阅读说明：本技术 一种毛刺球状结构的石墨相碳化氮/硫化镉光催化纳米复合材料及其制备方法与用途 (Graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with burr-like structure and preparation method and application thereof ) 是由 刘爱丽 王舜 金辉乐 李俊 霍锐 郑健宏 王继昌 于 2019-09-10 设计创作，主要内容包括：本发明公开了一种毛刺球状结构的石墨相碳化氮/硫化镉光催化纳米复合材料的制备方法,所述方法包括如下步骤：S1：尿素通过热缩聚法得到石墨相碳化氮；S2：将质量百分比为0-4wt％的石墨相碳化氮和硫化镉前驱体加到适量的乙二醇中,搅拌混匀,超声分散,得到前驱反应液；S3：将所述前驱反应液通过微波辅助加热法,快速合成毛刺球状结构的石墨相碳化氮/硫化镉光催化纳米复合材料。本发明的所制备的毛刺球状结构的石墨相碳化氮/硫化镉光催化纳米复合材料具有高效产氢、价廉易得、环境友好等优点,其在光解水制氢工业化领域具有巨大潜力。(The invention discloses a preparation method of a graphite phase nitrogen carbide/cadmium sulfide photocatalytic nano composite material with a burr spherical structure, which comprises the following steps: s1: the urea is subjected to thermal polycondensation to obtain graphite-phase nitrogen carbide; s2: adding graphite phase nitrogen carbide and cadmium sulfide precursors with the mass percent of 0-4 wt% into a proper amount of ethylene glycol, uniformly stirring and dispersing by ultrasound to obtain precursor reaction liquid; s3: and (3) rapidly synthesizing the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure by the precursor reaction solution through a microwave-assisted heating method. The graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure, which is prepared by the invention, has the advantages of high-efficiency hydrogen production, low price, easy obtainment, environment friendliness and the like, and has great potential in the field of industrialization of hydrogen production by photolysis.)

1. A preparation method of a graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with a burred spherical structure is characterized by comprising the following steps:

s1: the urea is subjected to thermal polycondensation to obtain graphite-phase nitrogen carbide;

s2: adding graphite phase nitrogen carbide and cadmium sulfide precursors with the mass percentage of 0.01-4 wt% into a proper amount of ethylene glycol, uniformly stirring and ultrasonically dispersing to obtain precursor reaction liquid;

s3: and (3) rapidly synthesizing the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure by the precursor reaction solution through a microwave-assisted heating method.

2. The method for preparing the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure according to claim 1, wherein the method comprises the following steps: in step S1, the graphite phase nitrogen carbide is obtained by calcining urea at 550 ℃ for 3 hours.

3. The method for preparing the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure according to claim 1, wherein the method comprises the following steps: in step S1, the graphite phase nitrogen carbide is g-phase graphite phase nitrogen carbide with the chemical formula of g-C₃N₄。

4. The method for preparing the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure according to claim 1, wherein the method comprises the following steps: in step S2, the mass percentage of the graphite phase nitrogen carbide and cadmium sulfide precursor is 0.01-4 wt%.

5. The method for preparing the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burred spherical structure according to claim 1, wherein the step S3 is as follows:

s3-1: heating the precursor reaction solution obtained in the step S2 from room temperature to 90 ℃ under the microwave power of 200W, and keeping the temperature for 10 minutes to obtain a first reaction solution;

s3-2: continuously heating the first reaction solution to 160 ℃, and keeping the temperature for 10 minutes to obtain a second reaction solution;

s3-3: naturally cooling the second reaction solution to room temperature, centrifuging at the centrifugal speed of 18000rpm for 5 minutes, dispersing the obtained precipitate with absolute ethanol and high-purity water successively, centrifuging for 3-5 times, and vacuum drying at 60 ℃ for 8 hours to obtain the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite with the burr spherical structure.

6. A graphite phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with a burr spherical structure obtained by the preparation method as set forth in any one of claims 1 to 6.

7. Use of the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with a burred spherical structure according to claim 6 as a photocatalyst in hydrogen production by photolysis of water.

8. Use according to claim 7, comprising: adding the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure into ultrapure water, performing ultrasonic dispersion, adding lactic acid after the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material is completely dissolved, uniformly mixing, transferring reaction liquid into a reactor, introducing inert gas after vacuum deoxygenation, filtering impure light by using an optical filter below 420nm under a light source, and performing photocatalytic water preparation on hydrogen.

9. Use according to claim 7, comprising: the mass volume ratio of the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure to water is 1:2.05mg/ml, and the mass volume ratio of the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure to lactic acid is 1:0.23 mg/ml.

Technical Field

The invention belongs to the field of photocatalytic nano materials, and particularly relates to a graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nano composite material with a burr spherical structure, a preparation method and application thereof.

Background

The generation of clean hydrogen energy by solar catalytic water cracking is considered to be one of the most promising strategies to solve global energy dilemma and environmental problems. To date, many semiconductors have been developed as potential candidates for this targeted photocatalytic reaction, such as metal oxides, metal sulfides, metal oxynitrides, and the like. However, most semiconductors such as TiO₂，SrTiO₃ZnS, etc. can only respond to approximately 4% of the ultraviolet radiation of solar energy. Therefore, it is still a great challenge to develop a photocatalyst that can effectively utilize solar energy and be practically applied.

Metal sulfide semiconductors have proven to be good candidates for visible light catalyzed hydrogen production due to appropriate band gap and catalytic properties. In particular, CdS with a band gap of 2.4eV has attracted much attention as the most promising photocatalyst because it can absorb visible light widely, is low in cost, and has an appropriate band edge potential. However, the problem with the CdS only material is that photo-generated charges quickly recombine and photo-etching is severe. To overcome these disadvantages, various strategies have been applied to construct various metal sulfides, surface modification, and semiconductor synthesis; research has shown that surface modification with a cocatalyst is an effective method for regulating and controlling the migration path of photogenerated charge carriers and reducing the activation barrier of redox reactions. For example:

CN103316693A discloses a preparation method of photocatalyst Cd/CdS containing a catalyst promoter Cd. According to the method, metal simple substance Cd is introduced into CdS as a cocatalyst, photo-generated electron and hole pairs can be effectively separated, the hydrogen production efficiency of the CdS through photocatalysis is greatly improved, and the application of the CdS in hydrogen production reaction through photocatalytic water decomposition is expanded; the efficient photocatalytic Cd/CdS is directly synthesized by adopting photochemistry, has relatively stable structure and performance, and can be recycled in the photocatalytic decomposition hydrogen production reaction. The method is simple, low in cost, high in yield and good in industrialization prospect.

CN103920505A discloses a visible light photocatalytic high-efficiency hydrogen production cadmium sulfide inverse opal structure and a preparation method thereof. The method is characterized in that polystyrene-methyl methacrylate-3-sulfoacid propyl potassium methacrylate template pellets are used as a template, cadmium sulfide nanocrystals are used as fillers, and the template pellets are prepared by deposition and calcination. The method has the advantages that the synthesis condition of the cadmium sulfide inverse opal structure is simple, the cost is low, the repeatability is high, the prepared sample is complete in shape, the inverse opal structure has remarkable advantages in the aspect of photolysis water to produce hydrogen, and the method has wide and potential energy application prospects.

CN104607231A discloses a carbon nitride photocatalyst with a three-dimensional ordered macroporous structure and a preparation method thereof. The carbon nitride photocatalyst has a regularly arranged three-dimensional ordered porous morphology, a macroporous cavity is spherical, and the diameter of the macroporous cavity is 100 nm-300 nm; the distance between two adjacent macroporous sphere centers is 110 nm-350 nm. The scanning electron microscope picture of the carbon nitride photocatalyst shows that the carbon nitride photocatalyst has a three-dimensional ordered macroporous structure, a macroporous cavity is spherical, and the diameter of the macroporous cavity is 100 nm-300 nm; the macroporous structure has a higher specific surface area, and other materials can be loaded in the cavity of the ordered macropores, the mass transfer is easy, and the photo-generated carriers can be quickly separated in the reaction. The structure of the carbon nitride photocatalyst obviously improves the photocatalytic performance of the catalyst, has higher performance of photolyzing water to produce hydrogen under visible light, and realizes efficient solar energy hydrolysis to produce hydrogen.

CN105772041A discloses a photocatalytic hydrogen production promoter, a photocatalytic system and a method for producing hydrogen. The cocatalyst is CoP and Co₂P、Fe₂P、FeP、Cu₃One or a mixture of more than two of P, ZnP, MoP and MnP. Also discloses a photocatalytic system containing the photocatalytic hydrogen production promoter, which comprises: a semiconductor,Cocatalyst, electron sacrificial agent and water. The method has the advantages of extremely high hydrogen production efficiency of the photocatalytic system, no need of adding a surface stabilizer, low cost, no need of degassing and more benefit for practical application.

CN107282075A discloses a preparation method of a composite photocatalyst of bismuth molybdate and cadmium sulfide. The bismuth molybdate and cadmium sulfide composite photocatalyst prepared by the method has a large-area contact interface, is beneficial to carrier separation, has stable structures and band gap matching, improves photocatalytic activity, has stable catalytic effect, and has excellent performance of photolyzing water to produce hydrogen, photodegrading organic pollutants, heavy metal ions and reducing carbon dioxide. The method has the advantages of common raw materials, simple preparation operation flow, easy realization of process parameters, low cost, simple and convenient operation, high yield and long cycle service life, and has wide application prospect and industrialization prospect in the fields of hydrogen production by photolysis of water, organic pollutant photodegradation, reduction of heavy metal ions and carbon dioxide and the like.

CN109201115A discloses a photocatalytic hydrogen production catalyst with HKUST-1 as a precursor, a preparation method and application thereof. The preparation method comprises the steps of firstly preparing HKUST-1; heating the prepared HKUST-1 to 300-; the method for decomposing water to produce hydrogen by using the photocatalytic hydrogen production catalyst comprises the steps of dispersing the photocatalyst in a mixed solution of water and a sacrificial reagent, removing air in a reaction system, and reacting for 4-8 hours under visible light, wherein the wavelength range of the visible light is 420-700 nm. The photocatalytic hydrogen production catalyst provided by the method can generate hydrogen under the visible light condition at normal temperature and normal pressure, and has the characteristics of high catalytic activity and good hydrogen production stability; and the catalyst has wide raw material source, low price and simple preparation method, and is suitable for large-scale production.

CN109999886A discloses a titanium dioxide/graphite phase carbon nitride Z-shaped heterojunction photocatalytic hydrogen production catalyst, a preparation method and application thereof. According to the method, the existence of the Z-shaped heterojunction enables the photocatalyst to have a wider light absorption range, so that more photo-generated electron-hole pairs can be generated; secondly, the existence of the Z-shaped heterojunction leads the photocatalyst to have better separation efficiency and transport efficiency of electron hole pairs; thereby obviously improving the efficiency of the catalytic photolysis of the hydrogen. The preparation method of the catalyst is simple, and the compounding of the titanium dioxide and the graphite phase carbon nitride is realized by adopting a solution-assisted assembly mode, so that the titanium dioxide and the graphite phase carbon nitride in the prepared catalyst have stronger interaction, and the catalyst is favorable for charge separation and transportation, thereby further improving the catalytic activity of the catalyst.

CN104959153A discloses a novel photocatalytic hydrogen production auxiliary agent, which is nano layered NiMoS, and a photocatalyst with a CdS @ NiMoS spiral structure is formed by modifying a one-dimensional rod-shaped CdS main catalyst. The preparation method of the photocatalyst realizes the synthesis of the spiral composite nano photocatalyst by a two-step hydrothermal technology, firstly CdS nano rods with uniform size and regular appearance are synthesized in an ethylenediamine system, and then Na nano rods are subjected to hydrothermal pressurization₂MoO₄、Ni(NO₃)₂Reacting with thiourea to synthesize corresponding layered sulfide NiMoS, and forming heterostructure CdS @ NiMoS with nano-rod-shaped CdS. The catalyst shows excellent photocatalytic hydrogen production performance, and the yield of the seawater hydrogen production can reach 19.147 mmol/g^-1·h^-1And a new catalyst research and development idea is provided for new energy development.

However, none of the substances prepared in the above methods has realized a catalyst morphology of a burred spherical structure, so that the specific surface area thereof is insufficient, and the reaction efficiency with water in the photocatalytic reaction is affected, and thus there is a need for improvement.

Disclosure of Invention

In order to solve the problems and the defects in the prior art, the invention aims to provide the preparation method of the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr-shaped structure, the method has the technical effects of simplicity, rapidness, greenness and low cost, and the synthesized graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material has good hydrogen production performance.

In order to achieve the above object, a first technical solution of the present invention is to provide a method for preparing a graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with a burred spherical structure, comprising the following steps:

s1: the urea is subjected to thermal polycondensation to obtain graphite-phase nitrogen carbide;

s2: adding graphite phase nitrogen carbide and cadmium sulfide precursors with the mass percent of 0-4 wt% into a proper amount of ethylene glycol, uniformly stirring and dispersing by ultrasound to obtain precursor reaction liquid;

s3: and (3) rapidly synthesizing the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure by the precursor reaction solution through a microwave-assisted heating method.

In the method for preparing the burr-spherical-structure graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material, in step S1, the graphite-phase nitrogen carbide is obtained by calcining urea at 550 ℃ for 3 hours.

In the method for preparing the burr-spherical-structure graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material, in step S1, the graphite-phase nitrogen carbide is g-phase graphite-phase nitrogen carbide (g-C)₃N₄)。

In the preparation method of the burr-spherical-structure graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material, in step S2, the mass percentage ratio of the graphite-phase nitrogen carbide to the cadmium sulfide precursor is 0.5 wt%.

In the preparation method of the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure, in step S3, the microwave-assisted heating method is a synthesis method which is simple and convenient to operate and rapid in reaction.

In the preparation method of the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure, the step S3 is specifically as follows:

s3-1: heating the precursor reaction solution obtained in the step S2 from room temperature to 90 ℃ under the microwave power of 200W, and keeping the temperature for 10 minutes to obtain a first reaction solution;

s3-2: continuously heating the first reaction solution to 160 ℃, and keeping the temperature for 10 minutes to obtain a second reaction solution;

s3-3: naturally cooling the second reaction solution to room temperature, centrifuging at the centrifugal speed of 18000rpm for 5 minutes, dispersing the obtained precipitate with absolute ethanol and high-purity water successively, centrifuging for 3-5 times, and vacuum drying at 60 ℃ for 8 hours to obtain the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite with the burr spherical structure, wherein the name of the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite is CN 0.5.

The inventor finds that when the preparation method is adopted, the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nano composite material with the burr spherical structure can be obtained, and when certain process parameters such as raw material dosage ratio, microwave power, constant temperature time and the like are changed, the photocatalytic composite material with the shape can not be obtained.

In a second aspect, the present invention relates to a graphite phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with a burr spherical structure obtained by the above preparation method.

The inventor finds that the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure has excellent photocatalytic performance, so that the composite material can be applied to the technical field of photolysis hydrogen production, and has good application prospect and industrialization potential.

Thus, in a third aspect, the present invention relates to the use of the burred-spheroidal structured graphitic-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material for photolytic hydrogen production.

The method is further characterized in that: adding ultrapure water into a photocatalytic nano composite material, dispersing the photocatalytic nano composite material by using ultrasound, adding lactic acid after the ultrapure water is completely dissolved, uniformly mixing, transferring the reaction liquid into a reactor, introducing inert gas after vacuum deoxygenation, using a simulated sunlight xenon lamp as a light source, filtering stray light by using an optical filter below 420nm, and finally detecting the generated H by using gas chromatography₂。

In the photolytic hydrogen production method, the mass-to-volume ratio of the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure to water is 1:2.05mg/ml, and the mass-to-volume ratio of the nanocomposite material to lactic acid is 1:0.23 mg/ml.

The inventor finds that the graphite-phase nitrogen carbide/cadmium sulfide photocatalytic nanocomposite material with the burr spherical structure and the specific morphology, which is obtained by the invention, can be used for preparing hydrogen by photolysis of water under the illumination condition, has a very excellent hydrogen production rate, provides a brand-new and efficient photolysis composite material for hydrogen production by photolysis, and has great application potential and industrial value in the industrial field.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is within the scope of the present invention for those skilled in the art to obtain other drawings based on the drawings without inventive exercise.

FIG. 1 shows g-C obtained in example 1 of the present invention₃N₄Low power SEM image (i.e., fig. 1(a)) and TEM image (i.e., fig. 1(b)) of the sample;

FIG. 2 is a low power SEM photograph (i.e., FIG. 2(a)), TEM photograph (i.e., inset of FIG. 2(a)), and HR-TEM photograph (i.e., FIG. 2(b)) of a sample prepared in example 1 of the present invention;

FIG. 3 shows the g-C values of different mass percentages obtained in example 1 of the present invention₃N₄Low magnification SEM image of/CdS sample, wherein (a) CN0, (b) CN0.25, (c) CN0.5, (d) CN0.75, (e) CN1, (f) CN2, (g) CN3, (h) CN 4;

FIG. 4 shows g-C obtained in example 1 of the present invention₃N₄(4 wt%)/CdS heterojunction samples STEM-HAADF and EDX plots;

FIG. 5 shows g-C obtained in example 1 of the present invention₃N₄(i.e., FIG. 5(a)) and different mass percentages of g-C₃N₄XRD pattern of/CdS sample (i.e. FIG. 5 (b));

FIG. 6 shows g-C obtained in example 1 of the present invention₃N₄(8 wt%)/CdS nanocomposite with high resolution XPS spectra, wherein (a) C1S, (b) N1S, (C) S2 p, (d) Cd 3d, and (e) XPS holo-spectrumA spectrum;

FIG. 7 shows the g-C values obtained in example 1 of the present invention in different mass percentages₃N₄UV-visible absorption spectrum of/CdS sample, in which BaSO₄Absorption as a blank;

FIG. 8 shows the g-C values obtained in example 1 of the present invention in different mass percentages₃N₄Nitrogen adsorption-desorption isotherms and corresponding pore size distributions for the/CdS samples (inset);

FIG. 9 shows g-C obtained in example 1 of the present invention₃N₄And g-C of different mass percentages₃N₄I-t curves for CdS samples, where (a) CdS (b) CN0.5(C) CN1(d) CN2 and (e) g-C₃N₄；

FIG. 10 shows the g-C values obtained in example 1 of the present invention in different mass percentages₃N₄The hydrogen production efficiency of the water by photocatalytic cracking of the/CdS sample is shown in the figure.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.