阅读说明：本技术 一种间接取代法构建氯空位氯氧化铋高活性光催化材料的合成方法 (Synthesis method for constructing chlorine vacancy bismuth oxychloride high-activity photocatalytic material by indirect substitution method ) 是由 王学文 王金桃 张荣斌 于 2021-07-28 设计创作，主要内容包括：本发明涉及一种间接取代法构建氯空位氯氧化铋高活性光催化材料的合成方法,以甘油为反应溶剂,五水硝酸铋、氯化钾和碘化钠为前驱体,在反应过程中甘油分子中的羟基与碘氯氧化铋固溶体(BiOCl-(1-x)I-(x))中的碘离子形成化学键合,形成氯空位。该间接取代法构建氯空位氯氧化铋高活性光催化材料的合成方法,以甘油水溶液为反应溶剂,通过甘油修饰后,BiOCl-(1-x)的价带位置更正,与传统用乙醇制备的BiOCl-(1-x)I-(x)相比,氧化能力大幅提升；以甘油水溶液为反应溶剂,构建了含有氯空位的BiOCl-(1-x),提高了光催化降解有机污染物和重金属离子的效率,通过甘油分子构建碘空位后,BiOCl-(1-x)的比表面积大大增加,为光催化反应提供了更多的活性位点,有利于催化剂表面吸附更多的有机分子,从而提高光催化降解效率。(The invention relates to a synthesis method for constructing a chlorine vacancy bismuth oxychloride high-activity photocatalytic material by an indirect substitution method, which takes glycerin as a reaction solvent, bismuth nitrate pentahydrate, potassium chloride and sodium iodide as precursors, and hydroxyl in glycerin molecules and bismuth oxychloride iodide solid solution (BiOCl) in the reaction process 1‑x I x ) The iodine ions in the solution form chemical bonding to form chlorine vacancies. The synthesis method for constructing the chlorine vacancy bismuth oxychloride high-activity photocatalytic material by the indirect substitution method comprises the steps of taking a glycerol aqueous solution as a reaction solvent, modifying by glycerol, and then obtaining BiOCl 1‑x Correction of valence band position of (A) with BiOCl prepared conventionally with ethanol 1‑x I x Compared with the prior art, the oxidation capacity is greatly improved; uses glycerin water solution as reaction solvent to construct BiOCl containing chlorine vacancy 1‑x The efficiency of photocatalytic degradation of organic pollutants and heavy metal ions is improved, and after iodine vacancies are constructed through glycerol molecules, BiOCl 1‑x The specific surface area of the catalyst is greatly increased, more active sites are provided for photocatalytic reaction, and the surface of the catalyst is favorable for adsorbing more organic molecules, so that the photocatalytic degradation efficiency is improved.)

1. A synthetic method for constructing a chlorine vacancy bismuth oxychloride high-activity photocatalytic material by an indirect substitution method is characterized by comprising the following steps of: using glycerin as reaction solvent, bismuth nitrate pentahydrate, potassium chloride and sodium iodide as precursors, and using hydroxyl in glycerin molecule and bismuth oxychloride sosoloid (BiOCI) as raw material_1-xI_x) The iodine ions in the solution form chemical bonding to form chlorine vacancies;

the method specifically comprises the following steps:

s1: weighing 1mmol of bismuth nitrate pentahydrate, adding a certain amount of deionized water, and performing ultrasonic dispersion;

s2: measuring a certain amount of glycerol, adding the glycerol into the solution in S1, and stirring the mixed solution at room temperature until the mixed solution is uniformly mixed;

s3: weighing 1mmol of KCI and Nal according to a stoichiometric ratio and dissolving in deionized water;

s4: dropwise adding the solution in the S3 into the solution in the S2, and stirring the mixed solution at room temperature;

s5: transferring the mixed solution in the S4 into a 100mL reaction kettle, and reacting for a period of time at a certain temperature;

s6: cooling the reaction kettle in S5 to room temperature and taking out to obtain BiOCI_1-xStanding the suspension for 1h, and pouring out the supernatant;

s7: washing the precipitate left in S6 with deionized water for 3-5 times, and collecting solid powder;

s8: drying the solid powder collected in S7 at 80 deg.C for 12h to obtain BiOCI_1-x。

2. The synthesis method for constructing the high-activity bismuth oxychloride photocatalytic material with the chlorine vacancy by the indirect substitution method according to claim 1, is characterized in that: the using amount of the deionized water in the S1 is 2-20 mL.

3. The synthesis method for constructing the high-activity bismuth oxychloride photocatalytic material with the chlorine vacancy by the indirect substitution method according to claim 1, is characterized in that: the dosage of the glycerol in the S2 is 15-45 mL.

4. The synthesis method for constructing the high-activity bismuth oxychloride photocatalytic material with the chlorine vacancy by the indirect substitution method according to claim 1, is characterized in that: the dosage of KCI in S3 is 0.015-0.06g, and the dosage of Nal is 0.03-0.12 g.

5. The synthesis method for constructing the high-activity bismuth oxychloride photocatalytic material with the chlorine vacancy by the indirect substitution method according to claim 1, is characterized in that: the reaction temperature in the S5 is 110-160 ℃, and the reaction time is 6-15 h.

6. The indirect substitution method for constructing the chlorine-vacancy bismuth oxychloride high-activity photocatalytic material according to claim 1The synthesis method is characterized in that: the BiOCI_1-xMainly flower-like nanospheres.

Technical Field

The invention relates to the technical field of photocatalysis, in particular to a synthesis method for constructing a chlorine vacancy bismuth oxychloride high-activity photocatalytic material by an indirect substitution method.

Background

Under the background of continuous social progress and continuous rising of the demand of people for good life, in order to maintain high-quality life and meet the development of various industries, the discharge amount of industrial wastewater and domestic sewage is increased year by year, so that the problem of water resource shortage is more serious, and the problem of environmental pollution is more prominent, therefore, the water pollution prevention and treatment and the effective sewage treatment are very important.

Photocatalysis is a green energy technology with great potential, has the advantages of high efficiency, greenness and the like in the aspect of water pollution treatment, and is expected to realize the technology of energy substitution and environmental purification, however, the semiconductor photocatalysis material has weak oxidation capacity and low utilization rate of solar energy, and is a key problem which restricts photocatalysis from basic research to industrial application.

As a typical layered ternary oxide semiconductor material, bismuth oxychloride (BiOCl) has the advantages of water decomposition to produce hydrogen, degrading pollutants and CO₂Potential application value in the aspects of photoreduction and the like, in the crystal lattice of BiOCl, [ Bi ]₂O₂]²⁺Cl of layer present in bilayer^-A non-polar structure is formed between the layers to generate a built-in electric field, which is beneficial to modifying the surface of the layer and improving the photocatalytic performance of the layer, and the defects of weaker oxidation capability of the catalyst, high recombination rate of photo-generated electron-hole pairs and the like restrict the application of the layer in the field of photocatalytic degradation of the layer_1-x) These problems can be effectively improved, and such a method has been rarely reported.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a synthesis method for constructing a chlorine vacancy bismuth oxychloride high-activity photocatalytic material by an indirect substitution method, which has the advantage of improving the photocatalytic degradation efficiency and solves the problems that the photo-generated electrons and holes of BiOCl are easy to be compounded and the valence band oxidation capability is weak.

In order to achieve the purpose, the invention provides the following technical scheme: a process for preparing the high-activity photocatalytic material of Cl-vacancy bismuth oxychloride by indirect substitution method features that glycerin is used as reaction solvent, bismuth nitrate pentahydrate, potassium chloride and sodium iodide are used as precursors, and the hydroxyl group in glycerin molecule and the solid solution of bismuth oxychloride iodide (BiOCl) are reacted_1-xl_x) The iodine ions in the solution form chemical bonding to form chlorine vacancies.

The method specifically comprises the following steps:

s1: weighing 1mmol of bismuth nitrate pentahydrate, adding a certain amount of deionized water, and performing ultrasonic dispersion;

s2: measuring a certain amount of glycerol, adding the glycerol into the solution in S1, and stirring the mixed solution at room temperature until the mixed solution is uniformly mixed;

s3: weighing 1mmol of KCl and Nal according to a stoichiometric ratio and dissolving in deionized water;

s4: dropwise adding the solution in the S3 into the solution in the S2, and stirring the mixed solution at room temperature;

s5: transferring the mixed solution in the S4 into a 100mL reaction kettle, and reacting for a period of time at a certain temperature;

s6: cooling the reaction kettle in S5 to room temperature and taking out to obtain BiOCl_1-xStanding the suspension for 1h, and pouring out the supernatant;

s7: washing the precipitate left in S6 with deionized water for 3-5 times, and collecting solid powder;

s8: drying the solid powder collected in S7 at 80 deg.C for 12h to obtain BiOCl_1-x。

Furthermore, the dosage of the deionized water in the S1 is 2-20 mL.

Further, the dosage of the glycerol in the S2 is 15-45 mL.

Furthermore, the dosage of KCl in S3 is 0.015-0.06g, and the dosage of Nal is 0.03-0.12 g.

Further, the reaction temperature in the S5 is 110-160 ℃, and the reaction time is 6-15 h.

Further, the BiOCl_1-xMainly flower-like nanospheres.

Compared with the prior art, the technical scheme of the application has the following beneficial effects:

1. the synthesis method for constructing the chlorine vacancy bismuth oxychloride high-activity photocatalytic material by the indirect substitution method comprises the steps of taking a glycerol aqueous solution as a reaction solvent, modifying by glycerol, and then obtaining BiOCl_1-xCorrection of valence band position of (A) with BiOCl prepared conventionally with ethanol_1-xl_xCompared with the prior art, the oxidation capacity is greatly improved; uses glycerin water solution as reaction solvent to construct BiOCl containing chlorine vacancy_1-xThe efficiency of photocatalytic degradation of organic pollutants and heavy metal ions is improved.

2. The synthesis method for constructing the high-activity photocatalytic material of chlorine vacancy bismuth oxychloride by the indirect substitution method comprises the following steps of modifying by glycerol molecules, and then preparing the BiOCl_1-xThe specific surface area of the catalyst is greatly increased, more active sites are provided for photocatalytic reaction, and the surface of the catalyst is favorable for adsorbing more organic molecules, so that the photocatalytic degradation efficiency is improved; after modification by glycerol molecules, BiOCl_1-xThe atomic structure on the surface is reconstructed, so that the recombination rate of photoproduction electrons and holes is reduced, the light utilization rate is improved, and the photocatalytic reaction is facilitated.

Drawings

FIG. 1 is BiOCl prepared with aqueous glycerol solution_1-xBiOCl prepared from glycerin aqueous solution and BiOCl prepared from ethanol_1-xl_xAn XRD pattern of (a);

FIG. 2 is BiOCl prepared with aqueous glycerol solution_1-x(a) BiOCl (b) prepared with aqueous glycerol solution and BiOCl prepared with ethanol_1-xl_x(c) SEM picture of (1);

FIG. 3 is BiOCl prepared with aqueous glycerol solution_1-xBiOCl prepared from glycerin aqueous solution and BiOCl prepared from ethanol_1-xl_xUltraviolet-visible absorption spectrum of (1);

FIG. 4 is BiOCl prepared with aqueous glycerol solution_1-xBiOCl prepared from glycerin aqueous solution and BiOCl prepared from ethanol_1-xl_xA degradation curve map of 35mg/L Cr (VI);

FIG. 5 shows BiOCl_1-xDegrading heavy metal ions Cr (VI) absorbance change curve map along with time under the ultraviolet irradiation.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A process for preparing the high-activity photocatalytic material of Cl-vacancy bismuth oxychloride by indirect substitution method features that glycerin is used as reaction solvent, bismuth nitrate pentahydrate, potassium chloride and sodium iodide are used as precursors, and the hydroxyl group in glycerin molecule and the solid solution of bismuth oxychloride iodide (BiOCl) are reacted_1-xl_x) The iodine ions in the catalyst form chemical bonding to form chlorine vacancies, regulate and control the position of a valence band and enhance the oxidation capability of the catalyst.

The method specifically comprises the following steps:

s1: weighing 1mmol of bismuth nitrate pentahydrate, adding a certain amount of deionized water, and performing ultrasonic dispersion for 2 min;

s2: measuring a certain amount of glycerol, adding the glycerol into the solution in S1, and stirring the mixed solution for 30min at room temperature;

s3: weighing 1mmol of KCl and Nal according to a stoichiometric ratio, and dissolving in 2mL of deionized water;

s4: dropwise adding the solution in the S3 into the solution in the S2, and stirring the mixed solution at room temperature for 1 h;

s5: transferring the mixed solution in the S4 into a 100mL reaction kettle, and reacting for a period of time at a certain temperature;

s6: cooling the reaction kettle in S5 to room temperature and taking out to obtain BiOCl_1-xStanding the suspension for 1h, and pouring out the supernatant;

s7: washing the precipitate left in S6 with deionized water for 3-5 times, and collecting solid powder;

s8: drying the solid powder collected in S7 at 80 deg.C for 12h to obtain BiOCl_1-x。

In this embodiment, the amount of deionized water in S1 is 2 to 10 mL; the using amount of the glycerol in the S2 is 20-40 mL; the dosage of KCl in S3 is 0.015-0.06g, and the dosage of Nal is 0.03-0.12 g; the reaction temperature in S5 is 120-150 ℃, and the reaction time is 10-13 h.

Note that BiOCl_1-xMainly flower-like nanospheres.

The invention uses glycerin to replace BiOCl under hydrothermal condition_1-xIn the process, 0 atom of a glycerol hydroxyl hollow orbit is easy to form a bond with iodide ions with a plurality of lone electrons at high temperature and high pressure to indirectly construct bismuth oxychloride (BiOCl) with chlorine vacancy_1-x) Finally, the glycerol on the surface of the catalyst is removed by washing with deionized water to obtain the bismuth oxychloride (BiOCl) for constructing chlorine vacancy by indirect substitution_1-x) BiOCl obtainable by EDX, prepared with ethanol_1-xl_xBiOCl prepared with an aqueous solution of glycerol at a Bi/I ratio of 1: 0.347_1-xThe ratio of Bi to l of (B) is 1: 0.073, BiOCl_1-xBi/I ratio BiOCl of_{1- x}l_xThe Bi/I ratio of (A) is much larger, which shows that the glycerin molecule forms chemical bonding with the iodide ion, thereby successfully constructing the BiOCl with the chlorine vacancy_1-xThe method adopts an indirect substitution method to construct the bismuth oxychloride (BiOCl) of the chlorine vacancy_1-x) The oxidation capacity is greatly increased, and photoproduction electrons and holes are easier to separate, so that the efficiency of photocatalytic degradation is improved, and the idea of constructing vacancies by an indirect substitution method can be applied to other photocatalysts.

Example 1

First, 0.485g of Bi (NO) is weighed₃)₃·5H₂O, adding 8mL of deionized water, performing ultrasonic dispersion for 2min, adding 32mL of glycerol, and stirring at room temperature for 30 min; then 0.015g of KCI and 0.12g of Nal are weighed and dissolved in 2mL of deionized water, and the solution is dripped into the solution drop by drop and stirred for 1 hour at room temperature; transferring the mixed solution into a 100mL reaction kettle, and reacting for 12h at 120 ℃; taking out the reaction kettle after the temperature of the reaction kettle is reduced to room temperature to obtain BiOCl_1-xStanding the suspension for 1h, pouring out supernatant, washing the left precipitate with deionized water for 3-5 times, and collecting solid powder; and finally, drying the collected solid powder at 80 ℃ for 12 hours to obtain the product.

Example 2

First, 0.485g of Bi (NO) is weighed₃)₃·5H₂O, adding 8mL of deionized water, performing ultrasonic dispersion for 2min, adding 32mL of glycerol, and stirring at room temperature for 30 min; then 0.03g of KCl and 0.09g of Nal are weighed and dissolved in 2mL of deionized water, and the solution is dripped into the solution drop by drop and stirred for 1 hour at room temperature; transferring the mixed solution into a 100mL reaction kettle, and reacting for 12h at 120 ℃; taking out the reaction kettle after the temperature of the reaction kettle is reduced to room temperature to obtain BiOCl_1-xStanding the suspension for 1h, pouring out supernatant, washing the left precipitate with deionized water for 3-5 times, and collecting solid powder; and finally, drying the collected solid powder at 80 ℃ for 12 hours to obtain the product.

Example 3

First, 0.485g of Bi (NO) is weighed₃)₃·5H₂O, adding 8mL of deionized water, performing ultrasonic dispersion for 2min, adding 32mL of glycerol, and stirring at room temperature for 30 min; then 0.045g of KCI and 0.06g of Nal are weighed and dissolved in 2mL of deionized water, and the solution is dripped into the solution drop by drop and stirred for 1h at room temperature; transferring the mixed solution into a 100mL reaction kettle, and reacting for 12h at 120 ℃; taking out the reaction kettle after the temperature of the reaction kettle is reduced to room temperature to obtain BiOCl_1-xStanding the suspension for 1h, pouring out supernatant, washing the left precipitate with deionized water for 3-5 times, and collecting solid powder; and finally, drying the collected solid powder at 80 ℃ for 12 hours to obtain the product.

Example 4

First, 0.485g of Bi (NO) is weighed₃)₃·5H₂O, adding 8mL of deionized water, performing ultrasonic dispersion for 2min, adding 32mL of glycerol, and stirring at room temperature for 30 min; then 0.06g of KCl and 0.03g of Nal are weighed and dissolved in 2mL of deionized water, and the solution is dripped into the solution drop by drop and stirred for 1 hour at room temperature; transferring the mixed solution into a 100mL reaction kettle, and reacting for 12h at 120 ℃; taking out the reaction kettle after the temperature of the reaction kettle is reduced to room temperature to obtain BiOCl_1-xSuspension ofStanding for 1h, pouring out supernatant, washing the left precipitate with deionized water for 3-5 times, and collecting solid powder; and finally, drying the collected solid powder at 80 ℃ for 12 hours to obtain the product.

The morphology and structure, and properties of the product obtained in the comparative example are shown in FIGS. 1-5.

As can be seen from FIG. 1, BiOCl without the introduction of iodide showed neither new peaks nor peak shifts compared to the standard PDF card (JCPDS: 06-0249), indicating that BiOCl prepared using an aqueous glycerol solution was phase-pure; however, BiOCl prepared with ethanol_1-xl_xThe diffraction peak of the solid solution shifts to the left because iodide ions replace chloride ions, thereby producing a solid solution; in addition, with BiOCl_1-xl_xIn contrast, BiOCl prepared with aqueous glycerol solution_1-xThe phase composition was not changed.

As can be seen from FIG. 2, with BiOCl prepared with aqueous glycerol solution and BiOCl prepared with ethanol_1-xl_xIn contrast, BiOCl prepared with aqueous glycerol solution alone_1-xAre flower-like nanospheres.

As can be seen from FIG. 3, the absorption band edge of the pure-phase BiOCl is around 350nm, and when iodide ions are introduced, the BiOCl_{1- x}l_xThe absorption band edge of the film is obviously red-shifted and is about 650 nm; BiOCl in comparison with pure-phase BiOCl_1-xThe absorption band edge of (a) is also red-shifted, around 560nm, which indicates that the construction of chlorine vacancies successfully introduces visible light absorption.

As can be seen from FIG. 4, BiOCl prepared with an aqueous solution of glycerol and BiOCl prepared with ethanol_1-xl_xThe degradation effect on 35mg/L Cr (VI) is general, and BiOCl prepared from glycerol aqueous solution_1-x35mg/L Cr (VI) can be almost completely degraded, which shows that the degradation performance is greatly improved after chlorine vacancies are constructed.

As can be seen from FIG. 5, the absorbance of Cr (VI) gradually decreased with the increase of the illumination time, indicating that BiOCl_1-xThe heavy metal ion Cr (VI) can be almost completely degraded within 35 min.

The results of the examples show that the invention producesBismuth oxychloride (BiOCl) with chlorine vacancy formation by indirect substitution_1-x) Has high oxidation capacity and can rapidly degrade heavy metal ions Cr (VI).

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.