阅读说明：本技术 一种刺球状Mo2C/CdS光催化剂及其制备方法、光催化方法 (Thorn-ball-shaped Mo2C/CdS photocatalyst, preparation method thereof and photocatalytic method ) 是由 周爱国 金森 夏启勋 王李波 郭奕彤 胡前库 于 2020-12-15 设计创作，主要内容包括：本发明属于光催化剂制备技术领域,特别涉及一种刺球状Mo-2C/CdS光催化剂及其制备方法、光催化方法。本发明的刺球状Mo-2C/CdS光催化剂为在Mo-2C MXene片层表面生长出纤锌矿型CdS后形成的刺球状异质结构,所述纤锌矿型CdS为纳米棒结构。该刺球结构有较大的比表面积,能够提供更多的活性位点,更有利于光催化制氢。同时,Mo-2C MXene的制备过程有着成本低、易实现等特点,因此使用这种廉价的材料作为共催化剂提高CdS的光催化制氢性能更加满足实际生产的要求。(The invention belongs to the technical field of photocatalyst preparation, and particularly relates to thorn-ball-shaped Mo 2 C/CdS photocatalyst, preparation method thereof and photocatalysis method. The invention relates to thorn-ball-shaped Mo 2 The C/CdS photocatalyst is Mo 2 A spiky-spherical heterostructure formed after wurtzite CdS grows on the surface of the C MXene lamella, wherein the wurtzite isThe CdS type is of a nanorod structure. The acanthosphere structure has larger specific surface area, can provide more active sites and is more beneficial to photocatalytic hydrogen production. At the same time, Mo 2 The preparation process of the C MXene has the characteristics of low cost, easiness in implementation and the like, so that the performance of photocatalytic hydrogen production of CdS improved by using the cheap material as a cocatalyst meets the requirement of actual production.)

1. Thorn-ball-shaped Mo₂C/CdS photocatalyst is characterized in that the spiky-shaped Mo₂The C/CdS photocatalyst is Mo₂And a spiked spherical heterostructure is formed after wurtzite CdS grows on the surface of the C MXene lamella, wherein the wurtzite CdS is of a nanorod structure.

2. The barbed spherical Mo according to claim 1₂The C/CdS photocatalyst is characterized in that the length of the nanorod is 200-300 nm, and the diameter of the nanorod is 40-50 nm.

3. The spinous spherical Mo of claim 1 or 2₂The preparation method of the C/CdS photocatalyst is characterized by comprising the following steps of:

(1) preparation of precursor solution

Dissolving water-soluble cadmium salt and thiourea in distilled water to obtain a precursor solution;

(2) cocatalyst Mo₂Addition of C MXene

Taking the mass of CdS generated by cadmium element and sulfur element in the precursor solution in the step (1) as the theoretical CdS mass, taking the theoretical CdS mass as the reference, and adding Mo according to the doping ratio of 0.1-7% in percentage by mass₂Uniformly mixing the C MXene powder and the precursor solution to obtain uniform dispersion liquid;

(3) addition of Ethylenediamine

Uniformly mixing ethylenediamine with the uniform dispersion liquid obtained in the step (2) to obtain a pre-decomposition solution;

(4) hydrothermal reaction to produce Mo₂C/CdS photocatalyst

Transferring the pre-decomposition solution obtained in the step (3) into a reaction kettle for hydrothermal reaction, and after the reaction is finished, performing post-treatment on the product to obtain Mo₂C/CdS photocatalyst.

4. The barbed spherical Mo according to claim 3₂The preparation method of the C/CdS photocatalyst is characterized in that in the step (1), the molar ratio of cadmium elements in the water-soluble cadmium salt to sulfur elements in thiourea is 1: (3-4);

preferably, the water-soluble cadmium salt is cadmium nitrate or cadmium nitrate tetrahydrate;

preferably, the cadmium nitrate tetrahydrate and the thiourea are both of analytical grade.

5. The barbed spherical Mo according to claim 3₂The preparation method of the C/CdS photocatalyst is characterized in that in the step (2), the doping ratio is 1.0-2.5%;

preferably, in the step (2), the mixing is performed uniformly by ultrasonic treatment;

preferably, in the step (2), the time of ultrasonic treatment in the mixing process is 1-5 h.

6. The barbed spherical Mo according to claim 3₂The preparation method of the C/CdS photocatalyst is characterized in that the volume ratio of the addition amount of ethylenediamine in the step (3) to the distilled water in the step (1) is 1: (2-4).

7. The barbed spherical Mo according to claim 3₂The preparation method of the C/CdS photocatalyst is characterized in that in the step (4), the temperature of the hydrothermal reaction is 180-200 ℃;

preferably, the time of the hydrothermal reaction is 24-36 h;

preferably, the post-treatment is: the product is centrifugally cleaned by using distilled water and absolute ethyl alcohol in sequence and then dried;

preferably, distilled water and absolute ethyl alcohol are sequentially used for centrifugally cleaning a product in the post-treatment process until the pH value of a cleaning solution is neutral;

preferably, the product is centrifugally cleaned by sequentially using distilled water and absolute ethyl alcohol in the post-treatment process, and then dried, wherein the drying is vacuum drying, and the drying time is 8-12 hours.

8. Use of the spinous spherical Mo of claim 1 or 2₂The photocatalysis method of the C/CdS photocatalyst is characterized by comprising the following steps of:

(i) preparation of sacrificial agent solution

Uniformly mixing lactic acid and distilled water to obtain a sacrificial agent solution;

(ii) addition of photocatalyst

The thorn ball shape Mo₂Uniformly dispersing the C/CdS photocatalyst in the sacrificial agent solution to obtain a pre-decomposition solution;

(iii) photocatalytic water splitting hydrogen production

And (3) placing the pre-decomposition solution in a reactor, and carrying out photocatalytic reaction under the conditions of vacuum and illumination.

9. The photocatalytic method according to claim 8, wherein in step (i), the volume ratio of lactic acid to distilled water is 1: (3-4.5);

preferably, the lactic acid is of analytical grade.

10. The photocatalytic method as set forth in claim 8, wherein in step (iii), the illumination condition is continuous illumination using a 300W xenon lamp with a filter capable of filtering light corresponding to a wavelength band with λ ≥ 420 nm;

preferably, the reactor is cooled while continuously illuminating to avoid overheating of the reaction solution.

Technical Field

The invention belongs to the technical field of photocatalyst preparation, and particularly relates to thorn-ball-shaped Mo₂C/CdS photocatalyst, preparation method thereof and photocatalysis method.

Background

Hydrogen has important applications in today's society as a clean energy source. The photocatalytic hydrolysis hydrogen production method is a low-cost and high-efficiency hydrogen production method. Since hydrogen production can be realized under visible light by the action of the catalyst, photocatalytic hydrolysis hydrogen production has been studied by many scientists in recent years. CdS is a common inorganic compound, and is proved to be a good photocatalyst by research due to a narrow band gap and good electron transmission capacity. But the rapid recombination of photogenerated electrons and holes limits the hydrogen production of CdS. In order to improve the photocatalytic hydrogen production performance, CdS and other materials are combined to form a heterostructure so as to improve the gas production. The common composite is noble metal, but the rare and expensive noble metal limits the practical application of the composite.

Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.

Disclosure of Invention

The invention aims to provide the Mo with a unique acanthosphere structure, obvious hydrogen production effect, simple preparation process and low preparation cost₂C/CdS photocatalyst.

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

thorn-ball-shaped Mo₂C/CdS photocatalyst, the spiky-shaped Mo₂The C/CdS photocatalyst is Mo₂And a spiked spherical heterostructure is formed after wurtzite CdS grows on the surface of the C MXene lamella, wherein the wurtzite CdS is of a nanorod structure.

Preferably, the length of the nanorod is 200-300 nm, and the diameter of the nanorod is 40-50 nm.

The above-mentioned thorn ball shape Mo₂The preparation method of the C/CdS photocatalyst comprises the following steps:

(1) preparation of precursor solution

Dissolving water-soluble cadmium salt and thiourea in distilled water to obtain a precursor solution;

(2) cocatalyst Mo₂Addition of C MXene

Taking the mass of CdS generated by cadmium element and sulfur element in the precursor solution in the step (1) as the theoretical CdS mass, taking the theoretical CdS mass as the reference, and adding Mo according to the doping ratio of 0.1-7% in percentage by mass₂Uniformly mixing the C MXene powder and the precursor solution to obtain uniform dispersion liquid;

(3) addition of Ethylenediamine

Uniformly mixing ethylenediamine with the uniform dispersion liquid obtained in the step (2) to obtain a pre-decomposition solution;

(4) hydrothermal reaction to produce Mo₂C/CdS photocatalyst

Transferring the pre-decomposition solution obtained in the step (3) into a reaction kettle for hydrothermal reaction, and after the reaction is finished, performing post-treatment on the product to obtain Mo₂C/CdS photocatalyst.

Preferably, in the step (1), the molar ratio of the cadmium element in the water-soluble cadmium salt to the sulfur element in the thiourea is 1: (3-4).

Preferably, the water-soluble cadmium salt is cadmium nitrate or cadmium nitrate tetrahydrate.

Preferably, the cadmium nitrate tetrahydrate and the thiourea are both of analytical grade.

Preferably, in the step (2), the doping ratio is 1.0-2.5%.

Preferably, in the step (2), the mixing is performed uniformly by using ultrasonic treatment.

Preferably, in the step (2), the time of ultrasonic treatment in the mixing process is 1-5 h.

Preferably, the volume ratio of the addition amount of ethylenediamine in the step (3) to the distilled water in the step (1) is 1: (2-4).

Preferably, in the step (4), the temperature of the hydrothermal reaction is 180-200 ℃.

Preferably, the hydrothermal reaction time is 24-36 h.

Preferably, the post-treatment is: the product was washed centrifugally with distilled water, absolute ethanol in this order, and then dried.

Preferably, the product is centrifugally washed by using distilled water and absolute ethyl alcohol in sequence in the post-treatment process until the pH of the washing liquid is neutral.

Preferably, the product is centrifugally cleaned by sequentially using distilled water and absolute ethyl alcohol in the post-treatment process, and then dried, wherein the drying is vacuum drying, and the drying time is 8-12 hours.

Adopts the thorn ball-shaped Mo₂The photocatalysis method of the C/CdS photocatalyst comprises the following steps:

(i) preparation of sacrificial agent solution

Uniformly mixing lactic acid and distilled water to obtain a sacrificial agent solution;

(ii) addition of photocatalyst

The thorn ball shape Mo₂Uniformly dispersing the C/CdS photocatalyst in the sacrificial agent solution to obtain a pre-decomposition solution;

(iii) photocatalytic water splitting hydrogen production

And (3) placing the pre-decomposition solution in a reactor, and carrying out photocatalytic reaction under the conditions of vacuum and illumination.

Preferably, in step (i), the volume ratio of lactic acid to distilled water is 1: (3-4.5).

Preferably, the lactic acid is of analytical grade.

Preferably, in step (iii), the illumination condition is continuous illumination by using a 300W xenon lamp with an optical filter, and the optical filter can filter light corresponding to a wavelength band with lambda being more than or equal to 420 nm;

preferably, the reactor is cooled while continuously illuminating to avoid overheating of the reaction solution.

Compared with the closest prior art, the technical scheme provided by the invention has the following excellent effects:

(1) by theoretical calculation, Mo₂After the C MXene and the CdS are combined, lower Gibbs binding energy is displayed, and photocatalytic hydrogen production is facilitated, so that a theoretical basis is provided for preparation of the composite photocatalyst. At the same time, Mo₂The preparation process of the C MXene has the characteristics of low cost, easiness in implementation and the like, so that the performance of photocatalytic hydrogen production of CdS improved by using the cheap material as a cocatalyst meets the requirements of actual production and life.

(2) Water-soluble cadmium salts and thioureas (CH) for use in the present invention₄N₂S) as precursor directly on Mo₂Wurtzite CdS grows from the C MXene powder, and a unique acanthosphere structure is formed in the alkaline environment of ethylenediamine. The acanthosphere structure has larger specific surface area, can provide more active sites and is more beneficial to photocatalytic hydrogen production.

(3) The preparation method disclosed by the invention is simple in equipment, low in raw material cost, low in preparation difficulty, easy to control, and convenient to popularize and produce in a large scale.

(4) The invention adopts Mo₂The C MXene serving as the photocatalyst can obviously reduce the cost of raw materials compared with common noble metals.

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 exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. Wherein:

FIG. 1 shows Mo prepared in example 1 of the present invention₂XRD pattern of C/CdS photocatalyst;

FIG. 2 shows Mo prepared in example 1 of the present invention₂A field emission scanning electron microscope image of the C/CdS photocatalyst;

FIG. 3 shows Mo prepared in example 1 of the present invention₂A hydrogen yield curve chart of hydrogen production by photocatalytic decomposition of water by using a C/CdS photocatalyst;

FIG. 4 shows Mo prepared in example 2 of the present invention₂XRD pattern of C/CdS photocatalyst;

FIG. 5 shows Mo prepared in example 2 of the present invention₂A field emission scanning electron microscope image of the C/CdS photocatalyst;

FIG. 6 shows Mo prepared in example 2 of the invention₂A hydrogen yield curve chart of hydrogen production by photocatalytic decomposition of water by using a C/CdS photocatalyst;

FIG. 7 shows Mo prepared in example 3 of the invention₂XRD pattern of C/CdS photocatalyst;

FIG. 8 shows Mo prepared in example 3 of the invention₂And a field emission scanning electron microscope image of the C/CdS photocatalyst.

FIG. 9 shows Mo prepared in example 3 of the invention₂A hydrogen yield curve chart of hydrogen production by photocatalytic decomposition of water by using a C/CdS photocatalyst;

FIG. 10 shows Mo prepared in example 4 of the present invention₂XRD pattern of C/CdS photocatalyst;

FIG. 11 shows Mo prepared in example 4 of the invention₂And a field emission scanning electron microscope image of the C/CdS photocatalyst.

FIG. 12 shows Mo prepared in example 4 of the invention₂A hydrogen yield curve chart of hydrogen production by photocatalytic decomposition of water by using a C/CdS photocatalyst;

FIG. 13 shows Mo prepared in example 5 of the invention₂XRD pattern of C/CdS photocatalyst;

FIG. 14 shows Mo prepared in example 5 of the invention₂And a field emission scanning electron microscope image of the C/CdS photocatalyst.

FIG. 15 shows Mo prepared in example 5 of the invention₂A hydrogen yield curve chart of hydrogen production by photocatalytic decomposition of water by using a C/CdS photocatalyst;

FIG. 16 shows Mo prepared in example 6 of the invention₂XRD pattern of C/CdS photocatalyst;

FIG. 17 shows Mo prepared in example 6 of the invention₂And a field emission scanning electron microscope image of the C/CdS photocatalyst.

FIG. 18 shows an embodiment of the present invention6 prepared Mo₂A hydrogen yield curve chart of hydrogen production by photocatalytic decomposition of water by using a C/CdS photocatalyst;

FIG. 19 shows Mo prepared in example 7 of the invention₂A low power field emission scanning electron microscope image of the C/CdS photocatalyst;

FIG. 20 shows Mo prepared in example 7 of the invention₂A high power field emission scanning electron microscope image of the C/CdS photocatalyst;

FIG. 21 shows Mo prepared in example 7 of the invention₂A hydrogen yield curve chart of hydrogen production by photocatalytic decomposition of water by using a C/CdS photocatalyst;

FIG. 22 shows Mo prepared in example 1 of the invention₂And a transmission electron microscope image of the CdS particles stripped from the C/CdS photocatalyst after ultrasonic treatment.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

MXene is a generic term for a series of two-dimensional carbides, nitrides or carbonitrides, which are obtained by selectively removing the A element in MAX phase of ternary layered compound by etching solution. Due to the unique two-dimensional structure and the large specific surface area, the binary compound with the structure similar to the graphene can load a large number of functional groups in the preparation process to obtain more active sites, so that MXene can be widely applied to the fields of electrochemical energy storage, adsorption, catalysis and the like.

The invention relates to thorn-ball-shaped Mo₂The C/CdS photocatalyst takes water-soluble cadmium salt as a cadmium source, thiourea as a sulfur source, Mo as the precursor of the cadmium source and the sulfur source in the environment of an alkaline organic solvent, namely ethylenediamine₂Preparation of Mo by using C MXene as nucleation carrier₂C/CdS photocatalyst.

The invention relates to thorn-ball-shaped Mo₂The preparation of the C/CdS photocatalyst specifically comprises the following steps:

(1) preparation of precursor solution

Mixing water-soluble cadmium salt (such as cadmium nitrate tetrahydrate and cadmium nitrate) and thiourea in a molar ratio of 1: (3-4) (for example, 1: 3, 1: 3.2, 1: 3.4, 1: 3.6, 1: 3.8 and 1: 4) are dissolved in distilled water to obtain a precursor solution, the morphology of the generated CdS is determined by the ratio of sulfur to cadmium in the precursor solution, and the excessive sulfur can generate obvious anisotropic CdS to form a spiky structure;

with cadmium nitrate tetrahydrate (Cd (NO)₃)₂·4H₂O) as cadmium source, Cd (NO)₃)₂·4H₂O and CH₄N₂The mass ratio of S is 1.53: 1.14, Cd (NO)₃)₂·4H₂The purity levels of O and thiourea are analytically pure, i.e. the content of effective components is more than 99%.

(2) Cocatalyst Mo₂Addition of C MXene

Taking the mass of CdS generated by cadmium element and sulfur element in the precursor solution in the step (1) as the theoretical CdS mass, and taking the theoretical CdS mass as the reference, and adding Mo at a doping ratio of 0.1-7% (such as 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%) in percentage by mass₂Uniformly mixing the C MXene powder and the precursor solution obtained in the step (1) to obtain uniform dispersion liquid;

it is understood that in order to obtain the above-mentioned homogeneous dispersion, treatment with stirring, sonication, etc. may be employed, and that in the case of using sonication, the treatment time is 1 hour.

(3) Addition of Ethylenediamine

Uniformly mixing ethylenediamine with the uniform dispersion liquid obtained in the step (2) to obtain a pre-decomposition solution;

the volume ratio of the ethylenediamine to the distilled water in the step (1) is 1: (2-4) (e.g., 1: 2, 1: 2.5, 1: 3, 1: 3.5, 1: 4);

it can be understood that, in order to mix the ethylenediamine and the homogeneous dispersion liquid uniformly, treatments such as shaking and stirring can be adopted, and generally, magnetic stirring can be adopted for 30min to meet the requirement.

(4) Hydrothermal reaction to produce Mo₂C/CdS photocatalyst

Transferring the pre-decomposition solution obtained in the step (3) into a reaction kettle for hydrothermal reaction, and after the reaction is finished, performing post-treatment on the product to obtain Mo₂A C/CdS photocatalyst;

the reaction kettle can be a general hydrothermal reaction kettle with a polytetrafluoroethylene lining, can resist a high-pressure environment, has the reaction temperature of 180-200 ℃ (such as 180 ℃, 185 ℃, 190 ℃, 195 ℃ and 200 ℃) and the reaction time of 24-36 h (such as 24h, 26h, 28h, 30h, 32h, 34h and 36h), obtains orange powder after the reaction is finished, centrifugally washes the orange powder for several times until the pH of the supernatant is approximately equal to 7, and then carries out vacuum drying for 8-12 h (such as 8h, 9h, 10h, 11h and 12h) to obtain the Mo-containing iron oxide₂C/CdS photocatalyst.

Mo of the invention₂The C/CdS photocatalyst is Mo₂The ZnO-based nano-rod structure is characterized in that a spiky-ball-shaped heterostructure is formed after wurtzite-type CdS grows on the surface of a C MXene lamella, the wurtzite-type CdS is a nano-rod structure, the length of each nano-rod is 200-300 nm (such as 200nm, 220nm, 240nm, 260nm, 280nm and 300nm), and the diameter of each nano-rod is 40-50 nm (such as 40nm, 42nm, 44nm, 46nm, 48nm and 50 nm).

By using the above Mo₂The photocatalysis method for producing hydrogen by decomposing water with the C/CdS photocatalyst comprises the following steps:

(i) preparation of sacrificial agent solution

Mixing and stirring 10mL of lactic acid and 40mL of distilled water to form a uniform lactic acid aqueous solution serving as a sacrificial agent solution in the photocatalytic hydrogen production process;

the lactic acid is of analytical purity grade, namely the content of effective components is more than 85%.

(ii) Addition of photocatalyst

A certain mass (e.g. 20mg, 50mg, 100mg, 1g) of Mo₂Adding C/CdS photocatalyst powder into step (i)In the sacrificial agent solution, the photocatalyst powder is evenly dispersed in the sacrificial agent by ultrasonic treatment for a period of time, and a pre-decomposition solution is obtained.

(iii) Photocatalytic water splitting hydrogen production

And (3) placing the pre-decomposition solution in the step (ii) into a reactor, continuously irradiating by using a 300W xenon lamp with an optical filter (lambda is more than or equal to 420nm) in a vacuum environment, and simultaneously cooling the reactor to prevent the reaction liquid from being overheated due to long-time irradiation of the xenon lamp. The generated hydrogen gas is fed to a gas chromatograph for analyzing the amount of hydrogen gas generated.

The present invention will be further described with reference to specific examples.

Example 1

Spinous spherical Mo of the present example₂The preparation method of the C/CdS photocatalyst comprises the following steps:

(1) preparation of precursor solution

1.53g of Cd (NO)₃)₂·4H₂O (i.e., 0.005mol) was dissolved in 40mL of distilled water, and then 1.14g of CH was added₄N₂S (namely 0.015mol), and stirring by magnetic force until the clear solution is formed into a precursor solution.

(2) Cocatalyst Mo₂Addition of C MXene

At a doping ratio of 2.5% (i.e. Mo)₂Mass ratio of C MXene to CdS), 17.5mg of Mo was added₂And (2) adding the C MXene powder into the precursor solution obtained in the step (1), and performing ultrasonic treatment for 1h to disperse the powder in the precursor solution to obtain a uniform dispersion liquid.

(3) Addition of Ethylenediamine

Adding 10mL of ethylenediamine into the uniform dispersion liquid obtained in the step (2), and magnetically stirring for 30min to uniformly mix the ethylenediamine and the mixed solution obtained in the step (2) to obtain a pre-reaction solution;

(4) hydrothermal reaction to produce Mo₂C/CdS photocatalyst

Pouring the pre-reaction solution obtained in the step (3) into 100mL of polytetrafluoroethylene lining, then placing the lining into a high-pressure reaction kettle, preserving the temperature for 24h at 180 ℃ to obtain orange powder, and centrifugally cleaning the synthesized orange powder by using distilled water and absolute ethyl alcohol to obtain the orange powderpH is approximately equal to 7, vacuum drying is carried out for 12h, and Mo is obtained₂C/CdS photocatalyst.

Spinous spherical Mo of the present example₂The specific process of decomposing water to generate hydrogen by the C/CdS photocatalyst under visible light comprises the following steps:

(i) preparation of sacrificial agent solution

Mixing and stirring 10mL of lactic acid and 40mL of distilled water to form a uniform lactic acid aqueous solution serving as a sacrificial agent solution in the photocatalytic hydrogen production process;

(ii) addition of photocatalyst

20mg of Mo₂Adding the C/CdS photocatalyst powder into the sacrificial agent solution in the step (i), and performing ultrasonic treatment for a period of time to uniformly disperse the photocatalyst powder in the sacrificial agent to obtain a pre-decomposition solution;

(iii) photocatalytic water splitting hydrogen production

And (3) placing the pre-decomposition solution in the step (ii) into a reactor, continuously irradiating by using a 300W xenon lamp with an optical filter (lambda is more than or equal to 420nm) in a vacuum environment, and simultaneously cooling the reactor to prevent the reaction liquid from being overheated due to long-time irradiation of the xenon lamp. The generated hydrogen gas is fed to a gas chromatograph for analyzing the amount of hydrogen gas generated.

In the process of preparing hydrogen by decomposing water through photocatalysis, no special requirements are required for the reactor, and the reactor can be used as long as a vacuum environment can be formed with a transmission gas pipeline and a light source enters the upper part of the reactor. FIG. 1 shows Mo obtained in this example₂The XRD pattern of the C/CdS photocatalyst powder shows that the phase composition of the C/CdS photocatalyst powder is mainly CdS, and the weaker peak appearing at 8.4 degrees is Mo₂C MXene, no other impurities were produced.

FIG. 2 shows Mo obtained in this example₂The field emission scanning electron microscope image of the C/CdS photocatalyst powder shows that the Mo prepared from the image₂The C/CdS photocatalyst powder structure presents a spiky spherical structure.

FIG. 3 shows Mo in this example₂The hydrogen production curve chart of the C/CdS photocatalyst photocatalytic water splitting hydrogen production shows that the hydrogen production shows a good linear increasing trend along with the illumination time.

Example 2

Spinous spherical Mo of the present example₂The preparation method of the C/CdS photocatalyst comprises the following steps:

(1) preparation of precursor solution

1.53g of Cd (NO)₃)₂·4H₂O (i.e., 0.005mol) was dissolved in 40mL of distilled water, and then 1.14g of CH was added₄N₂S (namely 0.015mol), and stirring by magnetic force until the clear solution is formed into a precursor solution.

(2) Cocatalyst Mo₂Addition of C MXene

At a doping ratio of 5% (i.e. Mo)₂Mass ratio of C MXene to CdS), adding 35mg of Mo₂And (2) adding the C MXene powder into the precursor solution obtained in the step (1), and performing ultrasonic treatment for 1h to disperse the powder in the precursor solution to obtain a uniform dispersion liquid.

(3) Addition of Ethylenediamine

Adding 10mL of ethylenediamine into the uniform dispersion liquid obtained in the step (2), and magnetically stirring for 30min to uniformly mix the ethylenediamine and the mixed solution obtained in the step (2) to obtain a pre-reaction solution;

(4) hydrothermal reaction to produce Mo₂C/CdS photocatalyst

Pouring the pre-reaction solution obtained in the step (3) into 100mL of polytetrafluoroethylene lining, then placing the lining in a high-pressure reaction kettle, preserving the temperature for 24h at 180 ℃ to obtain orange powder, centrifugally cleaning the synthesized orange powder by using distilled water and absolute ethyl alcohol until the pH value is approximately equal to 7, and drying the orange powder for 12h in vacuum to obtain Mo₂C/CdS photocatalyst.

Spinous spherical Mo of the present example₂The specific process of decomposing water to generate hydrogen by the C/CdS photocatalyst under visible light comprises the following steps:

(i) preparation of sacrificial agent solution

Mixing and stirring 10mL of lactic acid and 40mL of distilled water to form a uniform lactic acid aqueous solution serving as a sacrificial agent solution in the photocatalytic hydrogen production process;

(ii) addition of photocatalyst

20mg of Mo₂(ii) adding the C/CdS photocatalyst powder to the sacrificial agent in step (i) to obtain the catalystPerforming sound treatment for a period of time to uniformly disperse photocatalyst powder in a sacrificial agent to obtain a pre-decomposition solution;

(iii) photocatalytic water splitting hydrogen production

And (3) placing the pre-decomposition solution in the step (ii) into a reactor, continuously irradiating by using a 300W xenon lamp with an optical filter (lambda is more than or equal to 420nm) in a vacuum environment, and simultaneously cooling the reactor to prevent the reaction liquid from being overheated due to long-time irradiation of the xenon lamp. The generated hydrogen gas is fed to a gas chromatograph for analyzing the amount of hydrogen gas generated.

FIG. 4 shows Mo obtained in this example₂The XRD pattern of the C/CdS photocatalyst powder shows that the phase composition of the C/CdS photocatalyst powder is mainly CdS, and Mo is used₂Mo appearing at 8.4 ℃ with an increased amount of C MXene₂The peak intensity of C MXene also became large, and no other impurities were produced.

FIG. 5 shows Mo obtained in this example₂The field emission scanning electron microscope image of the C/CdS photocatalyst powder shows that the Mo prepared from the image₂The C/CdS photocatalyst powder structure presents a spiky spherical structure.

FIG. 6 shows Mo in the present embodiment₂The hydrogen production curve chart of the C/CdS photocatalyst photocatalytic water splitting hydrogen production shows that the hydrogen production shows a good linear increasing trend along with the illumination time.

FIG. 7 shows Mo obtained in this example₂The transmission electron microscope image of CdS nanoparticles stripped from C/CdS photocatalyst powder after ultrasonic treatment shows that Mo prepared in the embodiment₂CdS in the C/CdS photocatalyst has a nanorod structure with the length of 200-300 nm and the diameter of 40-50 nm.

Example 3

Spinous spherical Mo of the present example₂The preparation method of the C/CdS photocatalyst comprises the following steps:

(1) preparation of precursor solution

1.53g of Cd (NO)₃)₂·4H₂O (i.e., 0.005mol) was dissolved in 40mL of distilled water, and then 1.14g of CH was added₄N₂S (namely 0.015mol), magnetically stirring to obtain a clear solution,forming a precursor solution.

(2) Cocatalyst Mo₂Addition of C MXene

At a doping ratio of 0.1% (i.e., Mo)₂Mass ratio of C MXene to CdS), 0.7mg of Mo was added₂And (2) adding the C MXene powder into the precursor solution obtained in the step (1), and performing ultrasonic treatment for 1h to disperse the powder in the precursor solution to obtain a uniform dispersion liquid.

(3) Addition of Ethylenediamine

Adding 10mL of ethylenediamine into the uniform dispersion liquid obtained in the step (2), and magnetically stirring for 30min to uniformly mix the ethylenediamine and the mixed solution obtained in the step (2) to obtain a pre-reaction solution;

(4) hydrothermal reaction to produce Mo₂C/CdS photocatalyst

Pouring the pre-reaction solution obtained in the step (3) into 100mL of polytetrafluoroethylene lining, then placing the lining in a high-pressure reaction kettle, preserving the temperature for 26h at 190 ℃ to obtain orange powder, centrifugally cleaning the synthesized orange powder by using distilled water and absolute ethyl alcohol until the pH value is approximately equal to 7, and drying the orange powder for 8h in vacuum to obtain Mo₂C/CdS photocatalyst.

Spinous spherical Mo of the present example₂The specific process of decomposing water to generate hydrogen by the C/CdS photocatalyst under visible light comprises the following steps:

(i) preparation of sacrificial agent solution

Mixing and stirring 10mL of lactic acid and 40mL of distilled water to form a uniform lactic acid aqueous solution serving as a sacrificial agent solution in the photocatalytic hydrogen production process;

(ii) addition of photocatalyst

20mg of Mo₂Adding the C/CdS photocatalyst powder into the sacrificial agent in the step (i), and performing ultrasonic treatment for a period of time to uniformly disperse the photocatalyst powder in the sacrificial agent to obtain a pre-decomposition solution;

(iii) photocatalytic water splitting hydrogen production

And (3) placing the pre-decomposition solution in the step (ii) into a reactor, continuously irradiating by using a 300W xenon lamp with an optical filter (lambda is more than or equal to 420nm) in a vacuum environment, and simultaneously cooling the reactor to prevent the reaction liquid from being overheated due to long-time irradiation of the xenon lamp. The generated hydrogen gas is fed to a gas chromatograph for analyzing the amount of hydrogen gas generated.

FIG. 7 shows Mo obtained in this example₂The XRD pattern of the C/CdS photocatalyst powder shows that the phase composition of the C/CdS photocatalyst powder is mainly CdS, and Mo is used₂The addition amount of C MXene is small, and no obvious Mo appears at about 8.4 DEG₂C MXene peak, no other impurities were generated.

FIG. 8 shows Mo obtained in this example₂The field emission scanning electron microscope image of the C/CdS photocatalyst powder shows that the Mo prepared from the image₂The C/CdS photocatalyst powder structure presents a spiky spherical structure.

FIG. 9 shows Mo in this example₂The hydrogen production curve chart of the C/CdS photocatalyst photocatalytic water splitting hydrogen production shows that the hydrogen production shows a good linear increasing trend along with the illumination time.

Example 4

Spinous spherical Mo of the present example₂The preparation method of the C/CdS photocatalyst comprises the following steps:

(1) preparation of precursor solution

1.53g of Cd (NO)₃)₂·4H₂O (i.e., 0.005mol) was dissolved in 40mL of distilled water, and then 1.14g of CH was added₄N₂S (namely 0.015mol), and stirring by magnetic force until the clear solution is formed into a precursor solution.

(2) Cocatalyst Mo₂Addition of C MXene

At a doping ratio of 1% (i.e. Mo)₂Mass ratio of C MXene to CdS), 7mg of Mo was added₂And (2) adding the C MXene powder into the precursor solution obtained in the step (1), and performing ultrasonic treatment for 1h to disperse the powder in the precursor solution to obtain a uniform dispersion liquid.

(3) Addition of Ethylenediamine

Adding 10mL of ethylenediamine into the uniform dispersion liquid obtained in the step (2), and magnetically stirring for 30min to uniformly mix the ethylenediamine and the mixed solution obtained in the step (2) to obtain a pre-reaction solution;

(4) hydrothermal reaction to produce Mo₂C/CdS photocatalyst

Pouring the pre-reaction solution of step (3) into 100mL of polytetramethylenePlacing the obtained product in a vinyl fluoride lining, then placing the product in a high-pressure reaction kettle, keeping the temperature at 180 ℃ for 24h to obtain orange powder, centrifugally cleaning the synthesized orange powder by using distilled water and absolute ethyl alcohol until the pH value is approximately equal to 7, and drying the product in vacuum for 10h to obtain Mo₂C/CdS photocatalyst.

Spinous spherical Mo of the present example₂The specific process of decomposing water to generate hydrogen by the C/CdS photocatalyst under visible light comprises the following steps:

(i) preparation of sacrificial agent solution

Mixing and stirring 10mL of lactic acid and 40mL of distilled water to form a uniform lactic acid aqueous solution serving as a sacrificial agent solution in the photocatalytic hydrogen production process;

(ii) addition of photocatalyst

20mg of Mo₂Adding the C/CdS photocatalyst powder into the sacrificial agent in the step (i), and performing ultrasonic treatment for a period of time to uniformly disperse the photocatalyst powder in the sacrificial agent to obtain a pre-decomposition solution;

(iii) photocatalytic water splitting hydrogen production

And (3) placing the pre-decomposition solution in the step (ii) into a reactor, continuously irradiating by using a 300W xenon lamp with an optical filter (lambda is more than or equal to 420nm) in a vacuum environment, and simultaneously cooling the reactor to prevent the reaction liquid from being overheated due to long-time irradiation of the xenon lamp. The generated hydrogen gas is fed to a gas chromatograph for analyzing the amount of hydrogen gas generated.

FIG. 10 shows Mo obtained in this example₂The XRD pattern of the C/CdS photocatalyst powder shows that the phase composition of the C/CdS photocatalyst powder is mainly CdS, and Mo is used₂The addition amount of C MXene is small, and no obvious Mo appears at about 8.4 DEG₂C MXene peak, no other impurities were generated.

FIG. 11 shows Mo obtained in this example₂The field emission scanning electron microscope image of the C/CdS photocatalyst powder shows that the Mo prepared from the image₂The C/CdS photocatalyst powder structure presents a spiky spherical structure.

FIG. 12 shows Mo in this embodiment₂The hydrogen yield curve chart of the C/CdS photocatalyst photocatalytic water splitting hydrogen production shows that the hydrogen yield shows better along with the illumination timeA linear growth trend.

Example 5

Spinous spherical Mo of the present example₂The preparation method of the C/CdS photocatalyst comprises the following steps:

(1) preparation of precursor solution

1.53g of Cd (NO)₃)₂·4H₂O (i.e., 0.005mol) was dissolved in 40mL of distilled water, and then 1.14g of CH was added₄N₂S (namely 0.015mol), and stirring by magnetic force until the clear solution is formed into a precursor solution.

(2) Cocatalyst Mo₂Addition of C MXene

At a doping ratio of 1.5% (i.e. Mo)₂Mass ratio of C MXene to CdS), 10.5mg of Mo was added₂And (2) adding the C MXene powder into the precursor solution obtained in the step (1), and performing ultrasonic treatment for 1h to disperse the powder in the precursor solution to obtain a uniform dispersion liquid.

(3) Addition of Ethylenediamine

Adding 10mL of ethylenediamine into the uniform dispersion liquid obtained in the step (2), and magnetically stirring for 30min to uniformly mix the ethylenediamine and the mixed solution obtained in the step (2) to obtain a pre-reaction solution;

(4) hydrothermal reaction to produce Mo₂C/CdS photocatalyst

Pouring the pre-reaction solution obtained in the step (3) into 100mL of polytetrafluoroethylene lining, then placing the lining in a high-pressure reaction kettle, preserving the temperature for 36h at 180 ℃ to obtain orange powder, centrifugally cleaning the synthesized orange powder by using distilled water and absolute ethyl alcohol until the pH value is approximately equal to 7, and drying the orange powder for 12h in vacuum to obtain Mo₂C/CdS photocatalyst.

Spinous spherical Mo of the present example₂The specific process of decomposing water to generate hydrogen by the C/CdS photocatalyst under visible light comprises the following steps:

(i) preparation of sacrificial agent solution

Mixing and stirring 10mL of lactic acid and 40mL of distilled water to form a uniform lactic acid aqueous solution serving as a sacrificial agent solution in the photocatalytic hydrogen production process;

(ii) addition of photocatalyst

20mg of Mo₂C/CdS photocatalyst powder additionCarrying out ultrasonic treatment on the sacrificial agent in the step (i) for a period of time to uniformly disperse the photocatalyst powder in the sacrificial agent to obtain a pre-decomposition solution;

(iii) photocatalytic water splitting hydrogen production

And (3) placing the pre-decomposition solution in the step (ii) into a reactor, continuously irradiating by using a 300W xenon lamp with an optical filter (lambda is more than or equal to 420nm) in a vacuum environment, and simultaneously cooling the reactor to prevent the reaction liquid from being overheated due to long-time irradiation of the xenon lamp. The generated hydrogen gas is fed to a gas chromatograph for analyzing the amount of hydrogen gas generated.

FIG. 13 shows Mo obtained in this example₂The XRD pattern of the C/CdS photocatalyst powder shows that the phase composition of the C/CdS photocatalyst powder is mainly CdS, and Mo is used₂The addition amount of C MXene is small, and no obvious Mo appears at about 8.4 DEG₂C MXene peak, no other impurities were generated.

FIG. 14 shows Mo obtained in this example₂The field emission scanning electron microscope image of the C/CdS photocatalyst powder shows that the Mo prepared from the image₂The C/CdS photocatalyst powder structure presents a spiky spherical structure.

FIG. 15 shows Mo in this example₂The hydrogen production curve chart of the C/CdS photocatalyst photocatalytic water splitting hydrogen production shows that the hydrogen production shows a good linear increasing trend along with the illumination time.

Example 6

Spinous spherical Mo of the present example₂The preparation method of the C/CdS photocatalyst comprises the following steps:

(1) preparation of precursor solution

1.53g of Cd (NO)₃)₂·4H₂O (i.e., 0.005mol) was dissolved in 40mL of distilled water, and then 1.14g of CH was added₄N₂S (namely 0.015mol), and stirring by magnetic force until the clear solution is formed into a precursor solution.

(2) Cocatalyst Mo₂Addition of C MXene

At a doping ratio of 7% (i.e. Mo)₂Mass ratio of C MXene to CdS), adding 49mg of Mo₂Adding C MXene powder into the precursor solution in the step (1), carrying out ultrasonic treatment for 1h,so that the powder is dispersed in the precursor solution to obtain a uniform dispersion liquid.

(3) Addition of Ethylenediamine

Adding 10mL of ethylenediamine into the uniform dispersion liquid obtained in the step (2), and magnetically stirring for 30min to uniformly mix the ethylenediamine and the mixed solution obtained in the step (2) to obtain a pre-reaction solution;

(4) hydrothermal reaction to produce Mo₂C/CdS photocatalyst

Pouring the pre-reaction solution obtained in the step (3) into 100mL of polytetrafluoroethylene lining, then placing the lining in a high-pressure reaction kettle, preserving the temperature for 24h at 180 ℃ to obtain orange powder, centrifugally cleaning the synthesized orange powder by using distilled water and absolute ethyl alcohol until the pH value is approximately equal to 7, and drying the orange powder for 11h in vacuum to obtain Mo₂C/CdS photocatalyst.

Spinous spherical Mo of the present example₂The specific process of decomposing water to generate hydrogen by the C/CdS photocatalyst under visible light comprises the following steps:

(i) preparation of sacrificial agent solution

Mixing and stirring 10mL of lactic acid and 40mL of distilled water to form a uniform lactic acid aqueous solution serving as a sacrificial agent solution in the photocatalytic hydrogen production process;

(ii) addition of photocatalyst

20mg of Mo₂Adding the C/CdS photocatalyst powder into the sacrificial agent in the step (i), and performing ultrasonic treatment for a period of time to uniformly disperse the photocatalyst powder in the sacrificial agent to obtain a pre-decomposition solution;

(iii) photocatalytic water splitting hydrogen production

And (3) placing the pre-decomposition solution in the step (ii) into a reactor, continuously irradiating by using a 300W xenon lamp with an optical filter (lambda is more than or equal to 420nm) in a vacuum environment, and simultaneously cooling the reactor to prevent the reaction liquid from being overheated due to long-time irradiation of the xenon lamp. The generated hydrogen gas is fed to a gas chromatograph for analyzing the amount of hydrogen gas generated.

FIG. 16 shows Mo obtained in this example₂The XRD pattern of the C/CdS photocatalyst powder shows that the phase composition of the C/CdS photocatalyst powder is mainly CdS, and Mo is used₂Mo appearing at 8.4 ℃ with an increased amount of C MXene₂C MXeThe ne peak intensity also increased and no other impurities were produced.

FIG. 17 shows Mo obtained in this example₂The field emission scanning electron microscope image of the C/CdS photocatalyst powder shows that the Mo prepared from the image₂The C/CdS photocatalyst powder structure presents a spiky spherical structure.

FIG. 18 shows Mo in this example₂The hydrogen production curve chart of the C/CdS photocatalyst photocatalytic water splitting hydrogen production shows that the hydrogen production shows a good linear increasing trend along with the illumination time.

Example 7

Mo of the present example₂The preparation method of the C/CdS photocatalyst comprises the following steps:

(1) preparation of precursor solution

1.53g of Cd (NO)₃)₂·4H₂O (i.e., 0.005mol) was dissolved in 40mL of distilled water, and then 1.14g of CH was added₄N₂S (namely 0.015mol), and stirring by magnetic force until the clear solution is formed into a precursor solution.

(2) Cocatalyst Mo₂Addition of C MXene

At a doping ratio of 2.5% (i.e. Mo)₂Mass ratio of C MXene to CdS), 17.5mg of Mo was added₂And (2) adding the C MXene powder into the precursor solution obtained in the step (1), and performing ultrasonic treatment for 1h to disperse the powder in the precursor solution to obtain a uniform dispersion liquid.

(3) Addition of Ethylenediamine

Adding 20mL of ethylenediamine into the uniform dispersion liquid obtained in the step (2), and magnetically stirring for 30min to uniformly mix the ethylenediamine and the mixed solution obtained in the step (2) to obtain a pre-reaction solution;

(4) hydrothermal reaction to produce Mo₂C/CdS photocatalyst

Pouring the pre-reaction solution obtained in the step (3) into 100mL of polytetrafluoroethylene lining, then placing the lining in a high-pressure reaction kettle, keeping the temperature for 24h at 200 ℃ to obtain orange powder, centrifugally cleaning the synthesized orange powder by using distilled water and absolute ethyl alcohol until the pH value is approximately equal to 7, and drying the orange powder for 12h in vacuum to obtain Mo₂C/CdS photocatalyst.

Thorn ball shape M of the present embodimento₂The specific process of decomposing water to generate hydrogen by the C/CdS photocatalyst under visible light comprises the following steps:

(i) preparation of sacrificial agent solution

Mixing and stirring 10mL of lactic acid and 40mL of distilled water to form a uniform lactic acid aqueous solution serving as a sacrificial agent solution in the photocatalytic hydrogen production process;

(ii) addition of photocatalyst

20mg of Mo₂Adding the C/CdS photocatalyst powder into the sacrificial agent solution in the step (i), and performing ultrasonic treatment for a period of time to uniformly disperse the photocatalyst powder in the sacrificial agent to obtain a pre-decomposition solution;

(iii) photocatalytic water splitting hydrogen production

And (3) placing the pre-decomposition solution in the step (ii) into a reactor, continuously irradiating by using a 300W xenon lamp with an optical filter (lambda is more than or equal to 420nm) in a vacuum environment, and simultaneously cooling the reactor to prevent the reaction liquid from being overheated due to long-time irradiation of the xenon lamp. The generated hydrogen gas is fed to a gas chromatograph for analyzing the amount of hydrogen gas generated.

Mo obtained in this example as shown in FIGS. 19 and 20₂Scanning electron microscope images of low-power and high-power field emission of C/CdS photocatalyst powder, and Mo prepared by increasing the content of ethylenediamine can be known from the images₂The C/CdS photocatalyst powder can have a CdS nanorod structure with the length of 1-2 μm and the diameter of about 100 nm.

FIG. 21 shows Mo in this example₂The hydrogen production curve of hydrogen production by photocatalytic decomposition of water by the C/CdS photocatalyst shows that the hydrogen production is weaker in the early stage of illumination and gradually tends to linearly increase along with the extension of illumination time.

Example 7 differs from example 1 in that: the addition amount of the ethylenediamine is increased, and the prepared Mo₂The shape of the C/CdS photocatalyst powder has a CdS nanorod structure with the length of 1-2 mu m and the diameter of about 100nm, and the structure influences the hydrogen evolution performance from hydrogen evolution data.

FIG. 22 shows Mo obtained in example 1 of the present invention₂The C/CdS photocatalyst powder is stripped off after ultrasonic treatmentThe transmission electron microscope image of CdS nano-particles shows that Mo prepared in the embodiment₂CdS in the C/CdS photocatalyst has a nanorod structure with the length of 200-300 nm and the diameter of 40-50 nm.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.