阅读说明：本技术 三元水滑石光催化剂及其制备方法与应用 (Ternary hydrotalcite photocatalyst and preparation method and application thereof ) 是由 蒋光明 张瀞元 王霞玲 吕晓书 于 2020-06-07 设计创作，主要内容包括：本发明公开了一种三元水滑石光催化剂及其制备方法与应用；所述三元水滑石光催化剂包括Ni掺杂的镁铝水滑石纳米片。本发明利用Ni对镁铝水滑石进行进行掺杂改性,Ni离子可以改变其表面电子结构,从而改善电荷转移性能,抑制电子空穴复合以及自由基的形成,进而提高了其紫外光催化活性。本发明的Ni掺杂的镁铝水滑石纳米片是一种具有紫外光响应的光催化剂,可用于降解空气中的污染物NO,表现出了极高的反应活性和稳定性,并且对NO<Sub>2</Sub>的产生有明显的抑制作用,是潜在的高效环境修复材料,具有广阔的应用前景。(The invention discloses a ternary hydrotalcite photocatalyst and a preparation method and application thereof; the ternary hydrotalcite photocatalyst comprises Ni-doped magnesium-aluminum hydrotalcite nanosheets. According to the invention, Mg-Al hydrotalcite is doped and modified by Ni, and Ni ions can change the surface electron structure of the Mg-Al hydrotalcite, so that the charge transfer performance is improved, the electron hole recombination and the formation of free radicals are inhibited, and the ultraviolet catalytic activity of the Mg-Al hydrotalcite is further improved. The Ni-doped magnalium hydrotalcite nano-sheet isThe photocatalyst with ultraviolet response can be used for degrading pollutant NO in air, shows extremely high reaction activity and stability, and has NO response 2 The preparation has obvious inhibiting effect, is a potential high-efficiency environment repairing material, and has wide application prospect.)

1. A ternary hydrotalcite photocatalyst is characterized in that: the ternary hydrotalcite photocatalyst comprises Ni-doped magnesium-aluminum hydrotalcite nanosheets.

2. The three-way hydrotalcite photocatalyst of claim 1, characterized by: the chemical formula of the Ni-doped magnalium hydrotalcite nanosheet is (Ni)_xMg_1-x)₆Al₂(OH)₁₆CO₃·4H₂O, wherein x is 0.1 to 0.5.

3. The method of preparing the ternary hydrotalcite photocatalyst of claim 1 or 2, characterized in that: the method comprises the following steps:

(1) mixing and dissolving a magnesium source and a nickel source in water;

(2) adding an aluminum source into the solution obtained in the step (1), and uniformly stirring;

(3) adding urea serving as a precipitator into the solution obtained in the step (2), uniformly stirring and mixing, and then carrying out hydrothermal reaction on the solution; and after the hydrothermal reaction is finished, performing centrifugal separation, washing and drying the solid precipitate to obtain the Ni-doped magnesium-aluminum hydrotalcite nanosheet.

4. The method of preparing a ternary hydrotalcite photocatalyst according to claim 3, characterized in that: the molar ratio of the nickel source to the magnesium source is 1: 1-9.

5. The method of preparing a ternary hydrotalcite photocatalyst according to claim 3, characterized in that: the magnesium source is magnesium nitrate, the nickel source is nickel nitrate, and the aluminum source is aluminum nitrate.

6. The method of preparing a ternary hydrotalcite photocatalyst according to claim 3, characterized in that: in the step (3), the hydrothermal reaction temperature is 110-130 ℃, and the reaction time is 20-25 h.

7. Use of the three-way hydrotalcite photocatalyst according to claim 1 or 2 for photocatalytic degradation of NO.

Technical Field

The invention belongs to the technical field of photocatalysts, and particularly relates to a ternary hydrotalcite photocatalyst as well as a preparation method and application thereof.

Background

With the continuous progress of society and the rapid development of economy, energy shortage and environmental deterioration are serious problems which always plague people, and in the process of researching for solving the problems, the photocatalysis technology plays a role. In the field of environmental pollution control, the photocatalysis technology is an active free radical or radical (OH, O) generated by exciting a semiconductor through solar energy₂·、HO₂·，H₂O₂) The novel technology for efficiently removing various toxic and harmful substances in the environment is realized, and the novel technology has wide application prospect in the aspect of indoor air pollution treatment. At present, the novel photocatalytic material focuses more on the improvement of energy conversion efficiency, the expansion of light selection range, the inhibition of side reactions and the like, and therefore, the novel photocatalytic material has high light energy utilization rate and is used for inhibiting the generation of middle toxic by-products NO₂The semiconductor photocatalyst of (2) is urgent.

In the research of semiconductor photocatalysts, the layered structure and interlayer ions of the magnesium-aluminum hydrotalcite semiconductor are found to be exchangeable, and the energy band absorption of the magnesium-aluminum hydrotalcite semiconductor can be effectively regulated and controlled through regulating the types of metal ions of the laminates and through metal-metal charge transfer. In addition, the magnesium-aluminum hydrotalcite has the advantages of simple preparation method, low raw material price, low mammalian toxicity, excellent chemical stability, environmental friendliness and wide attention paid to the field of energy and environmental photocatalysis, and is widely applied to the fields of nitrogen fixation and ammonia synthesis, hydrogen hydrolysis, oxygen production, photodecomposition of organic pollutants, photodegradation of nitrogen oxides and the like (Lv, L, et al. adv. energy Mater.,2019,9(17), 1803358; Zhang, B., et al. colloid Surface A.,2017,520, 399-.

However, magnesium-aluminum hydrotalcite as a photocatalytic material still has a series of problems, especially high photoproduction electron-hole recombination rate, low quantum efficiency, unsatisfactory photocatalytic oxidation selectivity and the like, and is still very limited to be applied in the field of environmental purification.

Disclosure of Invention

In view of this, the present invention aims to provide a ternary hydrotalcite photocatalyst, and a preparation method and an application thereof, which can reduce the recombination of electrons and holes, and significantly improve the catalytic performance and selectivity.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a ternary hydrotalcite photocatalyst which comprises Ni-doped magnesium aluminum hydrotalcite nanosheets.

As a preferable technical scheme, the chemical formula of the Ni-doped magnesium-aluminum hydrotalcite nano-sheet is (Ni)_xMg_1-x)₆Al₂(OH)₁₆CO₃·4H₂O, wherein x is 0.1 to 0.5.

The invention provides a preparation method of a ternary hydrotalcite photocatalyst, which comprises the following steps:

(1) mixing and dissolving a magnesium source and a nickel source in water;

(2) adding an aluminum source into the solution obtained in the step (1), and uniformly stirring;

(3) adding urea serving as a precipitator into the solution obtained in the step (2), uniformly stirring and mixing, and then carrying out hydrothermal reaction on the solution; and after the hydrothermal reaction is finished, performing centrifugal separation, washing and drying the solid precipitate to obtain the Ni-doped magnesium-aluminum hydrotalcite nanosheet.

According to a preferable technical scheme, the molar ratio of the nickel source to the magnesium source is 1: 1-9.

According to a preferable technical scheme, the magnesium source is magnesium nitrate, the nickel source is nickel nitrate, and the aluminum source is aluminum nitrate.

In the preferable technical scheme, in the step (3), the hydrothermal reaction temperature is 110-130 ℃, and the reaction time is 20-25 h.

The invention also provides application of the ternary hydrotalcite photocatalyst in photocatalytic degradation of NO.

The invention has the beneficial effects that:

the invention utilizes Ni to dope and modify magnesium-aluminum hydrotalciteThe Ni ions can change the surface electronic structure, thereby improving the charge transfer performance, inhibiting the electron hole recombination and the formation of free radicals, and further improving the ultraviolet catalytic activity. The Ni-doped magnalium hydrotalcite nanosheet is a photocatalyst with ultraviolet response, can be used for degrading pollutant NO in air, shows extremely high reaction activity and stability, and has NO response₂The preparation has obvious inhibiting effect, is a potential high-efficiency environment repairing material, and has wide application prospect.

Drawings

In order to make the object, technical scheme and beneficial effect of the invention more clear, the invention provides the following drawings for explanation:

FIG. 1 is a transmission electron micrograph of the magnesium aluminum hydrotalcite prepared in comparative example 1;

FIG. 2 shows nickel prepared in example 1_0.5Magnesium aluminum hydrotalcite and nickel prepared in example 2_1.25A transmission electron microscope image of the magnesium aluminum hydrotalcite;

FIG. 3 shows nickel prepared in example 1_0.5A high-resolution transmission electron microscope image of the magnesium aluminum hydrotalcite;

FIG. 4 shows the Mg-Al hydrotalcite prepared in comparative example 1 and the Ni prepared in example 1_0.5Magnesium aluminum hydrotalcite and nickel prepared in example 2_1.25XRD pattern of Mg-Al hydrotalcite;

FIG. 5 shows nickel prepared in example 2_1.25The magnalium hydrotalcite is applied to XRD patterns before and after the NO in the air is removed;

FIG. 6 shows the Mg-Al hydrotalcite prepared in comparative example 1 and the Ni prepared in example 1_0.5Magnesium aluminum hydrotalcite and nickel prepared in example 2_1.25A comparison graph of the use effect of the magnesium-aluminum hydrotalcite when applied to the removal of NO in the air;

FIG. 7 shows nickel prepared in example 2_1.25Comparing the effect of the magnalium hydrotalcite on the multiple circulation and long-term removal of NO in the air;

FIG. 8 shows the Mg-Al hydrotalcite prepared in comparative example 1 and the Ni prepared in example 1_0.5Magnesium aluminum hydrotalcite and nickel prepared in example 2_1.25Magnesium aluminum hydrotalcite is generated when being applied to removing NO in airNO₂A comparative graph of (a).

Detailed Description

The present invention is further described with reference to the following drawings and specific examples so that those skilled in the art can better understand the present invention and can practice the present invention, but the examples are not intended to limit the present invention.

The methods used in the following examples are conventional methods unless otherwise specified. The materials or reagents required in the following examples are commercially available unless otherwise specified.