阅读说明：本技术 一种复合型纳米Ni-CdS材料及其制备方法和应用 (Composite nano Ni-CdS material and preparation method and application thereof ) 是由 黄凤萍 邹正波 李春花 刘纯 于 2021-08-31 设计创作，主要内容包括：本发明属于Ni-CdS材料制备技术领域,公开了一种复合型纳米Ni-CdS材料的制备方法,包括以下步骤：将Ni源和表面活性剂加入溶剂中,搅拌、超声分散使其充分溶解,得到Ni源溶液；在Ni源溶液中加入CdS粉体,搅拌至分散完全,得到含Ni源的CdS溶液；其中,Ni源和CdS粉体的摩尔比为3～5:10；将含Ni源的CdS溶液在60℃下搅拌,加入水合肼溶液,待颜色变为浅灰色,调节pH至14,反应后进行过滤、洗涤、干燥,得到复合型纳米Ni-CdS材料。本发明利用水合肼构造出还原体系,使充分分散在硫化镉表面上的离子,能够得到充分的反应,进而将金属镍负载在硫化镉表面形成异质结构,有效地促进光生电子和空穴的快速输运和分离,该复合材料的制备方法简单,操作简便,有利于大规模生产。(The invention belongs to the technical field of Ni-CdS material preparation, and discloses a preparation method of a composite nano Ni-CdS material, which comprises the following steps: adding a Ni source and a surfactant into a solvent, stirring, and performing ultrasonic dispersion to fully dissolve the Ni source and the surfactant to obtain a Ni source solution; adding CdS powder into the Ni source solution, and stirring until the CdS powder is completely dispersed to obtain a CdS solution containing a Ni source; wherein the molar ratio of the Ni source to the CdS powder is 3-5: 10; stirring the CdS solution containing the Ni source at 60 ℃, adding a hydrazine hydrate solution, adjusting the pH to 14 after the color is changed into light gray, and filtering, washing and drying after the reaction to obtain the composite nano Ni-CdS material. According to the invention, a reduction system is constructed by using hydrazine hydrate, so that ions fully dispersed on the surface of cadmium sulfide can be fully reacted, further, metal nickel is loaded on the surface of cadmium sulfide to form a heterostructure, and the rapid transportation and separation of photoproduction electrons and holes are effectively promoted.)

1. A preparation method of a composite nano Ni-CdS material is characterized by comprising the following steps:

(1) adding a Ni source and a surfactant into a solvent, stirring, and performing ultrasonic dispersion to fully dissolve the Ni source and the surfactant to obtain a Ni source solution;

(2) adding CdS powder into the Ni source solution, and stirring until the CdS powder is completely dispersed to obtain a CdS solution containing a Ni source; wherein the molar ratio of the Ni source to the CdS powder is 3-5: 10;

(3) stirring the CdS solution containing the Ni source at 60 ℃, adding a hydrazine hydrate solution, adjusting the pH to 14 after the color is changed into light gray, and filtering, washing and drying after the reaction to obtain the composite nano Ni-CdS material.

2. The preparation method of the composite nano Ni-CdS material as claimed in claim 1, wherein CdS powder is prepared by coprecipitation method, and the specific process is as follows:

(2.1) weighing the ratio of the taking liquid to 10 mmol: 100 ml: 10ml of Cd salt, NaOH solution and thiourea aqueous solution;

(2.2) dissolving the Cd salt in water, placing the solution in a constant-temperature water bath at the temperature of 30-60 ℃, and uniformly stirring to obtain a Cd salt solution;

(2.3) keeping stirring, then adding NaOH solution, and reacting for 30min at 30-60 ℃ to obtain Cd (OH)₂A solution;

(2.4) in Cd (OH)₂Dripping a thiourea aqueous solution into the solution, and reacting for 1-4h at 30-60 ℃ after finishing dripping;

and (2.5) standing for 9 hours at the temperature of 30-60 ℃ to obtain a precipitate, washing the precipitate, and drying to obtain CdS powder.

3. The preparation method of the composite nano Ni-CdS material as claimed in claim 2, wherein in step (2.1), the concentration of NaOH solution is 0.6-1 mol/L, and the concentration of thiourea aqueous solution is 0.6-1 mol/L.

4. The method for preparing the composite nano Ni-CdS material of claim 2, wherein in the step (2.1), distilled water or deionized water is used as water.

5. The preparation method of composite nano Ni-CdS material as claimed in claim 2, wherein in step (2.5), the washing is: and alternately cleaning for 3-5 times by using distilled water and absolute ethyl alcohol.

6. The method for preparing the composite nano Ni-CdS material of claim 1, wherein in the step (1), SDS and PVP are adopted as surfactants.

7. The preparation method of the composite nano Ni-CdS material as claimed in claim 1, wherein in the step (1), the time of ultrasonic dispersion is 30-60 min.

8. The method for preparing the composite nano Ni-CdS material as claimed in claim 1, wherein in the step (3), a sodium hydroxide solution is adopted to adjust the pH value; the drying conditions were: drying at 80 ℃ for 12-15 h.

9. The composite nano Ni-CdS material prepared by the preparation method of any one of claims 1-8.

10. The use of the composite nano Ni-CdS material of claim 9 as a photocatalyst in photocatalytic degradation.

Technical Field

The invention belongs to the technical field of Ni-CdS material preparation, and relates to a composite nano Ni-CdS material as well as a preparation method and application thereof.

Background

With the progress of social industrialization, the problem of environmental pollution is increasingly severe. Among them, the problem of water environment pollution is especially serious, since 1972 TiO₂Since the discovery of semiconductor photocatalytic water decomposition, the semiconductor photocatalytic technology becomes a preferred choice in the aspect of water pollution treatment due to the advantages of small secondary pollution, low use cost, sunlight utilization and the like. The CdS has the characteristics of economy, convenience and high efficiency because the CdS is a direct semiconductor with visible light absorption capacity and the band gap of the CdS is about 2.42eV, and the CdS can directly initiate a photocatalytic reaction under visible light, and has the characteristics of economy, convenience and high efficiency compared with the conventional TiO₂Because the forbidden band width is small, the photocatalytic reaction can directly occur under the excitation of visible light, and the short plate that the traditional wide forbidden band semiconductor can not catalytically degrade organic pollutants under the visible light is avoided. However, in practical application, there are many problems, mainly the defect that the CdS photocatalyst has a serious photo-corrosion phenomenon and photo-generated carriers are easy to recombine, resulting in low quantum efficiency of CdS photocatalysis. Aiming at the defects, researchers mainly carry out modification research on the CdS photocatalyst by means of metal deposition, semiconductor compounding and the like, wherein novel materials formed by compounding metal and semiconductors are not lacked, and material research schemes formed by compounding metal nickel and cadmium sulfide are rare.

Compared with noble metals such as gold (Au) and platinum (Pt), the metal nickel (Ni) has the characteristics of low cost, abundant reserves and the like. At present, metal nickel (Ni) and CdS semiconductor photocatalyst are combined to be applied to the aspect of solving water body pollution, and are concerned by people. The metal and semiconductor composite has a synergistic enhancement effect, and the addition of the metal nickel (Ni) has the effect of promoting the separation of CdS photo-generated electron-hole pairs and has a promotion effect on the photocatalytic performance and benefit of the material. However, the current Ni-loading method is mainly a photo-precipitation method, the production efficiency and reaction rate of the photocatalyst are limited to a great extent by the illumination intensity and illumination distance (distance between the light source and the reactor), and in the actual production, the source of the reaction energy is mainly taken from the light source, so the requirement on the light source is too high, the light source is required to perform long-time illumination, and the selection of the light source in the actual operation is very strict.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a preparation method of a composite Ni/CdS material, which solves the problems that a light precipitation method needs long-time light source irradiation and the light source selection is harsh.

The invention is realized by the following technical scheme:

a preparation method of a composite nano Ni-CdS material comprises the following steps:

(1) adding a Ni source and a surfactant into a solvent, stirring, and performing ultrasonic dispersion to fully dissolve the Ni source and the surfactant to obtain a Ni source solution;

(2) adding CdS powder into the Ni source solution, and stirring until the CdS powder is completely dispersed to obtain a CdS solution containing a Ni source; wherein the molar ratio of the Ni source to the CdS powder is 3-5: 10;

(3) stirring the CdS solution containing the Ni source at 60 ℃, adding a hydrazine hydrate solution, adjusting the pH to 14 after the color is changed into light gray, and filtering, washing and drying after the reaction to obtain the composite nano Ni-CdS material.

Further, the CdS powder is prepared by a coprecipitation method, and the specific process is as follows:

(2.1) weighing the ratio of the taking liquid to 10 mmol: 100 ml: 10ml of Cd salt, NaOH solution and thiourea aqueous solution;

(2.2) dissolving the Cd salt in water, placing the solution in a constant-temperature water bath at the temperature of 30-60 ℃, and uniformly stirring to obtain a Cd salt solution;

(2.3) keeping stirring, then adding NaOH solution, and reacting for 30min at 30-60 ℃ to obtain Cd (OH)₂A solution;

(2.4) in Cd (OH)₂Dripping a thiourea aqueous solution into the solution, and reacting for 1-4h at 30-60 ℃ after finishing dripping;

and (2.5) standing for 9 hours at the temperature of 30-60 ℃ to obtain a precipitate, washing the precipitate, and drying to obtain CdS powder.

Further, in the step (2.1), the concentration of the NaOH solution is 0.6-1 mol/L, and the concentration of the thiourea aqueous solution is 0.6-1 mol/L.

Further, in the step (2.1), distilled water or deionized water is used as water.

Further, in step (2.5), the washing is: and alternately cleaning for 3-5 times by using distilled water and absolute ethyl alcohol.

Further, in the step (1), SDS and PVP are used as the surfactant.

Further, in the step (1), the time of ultrasonic dispersion is 30-60 min.

Further, in the step (3), sodium hydroxide solution is adopted to adjust the pH value;

the drying conditions were: drying at 80 ℃ for 12-15 h.

The invention also discloses the composite nano Ni-CdS material prepared by the preparation method.

The invention also discloses application of the composite nano Ni-CdS material as a photocatalyst in photocatalytic degradation.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention discloses a preparation method of a composite Ni/CdS material, which comprises the steps of adding a Ni source and a surfactant into a solvent to prepare a Ni source solution, adding the surfactant to increase the dispersion degree of ions, so that the ions can be better dispersed on the surface of cadmium sulfide when being reduced into metal nickel, and providing a metal source for the subsequent reduction by using a hydrazine hydrate solution; then adding CdS powder into the Ni source solution, reducing Ni element by using hydrazine hydrate solution, and adjusting the pH value to an alkaline environment, wherein metal nickel is loaded on the surface of CdS to form Ni-CdS; drying for 9-13 h at 50-80 ℃, wherein proper drying temperature and drying time are beneficial to the crystallinity of the crystal in the crystal crystallization process, thereby influencing the material in the photocatalysis application. The key steps of the invention are the charging sequence of a plurality of raw materials and the preparation process of a reduction method, and the heterojunction formed by the composite photocatalyst can effectively promote the separation efficiency of electrons and holes. Compounding metal nickel and cadmium sulfide to obtain a composite Ni/CdS material, which is a new process for preparing a visible-light-driven photocatalyst; hydrazine hydrate is utilized to construct a unique reduction system, ions which are fully dispersed on the surface of cadmium sulfide can be fully reacted, and then metal nickel is loaded on the surface of cadmium sulfide to form a heterostructure, so that rapid transportation and separation of photo-generated electrons and holes are effectively promoted. The method gets rid of the dependence on harsh light source environment, realizes 'one-pot' solution in a reduction system, has simple preparation method and simple and convenient operation, and is beneficial to large-scale production.

Furthermore, the CdS is prepared by a precipitation method, compared with CdS prepared by other methods, the CdS is larger in specific surface area, better in dispersity and better and simpler in photocatalytic efficiency, the prepared CdS is of a fiber structure with 6 main crystal faces, and crystal face energy differences on different crystal faces can influence the separation of photo-generated electron-hole pairs, so that the separation of the electron-hole pairs can be effectively promoted, and the potential influence can be exerted on the photocatalytic performance of materials with different crystal forms.

Further, the concentration of the NaOH solution is 0.6-1 mol/L, the concentration of the thiourea aqueous solution is 0.6-1 mol/L, and when the concentration of the NaOH solution is too low, the generated Cd (OH)₂Less, and thus less CdS is produced by reduction; when the concentration of NaOH solution is too high, excess OH^-1Will inhibit Cd (OH)₂Eventually also leads to a reduction in the CdS amount. The concentration of the aqueous thiourea solution depends on Cd (OH)₂The amount of production of (c).

Furthermore, the water is distilled water or deionized water, so that the influence of impurities in the water can be eliminated.

Furthermore, the washing is to alternately wash the crystal for 3-5 times by using distilled water and absolute ethyl alcohol, the distilled water is used for removing impurities on the surface of the crystal, and the surface loss of the crystal crystallized in the washing process can be reduced by washing the crystal by using the absolute ethyl alcohol.

The invention also discloses the composite nano Ni-CdS material prepared by the preparation method, wherein a heterojunction can be formed between the metal nickel and the semiconductor CdS, and the heterojunction can promote the separation of photo-generated electron-hole pairs under the synergistic action, so that the photocatalysis effect of the composite material is improved.

The invention also discloses application of the composite nano Ni-CdS material in photocatalytic degradation, and tests show that the photocatalytic degradation effect of the Ni-CdS material on Methyl Orange (MO) is over 90%. Therefore, the prepared Ni-CdS material catalyst has higher catalytic degradation capability on Methyl Orange (MO) under visible light.

Drawings

FIG. 1 is an SEM image of CdS prepared by the method;

FIG. 2 is an SEM image of the composite Ni-CdS prepared by the method;

FIG. 3 is an XRD spectrum of CdS and Ni-CdS;

FIG. 4 is a graph of the photocatalytic degradation of CdS to methyl orange prepared at different reaction temperatures in examples 2-4;

FIG. 5 is a graph of the photocatalytic degradation of CdS to methyl orange in example 3 and examples 5-7 at different reaction times;

FIG. 6 is a photo-catalytic degradation diagram of composite Ni-CdS to methyl orange prepared in example 3 and examples 8-11 at different molar ratios of Ni source and CdS powder;

FIG. 7 is a graph comparing the photocatalytic degradation effect of the composite Ni-CdS prepared in comparative example 1 and comparative example 2 on methyl orange solution.

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings:

example 1

The invention discloses a preparation method of a composite nano Ni-CdS material, which specifically comprises the following steps:

step 1: weighing NiCl with the mass of 0.95g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

Step 2: and (2) strongly stirring the CdS solution containing the Ni source prepared in the step (1) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution when the color is changed into light gray, reacting for 3h, adjusting the pH value to 14, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

The method for degrading Methyl Orange (MO) is adopted for testing, the composite nano Ni-CdS material prepared in the embodiment is placed into 50mL of Methyl Orange (MO) solution with the concentration of 10mg/L, after the composite nano Ni-CdS material is firstly reacted in a dark room for 60min, the composite nano Ni-CdS material is irradiated under a visible light lamp for every 15min, the absorbance of the composite nano Ni-CdS material is separated and measured, the degradation rate of the Methyl Orange (MO) solution is calculated, and the degradation efficiency of the composite nano Ni-CdS material prepared in the embodiment to methyl orange is 85.74%.

Example 2

Step 1: 3.086g of Cd (NO) were weighed₃)₂·4H₂O for standby, preparing NaOH solution (C)₀1mol/L)100ml of thiourea aqueous solution (C)₀1mol/L)10ml, adding Cd (NO)₃)₂·4H₂Dissolving O in water, placing in a constant-temperature water bath at 30 ℃, and uniformly stirring; stirring, adding NaOH solution, and reacting at 30 deg.C for 30 min; finally, dropwise adding a thiourea aqueous solution, and reacting for 3 hours at 30 ℃ after the dropwise adding is finished; and (3) stopping stirring, keeping the temperature of 30 ℃ and standing for 9 hours, washing the obtained precipitate, and drying to obtain CdS powder.

Step 2: weighing NiCl with the mass of 0.95g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

And step 3: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution when the color is changed into light gray, reacting for 3h, adjusting the pH value to 14, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

The method for degrading Methyl Orange (MO) is adopted for testing, the CdS powder prepared in the step one and the composite nano Ni-CdS material prepared in the embodiment are respectively put into 50mL of Methyl Orange (MO) solution with the concentration of 10mg/L, after the reaction is carried out for 60min in a dark room, the CdS powder and the composite nano Ni-CdS material are irradiated under a visible light lamp for every 15min, the absorbance of the CdS powder and the composite nano Ni-CdS material is separated and measured, the degradation rate of the Methyl Orange (MO) solution is calculated, the photocatalytic efficiency of monomer cadmium sulfide to methyl orange is 23.48%, and the degradation efficiency of the composite nano Ni-CdS material prepared in the embodiment to methyl orange is 90.44%.

Example 3

Step 1: 3.086g of Cd (NO) were weighed₃)₂·4H₂O for standby, preparing NaOH solution (C)₀1mol/L)100ml of thiourea aqueous solution (C)₀3mol/L)10ml, adding Cd (NO)₃)₂·4H₂Dissolving O in water, placing in a constant-temperature water bath at 45 ℃, and uniformly stirring; stirring, adding NaOH solution, and reacting at 45 deg.C for 30 min; finally, dropwise adding a thiourea aqueous solution, and reacting for 3 hours at 45 ℃ after the dropwise adding is finished; keeping the temperature of 45 ℃ for standing for 9h after the stirring is stopped, washing the obtained precipitate, and drying to obtain CdS powder.

Step 2: weighing NiCl with the mass of 0.95g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

And step 3: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution when the color is changed into light gray, reacting for 3h, adjusting the pH value to 14, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

At the moment, the photocatalytic efficiency of the monomer cadmium sulfide to methyl orange is 24.35%, and the degradation efficiency of the composite photocatalyst to methyl orange is 93.83%.

Example 4

Step 1: 3.086g of Cd (NO) were weighed₃)₂·4H₂O for standby, preparing NaOH solution (C)₀1mol/L)100ml of thiourea aqueous solution (C)₀3mol/L)10ml, adding Cd (NO)₃)₂·4H₂Dissolving O in water, placing in a constant-temperature water bath at 60 ℃, and uniformly stirring; stirring, adding NaOH solution, and reacting at 60 deg.C for 30 min; finally, dropwise adding a thiourea aqueous solution, and reacting for 3 hours at 60 ℃ after the dropwise adding is finished; keeping the temperature of 60 ℃ after the stirring is closed and standing for 9 hours,and washing and drying the obtained precipitate to obtain CdS powder.

Step 2: weighing NiCl with the mass of 0.95g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

And step 3: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution for reacting for 3h after the color is changed into light gray, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

At the moment, the photocatalytic efficiency of the monomer cadmium sulfide to methyl orange is 21.97%, and the degradation efficiency of the composite photocatalyst to methyl orange is 90.58%.

As shown in fig. 4, a graph of the photocatalytic degradation of methyl orange by CdS prepared in examples 1 to 3 illustrates that the photocatalytic efficiency of the composite material of cadmium sulfide monomer material prepared at a temperature range of 30 to 60 ℃ has a certain influence. The cadmium sulfide monomer is most suitable to be prepared at 45 ℃.

Example 5

1.543g of Cd (NO) are weighed₃)₂·4H₂O for standby, preparing NaOH solution (C)₀1mol/L)50ml of thiourea aqueous solution (C)₀3mol/L)5ml, adding Cd (NO)₃)₂·4H₂Dissolving O in water, placing in a constant-temperature water bath at 45 ℃, and uniformly stirring; stirring, adding NaOH solution, and reacting at 45 deg.C for 30 min; finally, dropwise adding a thiourea aqueous solution, and reacting for 1h at 45 ℃ after dropwise adding; keeping the temperature of 45 ℃ for standing for 9h after the stirring is stopped, washing the obtained precipitate, and drying to obtain CdS powder.

Step 2: weighing NiCl with the mass of 0.95g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

And step 3: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution for reacting for 3h after the color is changed into light gray, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

The reaction time for preparing the cadmium sulfide monomer is shortened, when the reaction time for preparing the cadmium sulfide monomer is 1 hour, the photocatalytic efficiency of the prepared cadmium sulfide to methyl orange is 23.48%, and the degradation efficiency of the composite photocatalyst to methyl orange is 91.72%.

Example 6

Step 1: 1.543g of Cd (NO) are weighed₃)₂·4H₂O for standby, preparing NaOH solution (C)₀1mol/L)50ml of thiourea aqueous solution (C)₀3mol/L)5ml, adding Cd (NO)₃)₂·4H₂Dissolving O in water, placing in a constant-temperature water bath at 45 ℃, and uniformly stirring; stirring, adding NaOH solution, and reacting at 45 deg.C for 30 min; finally, dropwise adding a thiourea aqueous solution, and reacting for 2 hours at 45 ℃ after dropwise adding; keeping the temperature of 45 ℃ for standing for 9h after the stirring is stopped, washing the obtained precipitate, and drying to obtain CdS powder.

Step 2: weighing NiCl with the mass of 0.95g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

And step 3: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution for reacting for 3h after the color is changed into light gray, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

The reaction time for preparing the cadmium sulfide monomer is shortened, when the reaction time for preparing the cadmium sulfide monomer is 2 hours, the photocatalytic efficiency of the prepared cadmium sulfide to methyl orange is 24.13%, and the degradation efficiency of the composite photocatalyst to methyl orange is 92.89%.

Example 7

Step 1: 1.543g of Cd (NO) are weighed₃)₂·4H₂O for standby, preparing NaOH solution (C)₀1mol/L)50ml of thiourea aqueous solution (C)₀3mol/L)5ml, adding Cd (NO)₃)₂·4H₂Dissolving O in water, placing in a constant-temperature water bath at 45 ℃, and uniformly stirring; stirring, adding NaOH solution, and reacting at 45 deg.C for 30 min; finally, dropwise adding a thiourea aqueous solution, and reacting for 4 hours at 45 ℃ after the dropwise adding is finished; keeping the temperature of 45 ℃ for standing for 9h after the stirring is stopped, washing the obtained precipitate, and drying to obtain CdS powder.

Step 2: weighing NiCl with the mass of 0.95g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

And step 3: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution for reacting for 3h after the color is changed into light gray, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

As shown in fig. 5, the corresponding CdS-to-methyl orange photocatalytic degradation graphs of example 3 and examples 5-7 show that at 45 ℃, the optimum reaction time for preparing cadmium sulfide monomer is 3 hours, and when the reaction time for preparing cadmium sulfide monomer is increased to 4 hours, the photocatalytic efficiency of cadmium sulfide monomer to methyl orange is 23.92%, the photocatalytic efficiency of cadmium sulfide monomer is inhibited, and the proper reaction time has a certain effect on the catalytic efficiency of cadmium sulfide monomer material, and the degradation efficiency of composite photocatalyst to methyl orange is slightly decreased to 93.11% compared with example 2. Indicating that a reaction at 45 ℃ for 3h is most suitable.

Example 8

Step 1: 1.543g of Cd (NO) are weighed₃)₂·4H₂O for standby, preparing NaOH solution (C)₀1mol/L)50ml of thiourea aqueous solution (C)₀3mol/L)5ml, adding Cd (NO)₃)₂·4H₂Dissolving O in water, placing in a constant-temperature water bath at 45 ℃, and uniformly stirring; stirring, adding NaOH solution, and reacting at 45 deg.C for 30 min; finally, dropwise adding a thiourea aqueous solution, and reacting for 3 hours at 45 ℃ after the dropwise adding is finished; keeping the temperature of 45 ℃ for standing for 9h after the stirring is stopped, washing the obtained precipitate, and drying to obtain CdS powder.

Step 2: NiCl with the mass of 0.237g is weighed₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

And step 3: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution for reacting for 3h after the color is changed into light gray, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

Under the condition of determining the preparation conditions of the cadmium sulfide monomer, the concentration of the nickel source content in the solution is controlled, and when the concentration of the nickel source is 0.001mol, the degradation efficiency of the composite photocatalyst on methyl orange is 35.28%.

Example 9

Step 1: 1.543g of Cd (NO) are weighed₃)₂·4H₂O for standby, preparing NaOH solution (C)₀1mol/L)50ml of thiourea aqueous solution (C)₀3mol/L)5ml, adding Cd (NO)₃)₂·4H₂Dissolving O in water, placing in a constant-temperature water bath at 45 ℃, and uniformly stirring; stirring, adding NaOH solution, and reacting at 45 deg.C for 30 min; finally, dropwise adding a thiourea aqueous solution, and reacting for 180min at 45 ℃ after dropwise adding; keeping the temperature of 45 ℃ for standing for 9h after the stirring is stopped, washing the obtained precipitate, and drying to obtain CdS powder.

Step 2: weighing NiCl with the mass of 0.475g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

And step 3: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution for reacting for 1h after the color is changed into light gray, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

Under the condition of determining the preparation conditions of the cadmium sulfide monomer, the concentration of the nickel source content in the solution is controlled, and when the concentration of the nickel source is 0.002mol, the degradation efficiency of the composite photocatalyst on methyl orange is 49.46%.

Example 10

Step 1: 1.543g of Cd (NO) are weighed₃)₂·4H₂O for standby, preparing NaOH solution (C)₀1mol/L)50ml of thiourea aqueous solution (C)₀3mol/L)5ml, adding Cd (NO)₃)₂·4H₂Dissolving O in water, placing in a constant-temperature water bath at 45 ℃, and uniformly stirring; stirring, adding NaOH solution, and reacting at 45 deg.C for 30 min; finally, dropwise adding a thiourea aqueous solution, and reacting for 180min at 45 ℃ after dropwise adding; keeping the temperature of 45 ℃ for standing for 9h after the stirring is stopped, washing the obtained precipitate, and drying to obtain CdS powder.

Step 2: weighing NiCl with the mass of 0.713g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

And step 3: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution for reacting for 2h after the color is changed into light gray, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

Under the condition of determining the preparation conditions of the cadmium sulfide monomer, the concentration of the nickel source content in the solution is controlled, and when the concentration of the nickel source is 0.003mol, the degradation efficiency of the composite photocatalyst to methyl orange is 81.71%.

Example 11

Step 1: weighing 1.543g of Cd (b)NO₃)₂·4H₂O for standby, preparing NaOH solution (C)₀1mol/L)50ml of thiourea aqueous solution (C)₀3mol/L)5ml, adding Cd (NO)₃)₂·4H₂Dissolving O in water, placing in a constant-temperature water bath at 45 ℃, and uniformly stirring; stirring, adding NaOH solution, and reacting at 45 deg.C for 30 min; finally, dropwise adding a thiourea aqueous solution, and reacting for 180min at 45 ℃ after dropwise adding; keeping the temperature of 45 ℃ for standing for 9h after the stirring is stopped, washing the obtained precipitate, and drying to obtain CdS powder.

Step 2: weighing NiCl with the mass of 1.188g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

And step 3: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution for reacting for 4h after the color is changed into light gray, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

Under the condition of determining the preparation conditions of the cadmium sulfide monomer, the concentration of the nickel source content in the solution is controlled, and when the concentration of the nickel source is 0.005mol, the degradation efficiency of the composite photocatalyst on methyl orange is 87.88%.

From the examples 8 to 11, the molar ratio of the Ni source to the CdS powder is 1:10, 2:10, 3:10, 5:10, and in the example 3, the molar ratio of the Ni source to the CdS powder is 4:10, as shown in FIG. 6, it is feasible to obtain the molar ratio of the Ni source to the CdS powder of 3-5: 10, and the degradation efficiency of the obtained composite nano Ni-CdS material to methyl orange is over 80.

Comparative example 1

Step 1: weighing NiCl with the mass of 0.95g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

Step 2: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution for reacting for 4h after the color is changed into light gray, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

Under the condition of determining the preparation condition of the cadmium sulfide monomer and the concentration of a nickel source, the degradation efficiency of the prepared Ni-CdS material to methyl orange is 31.93% under the condition of controlling the pH value to be 12.

Comparative example 2

Step 1: weighing NiCl with the mass of 0.95g₂·6H₂O, 0.01g of SDS and 0.2g of PVP, adding 50mL of glycol solution, stirring, performing ultrasonic dispersion to fully dissolve the solution, adding 1.44g of CdS powder, and stirring until the solution is completely dispersed to obtain the CdS solution containing the Ni source.

Step 2: and (3) strongly stirring the CdS solution containing the Ni source prepared in the step (2) at 60 ℃ for 1h, adding 8mL of 85% hydrazine hydrate solution, adding 5mL of 1mol/L sodium hydroxide solution for reacting for 4h after the color is changed into light gray, and filtering, washing and drying after the reaction is completed to obtain the composite nano Ni-CdS material with photocatalytic performance.

Under the condition of determining the preparation conditions of the cadmium sulfide monomer and the concentration of the nickel source, and under the condition of controlling the pH value to be 13, the degradation efficiency of the prepared Ni-CdS material on methyl orange is 57.25%.

In conclusion, based on example 3, the cadmium sulfide monomer photocatalyst under the optimal process conditions is prepared, and the photocatalytic efficiency on methyl orange is 24.35%; when the molar ratio of the nickel source to the cadmium sulfide is 4:10, an optimal photocatalyst is obtained, and the photocatalytic efficiency on the methyl orange solution is 93.83%.

Under the condition of determining the final preparation process, the content of a small amount of nickel source and the excessively high reaction temperature influence the photocatalytic efficiency of the composite photocatalytic material and inhibit the photocatalytic effect of the composite photocatalytic material. Therefore, the Ni-CdS catalyst prepared in the embodiment 3 has higher catalytic degradation capability on a Methyl Orange (MO) solution under visible light, namely when the molar ratio of a nickel source to a cadmium source is 4:10, the prepared composite Ni-CdS material with the photocatalytic performance has the best catalytic degradation capability.

As shown in FIG. 1, which is an SEM image of CdS prepared by the method, the prepared CdS is uniform in appearance and distribution, granular and partially agglomerated.

As shown in FIG. 2, which is an SEM image of the composite nano Ni-CdS prepared by the invention, Ni and CdS form a cluster structure, and the CdS still keeps the original granular morphology.

As shown in fig. 3, an XRD spectrogram of CdS and Ni-CdS prepared in example 3 shows that the Ni-CdS composite photocatalyst shows CdS characteristic peaks at 2 θ ═ 24.8 °, 26.4 °, 28.1 °, 43.5 °, 47.7 °, and 51.6 °, and Ni characteristic diffraction peaks at 2 θ ═ 44.3 °, 51.6 °, and 76 °, which indicates that the Ni-CdS composite photocatalyst has been successfully prepared.

As shown in fig. 7, when the pH value is 12 or 13, the prepared Ni-CdS composite photocatalyst has a comparative graph of the photocatalytic degradation effect on the methyl orange solution, and it can be seen that when the pH value is lower (pH <14), the catalytic performance of the prepared Ni-CdS composite catalyst is not ideal.