阅读说明：本技术 一种钛酸铋复合光催化剂及其制备方法和应用 (Bismuth titanate composite photocatalyst and preparation method and application thereof ) 是由 陈海群 何光裕 罗静 陈群 赵宜涛 何大方 钱惺悦 袁菁菁 于 2021-09-29 设计创作，主要内容包括：本发明公开了一种钛酸铋复合光催化剂及其制备方法和应用,制备方法包括,溶胶-凝胶法制备Bi-(12)TiO-(20)凝胶,煅烧得到Bi-(12)TiO-(20)粉体；溶解氧化石墨胶体,分散,得氧化石墨烯分散液；在氧化石墨烯分散液中加入Bi-(12)TiO-(20)粉体,搅拌,超声,水热反应；抽滤、洗涤和干燥后研磨,得到钛酸铋复合光催化剂。本发明溶胶-凝胶法和水热法制备钛酸铋复合光催化剂,其中石墨烯的加入抑制了Bi-(12)TiO-(20)纳米颗粒的团聚,增加了催化剂和反应物的接触面积,加快了光生载流子的转移,避免其再次复合,从而提高光催化剂降解罗丹明B的性能。(The invention discloses a bismuth titanate composite photocatalyst, a preparation method and application thereof, wherein the preparation method comprises the step of preparing Bi by a sol-gel method 12 TiO 20 Gelling and calcining to obtain Bi 12 TiO 20 Powder; dissolving and dispersing the graphite oxide colloid to obtain a graphene oxide dispersion liquid; adding Bi into graphene oxide dispersion liquid 12 TiO 20 Powder, stirring, ultrasonic treatment and hydrothermal reaction; and carrying out suction filtration, washing, drying and grinding to obtain the bismuth titanate composite photocatalyst. The bismuth titanate composite photocatalyst is prepared by a sol-gel method and a hydrothermal method, wherein Bi is inhibited by adding graphene 12 TiO 20 Agglomeration of nanoparticles increases catalysisThe contact area of the agent and the reactant accelerates the transfer of photon-generated carriers and avoids the recombination of the photon-generated carriers, thereby improving the performance of the photocatalyst in degrading rhodamine B.)

1. A preparation method of a bismuth titanate composite photocatalyst is characterized by comprising the following steps: comprises the steps of (a) preparing a mixture of a plurality of raw materials,

preparation of Bi by sol-gel method₁₂TiO₂₀Gelling and calcining to obtain Bi₁₂TiO₂₀Powder;

dissolving and dispersing the graphite oxide colloid to obtain a graphene oxide dispersion liquid;

adding Bi into graphene oxide dispersion liquid₁₂TiO₂₀Powder, stirring, ultrasonic treatment and hydrothermal reaction;

and carrying out suction filtration, washing, drying and grinding to obtain the bismuth titanate composite photocatalyst.

2. The method for preparing the bismuth titanate composite photocatalyst as claimed in claim 1, wherein the method comprises the following steps: the sol-gel method for preparing Bi₁₂TiO₂₀Gelling, dissolving bismuth salt in ethylene glycol, dissolving n-butyl titanate in hydrogen peroxide, adding chelating agent into the two solutions, adjusting pH with ammonia water, and obtaining Bi in boiling water₁₂TiO₂₀And (4) gelling.

3. The method for preparing a bismuth titanate composite photocatalyst as claimed in claim 1 or 2, which is characterized in that: and dissolving the graphite oxide colloid, namely dissolving the graphite oxide colloid into distilled water to obtain the graphene oxide dispersion liquid with the concentration of 2.11 g/L.

4. The method for preparing the bismuth titanate composite photocatalyst as claimed in claim 3, wherein: the dispersion is ultrasonic dispersion, the ultrasonic power is 250W, the ultrasonic time is 20-50 min, and the ultrasonic frequency is 20-50 kHz.

5. The method for preparing a bismuth titanate composite photocatalyst as claimed in claim 3 or 4, wherein: adding Bi into the graphene oxide dispersion liquid₁₂TiO₂₀Powder of Bi in mass ratio₁₂TiO₂₀The mass ratio of the powder to the graphene oxide is 100: 1 to 7.

6. The method for preparing the bismuth titanate composite photocatalyst as claimed in any one of claims 1 to 5, wherein: the hydrothermal reaction is carried out at the reaction temperature of 120-180 ℃ for 12-18 h.

7. The method for preparing the bismuth titanate composite photocatalyst as claimed in any one of claims 1 to 5, wherein: the drying is vacuum drying, the drying temperature is 60-80 ℃, and the drying time is 12-24 h.

8. The bismuth titanate composite photocatalyst prepared by the preparation method of any one of claims 1 to 7.

9. The use of the bismuth titanate composite photocatalyst as claimed in claim 8 in rhodamine B degradation.

10. The use of claim 9, wherein: the concentration of rhodamine B is lower than 20 mg/L.

Technical Field

The invention belongs to the technical field of photocatalytic degradation, and particularly relates to a bismuth titanate composite photocatalyst as well as a preparation method and application thereof.

Background

Compared with an adsorption method, a biodegradation method and a catalytic oxidation method, the photocatalytic degradation method utilizing sunlight has the advantages of low cost, small pollution and the like, is an environment-friendly dye wastewater treatment method, and has great application prospect in the aspect of dye wastewater treatment. The most used photocatalytic materials at present are semiconductor materials, and among them, wide band gap semiconductor materials have unique photoelectric properties and thus are widely used in the field of photocatalysis.

The photocatalytic activity of bismuth titanate depends on the unique crystal structure and electronic structure of bismuth titanate, TiO6 octahedrons or TiO4 tetrahedrons exist in the crystal structures, and 6s2 lone pair electrons and Bi3+ with stereo activity exist in BiOn polyhedrons connected with TiO6 or TiO4, so that the bismuth titanate compound has wide application prospect in the field of photocatalysis. In order to inhibit the agglomeration of the nanoparticles and increase the stability of the nanoparticles, different carriers (such as two-dimensional carbon materials and zeolites) are designed to load the semiconductor material. However, these methods are relatively complex and costly, and therefore, it is necessary to develop a composite material which is simple and environmentally friendly and has high photocatalytic degradation performance.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

In view of the above and/or the deficiencies in the prior art, the present invention provides a bismuth titanate composite photocatalyst, and a preparation method and an application thereof.

The invention prepares Bi by a sol-gel method and a hydrothermal method₁₂TiO₂₀/RGO photocatalyst, in which the addition of graphene suppresses Bi₁₂TiO₂₀The agglomeration of the nano particles increases the contact area of the catalyst and the reactant, and improves the performance of the photocatalyst for degrading RhB.

In order to solve the technical problems, the invention provides the following technical scheme: a preparation method of a bismuth titanate composite photocatalyst comprises the following steps,

preparation of Bi by sol-gel method₁₂TiO₂₀Gelling and calcining to obtain Bi₁₂TiO₂₀Powder;

dissolving and dispersing the graphite oxide colloid to obtain a graphene oxide dispersion liquid;

adding Bi into graphene oxide dispersion liquid₁₂TiO₂₀Powder, stirring, ultrasonic treatment and hydrothermal reaction;

and carrying out suction filtration, washing, drying and grinding to obtain the bismuth titanate composite photocatalyst.

As a preferable scheme of the preparation method of the bismuth titanate composite photocatalyst, the method comprises the following steps: the sol-gel method for preparing Bi₁₂TiO₂₀Gelling, dissolving bismuth salt in ethylene glycol, dissolving n-butyl titanate in hydrogen peroxide, adding chelating agent into the two solutions, adjusting pH with ammonia water, and obtaining Bi in boiling water₁₂TiO₂₀And (4) gelling.

As a preferable scheme of the preparation method of the bismuth titanate composite photocatalyst, the method comprises the following steps: and dissolving the graphite oxide colloid, namely dissolving the graphite oxide colloid into distilled water to obtain the graphene oxide dispersion liquid with the concentration of 2.11 g/L.

As a preferable scheme of the preparation method of the bismuth titanate composite photocatalyst, the method comprises the following steps: the dispersion is ultrasonic dispersion, the ultrasonic power is 250W, the ultrasonic time is 20-50 min, and the ultrasonic frequency is 20-50 kHz.

As a preferable scheme of the preparation method of the bismuth titanate composite photocatalyst, the method comprises the following steps: adding Bi into the graphene oxide dispersion liquid₁₂TiO₂₀Powder of Bi in mass ratio₁₂TiO₂₀The mass ratio of the powder to the graphene oxide is 100: 1 to 7.

As a preferable scheme of the preparation method of the bismuth titanate composite photocatalyst, the method comprises the following steps: the hydrothermal reaction is carried out at the reaction temperature of 120-180 ℃ for 12-18 h.

As a preferable scheme of the preparation method of the bismuth titanate composite photocatalyst, the method comprises the following steps: the drying is vacuum drying, the drying temperature is 60-80 ℃, and the drying time is 12-24 h.

Another object of the present invention is to provide a bismuth titanate composite photocatalyst obtained by the preparation method described above.

The invention also aims to provide application of the bismuth titanate composite photocatalyst in degradation of rhodamine B.

As a preferable scheme of the application of the bismuth titanate composite photocatalyst in rhodamine B degradation, the method comprises the following steps: the concentration of rhodamine B is lower than 20 mg/L.

Compared with the prior art, the invention has the following beneficial effects:

the invention discloses a sol-gel method and a hydrothermal method for preparing Bi₁₂TiO₂₀/RGO photocatalyst, in which the addition of graphene suppresses Bi₁₂TiO₂₀The aggregation of the nano particles increases the contact area of the catalyst and the reactant, accelerates the transfer of a photon-generated carrier, and avoids the recombination of the photon-generated carrier, thereby improving the performance of the photocatalyst for degrading rhodamine B.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:

FIG. 1 shows Bi obtained in examples 1 and 3₁₂TiO₂₀XRD pattern of/RGO photocatalyst.

FIG. 2 shows Bi obtained in example 3₁₂TiO₂₀TEM image of/RGO photocatalyst.

FIG. 3 shows Bi obtained in example 3₁₂TiO₂₀The effect graph of the recycling of the/RGO photocatalyst.

FIG. 4 shows Bi contents of different graphene loadings obtained in examples 1 and 5₁₂TiO₂₀And the effect diagram of the control experiment for degrading rhodamine B under the catalysis of the/RGO photocatalyst.

FIG. 5 shows Bi obtained in example 3₁₂TiO₂₀Degradation pattern of/RGO photocatalyst on rhodamine B with different concentrations.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, specific embodiments thereof are described in detail below with reference to examples of the specification.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Example 1

(1) 2.90g of Bi (NO) are weighed out₃)₃〃5H₂O was completely dissolved in 30mL of ethylene glycol with stirringIn (1), uniformly dispersing the mixture;

(2) weighing 0.17g of n-butyl titanate, and dissolving in 5mL of 30% hydrogen peroxide solution to uniformly disperse the solution;

(3) weighing 4.20g of citric acid as a chelating agent, adding the citric acid into the two solutions, and adjusting the pH of the two solutions to 9 by ammonia water;

(4) mixing the two solutions together, stirring for 1h, and heating the obtained suspension in a boiling water bath to obtain Bi₁₂TiO₂₀Gelling;

(5) the obtained Bi₁₂TiO₂₀Drying the gel in a forced air drying box at 140 ℃ to form a fluffy precursor, putting the precursor in a tubular furnace, heating to 550 ℃ at the speed of 2 ℃/min, and calcining for 1h to obtain light yellow Bi₁₂TiO₂₀；

Prepared Bi is tested by degrading rhodamine B under simulated sunlight irradiation₁₂TiO₂₀The catalytic activity of (3). The reaction conditions for degrading rhodamine B are as follows: 40mL of 20mg/L rhodamine B aqueous solution, 10mg of catalyst, establishing absorption balance under the dark condition, and then starting light to perform photocatalytic reaction, wherein the degradation rate of the rhodamine B is found to be 75% in 210 min.

Example 2

(1) Weighing 0.097g (solid content is 2.11%) of graphite oxide in 30mL of deionized water solution, wherein the ultrasonic frequency is 50kHz, and the ultrasonic time is 30min, so that the graphite oxide is uniformly dispersed to obtain a graphene oxide dispersion liquid;

(2) 0.20g of Bi obtained by calcination in example 1 was weighed out₁₂TiO₂₀Adding the graphene oxide dispersion liquid which is uniformly dispersed by ultrasonic, stirring for 3 hours, and then carrying out ultrasonic treatment for 1 hour at the ultrasonic frequency of 50 kHz;

(3) placing the mixed solution in a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining, and reacting for 12 hours at 120 ℃;

(4) filtering to obtain solid, washing with distilled water and alcohol for several times, drying at 80 deg.C for 8 hr to obtain bismuth titanate composite photocatalyst, labeled as Bi₁₂TiO₂₀/RGO₁A composite photocatalyst;

by simulating sun illuminationTesting prepared Bi by degrading rhodamine B under radiation₁₂TiO₂₀/RGO₁Catalytic activity of the photocatalyst. The reaction conditions for degrading rhodamine B are as follows: 40mL of 20mg/L rhodamine B aqueous solution, 10mg of catalyst, establishing absorption balance under the dark condition, and then starting light to perform photocatalytic reaction, wherein the degradation rate of the rhodamine B is found to be 76% in 210 min.

Example 3

(1) Weighing 0.29g (solid content is 2.11%) of graphite oxide in 30mL of deionized water solution, wherein the ultrasonic frequency is 50kHz, and the ultrasonic time is 30min, so that the graphite oxide is uniformly dispersed to obtain a graphene oxide dispersion liquid;

(2) 0.20g of Bi obtained by calcination in example 1 was weighed out₁₂TiO₂₀Adding the graphene oxide dispersion liquid which is uniformly dispersed by ultrasonic, stirring for 3 hours, and then carrying out ultrasonic treatment for 1 hour at the ultrasonic frequency of 50 kHz;

(3) placing the mixed solution in a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining, and reacting for 12 hours at 120 ℃;

(4) filtering to obtain solid, washing with distilled water and alcohol for several times, drying at 80 deg.C for 8 hr to obtain bismuth titanate composite photocatalyst, labeled as Bi₁₂TiO₂₀/RGO₃A composite photocatalyst;

prepared Bi is tested by degrading rhodamine B under simulated sunlight irradiation₁₂TiO₂₀/RGO₃Catalytic activity of the photocatalyst. The reaction conditions for degrading rhodamine B are as follows: 40mL of 20mg/L rhodamine B aqueous solution, 10mg of catalyst, establishing absorption balance under the dark condition, and then starting light to perform photocatalytic reaction, wherein the degradation rate of the rhodamine B is found to be 98% in 210 min.

Bi₁₂TiO₂₀/RGO₃The results of 5-time RhB degradation experiments of the composite photocatalyst are shown in Table 1, and it can be seen from Table 1 that Bi₁₂TiO₂₀/RGO₃After the composite photocatalyst is recycled for 5 times, Bi₁₂TiO₂₀/RGO₃The degradation rate of rhodamine B in 210min of the photocatalyst is still up to 88.5%.

TABLE 1

FIG. 1 shows Bi obtained in examples 1 and 3₁₂TiO₂₀And Bi₁₂TiO₂₀/RGO₃XRD pattern of catalyst, Bi₁₂TiO₂₀/RGO₃And Bi₁₂TiO₂₀All peaks correspond to cubic phase structure Bi₁₂TiO₂₀Crystal face (JCPDS No.34-0097), and the peak type of the characteristic diffraction peak is sharp, and no impurity peak appears, which indicates that Bi₁₂TiO₂₀The sample has good crystallinity and high purity. Bi prepared by compounding with graphene₁₂TiO₂₀/RGO₃Its crystal face and Bi₁₂TiO₂₀The facets corresponded exactly and the RGO lamellae were successfully exfoliated.

Example 4

(1) Weighing 0.48g (solid content is 2.11%) of graphite oxide in 30mL of deionized water solution, wherein the ultrasonic frequency is 50kHz, and the ultrasonic time is 30min, so that the graphite oxide is uniformly dispersed to obtain a graphene oxide dispersion liquid;

(2) 0.20g of Bi obtained by calcination in example 1 was weighed out₁₂TiO₂₀Adding the graphene oxide dispersion liquid which is uniformly dispersed by ultrasonic, stirring for 3 hours, and then carrying out ultrasonic treatment for 1 hour at the ultrasonic frequency of 50 kHz;

(3) placing the mixed solution in a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining, and reacting for 12 hours at 120 ℃;

(4) filtering to obtain solid, washing with distilled water and alcohol for several times, drying at 80 deg.C for 8 hr to obtain bismuth titanate composite photocatalyst, labeled as Bi₁₂TiO₂₀/RGO₅A composite photocatalyst;

prepared Bi is tested by degrading rhodamine B under simulated sunlight irradiation₁₂TiO₂₀/RGO₅Catalytic activity of the photocatalyst. The reaction conditions for degrading rhodamine B are as follows: 40mL of 20mg/L rhodamine B aqueous solution, 10mg of catalyst, establishing absorption balance under the dark condition, and then starting light to perform photocatalytic reaction, wherein the degradation rate of the rhodamine B in 210min is found to be 81%.

Example 5

(1) Weighing 0.68g (solid content is 2.11%) of graphite oxide in 30mL of deionized water solution, wherein the ultrasonic frequency is 50kHz, and the ultrasonic time is 30min, so that the graphite oxide is uniformly dispersed to obtain a graphene oxide dispersion liquid;

(2) 0.20g of Bi obtained by calcination in example 1 was weighed out₁₂TiO₂₀Adding the graphene oxide dispersion liquid which is uniformly dispersed by ultrasonic, stirring for 3 hours, and then carrying out ultrasonic treatment for 1 hour at the ultrasonic frequency of 50 kHz;

(3) placing the mixed solution in a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining, and reacting for 12 hours at 120 ℃;

(4) filtering to obtain solid, washing with distilled water and alcohol for several times, drying at 80 deg.C for 8 hr to obtain bismuth titanate composite photocatalyst, labeled as Bi₁₂TiO₂₀/RGO₇A composite photocatalyst;

prepared Bi is tested by degrading rhodamine B under simulated sunlight irradiation₁₂TiO₂₀/RGO₁Catalytic activity of the photocatalyst. The reaction conditions for degrading rhodamine B are as follows: 40mL of 20mg/L rhodamine B aqueous solution, 10mg of catalyst, establishing absorption balance under the dark condition, and then starting light to perform photocatalytic reaction, wherein the degradation rate of the rhodamine B is found to be 87% in 210 min.

FIG. 3 shows Bi of different graphene loadings prepared in examples 1 to 5₁₂TiO₂₀FIG. 3 shows the catalytic degradation of rhodamine B by the/RGO photocatalyst in comparison with Bi₁₂TiO₂₀，Bi₁₂TiO₂₀/RGO₃The degradation rate of RhB was increased by 22%, and as the content of RGO increased, the degradation rate of RhB increased and then decreased. This is because the two-dimensional lamellar structure and the large specific surface area of graphene inhibit the agglomeration of nanoparticles, so that Bi₁₂TiO₂₀The nano particles have smaller particle size and better dispersibility, so that the contact area between the catalyst and reactants is increased, excellent catalytic activity is shown in the reaction process, and the degradation of RhB by the photocatalyst is facilitated. However, as the graphene content is further increased, Bi plays a major role₁₂TiO₂₀The amount is further reduced, resulting in a reduction in the catalytic performance of the composite.

Example 6

This example 6 is substantially the same as example 3 except that the reaction temperature in step (3) is different, and the catalytic activity of the prepared photocatalyst was tested by degrading rhodamine B under simulated solar irradiation. The reaction conditions for degrading rhodamine B are as follows: 40mL of 20mg/L rhodamine B aqueous solution, 10mg of catalyst, establishing absorption balance under a dark condition, and then starting light to perform a photocatalytic reaction, wherein the test results are specifically shown in Table 2.

TABLE 2

Reaction temperature	Degradation rate of 210min rhodamine B
		120℃	98％
140℃	80％
		160℃	70％
180℃	70％

As can be seen from the data in Table 2, Bi prepared at different hydrothermal temperatures was compared₁₂TiO₂₀/RGO₃The photocatalytic performance of the Bi is prepared when the hydrothermal temperature is 120 DEG C₁₂TiO₂₀/RGO₃The photocatalytic performance ofPreferably, it follows that 120 ℃ is the optimum experimental temperature.

Example 7

Bi prepared in example 3 was tested by simulated solar irradiation₁₂TiO₂₀/RGO₃The composite photocatalyst has catalytic activity of degrading rhodamine B with different concentrations. The reaction conditions for degrading rhodamine B with different concentrations are as follows: 40mL of rhodamine B aqueous solution with the concentrations of 10, 20, 30 and 40mg/L respectively, the dosage of the catalyst is 10mg, absorption balance is established under the dark condition, then the light is turned on for photocatalytic reaction, and the test result is shown in figure 4.

FIG. 4 shows Bi₁₂TiO₂₀/RGO₃An experimental result chart of degrading rhodamine B with different concentrations is shown in FIG. 4, when the initial concentration of RhB is lower than 20mg/L, RhB is Bi within 3h₁₂TiO₂₀the/RGO was completely degraded. When the initial concentration of RhB is 40mg/L, Bi₁₂TiO₂₀The degradation rate of the/RGO to the RhB is reduced to about 60 percent. This is mainly because: (1) the surface active sites of the photocatalyst are fixed, and only a certain concentration of RhB solution can be degraded in a certain range; (2) excess RhB deposits on the catalyst surface, resulting in catalyst deactivation.

The invention discloses a sol-gel method and a hydrothermal method for preparing Bi₁₂TiO₂₀/RGO photocatalyst, in which the addition of graphene suppresses Bi₁₂TiO₂₀The aggregation of the nano particles increases the contact area of the catalyst and the reactant, accelerates the transfer of a photon-generated carrier, and avoids the recombination of the photon-generated carrier, thereby improving the performance of the photocatalyst for degrading rhodamine B.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.