阅读说明：本技术 一种钛酸钴@氧化镍核壳光催化材料及其制备方法和应用 (Cobalt titanate @ nickel oxide core-shell photocatalytic material and preparation method and application thereof ) 是由 郭恩言 杨倩 卢启芳 魏明志 沈建兴 于 2019-11-06 设计创作，主要内容包括：本发明公开了一种钛酸钴@氧化镍分级核壳光催化材料及其制备方法和应用,钛酸钴@氧化镍分级核壳光催化材料由超薄氧化镍纳米片均匀生长在钛酸钴亚微米带上构成。其制备方法是首先利用静电纺丝技术得到钛酸钴前驱体纤维,煅烧后得到钛酸钴亚微米带。然后将得到的钛酸钴亚微米带在含有乙酸镍、六亚甲基四胺及柠檬酸钠的水溶液中进行油浴反应,煅烧后即得到钛酸钴@氧化镍分级核壳光催化材料。得到的钛酸钴@氧化镍分级核壳光催化材料,具有较大的比表面积,为光催化反应提供了更多的活性位点。同时具有光响应范围大、光生电子-空穴分离效率高、光催化能力强、循环稳定性好等优点,能够高效降解四环素,在光催化降解抗生素方面具有广泛的应用前景。(The invention discloses a cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material and a preparation method and application thereof. The preparation method comprises the steps of firstly obtaining cobalt titanate precursor fiber by utilizing an electrostatic spinning technology, and calcining to obtain the cobalt titanate submicron band. And then carrying out oil bath reaction on the obtained cobalt titanate submicron band in an aqueous solution containing nickel acetate, hexamethylenetetramine and sodium citrate, and calcining to obtain the cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material. The obtained cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material has a large specific surface area, and provides more active sites for photocatalytic reaction. Meanwhile, the method has the advantages of large photoresponse range, high photoproduction electron-hole separation efficiency, strong photocatalysis capability, good circulation stability and the like, can efficiently degrade tetracycline, and has wide application prospect in the aspect of photocatalytic degradation of antibiotics.)

1. The cobalt titanate @ nickel oxide hierarchical photocatalytic material is characterized in that nickel oxide nanosheets are uniformly distributed on the surface of a cobalt titanate submicron band to form a hierarchical core-shell structure.

2. The cobalt titanate @ nickel oxide hierarchical photocatalytic material of claim 1, characterized in that: the diameter of the cobalt titanate submicron band is about 400-500 nm, and the thickness is about 100-200 nm; the thickness of the nickel oxide nano sheet is about 10-30 nm.

3. A preparation method of a cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material is characterized by comprising the following steps:

(1) preparation of spinnable precursor sol

Dissolving tetra-n-butyl titanate and cobalt acetate in a solvent, adding polyvinylpyrrolidone (PVP), and stirring at room temperature to obtain a spinnable precursor sol;

(2) preparation of cobalt titanate submicron bands

And (2) performing electrostatic spinning on the spinnable precursor sol obtained in the step (1) under the conditions that the temperature is 15-35 ℃, the voltage is 10-30 kV, and the ejection rate is 0.1-1.5 mL/h to obtain precursor fiber. Heating the gel fiber to 600-800 ℃ at the rate of 1-5 ℃ per min, and preserving the temperature for 60-180 min to obtain a cobalt titanate submicron band;

(3) preparation of cobalt titanate @ nickel oxide core-shell photocatalytic material

And (2) dissolving nickel acetate, hexamethylenetetramine and sodium citrate into an aqueous solution at room temperature, adding the cobalt titanate submicron band prepared in the step (2), uniformly dispersing, carrying out oil bath reaction at 60-120 ℃ for 6-12 h, washing, drying and calcining to obtain the cobalt titanate @ nickel oxide core-shell photocatalytic material.

4. The preparation method of the cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material according to claim 3, wherein the molar ratio of tetra-n-butyl titanate to cobalt nitrate in the spinnable precursor sol in step (1) is 1: 1.

5. the preparation method of the cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material as claimed in claim 3, wherein the volume ratio of acetic acid to methanol in the mixed solvent in step (1) is 1: (2.5-3).

6. The preparation method of the cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material as claimed in claim 3, wherein the weight average molecular weight of the polyvinylpyrrolidone in the step (1) is 4 to 300 ten thousand.

7. The preparation method of the cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material as claimed in claim 3, wherein the acceptance distance of the electrostatic spinning in the step (2) is 20-35 cm; the spraying rate is 1.5 mL/h, the voltage is 20-30kV, and the temperature is 20-25 ℃.

8. The cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material according to claim 3, wherein the molar ratio of Ni to Co is 1: (0.5-2).

9. The application of the cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material in the claims 1-2 is characterized in that: the method is applied to the photocatalytic degradation of tetracycline.

10. The application of the cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material according to claim 9 is characterized in that: the tetracycline is catalytically degraded under the condition of simulating solar illumination.

Technical Field

The invention belongs to the technical field of photocatalysis, and relates to a cobalt titanate @ nickel oxide core-shell photocatalytic material, a preparation method thereof and application thereof in catalytic degradation of antibiotics under simulated solar illumination conditions.

Background

The semiconductor photocatalyst is widely concerned by people with the advantages of energy conservation, environmental protection, no secondary pollution and the like, and the application of the semiconductor photocatalyst in the aspect of antibiotic degradation has important significance for solving the problem of water body environmental pollution.

Cobalt titanate is a classic perovskite oxide, and is widely applied to the field of photocatalysis due to the narrow band gap, the proper electronic band structure and the strong visible light absorption capacity. However, cobalt titanate has the disadvantages of high recombination rate of photo-generated electron hole pairs, few photocatalytic active sites, low catalytic efficiency and the like, and is not beneficial to light energy conversion, high-efficiency degradation and cyclic utilization of the photocatalyst, so that the practical application of the cobalt titanate is greatly limited.

Therefore, the invention has the advantages of simple preparation, high photocatalytic activity and high recycling efficiency of the photocatalytic material, and has great application value. Nickel oxide is used as a typical p-type semiconductor, and is widely applied to the field of photocatalysis due to the characteristics of low cost, abundant earth resources, super-hole fluidity and the like. And nickel oxide has a suitable band edge that can be well matched to cobalt titanate. In addition, the hierarchical core-shell structure constructed by interface engineering has proved to be a promising photocatalytic material. In a hierarchical architecture, the presence of interfaces between core-shell layers has a significant impact on the corresponding surface redox reactions.

At present, no relevant report is found for constructing a cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation method of a cobalt titanate @ nickel oxide hierarchical core-shell structure photocatalyst. According to the invention, the one-dimensional cobalt titanate submicron band is prepared, and the cobalt titanate @ nickel oxide composite photocatalyst material is prepared in situ by taking the one-dimensional cobalt titanate submicron band as a matrix, so that the prepared photocatalyst has high catalytic activity and good circulation stability, and a new green and efficient way for degrading antibiotics is provided.

The invention aims to provide a preparation method of a cobalt titanate @ nickel oxide photocatalytic material with a hierarchical core-shell structure.

The second purpose of the invention is to provide the cobalt titanate @ nickel oxide core-shell structure photocatalyst prepared by the method, which has high-efficiency and stable photocatalytic activity under simulated sunlight.

The third purpose of the invention is to provide the application of the cobalt titanate @ nickel oxide hierarchical core-shell structure photocatalyst in the photocatalytic degradation material for removing antibiotics.

The technical scheme of the invention is as follows:

the composite photocatalytic material is characterized by being of a core-shell hierarchical structure consisting of cobalt titanate and nickel oxide.

According to the invention, preferably, the composite structure is a one-dimensional hierarchical core-shell submicron band with the length of 3-5 μm, and the core-shell submicron band is formed by uniformly growing NiO nano-sheets on CoTiO₃A sub-micron band surface, said CoTiO₃The diameter of the submicron band core is about 400-500 nm, the thickness is about 100-200 nm, and the thickness of the NiO nano-plate is about 10-30 nm.

According to the invention, the preferable preparation method of the cobalt titanate @ nickel oxide hierarchical core-shell photocatalyst comprises the following steps:

(1) preparation of spinnable precursor sol

Dissolving tetra-n-butyl titanate and cobalt acetate in a solvent, adding polyvinylpyrrolidone (PVP), and stirring at room temperature to obtain a spinnable precursor sol;

(2) preparation of cobalt titanate submicron bands

And (2) performing electrostatic spinning on the spinnable precursor sol obtained in the step (1) under the conditions that the temperature is 15-35 ℃, the voltage is 10-30 kV, and the ejection rate is 0.1-1.5 mL/h to obtain precursor fiber. And (3) heating the gel fiber to 600-800 ℃ at the speed of 1-5 ℃ per min, and preserving the temperature for 60-180 min to obtain the cobalt titanate submicron band.

(3) Preparation of cobalt titanate @ nickel oxide core-shell photocatalytic material

And (2) dissolving nickel acetate, hexamethylenetetramine and sodium citrate into an aqueous solution at room temperature, adding the cobalt titanate submicron band prepared in the step (2), uniformly dispersing, carrying out oil bath reaction at 60-120 ℃ for 6-12 h, washing, drying and calcining to obtain the cobalt titanate @ nickel oxide core-shell photocatalytic material.

According to the present invention, the solvent in step (1) is preferably a mixed solvent of acetic acid and methanol.

According to the present invention, the volume ratio of acetic acid to methanol in the mixed solvent in step (1) is preferably 1: (2-4). Further preferably, the volume ratio of acetic acid to methanol in the mixed solvent is 1: (2.5-3).

Preferably according to the invention, the molar ratio of Ti and Co in step (1) is 1: 1.

preferably according to the invention, the receiving distance of the electrostatic spinning in the step (2) is 20-35 cm; the spraying rate is 1.5 mL/h, the voltage is 20-30kV, and the temperature is 20-25 ℃.

Preferably, in step (2), the temperature is raised to 700-800 ℃ at a rate of 1-3 ℃/min, and the temperature is maintained for 60-120 min. The cobalt titanate photocatalyst prepared under the temperature-rising condition is in a submicron band structure.

Preferably, according to the invention, the volume of the aqueous solution in step (3) is 60-80 mL.

According to the invention, the molar ratio of the nickel acetate, the hexamethylenetetramine and the sodium citrate in the step (3) is (1-2): (1-2): (0.1-0.2).

Preferably according to the invention, the molar ratio of Co and Ni in step (3) is 1: (0.5-2).

Preferably, according to the invention, in step (3), the oil bath is carried out at 80-100 ℃ for 6-8 h.

According to the present invention, the washing manner in the step (3) is preferably: washing with deionized water and absolute ethyl alcohol alternately.

According to the present invention, the drying conditions in the step (3) are preferably as follows: drying at 40-120 deg.C for 20-40 h.

The cobalt titanate @ nickel oxide hierarchical core-shell photocatalytic material is applied to photocatalytic degradation of tetracycline.

The invention has the following beneficial effects:

the invention prepares the cobalt titanate @ nickel oxide composite photocatalytic material with the hierarchical core-shell structure by a method of combining electrostatic spinning and oil bath. The method takes cobalt titanate as a substrate, and modifies ultrathin nickel oxide nanosheets on a submicron band of the cobalt titanate, so that the cobalt titanate has a large specific surface area, provides more active reaction sites for photocatalytic reaction, has the advantages of large photoresponse range, high photoproduction electron-hole separation efficiency, strong photocatalytic capacity, good circulation stability and the like, and can efficiently degrade tetracycline, and the degradation rate of the tetracycline within 180 min can reach 92.5%.

Drawings

FIG. 1 shows CoTiO prepared in example 1₃X-ray diffraction (XRD) spectrogram of the @ NiO hierarchical core-shell photocatalytic material.

FIG. 2 shows CoTiO produced in example 1₃An SEM image of the @ NiO hierarchical core-shell photocatalytic material; in the figure, a is CoTiO₃The @ NiO hierarchical core-shell photocatalytic material is an SEM image with low magnification, and b is an SEM image with high magnification.

FIG. 3 shows CoTiO prepared in example 1₃A TEM image of the @ NiO graded core-shell photocatalytic material; in the figure, a is CoTiO₃And the @ NiO hierarchical core-shell photocatalytic material is a TEM image with low magnification, and b is a TEM image with high magnification.

FIG. 4 shows CoTiO prepared in example 2₃An SEM image of the @ NiO hierarchical core-shell photocatalytic material; in the figure, a is CoTiO₃The @ NiO hierarchical core-shell photocatalytic material is an SEM image with low magnification, and b is an SEM image with high magnification.

FIG. 5 shows CoTiO prepared in example 3₃An SEM image of the @ NiO hierarchical core-shell photocatalytic material; in the figure, a is CoTiO₃The @ NiO hierarchical core-shell photocatalytic material is an SEM image with low magnification, and b is an SEM image with high magnification.

FIG. 6 shows CoTiO produced in example 1₃The absorbance curve of the @ NiO hierarchical core-shell photocatalytic material for photocatalytic degradation of tetracycline under the irradiation of a simulated sunlight light source; the curves in the graph correspond to the 0-180 min in the graph from top to bottom in sequence.

Detailed Description

The invention will be further illustrated with reference to specific examples, without limiting the scope of the invention thereto. Meanwhile, the experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials, unless otherwise indicated, are commercially available; the equipment used is conventional equipment. Wherein: the polyvinylpyrrolidone is polyvinylpyrrolidone K90, and has a weight average molecular weight of 130 ten thousand.