阅读说明：本技术 一种可见光响应的B,N共掺杂SnO2/TiO2前驱体及其制备方法和应用 (B, N codoped SnO responding to visible light2/TiO2Precursor and preparation method and application thereof ) 是由 马智烨 吴雨桓 叶丽 陈凤华 赵彤 于 2020-04-26 设计创作，主要内容包括：本发明公开了一种可见光响应的B,N共掺杂SnO<Sub>2</Sub>/TiO<Sub>2</Sub>前驱体及其制备方法和应用,所述SnO<Sub>2</Sub>/TiO<Sub>2</Sub>前驱体中,B、N、Sn和Ti元素的摩尔比为0.1～0.5:1～3:0.01～0.1:1。所述前驱体以钛酸酯、锡酸酯为Ti和Sn元素的来源,结合致孔剂,和含B和N元素的物质,并通过调节螯合剂、水和一元醇的含量,使各元素在前驱体中的均匀分布。本发明提供的前驱体可溶于常见的有机溶剂中,进而通过浸渍使其负载在石英棉、玻璃片、纤维等基质上,负载后在空气中焙烧即可得到负载型的光催化剂,既解决了普通TiO<Sub>2</Sub>光催化剂对可见光无响应的问题,也解决了实际应用中催化剂沉降慢、难回收利用等问题。(The invention discloses a B, N codoped SnO with visible light response 2 /TiO 2 Precursor, preparation method and application thereof, and SnO 2 /TiO 2 In the precursor, the molar ratio of B, N, Sn to Ti element is 0.1-0.5: 1-3: 0.01-0.1: 1. The precursor is prepared from titanate and stannate as sources of Ti and Sn elements, a pore-forming agent and a substance containing B and N elements, and the elements are uniformly distributed in the precursor by adjusting the contents of a chelating agent, water and monohydric alcohol. The precursor provided by the invention can be dissolved in commonThe organic solvent is further impregnated to be loaded on substrates such as quartz cotton, glass sheets, fibers and the like, and the loaded photocatalyst can be obtained by roasting in the air after being loaded, so that the problem of common TiO is solved 2 The photocatalyst has no response to visible light, and the problems of slow sedimentation, difficult recycling and the like of the catalyst in practical application are solved.)

1. B, N codoped SnO responding to visible light₂/TiO₂A precursor, characterized in that said SnO₂/TiO₂In the precursor, the molar ratio of B, N, Sn to Ti element is 0.1-0.5: 1-3: 0.01-0.1: 1.

2. The visible-light-responsive B, N-codoped SnO of claim 1₂/TiO₂The precursor is characterized in that the precursor can be dissolved in methanol, ethanol, isopropanol, ethylene glycol monomethyl ether and ethylene glycol ethyl ether;

preferably, the precursor solution remains clear and transparent after 1 year of storage at room temperature.

3. The visible-light-responsive B, N-codoped SnO of claim 1 or 2₂/TiO₂The preparation method of the precursor is characterized by comprising the following steps:

(1) mixing titanate, stannate and pore-foaming agent, and heating for reaction to obtain a solution;

(2) adding boric acid into the solution obtained in the step (1), and reacting until the solution is clear and transparent;

(3) adding acetamide into the solution obtained in the step (2), and reacting until the solution is clear and transparent;

(4) adding a chelating agent into the solution obtained in the step (3), then adding a mixed solution of water and monohydric alcohol, heating and refluxing, cooling, and distilling at normal pressure to remove the solvent to obtain the B and N co-doped SnO₂/TiO₂And (3) precursor.

4. The method according to claim 3, wherein in the step (1), the molar ratio of the Sn element to the Ti element is 0.01 to 0.1: 1; the mass ratio of the pore-foaming agent to Ti element in the system is 0.5-4: 1; the heating reaction temperature is 85-125 ℃, and the reaction time is 0.5-3 h;

the stannate is selected from one or more of tetraethyl stannate, tetra-n-propyl stannate, tetra-isopropyl stannate, tetrabutyl stannate and tetraisobutyl stannate;

preferably, the titanate is selected from one or more of tetraethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetrabutyl titanate and tetraisobutyl titanate;

preferably, the porogen is selected from polyethylene glycol and/or polypropylene glycol.

5. The preparation method according to claim 3, wherein in the step (2), the molar ratio of the B element in the boric acid to the Ti element in the system is 0.1-0.5: 1;

preferably, the reaction temperature is 80-125 ℃, and the reaction time is 0.5-3 h.

6. The preparation method according to claim 3, wherein in the step (3), the molar ratio of the N element in the acetamide to the Ti element in the system is 1-3: 1;

preferably, the reaction temperature is 80-125 ℃, and the reaction time is 0.5-5 h.

7. The preparation method according to claim 3, wherein in the step (4), the molar ratio of the chelating agent to Ti element in the system is 0.2-1: 1; in the mixed solution of water and monohydric alcohol, the molar ratio of water to monohydric alcohol is 1: 5-20, and the molar ratio of water to Ti element in the system is 0.5-1.5: 1; adding the chelating agent into the solution obtained in the step (3) at room temperature to 100 ℃; the heating reflux time is 0.5-3 h;

preferably, the chelating agent is selected from acetylacetone and/or ethyl acetoacetate; the monohydric alcohol is selected from one or more of ethanol, n-propanol, isopropanol, n-butanol and isobutanol.

8. The visible-light-responsive B, N-codoped SnO of claim 1 or 2₂/TiO₂The application of the precursor in preparing the catalyst;

preferably, the visible light-responsive B, N-codoped SnO₂/TiO₂Application of precursor in preparation ofPreparing a powder catalyst or a supported catalyst; the supported catalyst is supported on a substrate such as a coating, a fiber and the like.

9. B, N codoped SnO responding to visible light₂/TiO₂Photocatalyst, characterized in that said SnO₂/TiO₂The photocatalyst is prepared from the B, N codoped SnO as claimed in claim 1 or 2₂/TiO₂Preparing a precursor;

preferably, the visible light-responsive B, N-codoped SnO₂/TiO₂The photocatalyst has SnO₂/TiO₂A heterojunction structure;

preferably, the visible light-responsive B, N-codoped SnO₂/TiO₂The specific surface area of the photocatalyst is 50-300 m²/g。

10. Visible light response load type B and N co-doped SnO₂/TiO₂The photocatalyst is characterized in that the supported B and N codoped SnO₂/TiO₂The photocatalyst is B, N codoped SnO as claimed in claim 9₂/TiO₂The photocatalyst is prepared by loading a carrier, and the loaded B and N codoped SnO₂/TiO₂The loading rate of the photocatalyst on the carrier is 2-15%;

preferably, the support is alumina fiber.

Technical Field

The invention belongs to the technical field of composite materials, and particularly relates to a B and N co-doped SnO with visible light response₂/TiO₂A precursor and a preparation method and application thereof.

Background

In recent years, energy shortage and environmental pollution become two major problems that have become increasingly serious. The content of the organic pollutants which are difficult to degrade in the air and water is increased, so that the ecological environment and the human health are seriously threatened. Various new pollutants such as pharmaceuticals and personal care, internal interferon and volatile organic compounds all place higher demands on environmental treatment technologies.

Quinolone antibiotics (including ofloxacin, norfloxacin, ciprofloxacin and the like) are widely applied to livestock breeding, aquatic products and other breeding industries and are a kind of medicaments commonly used by people and livestock due to the characteristics of wide antibacterial spectrum, strong antibacterial activity, no cross drug resistance with other antibacterial medicaments, small toxic and side effects and the like. Most quinolone antibiotics are not completely metabolized in the human body, are discharged out of the body as metabolites, are accumulated in the human body through a food chain, or induce the generation of antibiotic resistance genes, and are harmful to human health and ecological safety. Among the commonly used semiconductor photocatalysts, TiO₂The photocatalyst has the advantages of high activity, good stability, no secondary pollution, no harm to human bodies, low price and the like, and becomes the photocatalyst which is most valued and has wide application prospect.

Romana Khan et al (Khan, r.and t. -j.kim (2009). "Preparation and application visual-light-responsive Ni-bonded and SnO₂-coupled TiO₂nanocomposite catalysts, "journal of Hazardous Materials 163(2-3):1179-₂And xNi-TiO₂SnO by ligand exchange reaction₂With TiO₂Coupling, and finally heat treating to obtainA catalyst. The photocatalysis test shows that: xNi-TiO₂–SnO₂The composite material has good visible light response photocatalytic activity, and the capability of degrading toluene is superior to that of TiO₂，xNi–TiO₂And TiO₂–SnO₂. However, the catalyst obtained is in the form of powder, which is not favorable for recycling the catalyst, so that the utilization rate of titanium dioxide per unit mass is low.

Amandeep Kaur et al (Kaur, A., et al. (2018). "plain synthesis of CdS/TiO₂Synthesis of CdS/TiO by hydrothermal method from nanocomposite and the above catalytic activity for the provision of a stoichiometric defect, Journal of photochemical Chemistry and Photobiology A, Chemistry 360:34-43₂And (3) nanoparticles. The photocatalytic test shows that the degradation rate of ofloxacin at 180min under visible light is 86 percent, which is superior to that of pure TiO₂The degradation efficiency of (a). However, the obtained catalyst has long degradation time and low efficiency, and exists in a particle form, so that the catalyst is not beneficial to recovery and practical application.

Vibha Bhatia et al (Vibha Bhatia, et al (2016) "Enhanced photocatalytic degradation of ofloxacin by co-doped titanium dioxide under colloidal irradiation," isolation and Purification Technology 161: 1-7) used co-doped titanium dioxide to carry out photocatalytic degradation of ofloxacin, and doped with different amounts of bismuth and nickel, respectively, and when the doping amount is 0.25%, the specific surface area is 74m²(ii) in terms of/g. The photocatalysis test result shows that Bi and Ni are codoped with TiO₂The efficiency of irradiation for 6h under visible light was 86%. However, the obtained catalyst has long degradation time and low efficiency, and exists in a particle form, so that the catalyst is not beneficial to recovery and practical application.

In summary, the TiO prepared by the prior art₂The photocatalyst has the problems of long degradation time, low degradation efficiency and the like when being used for degrading ofloxacin, and is difficult to realize the rapid and efficient degradation of a great amount of antibiotic pollutants existing in water at present; the existing catalyst generally exists in a powder form, and the problems of continuous separation, recovery, reutilization and the like of the catalyst are difficult to realize; meanwhile, ordinary TiO₂The photocatalyst only responds to ultraviolet light, and the ultraviolet light in the sunlight only accounts for less than 5 percentSeverely limit TiO₂Practical application of the photocatalyst.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a visible light response B, N codoped SnO₂/TiO₂The precursor is prepared by using titanate and stannate as sources of Ti and Sn elements, combining a pore-forming agent and a substance containing B and N elements, and enabling the elements to be uniformly distributed in the precursor by adjusting the contents of a chelating agent, water and monohydric alcohol. The precursor provided by the invention can be dissolved in common organic solvents, and then is loaded on substrates such as quartz cotton, glass sheets, fibers and the like through impregnation, so that the visible light-responsive supported photocatalyst is obtained.

In order to solve the technical problems, the invention adopts the technical scheme that:

the invention provides a B, N codoped SnO with visible light response₂/TiO₂Precursor of said SnO₂/TiO₂In the precursor, the molar ratio of B, N, Sn to Ti element is 0.1-0.5: 1-3: 0.01-0.1: 1.

The further scheme of the invention is as follows: the precursor can be dissolved in methanol, ethanol, isopropanol, ethylene glycol monomethyl ether and ethylene glycol ethyl ether; preferably, the precursor solution remains clear and transparent after 1 year of storage at room temperature.

The invention also provides the B and N codoped SnO₂/TiO₂The preparation method of the precursor comprises the following steps:

(1) mixing titanate, stannate and pore-foaming agent, placing the mixture in a reaction vessel, and heating for reaction to obtain a solution;

(2) adding boric acid into the solution obtained in the step (1), and reacting until the solution is clear and transparent;

(3) adding acetamide into the solution obtained in the step (2), and reacting until the solution is clear and transparent;

(4) adding a chelating agent to the solution obtained in step (3), and then adding water and a monohydric alcoholHeating and refluxing the mixed solution of alcohol, cooling, distilling at normal pressure to remove the solvent to obtain the B and N codoped SnO₂/TiO₂And (3) precursor.

In the scheme, stannic acid ester is used as a source of Sn element, and neutral stannic acid ester can maintain the activity of the Sn element in a balanced state in the subsequent hydrolysis reaction process, so that each element in the prepared precursor is uniformly distributed to obtain a precursor solution which can keep a clear and transparent state for a long time, which is very important for preparing the supported catalyst. Researchers of the present invention have also used tin salts (such as tin tetrachloride and tin nitrate) as the source of Sn element, and although the prepared precursor may not have gelation for a long time (3 months), the subsequent photocatalyst or supported photocatalyst has poor ofloxacin digestion efficiency, and digestion capacity gradually decreases with the increase of the use times during recycling, because compared with stannate, acidic inorganic tin salts have weaker control ability on the reaction activity of Sn element in the reaction process, resulting in less ideal distribution effect of Sn element in the final precursor, and Cl element^-Ions or NO₃ ^-The catalyst is easily deactivated by the residual ions in the catalyst.

According to the preparation method, in the step (1), the molar ratio of Sn element to Ti element is 0.01-0.1: 1; the mass ratio of the pore-foaming agent to Ti element in the system is 0.5-4: 1; the heating reaction temperature is 85-125 ℃, and the reaction time is 0.5-3 h; the stannate is selected from one or more of tetraethyl stannate, tetra-n-propyl stannate, tetra-isopropyl stannate, tetrabutyl stannate and tetraisobutyl stannate; preferably, the titanate is selected from one or more of tetraethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetrabutyl titanate and tetraisobutyl titanate; preferably, the porogen is selected from polyethylene glycol and/or polypropylene glycol.

According to the preparation method, in the step (2), the molar ratio of the B element in the boric acid to the Ti element in the system is 0.1-0.5: 1; preferably, the reaction temperature is 80-125 ℃, and the reaction time is 0.5-3 h.

In the scheme, the boric acid is added into the solution obtained in the step (1) at the temperature of 60-95 ℃.

According to the preparation method, in the step (3), the molar ratio of the N element in the acetamide to the Ti element in the system is 1-3: 1; preferably, the reaction temperature is 80-125 ℃, and the reaction time is 0.5-5 h.

In the scheme, the acetamide is added into the solution obtained in the step (2) at the temperature of 50-95 ℃.

According to the preparation method, in the step (4), the molar ratio of the chelating agent to Ti element in the system is 0.2-1: 1; in the mixed solution of water and monohydric alcohol, the molar ratio of water to monohydric alcohol is 1: 5-20, and the molar ratio of water to Ti element in the system is 0.5-1.5: 1; adding the chelating agent into the solution obtained in the step (3) at room temperature to 100 ℃; the heating reflux time is 0.5-3 h; preferably, the chelating agent is selected from acetylacetone and/or ethyl acetoacetate; the monohydric alcohol is selected from one or more of ethanol, n-propanol, isopropanol, n-butanol and isobutanol.

The invention also provides the visible light response B, N codoped SnO₂/TiO₂The application of the precursor in preparing the catalyst; preferably, the visible light-responsive B, N-codoped SnO₂/TiO₂The precursor is applied to the preparation of a powder catalyst or a supported catalyst; the supported catalyst is supported on a substrate such as a coating, a fiber and the like.

The invention also provides B and N codoped SnO with visible light response₂/TiO₂Photocatalyst of said SnO₂/TiO₂The photocatalyst is prepared from the B, N codoped SnO₂/TiO₂Preparing a precursor; preferably, the visible light-responsive B, N-codoped SnO₂/TiO₂The photocatalyst has SnO₂/TiO₂A heterojunction structure; preferably, the visible light-responsive B, N-codoped SnO₂/TiO₂The specific surface area of the photocatalyst is 50-300 m²/g。

In the above scheme, the photocatalyst may be prepared by co-doping B and N with SnO₂/TiO₂And roasting the precursor in an air atmosphere at the temperature of 300-450 ℃ to obtain powder. In the inorganic process of the precursor, the high molecular chain segment is cracked and SnO is generated in situ₂/TiO₂The heterojunction structure in the catalyst microstructure improves the carrier separation capability of the catalyst, thereby improving the photodegradation efficiency.

The invention also provides a visible light response load type B and N co-doped SnO₂/TiO₂Photocatalyst, the supported B, N codoped SnO₂/TiO₂The photocatalyst is B, N codoped SnO₂/TiO₂The photocatalyst is prepared by loading a carrier, and the loaded B and N codoped SnO₂/TiO₂The loading rate of the photocatalyst on the carrier is 2-15%; the carrier is selected from one of fiber, molecular sieve or glass sheet; preferably, the support is alumina fiber.

In the scheme, the visible light response load type B and N co-doped SnO₂/TiO₂The photocatalyst is prepared by the following method: co-doping the B, N with SnO₂/TiO₂Dissolving the precursor in an organic solvent, adding a surfactant, soaking the carrier in the solution after the precursor is completely dissolved, heating and refluxing for reaction for 0.5-2 h, and curing and cracking the carrier loaded with the precursor to obtain the photocatalyst. Wherein the organic solvent is selected from one or more of n-propanol, n-butanol, ethylene glycol monomethyl ether and ethylene glycol ethyl ether; the mass fraction of Ti element in the organic solvent can be 0.2-1.5 wt%; the surfactant is selected from one or more of polyvinylpyrrolidone, polyethylene glycol and polypropylene glycol, and the mass fraction of the surfactant in the solution is 0.5-2 wt%;

after adopting the technical scheme, compared with the prior art, the invention has the following beneficial effects:

1. the B, N codoped SnO provided by the invention₂/TiO₂The precursor is prepared by taking titanate and stannate as sources of Ti and Sn elements, combining a pore-forming agent and a substance containing B and N elements, adjusting the contents of a chelating agent, water and monohydric alcohol,the elements are uniformly distributed in the precursor, so that the precursor has better storage stability;

2. the invention co-dopes B and N with SnO by means of high-temperature cracking and the like₂/TiO₂The prepared catalyst not only has higher surface area, but also can respond to visible light wave bands, and has good catalytic capability under the non-ultraviolet irradiation condition.

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without limiting the invention to the right. It is obvious that the drawings in the following description are only some embodiments, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:

FIG. 1 shows a visible-light-responsive B, N-codoped SnO prepared in example 2 of the present invention₂/TiO₂SEM image of photocatalyst;

FIG. 2 shows a visible-light-responsive supported B, N-codoped SnO prepared in example 2 of the present invention₂/TiO₂SEM images of the photocatalyst before and after loading.

It should be noted that the drawings and the description are not intended to limit the scope of the inventive concept in any way, but to illustrate it by a person skilled in the art with reference to specific embodiments.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and the following embodiments are used for illustrating the present invention and are not intended to limit the scope of the present invention.