阅读说明：本技术 F掺杂ZnCdS固溶体光催化材料及制备方法和应用 (F-doped ZnCdS solid solution photocatalytic material and preparation method and application thereof ) 是由 许晖 孙培培 莫曌 杨文书 陈志刚 于 2021-01-28 设计创作，主要内容包括：本发明涉及光催化材料的制备和光解水产氢技术领域,具体涉及F掺杂Zn CdS固溶体光催化材料及制备方法和应用。本发明首先通过水热合成的方法得到纳米花状的ZnCdS,再通过第二次水热方法得到F掺杂ZnCdS。一方面F元素掺杂可以调控ZnCdS的能带结构和增强其光吸收能力,进而提高其光催化制氢性能,另一方面F元素掺杂也能够提高硫化锌镉的比表面,从而提供更多的活性位点。利用F元素的掺杂调控ZnCdS对光的吸收能力以及能带结构,促进半导体在可见光照射下催化水分解制氢的性能。(The invention relates to the technical field of preparation of photocatalytic materials and hydrogen production by photolysis, in particular to a F-doped Zn CdS solid solution photocatalytic material, and a preparation method and application thereof. According to the invention, firstly, the nano flower-shaped ZnCdS is obtained by a hydrothermal synthesis method, and then the F-doped ZnCdS is obtained by a second hydrothermal method. On one hand, the F element doping can regulate and control the energy band structure of ZnCdS and enhance the light absorption capacity of the ZnCdS, so that the photocatalytic hydrogen production performance of the ZnCdS is improved, and on the other hand, the F element doping can also improve the specific surface of the zinc cadmium sulfide, so that more active sites are provided. The absorption capacity and the energy band structure of ZnCdS to light are regulated and controlled by doping of F element, so that the performance of catalyzing water decomposition to prepare hydrogen of a semiconductor under the irradiation of visible light is promoted.)

A preparation method of a F-doped ZnCdS solid solution photocatalytic material is characterized by comprising the following specific steps of:

(1) firstly, putting zinc acetate, cadmium acetate dihydrate and thiourea in deionized water, and magnetically stirring and dissolving at normal temperature to obtain a clear mixed solution;

(2) transferring the obtained mixed solution to a hydrothermal reaction kettle for reaction; standing the obtained reaction product, and then centrifugally separating, washing and drying to obtain flower-shaped ZnCdS;

(3) placing the obtained flower-shaped ZnCdS and ammonium fluoride in deionized water, and magnetically stirring at normal temperature to dissolve the flower-shaped ZnCdS and the ammonium fluoride to obtain a mixed dispersion liquid;

(4) transferring the obtained mixed dispersion liquid to a hydrothermal reaction kettle for reaction; and standing the obtained reaction product, and then centrifugally separating, washing and drying to obtain the F-doped ZnCdS.

2. The method for preparing a F-doped ZnCdS solid solution photocatalytic material according to claim 1, wherein in the step 1, a mass ratio of zinc acetate, cadmium acetate dihydrate, thiourea and deionized water is 0.2-1: 0.3-1.2: 0.2-1: 15-65, and the stirring time is 30-60 min.

3. The method for preparing a F-doped ZnCdS solid solution photocatalytic material as defined in claim 1, wherein in step 2, the reaction temperature is 160-180 ℃, and the reaction time is 8-12 h.

4. The method for preparing a F-doped ZnCdS solid solution photocatalytic material according to claim 1, wherein in the step 3, the mass ratio of flower-like ZnCdS to ammonium fluoride is 1: 1.

5. the method for preparing a F-doped ZnCdS solid solution photocatalytic material as defined in claim 1, wherein in step 4, the reaction temperature is 180 ℃ and the reaction time is 12-24 h.

6. Use of the F-doped ZnCdS solid solution photocatalytic material prepared by any one of the preparation methods of claims 1 to 5, characterized in that water is decomposed to produce hydrogen by photocatalysis under the irradiation time of visible light.

Technical Field

The invention relates to the technical field of preparation of photocatalytic materials and hydrogen production through photolysis, in particular to a F-doped ZnCdS solid solution photocatalytic material, and a preparation method and application thereof.

Background

Over the past few decades, the high dependence and overuse of fossil fuels has led to very serious energy crisis and environmental problems, and therefore energy production and environmental remediation are currently of paramount importance. Hydrogen energy is considered an ideal alternative energy source to fossil fuels because of its high specific enthalpy and lack of environmental pollution. In recent years, the decomposition of water by means of semiconductor photocatalysts is considered to be one of the most promising green technologies for obtaining hydrogen, which can directly utilize inexhaustible solar energy as a driving force to catalyze the decomposition of water by means of photocatalysts to obtain hydrogen. However, the known photocatalysts have great problems in light absorption capacity, catalytic efficiency and cost, and thus the development of photocatalytic water splitting technology is limited. In response to these problems, studies are currently being made to improve photocatalysts mainly by element doping.

Metal sulfide photocatalysts with high activity and visible light response are widely used in the field of photocatalysis and have been shown to be effective in driving water decomposition in the presence of sacrificial reagents. Particularly, the photocatalyst based on the bimetallic zinc cadmium sulfide shows very high photocatalytic hydrogen production activity, but the fast carrier recombination efficiency and unstable factors caused by photo-corrosion greatly limit the application of the photocatalyst.

Disclosure of Invention

Aiming at the technical problems, the invention provides an F-doped ZnCdS solid solution photocatalytic material and a preparation method and application thereof, wherein the method comprises the steps of firstly obtaining nano flower-shaped ZnCdS (CZS) by a hydrothermal synthesis method, and then obtaining the F-doped ZnCdS (0.1F-CZS) by a second hydrothermal method. The absorption capacity and the energy band structure of ZnCdS (CZS) to light are regulated and controlled by doping of the F element, so that the performance of catalyzing water decomposition of a semiconductor to prepare hydrogen under the irradiation of visible light is promoted; on one hand, the F element doping can regulate and control the energy band structure of ZnCdS (CZS) and enhance the light absorption capacity of the ZnCdS (CZS), so that the photocatalytic hydrogen production performance of the ZnCdS is improved, and on the other hand, the F element doping can also improve the specific surface of the cadmium zinc sulfide, so that more active sites are provided.

The technical scheme for realizing the aim of the invention is as follows:

the preparation method of the F-doped ZnCdS photocatalytic material comprises the following steps:

(1) firstly, putting zinc acetate, cadmium acetate dihydrate and thiourea in deionized water, and magnetically stirring and dissolving at normal temperature to obtain a clear mixed solution;

(2) transferring the obtained mixed solution to a hydrothermal reaction kettle for reaction; standing the obtained reaction product, and then centrifugally separating, washing and drying to obtain flower-shaped ZnCdS;

(3) placing the obtained flower-shaped ZnCdS and ammonium fluoride in deionized water, and magnetically stirring at normal temperature to dissolve the flower-shaped ZnCdS and the ammonium fluoride to obtain a mixed dispersion liquid;

(4) transferring the obtained mixed dispersion liquid to a hydrothermal reaction kettle for reaction; and standing the obtained reaction product, and then centrifugally separating, washing and drying to obtain the F-doped ZnCdS.

In the preparation method, in the step 1, the mass ratio of zinc acetate, cadmium acetate dihydrate, thiourea and deionized water is 0.2-1: 0.3-1.2: 0.2-1: 15-65, and the stirring time is 30-60 min.

In the preparation method, in the step 2, the reaction temperature is 160-180 ℃, and the reaction time is 8-12 h.

In the above preparation method, in the step 3, the mass ratio of the flower-shaped zncds (czs) to the ammonium fluoride is 1: 1.

in the preparation method, in the step 4, the reaction temperature is 180 ℃, and the reaction time is 12-24 h.

Compared with the prior art, the invention has the following remarkable advantages: by doping the F element, the hydrogen production efficiency of photolysis of ZnCdS (CZS) with a flower-shaped structure can be effectively promoted. The synthesis method disclosed by the invention is simple, high in controllability, low in cost and excellent in industrial application prospect.

Drawings

FIG. 1 is an XRD plot of F-doped ZnCdS (0.1F-CZS) prepared according to the present invention;

FIG. 2 is an SEM image of F-doped ZnCdS (0.1F-CZS) prepared by the present invention;

FIG. 3 is a solid UV diffuse reflectance plot of F-doped ZnCdS (0.1F-CZS) prepared according to the present invention;

FIG. 4 shows N of F-doped ZnCdS (0.1F-CZS) prepared according to the present invention₂Isothermal adsorption-desorption curve diagram;

FIG. 5 is a photo-current plot of F-doped ZnCdS (0.1F-CZS) prepared according to the present invention;

FIG. 6 is a graph showing hydrogen production by photocatalytic decomposition of F-doped ZnCdS (0.1F-CZS) prepared by the present invention under visible light irradiation time.

Detailed Description

The invention is explained in further detail below with reference to the drawing.

Example 1: the invention relates to a F-doped ZnCdS solid solution photocatalytic material as well as a preparation method and application thereof, and specifically comprises the following steps:

the first step is as follows: putting zinc acetate, cadmium acetate dihydrate and thiourea into deionized water, magnetically stirring and dissolving at normal temperature, putting 0.9g of zinc acetate, 1.2g of cadmium acetate dihydrate and 0.9g of thiourea into a beaker filled with 65mL of deionized water, magnetically stirring and dispersing at normal temperature, and stirring for 30min to obtain a clear mixed solution;

the second step is that: transferring the obtained mixed solution to a 100mL hydrothermal reaction kettle, putting the hydrothermal reaction kettle into a constant-temperature oven for reaction for 8 hours at 160 ℃, then naturally cooling the reaction kettle to room temperature, centrifugally separating, washing with deionized water for 3-5 times, washing with ethanol for 2-3 times, and drying in the constant-temperature oven at 60 ℃ to obtain flower-shaped ZnCdS;

the third step: weighing 0.1g of flower-shaped ZnCdS (CZS) and dispersing in a beaker filled with 30mL of deionized water, adding 0.1g of ammonium fluoride, and magnetically stirring and dispersing at normal temperature for 30min to obtain a mixed dispersion liquid;

the fourth step: and transferring the obtained mixed dispersion liquid to a 50mL hydrothermal reaction kettle, putting the hydrothermal reaction kettle into a constant-temperature oven for reaction for 12h at 180 ℃, naturally cooling the reaction kettle to room temperature, performing centrifugal separation, washing the obtained substance with deionized water for 3-5 times, washing the substance with ethanol for 2-3 times, and drying the substance in the constant-temperature oven at 60 ℃ to obtain F-doped ZnCdS (0.1F-CZS).

FIG. 1 shows the X-ray diffraction pattern of ZnCdS (CZS) and ZnCdS (0.1F-CZS) photocatalytic materials prepared in this example. The crystallinity of the ZnCdS (0.1F-CZS) sample is reduced, and the crystallinity of the ZnCdS (0.1F-CZS) sample is not obviously changed.

FIG. 2 is a scanning electron microscope image of ZnCdS (CZS) and ZnCdS (0.1F-CZS) photocatalytic materials prepared in this example, wherein the prepared sample is a flower-like structure assembled by nanoparticles.

Fig. 3 is a solid ultraviolet diffuse reflection diagram of the ZnCdS (CZS) and ZnCdS (0.1F-CZS) photocatalytic materials prepared in this embodiment, where the absorption capability of ZnCdS (0.1F-CZS) to light in the visible light region is enhanced, which is beneficial to the improvement of the photocatalytic performance.

FIG. 4 shows the N of the photocatalytic materials ZnCdS (CZS) and ZnCdS (0.1F-CZS) prepared in this example₂Isothermal adsorption-desorption curve diagram. From the data it can be calculated that the specific surface of ZnCdS (0.1F-CZS) is raised by a factor of 2 (2.1 m)²/g vs 4.2m²/g), and the large specific surface can effectively improve the capacity of photocatalytic hydrogen production.

FIG. 5 is a photo current diagram of ZnCdS (CZS) and ZnCdS (0.1F-CZS) photocatalysts prepared in the example. The F-doped sample shows stronger photocurrent intensity, which indicates that the F-doped sample has better photoelectric carrier separation efficiency, thereby promoting the photocatalytic hydrogen production performance.

FIG. 6 is a graph showing hydrogen production from photocatalytic decomposition of ZnCdS (CZS) and ZnCdS (0.1F-CZS) photocatalytic materials prepared in this example under visible light irradiation time. Under the irradiation of visible light, no cocatalyst is added, the mass of the catalyst is 50mg in the mixed solution of 0.1M of nonahydrate and sodium sulfide and 0.1M of anhydrous sodium sulfite, and the hydrogen production by water decomposition can be effectively realized by 100ML of the mixed solution. It is clear from the figure that the activity of ZnCdS (0.1F-CZS) is significantly enhanced, probably 6.6 times that of ZnCdS (CZS).