阅读说明：本技术 一种BiOBr/TiO2复合光催化剂及其制备方法 (BiOBr/TiO2 composite photocatalyst and preparation method thereof ) 是由 王军 伍水生 余江鸿 高颖 吴斌 王进龙 张析 周涛 王长征 赵坤 王源瑞 张 于 2019-08-19 设计创作，主要内容包括：本发明公开了一种BiOBr/TiO2复合光催化剂及其制备方法,所述BiOBr/TiO2复合光催化剂中铋元素、钛元素含量的摩尔比为1:5或1:1或1:2.5或1:7.5或1:10或5:1或10:1。该复合光催化剂的制备方法为称取适量的Bi(NO<Sub>3</Sub>)<Sub>3</Sub>.5H<Sub>2</Sub>O和CTAB分别溶解于无水乙醇中,然后将两种溶液混合均匀；再称取适量的TBOT,溶解于无水乙醇中,加入前面所制备的混合溶液中；将混合溶液磁力搅拌、恒温反应、冷却、用去离子水和无水乙醇交替洗涤数次、产物干燥后即可制得。本发明所述BiOBr/TiO2复合光催化剂合成简单,成本低,能够显著降低光生电子和空穴的复合,提高光催化性能。可广泛应用于光催化处理污水和净化空气等环保领域。(The invention discloses a BiOBr/TiO2 composite photocatalyst and a preparation method thereof, wherein the molar ratio of bismuth element to titanium element in the BiOBr/TiO2 composite photocatalyst is 1:5 or 1:1 or 1:2.5 or 1:7.5 or 1:10 or 5:1 or 10: 1. The preparation method of the composite photocatalyst comprises weighing appropriate amount of Bi (NO) 3 ) 3 .5H 2 Dissolving O and CTAB in absolute ethyl alcohol respectively, and then mixing the two solutions uniformly; weighing a proper amount of TBOT, dissolving the TBOT in absolute ethyl alcohol, and adding the TBOT into the prepared mixed solution; and magnetically stirring the mixed solution, reacting at constant temperature, cooling, alternately washing with deionized water and absolute ethyl alcohol for several times, and drying the product to obtain the catalyst. The BiOBr/TiO2 composite photocatalyst is simple to synthesize and low in cost, and can remarkably reduce the recombination of photo-generated electrons and holes and improve the photocatalytic performance. Can be widely usedThe method is widely applied to the environmental protection fields of photocatalytic sewage treatment, air purification and the like.)

1. A BiOBr/TiO2 composite photocatalyst is characterized in that: the molar ratio of the bismuth element to the titanium element in the BiOBr/TiO2 composite photocatalyst is 1:5 or 1:1 or 1:2.5 or 1:7.5 or 1:10 or 5:1 or 10: 1.

2. The BiOBr/TiO2 composite photocatalyst as claimed in claim 1, wherein: the molar ratio of the bismuth element to the titanium element in the BiOBr/TiO2 composite photocatalyst is 1: 1.

3. A preparation method of a BiOBr/TiO2 composite photocatalyst is characterized by comprising the following steps: it comprises the following steps:

step one, weighing 0.6-6.0gBi (NO)₃)₃.5H₂Dissolving O and 1.2g CTAB in 20ml of absolute ethyl alcohol respectively, and then uniformly mixing the two solutions;

step two, weighing 0.42-4.2g of TBOT, dissolving in 30ml of absolute ethyl alcohol, and adding into the mixed solution prepared in the step one;

step three, magnetically stirring the mixed solution prepared in the step two for 0.5-1h, then transferring the mixed solution into a high-temperature reaction kettle, and reacting for 10h at the constant temperature of 150 ℃; naturally cooling to room temperature, carrying out suction filtration, alternately washing with deionized water and absolute ethyl alcohol for a plurality of times, collecting the product, and drying the product in an oven at 80 ℃ for 5 hours to obtain the dried BiOBr/TiO2 composite photocatalyst.

Wherein: in the first step, CTAB is short for hexadecyl trimethyl ammonium bromide, and the chemical molecular formula is as follows: c₁₉H₄₂BrN; TBOT in the second step is short for butyl titanate, and the chemical molecular formula is C₁₆H₃₆O₄Ti。

Technical Field

The invention relates to the technical field of photocatalysts, in particular to a BiOBr/TiO2 composite photocatalyst and a preparation method thereof.

Background

The environmental pollution includes water pollution, light pollution, air pollution, heavy metal pollution and the like. Covers the fields of civil use, industry, commerce, military and the like, and the improvement and treatment of environmental pollution become more and more important. The photocatalytic material has potential application in the aspect of pollutant treatment, and the photocatalytic reaction carried out by utilizing solar energy is generally concerned about environmental improvement and energy development.

TiO₂The photocatalyst has the advantages of good stability, low cost, no toxicity, no secondary pollution, easy doping modification and the like, so that the photocatalyst is considered as an ideal photocatalytic material, and is widely researched. But TiO2₂There are two drawbacks: (1) the forbidden band range is wider and is 3.2eV, and the utilization rate of light is low; (2) the recombination rate of photo-generated electrons and holes is high, and the photon efficiency is poor. These two drawbacks limit TiO₂Practical application of (2), therefore, TiO is required₂Modification studies were conducted to improve their photocatalytic properties.

Disclosure of Invention

The invention aims to provide a BiOBr/TiO2 composite photocatalyst and a preparation method thereof, wherein the BiOBr and TiO2 composite photocatalyst is prepared by using BiOBr and TiO₂The photocatalyst is compounded to prepare the photocatalyst with high activity and universality under visible light.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following contents:

the molar ratio of the contents of bismuth and titanium in the BiOBr/TiO2 composite photocatalyst is 1:5 or 1:1 or 1:2.5 or 1:7.5 or 1:10 or 5:1 or 10: 1.

Preferably, the molar ratio of the bismuth element to the titanium element in the BiOBr/TiO2 composite photocatalyst is 1: 1.

A preparation method of a BiOBr/TiO2 composite photocatalyst comprises the following steps:

step one, weighing 0.6-6.0gBi (NO)₃)₃.5H₂Dissolving O and 1.2g CTAB in 20ml of absolute ethyl alcohol respectively, and then uniformly mixing the two solutions;

step two, weighing 0.42-4.2g of TBOT, dissolving in 30ml of absolute ethyl alcohol, and adding into the mixed solution prepared in the step one;

step three, magnetically stirring the mixed solution prepared in the step two for 0.5h, then transferring the mixed solution into a high-temperature reaction kettle, and reacting for 10h at the constant temperature of 150 ℃; naturally cooling to room temperature, carrying out suction filtration, alternately washing with deionized water and absolute ethyl alcohol for a plurality of times, collecting the product, and drying the product in an oven at 80 ℃ for 5 hours to obtain the dried flower-shaped BiOBr/TiO2 composite photocatalyst.

Wherein: in the first step, CTAB is short for hexadecyl trimethyl ammonium bromide, and the chemical molecular formula is as follows: c₁₉H₄₂BrN; TBOT in the second step is short for butyl titanate, and the chemical molecular formula is C₁₆H₃₆O₄Ti。

BiOBr as a novel narrow-band-gap semiconductor material (the forbidden band width is 2.5-2.9eV) has unique electronsStructure, good optical property and catalytic property. By utilizing the advantages of better activity and stability on various dyes and the like, the dye can react with TiO₂The photocatalyst is compounded, and the photocatalyst with high activity and universality under visible light can be prepared.

CTAB is white or light yellow crystal to powder, has pungent smell, is easily dissolved in isopropanol, is soluble in water, generates a large amount of foam during oscillation, and can have good coordination with anionic, nonionic and amphoteric surfactants. Has excellent penetrating, softening, emulsifying, antistatic, biological degrading and sterilizing performance.

TBOT is colorless to light yellow liquid, is inflammable and low in toxicity, is a glassy solid at the temperature of below-55 ℃, is dissolved in most organic solutions except ketones, and has the relative density of 0.966, the boiling point of 310-314 ℃, the flash point of 76.7 ℃ and the refractive index of 1.486. The product can rapidly absorb moisture and decompose in air, has very high chemical activity on water, and can be hydrolyzed to generate Ti (OH)₄And therefore, must be stored in an anhydrous environment. Is soluble in most organic solvents. Due to its moisture absorbing properties, the used straws and the like are cleaned in time.

The BiOBr/TiO2 composite photocatalyst prepared by the invention is simple to synthesize, low in cost, high in specific surface area and excellent in mesoporous structure, and can remarkably reduce the recombination of photo-generated electrons and holes and improve the photocatalytic performance. Can be widely applied to the environmental protection fields of photocatalytic sewage treatment, air purification and the like.

As shown in figure 1, under the irradiation of visible light for 20min, BiOBr/TiO prepared by the invention₂The degradation rate of the composite photocatalyst to rhodamine B is as high as 98.98%. And BiOBr and TiO singly₂The degradation rate of rhodamine B under the same conditions is 85.93% and 47.43% respectively.

Drawings

FIG. 1 is an electron microscope scan of a BiOBr/TiO2 composite photocatalyst according to the invention;

FIG. 2 shows the BiOBr/TiO2 composite photocatalyst and single BiOBr and TiO₂XRD (X-ray powder diffraction) pattern of (a);

FIG. 3 is a graph of the present invention preparedThe BiOBr/TiO2 composite photocatalyst and the single BiOBr and TiO₂A degradation rate contrast graph of rhodamine B under the same conditions;

FIG. 4 is a structural diagram of rhodamine B.

Detailed Description

The invention is described in further detail below with reference to the figures and specific examples.