阅读说明：本技术 一种ZnTiO3/Bi4NbO8Cl复合光催化剂材料的制备方法 (ZnTiO compound3/Bi4NbO8Preparation method of Cl composite photocatalyst material ) 是由 王诚澎 于 2019-08-08 设计创作，主要内容包括：本发明公开了一种ZnTiO_3半导体修饰改性Bi_4NbO_8Cl的复合光催化剂的简单制备方法。该方法以氧化铋、氯氧化铋和五氧化二铌为原料,通过球磨、煅烧合成了Bi_4NbO_8Cl；通过沉淀法制备得到了ZnTiO_3；随后经过研磨、超声、煅烧的方法,制备得到ZnTiO_3/Bi_4NbO_8Cl复合光催化剂。该实验方法比较安全可靠,操作简便。ZnTiO_3与Bi_4NbO_8Cl呈现交叉带隙的特点,将两者复合后ZnTiO_3可以作为能量的浅势捕获阱,使光生电子更容易从Bi_4NbO_8Cl的导带迁移到ZnTiO_3的导带,光生空穴则更容易从ZnTiO_3的价带迁移到Bi_4NbO_8Cl的价带,从而促进光生载流子的分离效率,进而提高复合催化剂的性能。(The invention discloses ZnTiO 3 Semiconductor modified Bi 4 NbO 8 A simple preparation method of the Cl composite photocatalyst. The method takes bismuth oxide, bismuth oxychloride and niobium pentoxide as raw materials, and synthesizes Bi through ball milling and calcination 4 NbO 8 Cl; ZnTiO is prepared by a precipitation method 3 (ii) a Then the ZnTiO is prepared by grinding, ultrasonic and calcining 3 /Bi 4 NbO 8 And (3) a Cl composite photocatalyst. The experimental method is safe and reliable, and is simple and convenient to operate. ZnTiO 2 3 And Bi 4 NbO 8 Cl presents the characteristic of cross band gap, and ZnTiO is compounded by the Cl and the Cl 3 Can be used as shallow potential trapping trap of energy to make photo-generated electrons more easily from Bi 4 NbO 8 Transfer of Cl conduction band to ZnTiO 3 The conduction band, photogenerated holes, is more easily removed from ZnTiO 3 To Bi 4 NbO 8 The valence band of Cl, thereby promoting the separation efficiency of photon-generated carriers and further improving the performance of the composite catalyst.)

1. ZnTiO compound₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized by comprising the following steps:

(1)Bi₄NbO₈preparation of Cl: weighing bismuth oxide, bismuth oxychloride and niobium pentoxide in a mass ratio of 3:2:1, adding a certain volume of absolute ethyl alcohol and a certain number of agate balls, carrying out ball milling at a certain rotating speed for a period of time, taking out a mixed solution, drying, and then carrying out high-temperature calcination to obtain Bi₄NbO₈And (3) Cl powder. In the step Bi₄NbO₈And (3) preparing Cl, wherein the total mass of the added samples is 6-36g, the added absolute ethyl alcohol is 10-60mL, the diameter of the needed agate balls is 5-10mm, and the number of the needed agate balls is 20-100. The ball milling speed is 300r/min, and the ball milling time is 2 h. To obtain Bi₄NbO₈The high-temperature calcination temperature of the Cl powder is 600 ℃, and the time is 10 hours.

(2)ZnTiO₃The preparation of (1): dissolving 3.1mL of butyl titanate in 10mL of absolute ethyl alcohol to form a solution A; dissolving 1.5mL of glacial acetic acid and 2.75g of zinc nitrate hexahydrate in 10mL of absolute ethyl alcohol successively to form a solution B; slowly dripping the solution B into the solution A under the stirring state, stirring for 30min, then aging for 24h, then drying at 105 ℃ for 12h, and calcining the obtained precursor at 600 ℃ for 3h to obtain ZnTiO₃And (3) powder.

(3)ZnTiO₃And Bi₄NbO₈And (3) Cl compounding: weighing a certain amount of ZnTiO according to a certain mass ratio₃And Bi₄NbO₈Cl, grinding for a period of time, transferring into a beaker, adding a certain amount of absolute ethyl alcohol, carrying out ultrasonic treatment for a period of time, drying, and calcining the dried powder at a certain temperature for a certain time to obtain ZnTiO₃/Bi₄NbO₈And (3) preparing the Cl composite photocatalyst material.

2. Such asA ZnTiO compound as defined in claim 1₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized in that ZnTiO in the step (3)₃Is Bi₄NbO₈5% -30% of Cl.

3. ZnTiO of claim 1, wherein₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized in that the grinding time is 5-60min when the composite material is prepared in the step (3).

4. ZnTiO of claim 1, wherein₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized in that the amount of the absolute ethyl alcohol added in the step (3) is 5-30mL when the composite material is prepared.

5. ZnTiO of claim 1, wherein₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized in that the ultrasonic time is 10-60min when the composite material is prepared in the step (3).

6. ZnTiO of claim 1, wherein₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized in that in the step (3), the heat treatment temperature of the dried powder in a muffle furnace is 200-550 ℃, the time is 0.5-3h, and the heating rate is 2-8 ℃/min.

The technical field is as follows:

the invention relates to a preparation method of an inorganic composite modified photocatalyst, in particular to a semiconductor compositeA preparation method of the synthetic modified material. More specifically, Bi₄NbO₈Cl as a main component, ZnTiO₃Removing the doping, and mixing the two by a mechanical method to obtain ZnTiO₃Modified Bi₄NbO₈A composite photocatalytic material of Cl. The technology belongs to the field of preparation of composite modification of catalysts.

Background art:

since the 21 st century, the economic and technological levels of China have rapidly developed and are ascending at the leading edge of the world, and meanwhile, the conditions that the environmental pollution is increasingly serious and the energy is gradually exhausted appear in China. The phenomenon of water pollution is particularly serious, so that the improvement of environmental pollution and the reasonable utilization of energy are matters which are not slow at all. In the last decades, the research on photocatalytic materials has mainly focused on metal oxides or nitrogen oxides, but both of these types of substances have major drawbacks: for metal oxide, the forbidden band width is large, and the absorbable visible light frequency band only accounts for about 4% of the spectrum; nitrogen oxides are unstable and easily decomposed under sunlight irradiation. Scientists have gradually explored the preparation of oxychloride with chlorine instead of nitrogen, where Bi₄NbO₈Cl is a representative such photocatalyst. Bi₄NbO₈The band gap of Cl is about 2.39eV, and the Cl has stronger response to ultraviolet light; in addition, the photocatalyst has the characteristics of long effective action time, no environmental pollution and the like, so that the photocatalyst becomes an ideal photocatalytic material. Although Bi₄NbO₈Cl has certain advantages as a photocatalyst, but the following two problems still exist in the using process:

(1)Bi₄NbO₈the Cl has a wide forbidden band (2.39eV), and can only absorb short-wave light with a wavelength below 520nm, but the energy of partial ultraviolet light below 387nm only accounts for 5% of the solar energy. Therefore, how to expand the visible light response capability of the catalyst affects Bi₄NbO₈And the Cl can be used as an important factor for large-scale practical application.

(2)Bi₄NbO₈Cl is used as a single semiconductor material, and compared with a modified catalyst, the Cl has the advantages that the photogenerated carrier recombination rate is still higher, and the lower carrier separation efficiency is constantTo a certain extent limit Bi₄NbO₈And (3) practical application of Cl.

In order to solve the above problems, Bi is required to be present₄NbO₈And performing modification treatment on Cl. Yong You^[1]Et al prepared g-C by high energy ball milling₃N₄/Bi₄NbO₈Cl composite with pure g-C₃N₄And Bi₄NbO₈Compared with Cl, the activity of photocatalytic hydrogen production is obviously improved. Wei Zhidong^[2]Et al prepared Bi doped with yttrium₄NbO₈Cl/Nb₂O₅The novel heterojunction can also improve the capacity of photocatalytic hydrogen production. ZnTiO 2₃The performance of the photocatalyst has been proved by a large number of experiments, such as Jianjing^[3]The sol-gel method is adopted by the people to prepare the nano-grade zinc titanate powder, active red and purple dye is degraded under ultraviolet-visible light, and the dye is degraded into inorganic micromolecules by photocatalysis after 30min, thereby proving that ZnTiO₃-TiO₂Has better activity to the photocatalytic degradation of water-soluble dyes. However, there is no prior art relating to the incorporation of Bi₄NbO₈Cl and ZnTiO₃Modification is carried out in a compounding way to improve the related reports of photocatalytic degradation of pollutants.

The invention content is as follows:

the purpose of the invention is to provide a compound of Bi₄NbO₈A preparation method for modifying Cl so as to overcome the defect of single Bi at present₄NbO₈The Cl catalyst has insufficient performance. Through repeated exploration, a ZnTiO is obtained₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material comprises the following steps:

1. ZnTiO compound₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized by comprising the following steps:

(1)Bi₄NbO₈preparation of Cl: weighing bismuth oxide, bismuth oxychloride and niobium pentoxide in a mass ratio of 3:2:1, putting the bismuth oxide, the bismuth oxychloride and the niobium pentoxide into an agate ball milling tank, adding a certain volume of absolute ethyl alcohol and a certain number of agate balls, carrying out ball milling at a certain rotating speed for a period of time, taking out a mixed solution, and drying the mixed solutionThen calcining at high temperature to obtain Bi₄NbO₈And (3) Cl powder. In the step Bi₄NbO₈And (3) preparing Cl, wherein the total mass of the added samples is 6-36g, the added absolute ethyl alcohol is 10-60mL, the diameter of the needed agate balls is 5-10mm, and the number of the needed agate balls is 20-100. The ball milling speed is 300r/min, and the ball milling time is 2 h. To obtain Bi₄NbO₈The high-temperature calcination temperature of the Cl powder is 600 ℃, and the time is 10 hours.

(2)ZnTiO₃The preparation of (1): dissolving 3.1mL of butyl titanate in 10mL of absolute ethyl alcohol to form a solution A; dissolving 1.5mL of glacial acetic acid and 2.75g of zinc nitrate hexahydrate in 10mL of absolute ethyl alcohol successively to form a solution B; slowly dripping the solution B into the solution A under the stirring state, stirring for 30min, then aging for 24h, then drying at 105 ℃ for 12h, and calcining the obtained precursor at 600 ℃ for 3h to obtain ZnTiO₃And (3) powder.

(3)ZnTiO₃And Bi₄NbO₈And (3) Cl compounding: weighing a certain amount of ZnTiO according to a certain mass ratio₃And Bi₄NbO₈Cl, grinding for a period of time, transferring into a beaker, adding a certain amount of absolute ethyl alcohol, carrying out ultrasonic treatment for a period of time, drying, and calcining the dried powder at a certain temperature for a certain time to obtain ZnTiO₃/Bi₄NbO₈And (3) preparing the Cl composite photocatalyst material.

2. ZnTiO of claim 1, wherein₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized in that ZnTiO in the step (3)₃Is Bi₄NbO₈5% -30% of Cl.

3. ZnTiO of claim 1, wherein₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized in that the grinding time is 5-60min when the composite material is prepared in the step (3).

4. ZnTiO of claim 1, wherein₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized in that the amount of the absolute ethyl alcohol added in the step (3) is 5-30mL when the composite material is prepared.

5、ZnTiO of claim 1, wherein₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized in that the ultrasonic time is 10-60min when the composite material is prepared in the step (3).

6. ZnTiO of claim 1, wherein₃/Bi₄NbO₈The preparation method of the Cl composite photocatalyst material is characterized in that in the step (3), the heat treatment temperature of the dried powder in a muffle furnace is 200-550 ℃, the time is 0.5-3h, and the heating rate is 2-8 ℃/min.

The invention has the advantages that:

(1) the preparation method adopted by the invention has the advantages of simple equipment, lower cost and high safety.

(2)ZnTiO₃And Bi₄NbO₈Cl presents the characteristic of cross band gap, and ZnTiO is compounded by the Cl and the Cl₃The composite catalyst can be used as a shallow potential capture trap of energy, promotes the separation of photon-generated carriers, reduces the generation of photocurrent, and further improves the performance of the composite catalyst.

Description of the drawings:

FIG. 1, Bi₄NbO₈Cl、ZnTiO₃And 20% ZnTiO₃/Bi₄NbO₈XRD spectrum of Cl (20% BZT)

FIG. 2, 20% ZnTiO₃/Bi₄NbO₈HRTEM image of Cl composite photocatalyst

FIG. 3, Bi₄NbO₈Cl、ZnTiO₃And 20% ZnTiO₃/Bi₄NbO₈Catalytic degradation diagram of Cl (20% BZT) composite photocatalyst

The first embodiment is as follows:

(1)Bi₄NbO₈preparation of Cl: weighing 9gBi₂O₃6gBiOCl and 3gNb₂O₅Dissolving in 30ml of absolute ethyl alcohol, putting into an agate ball milling tank, and putting 50 agate balls with the diameter of 10 mm. Ball-milling the mixed solution in a ball mill for 2h at the rotation speed of 300r/min, and drying the ball-milled mixed solution at 60 ℃ for 12 h. The dried powder is calcined for 10 hours at 600 ℃ after being ground, the heating rate is 5 ℃/min, and bright yellow Bi is obtained₄NbO₈And (3) Cl powder.

(2)ZnTiO₃The preparation of (1): dissolving 3.1mL of butyl titanate in 10mL of absolute ethyl alcohol to form a solution A; dissolving 1.5mL of glacial acetic acid and 2.75g of zinc nitrate hexahydrate in 10mL of absolute ethyl alcohol successively to form a solution B; slowly dripping the solution B into the solution A under the stirring state, stirring for 30min, then aging for 24h, then drying at 105 ℃ for 12h, and calcining the obtained precursor at 600 ℃ for 3h to obtain ZnTiO₃And (3) powder.

(3)ZnTiO₃And Bi₄NiO₈And (3) Cl compounding: 0.4g of Bi was weighed out separately₄NbO₈Cl and 0.08g ZnTiO₃Grinding the powder in a mortar for 10min, pouring into a beaker, adding 10mL of anhydrous ethanol, performing ultrasonic treatment for 30min, and drying at 60 ℃ for 6 h. Heat-treating the dried powder at 300 deg.C for 2h with a heating rate of 5 deg.C/min to obtain 20% ZnTiO₃/Bi₄NbO₈The Cl composite photocatalyst is simplified to 20 percent BZT.

The photocatalytic performance test uses a xenon lamp as a light source under the room temperature condition, and takes the degradation rate of rhodamine B (RHB) as an evaluation index. We also set a blank as a control experiment, trying to change ZnTiO₃Different composite catalysts are prepared by doping amount. ZnTiO 2₃The doping amounts of (A) are 10%, 20% and 30%, respectively. It was found that the composite heterogeneous catalyst has the best performance when the doping amount is 20%. The experimental procedure was as follows: a clean quartz tube was charged with 0.05g of photocatalyst and 50mL of 5mg/L RHB solution to keep the distance between each tube and the light source equal. Standing in the dark for 30min to ensure that the adsorption and desorption of the RHB on the surface of the sample reach balance; then, the circulating cooling water, the xenon lamp light source, the stirrer and the revolution knob are turned on, timing is started after the light is stabilized, and illumination is carried out for 300 min. During the illumination, samples were taken every 30min, with a sample volume of about 3 mL. The sample was poured into a centrifuge tube and centrifuged to take out the supernatant, and the supernatant was tested for absorbance at 553 nm.

As can be seen from fig. 1: pure Bi₄NbO₈Diffraction peaks of Cl at 29 ° and 32 ° at 2 θ correspond to standard card No.84-0843The (116) and (020) crystal planes of (A); pure ZnTiO₃The diffraction peaks at 2 θ of 35 ° and 30 ° correspond to the (311) and (220) crystal planes of standard card No. 39-0190. Doped ZnTiO₃Then, it can be clearly found to belong to ZnTiO₃The peak of (2 θ) 35 ° appears in Bi₄NbO₈Cl/ZnTiO₃In the diffraction pattern of (a). This therefore indicates that Bi₄NbO₈Cl and ZnTiO₃Successfully combined together. From the enlarged view of FIG. 2, Bi is clearly seen₄NbO₈ZnTiO adhesion to Cl₃Particles of which Bi₄NbO₈The Cl interplanar spacing of 0.254nm corresponds to the (311) interplanar; the ZnTiO3 crystal face spacing of 0.375nm corresponding to the (112) crystal face further proves that the composite ZnTiO can be successfully obtained₃/Bi₄NbO₈And (4) Cl. C/C in FIG. 3₀For evaluating the catalytic degradation efficiency of the samples. Under the same conditions for ZnTiO₃RHB degradation rate of about 65%, sample Bi₄NbO₈The Cl degradation rate was about 90%. Bi₄NbO₈Cl and ZnTiO₃After compounding, 20% ZnTiO₃/Bi₄NbO₈The Cl composite catalyst has high photocatalytic efficiency which can reach about 97 percent. So to speak, we prepared ZnTiO₃/Bi₄NbO₈The Cl composite catalyst actually improves Bi₄NbO₈The photocatalytic performance of Cl, namely the heterojunction formed by compounding the Cl and the Cl inhibits ZnTiO₃/Bi₄NbO₈The combination of photo-generated carriers in the Cl system improves the photocatalytic activity.

Reference to the literature

[1]You Y,Wang S,Xiao K,et al.Z-Scheme g-C₃N₄/Bi₄NbO₈Cl Heterojunction for Enhanced Photocatalytic Hydrogen Production[J].ACS Sustainable Chemistry& Engineering.2018,6,16219-16227.

[2]Zhidong W,Junying L,Wenjian F,et al.Enhanced photocatalytic hydrogen evolution using a novel in situ heterojunction yttrium-dopedBi₄NbO₈[email protected]₂O₅[J]. International Journal of Hydrogen Energy,2018:14281-14292.

[3] Jiangzheng, Tanggudong, Dajie, preparation of nano-scale zinc titanate powder and application thereof in photocatalytic dye degradation [ J ]. Spectroscopy laboratory, 2002,19(5):593-595.