阅读说明：本技术 一种NYF-Ti二元复合光催化剂及其制备方法 (NYF-Ti binary composite photocatalyst and preparation method thereof ) 是由 徐璇 付诗琪 张影 罗玉洁 何倩 吕秀龙 谷晓松 颜秋彤 于 2020-06-19 设计创作，主要内容包括：一种NYF-Ti二元复合光催化剂及其制备方法。本发明二元复合光催化剂不仅复合了上转换材料,实现对可见光和近红外的吸收和转化,还增加了整个光催化材料在可见光区的吸光强度,进一步促进了复合光催化剂,提高催化剂的杀菌活性。本发明制备方法首先利用水热法合成的呈现出规则的六棱柱状的NYF,然后采用溶胶凝胶法将TiO<Sub>2</Sub>负载在NYF表面,获得核壳结构的NYF-Ti。本发明二元复合光催化剂制备工艺简单。(An NYF-Ti binary composite photocatalyst and a preparation method thereof. The binary composite photocatalyst not only compounds the up-conversion material to realize the absorption and conversion of visible light and near infrared, but also increases the light absorption intensity of the whole photocatalytic material in a visible light region, further promotes the composite photocatalyst and improves the bactericidal activity of the photocatalyst. The preparation method firstly utilizes NYF which is synthesized by a hydrothermal method and presents a regular hexagonal prism shape, and then adopts a sol-gel method to prepare TiO 2 The surface of NYF is loaded to obtain NYF-Ti with a core-shell structure. The invention discloses a preparation process of a binary composite photocatalystIt is simple.)

1. An NYF-Ti binary composite photocatalyst is characterized in that the NYF-Ti binary composite photocatalyst is β -NaYF₄:Pr³⁺,Li⁺@TiO₂。

2. The NYF-Ti binary composite photocatalyst as claimed in claim 1, which is prepared from β -NaYF₄:Pr³⁺,Li⁺Flocculent TiO of the core₂Coating the surface of the substrate; it is in a hexagonal prism shape, the diameter is 2-3 μm, and the height is 3-5 μm.

3. The preparation method of NYF-Ti binary composite photocatalyst as claimed in claim 1 or 2, which comprises the following steps:

(1) to uniform dispersion of YCl₃、PrCl₃Adding EDTA into a mixed hydrochloric acid solution of LiCl, stirring, adding a NaF solution, adjusting the pH value to be alkaline to form a solution A by ammonia water, transferring the solution A to a reaction kettle after vigorous stirring, reacting for 20-28 h at the temperature of 150-250 ℃, cooling, washing the solid, and drying to obtain an up-conversion material β -NaYF₄:Pr³⁺,Li⁺(abbreviated NYF);

(2) the up-conversion material β -NaYF prepared in the step (1) is used₄:Pr³⁺,Li⁺Uniformly dispersing in ethanol, adding tetrabutyl titanate, vigorously stirring to obtain a suspension B, dropwise adding an ethanol aqueous solution into the suspension B, stirring, drying, and calcining at 400-500 ℃ to obtain the up-conversion photocatalytic material β -NaYF₄:Pr³⁺,Li⁺@TiO₂。

4. The method for preparing NYF-Ti binary composite photocatalyst as claimed in claim 3, wherein, in step (1), the mixed hydrochloric acid solution is prepared from YCl₃Solution, PrCl₃Mixing the solution with LiCl solution to obtain YCl₃Solution, PrCl₃Solution and LiCl solution, respectively from Y₂O₃、Pr₆O₁₁And Li₂Dissolving O in hydrochloric acid solution.

5. The method for preparing NYF-Ti binary composite photocatalyst according to claim 3 or 4, wherein in the step (1), YCl is contained in the mixed hydrochloric acid solution₃、PrCl₃The mass ratio of LiCl to LiCl is 200 to (2.8-3.2) to (17.8-18.2); preferably, in step (1), YCl₃The mass ratio to NaF was 9: 2; preferably, in step (1), said YCl₃Solution, PrCl₃The concentration of the solution and the concentration of the LiCl solution are both 0.05-0.15 mol/L; preferably, the concentration of the NaF solution is 0.4-0.6 mol/L; preferably, in step (1), the concentration of EDTA in the solution A is 0.025 mol/L.

6. The preparation method of NYF-Ti binary composite photocatalyst according to any one of claims 3 to 5, wherein in the step (1), the pH is adjusted to 8.5 to 9.0, and the vigorous stirring time is 50 to 70 min.

7. The preparation method of NYF-Ti binary composite photocatalyst according to any one of claims 3 to 6, wherein in the step (1), the reaction temperature is 190-210 ℃, and the reaction time is 23-25 h.

8. The preparation method of NYF-Ti binary composite photocatalyst according to any one of claims 3 to 7, wherein in the step (2), the butyl titanate and the up-conversion material β -NaYF₄:Pr³⁺,Li⁺The mass ratio of (A) to (B) is 13.5: 1; preferably, in the step (2), the volume ratio of ethanol to water in the ethanol aqueous solution is 20: 3; preferably, in the step (2), the dropping speed is 1 mL/min.

9. The preparation method of NYF-Ti binary composite photocatalyst according to any one of claims 3 to 8, wherein in the steps (1) and (2), the drying temperature is 50-70 ℃, and the drying time is 11-13 h.

10. The preparation method of NYF-Ti binary composite photocatalyst according to any one of claims 3 to 9, wherein in the step (2), the calcination temperature is 440-460 ℃, the calcination time is 1-3 h, and the temperature rise rate is 2 ℃/min.

Technical Field

The invention relates to the field of materials, and particularly relates to an NYF-Ti binary composite photocatalyst and a preparation method thereof.

Background

The photocatalytic material is another promising bactericidal material, and has the characteristics of rapid action effect, strong bactericidal power, thorough killing performance, good applicability, good chemical stability and the like, so that the photocatalytic material becomes a research hotspot of people. At present, common technologies such as chlorine disinfection, ozone disinfection, ultraviolet disinfection and the like at home and abroad have the defects of high energy consumption, easy generation of disinfection byproducts and the like, and if a visible light sterilization material which has high sterilization efficiency, wide application range, good stability and cyclic utilization can be developed, the existing disinfection technology can be greatly improved. The bacteria are inactivated by the oxidation reduction of electrons and holes generated in the photocatalysis process and active oxygen species formed on the surface of the catalyst on the internal and external components of the bacteria cells, so that the sterilization and disinfection effects are achieved. The semiconductor-based photocatalytic sterilization technology has little pollution to the environment, does not generate byproducts harmful to human bodies, and can be used for treating the degradation of organic matters in the environment, so that the semiconductor-based photocatalytic sterilization technology is possible to develop into a safe and feasible sterilization technology.

The most studied current germicidal materials are based on TiO₂Photocatalysis of semiconductorsAnd (5) sterilizing. TiO, in contrast to other photocatalysts₂Its main advantage is ① that the catalytic activity of semiconductor photocatalyst depends mainly on the carrier concentration and the ability of surface adsorption to give or receive photon-generated electrons₂And ZnO has the best photocatalytic activity, but ZnO has poor stability, so the application is limited, ② TiO₂Has relatively good matching property with solar spectrum, high photocatalytic activity, ③ has good chemical stability and light corrosion resistance, ④ TiO₂Low cost, no toxicity, no secondary pollution and low use cost. TiO2₂Has been applied to various fields as the most commonly used photocatalyst at present, and has been developed for practical use.

But TiO2₂The absorption peak of the compound is in an ultraviolet region, the ultraviolet light in sunlight only accounts for 5 percent, and visible light and infrared light cannot be utilized, which greatly restricts TiO₂The photocatalyst is practically applied to the field of photodegradation.

The up-conversion material can realize the conversion from visible light to ultraviolet light due to the unique up-conversion characteristic, and the rare earth element praseodymium (Pr) can generate ultraviolet light with the best sterilizing effect in the UVC wave band (200) and 280nm) under the excitation of the visible light. Meanwhile, the photocatalytic material can generate active species with strong oxidation reduction property by utilizing light energy, has no obvious selectivity when treating microbial pollution, can efficiently kill microorganisms, has good stability, and shows good application prospect as a sterilization material. The photocatalytic material is another promising bactericidal material, and has the characteristics of rapid action effect, strong bactericidal power, thorough killing performance, good applicability, good chemical stability and the like, so that the photocatalytic material becomes a research hotspot of people. Therefore, many researchers now compound the photocatalyst and the upconversion material to form an upconversion photocatalyst, thereby improving the photocatalytic efficiency of the tube catalyst.

CN110038600A discloses a high-efficiency near-infrared light responsive composite photocatalyst, which is an up-conversion material NaGdF₄:49％Yb/1％[email protected]₄With photocatalyst TiO₂Compounding to obtain the invented composite photocatalyst. NaGdF_4:Yb/[email protected]₄@TiO₂The catalyst can rapidly degrade the fuel-containing rhodamine B wastewater in class under near infrared light, the technology can efficiently utilize solar energy, effectively solves the organic pollutants in the water body, is safe and nontoxic, and does not cause secondary pollution to the environment.

CN109382121A discloses a NaYF₄:Yb³⁺,Tm³⁺@NaYF₄:Yb³⁺,Nd³⁺@TiO₂A composite up-conversion photocatalytic material belongs to the technical field of up-conversion luminescence and photocatalytic materials. The catalyst is prepared from NaYF₄:Yb³⁺,Tm³⁺、NaYF₄:Yb³⁺,Nd³⁺And TiO₂Is compounded, wherein, the NaYF is₄:Yb³⁺,Tm³⁺And NaYF₄:Yb³⁺,Nd³⁺Forming a core-shell structure, said TiO₂Coated on NaYF₄:Yb³⁺,Tm³⁺@NaYF₄:Yb³⁺,Nd³⁺Surface of core-shell structure. The catalyst is prepared by reacting TiO₂Coated on NaYF₄:Yb³⁺,Tm³⁺@NaYF₄:Yb³⁺,Nd³⁺On the core-shell structure, the TiO is expanded₂The wavelength range of the response can drive the full spectral response.

Disclosure of Invention

The invention aims to overcome the defects and provide an NYF-Ti binary composite photocatalyst and a preparation method thereof. The binary composite photocatalyst has simple preparation process.

NYF-Ti binary composite photocatalyst which is β -NaYF₄:Pr³⁺,Li⁺@TiO₂。

Preferably, said NYF-Ti binary composite photocatalyst β -NaYF₄:Pr³⁺,Li⁺Flocculent TiO of the core₂Coating the surface of the substrate; it is in a hexagonal prism shape, the diameter is 2-3 μm, and the height is 3-5 μm.

The preparation method of the NYF-Ti binary composite photocatalyst comprises the following steps:

(1) to uniform dispersion of YCl₃、PrCl₃Adding EDTA into a mixed hydrochloric acid solution of LiCl, stirring, adding a NaF solution, adjusting the pH value to be alkaline to form a solution A by ammonia water, transferring the solution A to a reaction kettle after vigorous stirring, reacting for 20-28 h at the temperature of 150-250 ℃, cooling, washing the solid, and drying to obtain an up-conversion material β -NaYF₄:Pr³⁺,Li⁺(abbreviated NYF);

(2) the up-conversion material β -NaYF prepared in the step (1) is used₄:Pr³⁺,Li⁺Uniformly dispersing in ethanol, adding tetrabutyl titanate, vigorously stirring to obtain a suspension B, dropwise adding an ethanol aqueous solution into the suspension B, stirring, drying, and calcining at 400-500 ℃ to obtain the up-conversion photocatalytic material β -NaYF₄:Pr³⁺,Li⁺@TiO₂。

The preparation method utilizes the up-conversion material to modify TiO₂NYF-Ti photocatalyst with a core-shell structure is prepared, wherein NYF material is used as the core structure, and a photocatalytic material TiO is loaded on the outer layer₂(ii) a NYF absorbs visible light and emits ultraviolet light in UVC range, part of the ultraviolet light is used for sterilization, and the other part of the ultraviolet light is used for exciting the loaded TiO₂So that the active substances with strong oxidation reduction property are generated for disinfection and sterilization.

Preferably, in step (1), the mixed hydrochloric acid solution is prepared from YCl₃Solution, PrCl₃Mixing the solution with LiCl solution to obtain YCl₃Solution, PrCl₃Solution and LiCl solution, respectively from Y₂O₃、Pr₆O₁₁And Li₂Dissolving O in hydrochloric acid solution (preferably 1-3M hydrochloric acid solution).

Preferably, in the step (1), YCl is added to the mixed hydrochloric acid solution₃、PrCl₃And of LiClThe mass ratio of the components is 200 to (2.8-3.2) to (17.8-18.2). Preferably, in step (1), YCl₃The mass ratio to NaF was 9: 2.

Preferably, in step (1), said YCl₃Solution, PrCl₃The concentration of the solution and the concentration of the LiCl solution are both 0.05-0.15 mol/L. Preferably, the concentration of the NaF solution is 0.4-0.6 mol/L.

Preferably, in step (1), the concentration of EDTA in the solution A is 0.025 mol/L.

Preferably, in the step (1), the pH is adjusted to 8.5-9.0, and the vigorous stirring time is 50-70 min.

Preferably, in the step (1), the reaction temperature is 190-210 ℃, and the reaction time is 23-25 h.

Preferably, in step (2), the butyl titanate is mixed with the upconverting material β -NaYF₄:Pr³⁺,Li⁺The mass ratio of (A) to (B) is 13.5: 1.

preferably, in the step (2), the volume ratio of ethanol to water in the ethanol aqueous solution is 20: 3.

preferably, in the step (2), the dropping speed is 1 mL/min.

Preferably, in the steps (1) and (2), the drying temperature is 50-70 ℃, and the drying time is 11-13 h.

Preferably, in the step (2), the calcining temperature is 440-460 ℃, the calcining time is 1-3 h, and the heating rate is 2 ℃/min.

The invention has the beneficial effects that:

(1) the preparation method firstly utilizes NYF which is synthesized by a hydrothermal method and presents a regular hexagonal prism shape, and then adopts a sol-gel method to prepare TiO₂Loading on NYF surface to obtain NYF-Ti with core-shell structure, wherein the prepared NYF-Ti has diameter of 2-3um, height of 3-5um, size substantially identical to NYF, and surface TiO with hexagonal prism₂Is flocculent, has a small thickness, and is uniformly wrapped on the surface of the hexagonal prism NYF.

(2) The up-conversion material of the invention is used for preparing photocatalyst TiO₂The modification can reduce TiO to different degrees₂The forbidden band width of (A) to catalyze the light of the materialThe absorption range is widened to the visible light region; composite TiO₂The absorption of the later NYF-Ti in a visible light region is enhanced, which shows that the modification of the up-conversion material is beneficial to the absorption of the whole sterilization material to visible light, and is beneficial to the up-conversion process and the photocatalytic sterilization process, so that the optical performance of the composite material is more excellent, the recombination rate of photo-generated electron-hole pairs in a system is reduced, the carrier migration rate is higher, and the photocatalytic performance of the composite material is stronger.

(3) The photocatalytic material prepared by the method utilizes ultraviolet light of UVC (200-280nm) emitted by the up-conversion material NYF to sterilize, and meanwhile, TiO is used for sterilizing₂The ultraviolet light in sunlight and the ultraviolet light in a UVC section are absorbed and converted into strong oxidation-reduction substances for sterilization, the excellent sterilization effect is achieved, the three-hour sterilization efficiency of NYF-Ti can reach 99.9999% under the best experimental condition, the good sterilization efficiency is achieved under different coexisting ions and different bacteria types, and the sterilization performance of the composite photocatalytic material is proved to have good wide applicability.

Drawings

FIG. 1 is an XRD pattern of binary composite photocatalyst NYF-Ti prepared in example 1;

FIG. 2 is an SEM image of the binary composite photocatalyst NYF-Ti prepared in example 1, which is 5000 times larger at 1 μm;

FIG. 3 is a TEM image of the binary composite photocatalyst NYF-Ti prepared in example 1, enlarged at 0.5 μm;

FIG. 4 is an XPS plot of binary composite photocatalyst NYF-Ti prepared in example 1, wherein a is a full spectrum of NYF-Ti, and b-e are ion peak bitmaps of Y, F, Ti, O in that order;

FIG. 5 is a diagram of a UV-Vis DRS of the binary composite photocatalyst NYF-Ti prepared in example 1, wherein the left diagram is a UV-Vis spectrum, and the right diagram is a forbidden band width diagram;

FIG. 6 is a graph of the bactericidal efficiency of the samples prepared in example 1 in the presence of common coexisting ions, where a is 0.9% Na₂SO₄B is 0.9% NaNO₃；

FIG. 7 is a graph showing the bactericidal efficiency of the sample prepared in example 1 and other photocatalysts against different bacterial species, wherein a is Staphylococcus aureus, b is Salmonella, c is Shigella, and d is Escherichia coli.

Detailed Description

The present invention will be further described with reference to the following examples and the accompanying drawings.

The raw materials and equipment used in the present invention are commercially available or commonly used in the art, and the methods in the examples are conventional in the art unless otherwise specified.