阅读说明：本技术 一种硅掺杂的三氧化钨卤氧化铋复合光催化材料及其制备方法 (Silicon-doped tungsten trioxide bismuth oxyhalide composite photocatalytic material and preparation method thereof ) 是由 吕源财 余健英 刘明华 刘以凡 于 2021-01-27 设计创作，主要内容包括：本发明公开了一种硅掺杂的三氧化钨卤氧化铋复合光催化材料及其制备方法,步骤为：通过设计含有WO-3的A液和含有BiOX的B液,根据不同配比混合后添加不同含量硅源分散形成前驱体溶液后,移入水热反应釜,180℃加热反应24h,待反应釜自然降温,将产物用超纯水、无水乙醇洗涤,-40℃冷冻干燥得到硅掺杂的WO-3/BiOX复合半导体。本发明通过设计A、B液以及前驱体反应体系,一步水热,制备工艺简单,易于调控水热反应条件,选用的原料来源广泛,符合实际生产需要,在光催化灭菌、有机污水处理等领域具有较大的应用潜力。(The invention discloses a silicon-doped tungsten trioxide bismuth oxyhalide composite photocatalytic material and a preparation method thereof, and the preparation method comprises the following steps: by designing to contain WO 3 Mixing the solution A and the solution B containing BiOX according to different proportions, adding silicon sources with different contents, dispersing to form precursor solution, transferring into a hydrothermal reaction kettle, heating at 180 ℃ for 24 hours, and waiting for reactionNaturally cooling the reaction kettle, washing the product with ultrapure water and absolute ethyl alcohol, and freeze-drying at-40 ℃ to obtain silicon-doped WO 3 a/BiOX compound semiconductor. According to the invention, by designing A, B liquid and a precursor reaction system, one-step hydrothermal reaction is realized, the preparation process is simple, the hydrothermal reaction conditions are easy to regulate and control, the selected raw materials are wide in source, the actual production requirements are met, and the method has great application potential in the fields of photocatalytic sterilization, organic sewage treatment and the like.)

1. Silicon-doped WO₃The synthesis method of the BiOX composite photocatalytic material is characterized by comprising the following steps of: dispersing a tungsten source in ultrapure water, and then sequentially adding citric acid, glucose and hydrochloric acid to form a solution containing WO₃The solution A of (1); dispersing a bismuth source in ethylene glycol, and mixing with a halogen salt solution dispersed in ultrapure water to form a BiOX-containing solution B; mixing the A, B solutions, dispersing in AB mixed solution by adding silicon sources with different contents to obtain precursors with uniform components, transferring into a hydrothermal reaction kettle for reaction, washing the product with ultrapure water and absolute ethyl alcohol after the reaction kettle is naturally cooled, and freeze-drying at-40 ℃ to obtain silicon-doped WO₃a/BiOX compound semiconductor.

2. The synthesis method according to claim 1, wherein the components comprise, in parts by mass: 3.9-8.5 parts of tungsten source, 30 parts of ultrapure water, 2.8-6.25 parts of citric acid, 8.9-19.45 parts of glucose, 0.6-0.85 part of hydrochloric acid, 4.8-10.5 parts of bismuth source, 16.65 parts of ethylene glycol, 1.2-2.35 parts of halogen salt in a halogen salt solution of the ultrapure water and 2.5 parts of ultrapure water; the concentration of the hydrochloric acid is 218.8 g/L.

3. The method of synthesis according to claim 1, characterized in that: the bismuth source comprises bismuth nitrate pentahydrate, the tungsten source comprises sodium tungstate, and the silicon source comprises silicotungstic acid or sodium silicate.

4. A synthesis method according to claim 3, characterized in that the concentration of silicotungstic acid in the silicon source in the AB mixed liquor is 3.92 g/L-5.73 g/L.

5. The synthesis method according to claim 3, wherein the concentration of sodium silicate in the silicon source in the AB mixed solution is 0.71 g/L-1.37 g/L.

6. The method of synthesizing of claim 1 wherein said BiOX comprises any one of BiOBr, BiOI, BiOCl and said halide salt comprises any one of KBr, KI, KCl.

7. The method of synthesis according to claim 1, characterized in that: and (3) placing the precursor in a hydrothermal reaction kettle, and heating from room temperature to 180 ℃ for reaction for 24 hours at the heating rate of 5 ℃/min.

8. Silicon-doped WO prepared by the method of claim 1₃a/BiOX compound semiconductor.

9. WO doping silicon as defined in claim 8₃Use of a/BiOX compound semiconductor, characterized in that: the photocatalyst is applied to the fields of photocatalytic sterilization scenes and organic sewage treatment, wherein the sterilization scenes comprise gram-negative bacteria and gram-positive bacteria.

Technical Field

The invention belongs to the technical fields of material chemistry, catalytic chemistry, organic sewage treatment and inorganic sterilization, and particularly relates to silicon-doped WO₃A preparation method of a BiOX composite photocatalytic sterilization material and an obtained product.

Background

Various pathogenic microorganisms in nature are widely distributed and grow, reproduce and even mutate under certain conditions, so that the various materials are decomposed, deteriorated and putrefactive, and even seriously threaten the health of human beings. Therefore, how to effectively sterilize becomes one of the global important strategic issues.

The photocatalysis technology is an innovative technology in the aspect of chemical sterilization, and can utilize solar energy to excite a semiconductor photocatalysis material to generate photoproduction electrons and holes, so that bacteria lose the multiplication capacity and are decomposed as organic matters, and the effects of antibiosis and self-cleaning can be simultaneously obtained. Compared with other methods, the process is carried out at normal temperature and normal pressure, the raw materials are simple and easy to obtain, the solar energy is directly utilized without consuming auxiliary energy, and the preparation materials can be recycled, so the method is regarded as the most promising water sterilization method.

The core of photocatalytic sterilization is a photocatalytic material, and development of efficient visible light catalytic sterilization materials has become a hot point of research, wherein a p-type semiconductor material taking BiOX as a center has good chemical stability and eco-friendliness, shows remarkable photocatalytic performance, and becomes a new hot point of recent attention of researchers, but still has shortcomings.

To solve the problem that the photo-generated electron-hole pairs are quickly recombined and then are quantitatively generatedThe method mainly adopts the research methods of ion doping, plasma noble metal modification and narrow-band semiconductor compound construction heterostructure, wherein a large amount of photocatalysis researches show that the construction of a p-n heterojunction is an effective method for improving the photocatalysis activity, the method can obviously improve the visible light absorption and utilization of BiOX, and improve the separation and transmission rate of photo-generated charges, so that the photocatalysis activity is obviously improved. In visible light driven photocatalysts, WO₃Is an important n-type semiconductor, however, pure WO₃The photocatalytic activity alone is not ideal due to the rapid recombination of photogenerated carriers. At present, the existing research shows that the visible light photocatalysis performance can be obviously improved by doping the non-metal ions. Because the doping process can generate material defects, more oxygen vacancies are produced, and the surface of the composite photocatalytic material has better interface charge transfer under the irradiation of visible light, thereby generating abundant active oxygen to improve the photocatalytic performance. Thus, a silicon-doped WO is formed₃The BiOX composite photocatalytic material is beneficial to separation of photoproduction electrons and holes, can widen the light absorption range of the material, improves the utilization rate of light energy, improves the photocatalytic sterilization performance and improves the treatment efficiency of degrading organic sewage.

A, B solution designed by the invention is mixed and then added with a silicon source to form a precursor solution, and the precursor solution is hydrothermally synthesized into silicon-doped WO with heterojunction in one step₃the/BiOX composite photocatalytic material shows excellent photocatalytic sterilization, chemical stability and structural stability in photocatalytic reaction.

Disclosure of Invention

The invention relates to a silicon-doped WO₃A BiOX composite photocatalytic material and a preparation method thereof. The preparation method disclosed by the invention is simple in preparation process, easy to regulate and control, wide in source of selected raw materials, and capable of meeting the actual production requirements, and has great application potential in the fields of photocatalytic sterilization, organic sewage degradation and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

silicon-doped WO₃The synthesis method of the/BiOX composite photocatalytic material is to design A, B liquid to be mixed and then add a silicon source to reach oneStep hydrothermal reaction for preparing silicon-doped WO₃A compound semiconductor of/BiOX.

The preparation method comprises the following specific steps:

dispersing a tungsten source in certain ultrapure water, adding citric acid and glucose, stirring, adding hydrochloric acid, and continuously stirring until the solution turns from white to yellow deposits;

and B, liquid B: dispersing a bismuth source in ethylene glycol, uniformly stirring, mixing with a halogen salt solution dispersed in ultrapure water, and continuously stirring to be milky white.

The components comprise the following components in parts by mass: 3.9-8.5 parts of tungsten source, 30 parts of ultrapure water, 2.8-6.25 parts of citric acid, 8.9-19.45 parts of glucose, 0.6-0.85 part of hydrochloric acid, 4.8-10.5 parts of bismuth source, 16.65 parts of ethylene glycol, 1.2-2.35 parts of halogen salt in a halogen salt solution of the ultrapure water and 2.5 parts of ultrapure water; the concentration of the hydrochloric acid is 218.8 g/L.

Mixing the solution A and the solution B, adding a silicon source, continuously reacting uniformly, and then placing the mixture into a hydrothermal reaction kettle to perform hydrothermal reaction for 24 hours at the temperature rising speed of 5 ℃/min from room temperature to 180 ℃. And cooling to room temperature after the reaction is finished, washing the product by using ultrapure water and absolute ethyl alcohol to obtain a powder solid, and freeze-drying at-40 ℃ to obtain the final composite photocatalytic semiconductor. The bismuth source is bismuth nitrate pentahydrate, the tungsten source is sodium tungstate, and the silicon source is silicotungstic acid or sodium silicate, wherein the concentration of the silicotungstic acid in the AB mixed solution is 3.92 g/L-5.73 g/L, and the concentration of the sodium silicate in the AB mixed solution is 0.71 g/L-1.37 g/L.

The BiOX comprises any one of BiOBr, BiOI and BiOCl, and the halide salt comprises any one of KBr, KI and KCl.

A silicon-doped WO as described above₃the/BiOX composite semiconductor is applied to photocatalysis sterilization and organic sewage degradation scenes, and the sterilization scenes comprise gram-negative bacteria and gram-positive bacteria.

The invention has the following remarkable advantages:

(1) the first-time utilization design of the invention respectively comprises WO₃Mixing with A, B solution of BiOX, adding silicon source to achieve one-step hydrothermal synthesis of silicon-doped WO₃BiOX compound semiconductor, whole processIs simple and easy to control, meets the actual production requirement and is beneficial to large-scale popularization.

(2) Silicon doped WO₃the/BiOX composite semiconductor effectively separates photoproduction electrons and holes, greatly reduces the recombination rate of the photoproduction electron holes, increases the specific surface area of the material, improves the transmission efficiency of the photoproduction electrons, can efficiently carry out photocatalytic sterilization and degrade organic sewage, has high stability, and has strong practical value and application prospect.

Drawings

FIG. 1 shows WO obtained in example 1₃XRD contrast diagram of/BiOBr @ Si composite semiconductor.

FIG. 2 shows WO obtained in example 1₃Comparison effect of/BiOBr @ Si composite semiconductor photocatalytic inactivated Escherichia coli.

FIG. 3 shows the comparative effect of photocatalytic degradation of organic contaminated wastewater by all the compound semiconductors obtained in examples 1 to 4 (rhodamine B simulates organic contaminated wastewater).

Detailed Description

The following are 4 examples of the present invention, it being understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present application.

Example 1

Preparing a solution A: dispersing 3.9kg of sodium tungstate in 30kg of ultrapure water, adding 2.8kg of citric acid and 8.9kg of glucose, magnetically stirring for 10min at the speed of 400r/min, adding 0.85kg of hydrochloric acid (218.8 g/L), and continuously stirring until the solution is white and yellow deposits appear;

preparing a solution B: 4.8kg of bismuth nitrate pentahydrate is dispersed in 16.65kg of ethylene glycol, uniformly stirred, mixed with 1.2kg of KBr solution dispersed in 2.5kg of ultrapure water, and continuously stirred until the mixture is milky.

Mixing the solution A and the solution B, adding 28.4kg of hydrated silicotungstic acid, continuously stirring uniformly, and then placing the mixture into a reaction kettle to be heated from room temperature to 180 ℃ for reaction for 24 hours according to the heating rate of 5 ℃/min. Cooling to room temperature after the reaction is finished, placing the product in ultrapure water and absolute ethyl alcohol for washing for a plurality of times to obtain brown solid, and freeze-drying at-40 ℃ for 12h to obtain WO₃a/BiOBr @ Si composite semiconductor.

Example 2

Preparing a solution A: dispersing 5.35kg of sodium tungstate in 30kg of ultrapure water, adding 3.9kg of citric acid and 12.25kg of glucose, magnetically stirring for 10min at the speed of 400r/min, adding 0.85kg of hydrochloric acid (218.8 g/L), and continuously magnetically stirring until the solution is white and yellow deposits appear;

preparing a solution B: dispersing 6.6kg of bismuth nitrate pentahydrate into 16.65kg of ethylene glycol, uniformly stirring, mixing with 2.3kg of KI solution dispersed in 2.5kg of ultrapure water, and continuously reacting until the mixed solution is uniform;

mixing the solution A and the solution B, adding 19.6kg of hydrated silicotungstic acid, continuously stirring uniformly, and then placing the mixture into a reaction kettle to be heated from room temperature to 180 ℃ for reaction for 24 hours according to the heating rate of 5 ℃/min. Cooling to room temperature after the reaction is finished, placing the product in ultrapure water and absolute ethyl alcohol for washing for a plurality of times, and freeze-drying at-40 ℃ for 12h to obtain WO₃a/BiOI @0.5Si composite semiconductor.

Example 3

Preparing a solution A: dispersing 7.8kg of sodium tungstate in 30kg of ultrapure water, adding 5.7kg of citric acid and 17.8kg of glucose, magnetically stirring for 10min at the speed of 400r/min, adding 0.6kg of hydrochloric acid (218.8 g/L), and continuously magnetically stirring until the solution is white and yellow deposits appear;

preparing a solution B: dispersing 9.6kg of bismuth nitrate pentahydrate in 16.9kg of ethylene glycol, uniformly stirring, and mixing with 2.35kg of KBr solution dispersed in 2.5kg of ultrapure water until the solution is uniform;

mixing the solution A and the solution B, adding 6.75kg of sodium silicate, continuously stirring uniformly, and then placing the mixture into a reaction kettle to heat from room temperature to 180 ℃ for reaction for 24 hours according to the heating rate of 5 ℃/min. Cooling to room temperature after the reaction is finished, placing the product in ultrapure water and absolute ethyl alcohol for washing for a plurality of times to obtain brown solid, and freeze-drying at-40 ℃ for 12h to obtain WO₃a/BiOBr @1.2Si compound semiconductor.

Example 4

Preparing a solution A: dispersing 8.5kg of sodium tungstate in 30kg of ultrapure water, adding 6.25kg of citric acid and 19.45kg of glucose, magnetically stirring for 10min at the speed of 400r/min, adding 0.6kg of hydrochloric acid (218.8 g/L), and continuously magnetically stirring until the solution is white and yellow deposits appear;

preparing a solution B: dispersing 10.5kg of bismuth nitrate pentahydrate in 16.9kg of ethylene glycol, uniformly stirring, and mixing with 1.6kg of KCl solution dispersed in 2.5kg of ultrapure water;

mixing the solution A and the solution B, adding 3.7kg of sodium silicate, continuously stirring uniformly, and then placing the mixture into a reaction kettle to heat from room temperature to 180 ℃ for reaction for 24 hours according to the heating rate of 5 ℃/min. Cooling to room temperature after the reaction is finished, placing the product in ultrapure water and absolute ethyl alcohol for washing for a plurality of times, and freeze-drying at-40 ℃ for 12h to obtain WO₃a/BiOCl @0.6Si compound semiconductor.

FIG. 1 shows WO obtained in example 1₃XRD contrast diagram of the/BiOBr @ Si composite semiconductor, from which the prepared catalyst can be found to be in cubic phase.

Example 5 photocatalytic sterilization testing was characterized by the following coating count method.

The specific operation process is as follows:

(1) preparation of E.coli bacterial suspension

All operations were performed in a clean bench. And scratching a proper amount of escherichia coli lawn in a germ tube containing escherichia coli by using the inoculating loop subjected to high-temperature sterilization treatment, and quickly transferring the escherichia coli lawn to a prepared LB liquid culture medium. Culturing the culture medium inoculated with thallus in a constant temperature oscillator at 37 deg.C and 170 r/min for 18h, centrifuging the liquid culture medium at 8000rmp for 10min, washing with sterile water, diluting with physiological saline (0.9% NaCl) until the absorbance of ultraviolet-visible spectrophotometer is 1 (wavelength is 600 nm), diluting 1000 times, and making into 10-fold concentrate⁶CFU/mL of E.coli suspension.

(2) Sterilization test procedure

Accurately, 5mL of the bacterial suspension was measured and transferred to 45mL of sterile physiological saline (0.9% NaCl) at a concentration of about 10⁵CFU/mL was added with 20mg of the catalyst prepared in example 1. A blank control of a catalyst group without light and a catalyst group without light is arranged. The experimental process comprises the following steps: the reaction mixture was stirred for 30min to disperse the bacteria uniformly under dark conditions, and 1mL of the reaction mixture was used as the first sample. Then turning on the light source (500W xenon lamp), fitting 420nm filter, filtering out invisible light, and timing each timeSucking 1mL of reaction solution for 3h, and performing quantitative analysis as a solution to be detected.

(3) Counting by coating plate method

The number of bacteria in the test solution was counted by dilution spread plate method. And (3) serially diluting the solution to be detected by 10 times. Sucking 0.1mL of diluted solution to be tested, dripping the diluted solution to be tested into an LB solid culture medium, evenly coating, inverting the solid culture medium, putting the culture dish into a biochemical incubator at 37 ℃ for culturing for 24 hours, then placing the culture dish on an automatic colony counter for counting, selecting a culture medium with the colony number of 30-300, and simultaneously preparing three culture media according to the dilution degree so as to ensure the accuracy. For the evaluation of the sterilization effect in the experiment, the survival rate of bacteria is taken as an index, and the calculation formula is as follows: bacterial survival = N_t/N₀×100%（N₀And N_tThe CFU numbers of the bacteria before and after the reaction are represented, respectively. CFU is colony forming unit, representing the number of viable bacteria per unit volume). FIG. 2 shows WO obtained in example 1₃a/BiOBr @ Si composite semiconductor photocatalysis colibacillus killing comparative effect graph.

Example 6 photocatalytic degradation of organic contaminated wastewater test

Example 1, example 2, example 3 and example 4 photocatalytic degradation of organic contaminated wastewater was characterized by degradation of rhodamine B.

The specific operation process is as follows:

organic pollutants characterized by rhodamine B are used for researching the photocatalytic performance of different composite photocatalysts. The experiment is carried out in a photocatalytic reaction box, a light source is cooled by a circulating condensed water machine, and meanwhile, the temperature of a reaction system is maintained to be 25 ℃, and the method comprises the following specific steps: weighing 10mg of the catalyst prepared in the examples 1-4 into a 50mL glass reaction tube, adding 38.4mL of ultrapure water, carrying out ultrasonic oscillation for 2min to uniformly disperse the sample, adding 1.6mL of 1000mg/L RhB solution under the condition of magnetic stirring, and stirring for 30min in the dark to achieve adsorption-desorption balance. A300W xenon lamp was used as the light source, and a 420nm filter was used to filter out the UV light. Sampling 3.0mL at intervals after illumination, filtering with a 0.22 μm glass fiber filter, measuring the absorbance of the filtrate by an ultraviolet-visible spectrophotometer after the reaction is finished, and calculating the solutionResidual concentration of RhB in (c). R = (1-C/C)₀) 100% is the formula for calculating the removal rate of rhodamine B. Wherein R is the removal rate (%) of rhodamine B, C is the residual concentration (mg/L) of rhodamine B, and C is₀The initial concentration (mg/L) of rhodamine B. FIG. 3 is a graph showing the comparative effect of the composite semiconductor photocatalytically degraded rhodamine B obtained in examples 1 to 4.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.