrafluoroethylene liner is taken out after cooling to room temperature, the reaction solution is poured out, and the reaction solution is centrifuged to obtain a precipitate. The precipitate is repeatedly washed with deionized water and ethanol for 6 times, and dried at 65°C for 12 hours to obtain BiOBr.

7. The method for preparing BiOBr for electrocatalytic reduction of oxygen according to claim 1, characterized in that: The BiOBr has a flower-like structure, and the flower-like structure is self-assembled from a plurality of BiOBr nanosheets.

8. BiOBr prepared according to the method for preparing BiOBr for electrocatalytic reduction of oxygen according to any one of claims 1 to 7.

9. The use of BiOBr according to claim 8, characterized in that: The BiOBr electrocatalyzes the oxidation of 2e - The application of the reduction reaction to H2O2 is as follows: the prepared BiOBr is mixed with XC-72R in a mass ratio of 3:2, and the mixture is prepared into ink and coated on a glassy carbon electrode. After drying, the ink is used as a working electrode in an oxygen-saturated 0.1M KOH solution to test the performance of the electrocatalytic reduction of oxygen to hydrogen peroxide.

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