阅读说明：本技术 一种NiO/CuO复合材料及其制备方法和应用 (NiO/CuO composite material and preparation method and application thereof ) 是由 孙海燕 吕洪水 陶芙蓉 于 2019-09-25 设计创作，主要内容包括：本发明涉及一种NiO/CuO复合材料及其制备方法和应用。由NiO和CuO组成,为三维多孔网状结构,平均粒径为20nm,比表面积为20-50m<Sup>2</Sup>/g。通过静电纺丝和煅烧的方法得到NiO/CuO复合材料。解决了现有的催化剂中金属的残留量过大的问题,避免造成水体的二次污染,回收的催化剂可以循环利用,循环利用的催化效率较高,可以重复用于水体中的4-NP的还原,提供了一种能够快速有效的催化NaBH<Sub>4</Sub>还原4-NP的催化剂和方法。(The invention relates to a NiO/CuO composite material and a preparation method and application thereof. Consists of NiO and CuO, is a three-dimensional porous network structure, has an average grain diameter of 20nm and a specific surface area of 20-50m 2 (ii) in terms of/g. The NiO/CuO composite material is obtained by electrostatic spinning and calcining. Solves the problem of overlarge residual quantity of metal in the prior catalyst, avoids causing secondary pollution of water, recycles the catalyst, has higher catalytic efficiency, can be repeatedly used for the reduction of 4-NP in water, and provides the NaBH catalyst which can quickly and effectively catalyze 4 Catalyst for reduction of 4-NPAn agent and a method.)

1. A NiO/CuO composite material is characterized in that: consists of NiO and CuO, is a three-dimensional porous reticular structure, has an average diameter of 20nm and a specific surface area of 20-50m²/g。

2. The NiO/CuO composite of claim 1, wherein: the specific surface area is 25-46m²/g。

3. The NiO/CuO composite of claim 1, wherein: the molar ratio of NiO to CuO is 1: 2-2: 1.

4. The method for preparing the NiO/CuO composite material according to any one of claims 1 to 3, wherein the NiO/CuO composite material comprises the following steps: the method comprises the following specific steps:

dissolving polyvinylpyrrolidone in absolute ethyl alcohol, adding aqueous solution of nickel salt and copper salt to obtain mixed solution, performing electrostatic spinning by using the mixed solution, collecting and drying a product of the electrostatic spinning, and calcining to obtain the NiO/CuO composite material.

5. The method for preparing the NiO/CuO composite material according to claim 4, wherein: the volume of absolute ethanol corresponding to 1.0g of polyvinylpyrrolidone is 8-12mL, and the average molecular weight of polyvinylpyrrolidone is 1300000.

6. The method for preparing the NiO/CuO composite material according to claim 4, wherein: the nickel salt and the copper salt are inorganic salts with crystal water, and the mass ratio of the nickel salt to the copper salt is preferably 1.2-1.3: 1.

7. The method for preparing the NiO/CuO composite material according to claim 4, wherein: the nickel ion concentration of the nickel salt aqueous solution is 0.062 to 0.13mol/L, and the copper ion concentration of the copper salt aqueous solution is 0.13 to 0.25 mol/L.

8. The method for preparing the NiO/CuO composite material according to claim 4, wherein: the conditions of electrostatic spinning are as follows: the inner diameter of the needle is 0.4-0.5mm, the voltage is 18-22Kv, the receiving distance is 18-22cm, and the pumping speed is 0.002-0.004 mm/s.

9. The method for preparing the NiO/CuO composite material according to claim 4, wherein: the drying temperature is 70-90 ℃, and the drying time is 10-14 h;

Or, the temperature in the calcining process is 440-460 ℃, and the calcining time is 1.5-2.5 h;

Or the heating rate of the calcination is 0.8-1.2 ℃/min.

10. The use of the NiO/CuO composite material as claimed in any one of claims 1 to 3 in catalyzing NaBH₄The application of reducing 4-NP.

Technical Field

The invention belongs to the technical field of metal oxide material preparation, and particularly relates to a NiO/CuO composite material, and a preparation method and application thereof.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

4-nitrophenol (4-NP) is a toxic pollutant that is widely present in agricultural and industrial wastewater. Short exposure to 4-NP causes symptoms such as headache, nausea, cyanosis, lethargy, etc., and is classified as one of the most toxic substances by the U.S. environmental protection agency. In order to effectively remove them, researchers have developed many methods such as electrochemical oxidation, photo-assisted reaction, microbial degradation, and microwave-assisted degradation. In addition, there is a method of catalyzing NaBH using a suitable catalyst₄The method is simple to operate and environment-friendly, and the catalytic product of the method is 4-nitroaniline (4-AP), which is an important chemical intermediate product and can be used for producing analgesics, antipyretics, polymers, dyes and the like.

disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a NiO/CuO composite material, and a preparation method and application thereof.

In order to solve the technical problems, the technical scheme of the invention is as follows:

In a first aspect, the NiO/CuO composite material consists of NiO and CuO, has a three-dimensional porous network structure, and has an average particle size of 20nm and a specific surface area of 20-50m²/g。

Preferably, the specific surface area is 25 to 46m²(ii) in terms of/g. Preferably, the molar ratio of NiO to CuO is 1: 2-2: 1.

the catalytic performance of the material can be effectively improved by improving the interface characteristic between the catalyst and the reaction liquid. The good interface can not only maximally adsorb reaction substrates, but also promote the transmission of electrons, thereby increasing the reaction rate. The porosity and the interlaced structure of the catalyst are advantageous for the appearance of a specific interface structure. The nanofiber structure material generally has higher specific surface area and porous structure, so that the adsorption of a reaction substrate is facilitated; meanwhile, the staggered structure among the fibers also contributes to substrate diffusion, so that the catalytic performance of the material is improved.

In a second aspect, a preparation method of the NiO/CuO composite material comprises the following specific steps:

Dissolving polyvinylpyrrolidone in absolute ethyl alcohol, adding aqueous solution of nickel salt and copper salt to obtain mixed solution, performing electrostatic spinning by using the mixed solution, collecting and drying a product of the electrostatic spinning, and calcining to obtain the NiO/CuO composite material.

Electrospinning in combination with suitable calcination techniques is a simple and straightforward method of preparing metal oxide fibers, and the sample components are easily adjusted. Therefore, the fiber composite is prepared by utilizing the electrostatic spinning technology and applied to catalyzing NaBH under mild conditions₄Reducing 4-NP.

In some embodiments, 1.0g polyvinylpyrrolidone corresponds to a volume of absolute ethanol of 8-12mL, and the polyvinylpyrrolidone has an average molecular weight of 1300000. In some embodiments, the nickel salt and the copper salt are inorganic salts with crystal water, and the mass ratio of the nickel salt to the copper salt is preferably 1.2-1.3: 1. the reason why the invention selects the nickel and the copper is that the composite material obtained by matching the copper salt and the nickel salt has better catalytic performance, and if the composite material is compounded with other metal elements, the composite material does not have better catalytic performance. The catalytic performance of the material can be improved by adjusting the molar ratio of the nickel salt to the copper salt, and if the molar ratio exceeds or is lower than the above ratio, the structure of the material can be changed, so that the catalytic performance is reduced.

In some embodiments, the aqueous nickel salt solution has a nickel ion concentration of 0.062 to 0.13mol/L and the aqueous copper salt solution has a copper ion concentration of 0.13 to 0.25 mol/L. In some embodiments, the conditions of electrospinning are: the inner diameter of the needle is 0.4-0.5mm, the voltage is 18-22Kv, the receiving distance is 18-22cm, and the pumping speed is 0.002-0.004 mm/s. The electrospinning conditions affect the diameter of the pores and the distribution of the pores of the three-dimensional network structure to be finally obtained, so that the three-dimensional network structure is prepared, and the composite material with the porous structure is formed.

In some embodiments, the temperature of drying is 70-90 ℃ and the time of drying is 10-14 h. In some embodiments, the temperature of the calcination process is 440-460 ℃ and the calcination time is 1.5-2.5 h. The temperature of the calcination should not be too high, which would otherwise cause the porous structure to disappear, and too low, which would result in incomplete removal of the organic material and formation of metal oxides. In some embodiments, the temperature ramp rate for calcination is from 0.8 to 1.2 deg.C/min.

In a third aspect, the NiO/CuO composite material is used for catalyzing NaBH₄The application of reducing 4-NP.

The invention has the beneficial effects that:

The invention provides a method for catalyzing NaBH in water environment₄The 4-NP is reduced, the catalyst recovered after catalysis can be recycled, the recycling catalytic efficiency is high, the catalyst can be repeatedly used for reducing the 4-NP in the water body, and the NaBH can be quickly and effectively catalyzed₄Catalysts and methods for reducing 4-NP;

The preparation method of the NiO/CuO composite material utilizes the electrostatic spinning technology and the calcination method to obtain the composite material with a three-dimensional porous structure, provides larger adsorption and catalysis space for the catalyst, simultaneously improves the overall catalysis performance of the catalyst by the matching of NiO and CuO, and has good metal element bonding strength of the catalyst, so that the catalyst can be recycled;

the composite material prepared by the specific ratio of NiO and CuO has more oxygen vacancies, and a stable three-dimensional network porous structure can be obtained only by the specific ratio, so that the catalyst with good catalytic performance is obtained.

drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and 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 and not to limit the invention.

FIG. 1 is an XRD spectrum of a NiO/CuO composite material prepared in example 1;

FIG. 2 is an XPS spectrum of the NiO/CuO composite prepared in example 1: full spectrum (a), O1s (b), Cu 2p (c), Ni 2p (d);

FIG. 3 is an SEM picture of the NiO/CuO composite prepared in example 1 before and after calcination;

FIG. 4 is an EDS spectrum (a), SEM (b), and EDS face scan results (c) of the NiO/CuO composite prepared in example 1, with the scale in all figures being 200 μm;

FIG. 5 is SEM pictures of gel fibers (a, c, e) before calcination and products (b, d, f) after calcination of example 1, comparative example 1 and comparative example 2;

FIG. 6 is N of NiO/CuO composites prepared in examples, comparative examples 1 and 2₂Adsorption and desorption curves;

FIG. 7 is a graph relating the catalytic reactions of the NiO/CuO composite prepared in example 1 with the materials prepared in comparative examples 3-4;

FIG. 8 is a NiO/Co example prepared in comparative example 5₃O₄Scanning electron microscope photos of the composite material and relevant catalytic reaction curves of the composite material;

Fig. 9 is an O1s spectrum for NiO/CuO composites prepared in examples 1-3 (a) Ni/Cu ═ 2:1, (b) Ni/Cu ═ 1:1, and (c) Ni/Cu ═ 1: 2;

FIG. 10 shows the cycle test results of the NiO/CuO composite prepared in example 1;

FIG. 11 is an SEM picture of the NiO/CuO composite prepared in example 1 after cycle testing.

Detailed Description

it is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The phase of the samples was determined by the X-Ray powder Diffraction (XRD, instrument model: Bruker, D8-ADVANCE) method using a graphite monochromator, CuK α radiation (λ ═ 0.15418 nm). The morphology and structure of the samples were investigated by means of High-Resolution Transmission Electron microscopy (HR-TEM, Instrument model: JEM-2100, acceleration Voltage: 200kV) and Scanning Electron microscopy (SEM, Hitachi). XPS spectra were obtained at Thermo XPS ESCALBxi +, with Al K α as the X-ray source and corrected for the spectra with the C1s line at 284.8 eV. The desorption curve for N2 was determined at V-sorb2800p at liquid nitrogen temperature (T ═ 196 ℃).

The invention will be further illustrated by the following examples