阅读说明：本技术 一种全二维三元复合物g-C3N4/MoS2/SnS2可见光响应光催化剂、制备方法 (Full two-dimensional ternary complex g-C3N4/MoS2/SnS2Visible light response photocatalyst and preparation method thereof ) 是由 陈昌兆 王千 倪晓 于 2019-09-23 设计创作，主要内容包括：本发明公开了一种全二维三元复合物g-C_3N_4/MoS_2/SnS_2可见光响应光催化剂、制备方法,将水合钼酸钠：硫代乙酰胺：水合硅钨酸溶解在去离子水中,得到MoS_2纳米片；将MoS_2溶解在去离子水中,加入水合氯化锡和柠檬酸,得到MoS_2/SnS_2复合纳米片；将尿素加热粉末溶解并超声处理,块状剥离得到片状g-C_3N_4；将MoS_2/SnS_2复合纳米片与片状g-C_3N_4复合得到三元复合物g-C_3N_4/MoS_2/SnS_2的纳米片。本发明制备的复合物中三种单元相面面接触有效复合,呈现交错型能级结构不仅增大了对可见光的吸收,还促进了电子-空穴对的分离,提高了光催化效率,有望广泛应用于光催化降解有机物领域,具有较好的发展前景。(The invention discloses a full two-dimensional ternary complex g-C 3 N 4 /MoS 2 /SnS 2 A visible light response photocatalyst and a preparation method thereof are prepared by mixing sodium molybdate hydrate: thioacetamide: dissolving hydrated silicotungstic acid in deionized water to obtain MoS 2 Nanosheets; mixing MoS 2 Dissolving in deionized water, adding stannic chloride hydrate and citric acid to obtain MoS 2 /SnS 2 Composite nanosheets; heating urea to dissolve the powder, performing ultrasonic treatment, and stripping the block to obtain flake g-C 3 N 4 (ii) a Mixing MoS 2 /SnS 2 Composite nanosheet and platelet g-C 3 N 4 Compounding to obtain ternary compound g-C 3 N 4 /MoS 2 /SnS 2 A nanosheet of (a). The three units in the compound prepared by the invention are in surface-to-surface contact and effectively compounded, and the compound presents a staggered energy level structure, so that the absorption of visible light is increased, the separation of electron-hole pairs is promoted, the photocatalytic efficiency is improved, the compound is expected to be widely applied to the field of photocatalytic degradation of organic matters, and the compound has a good development prospect.)

1. Full two-dimensional ternary complex g-C₃N₄/MoS₂/SnS₂The preparation method of the visible light response photocatalyst is characterized by comprising the following steps:

(1)MoS₂synthesis of nanosheets

Mixing sodium molybdate hydrate with sodium molybdate hydrate according to the molar ratio of 1-3: 15-25: 1-3: thioacetamide: dissolving hydrated silicotungstic acid in deionized water to prepare a solution with the concentration of 0.1-0.2 mo/L, magnetically stirring the solution until the solution is completely dissolved, heating the mixed solution to 200-250 ℃, keeping the mixed solution for 20-25 h, naturally cooling the mixed solution to room temperature, centrifugally dispersing reaction products, washing the reaction products for a plurality of times by using the deionized water and ethanol to obtain a black precursor, and drying the black precursor to obtain MoS₂Nanosheets;

(2)MoS₂/SnS₂synthesis of composite nanosheets

Mixing MoS₂Dissolving in deionized water, adding tin chloride hydrate and citric acid, standing for 1-2 h, adding thiourea, and magnetically stirring for at least 30min, wherein the weight ratio of the tin chloride hydrate: citric acid: the molar ratio of thiourea is 1-2: 4-6: 7-9, heating the mixed solution to 180-200 ℃, keeping the temperature for 10-14 hours, naturally cooling to room temperature, centrifugally dispersing reaction products, washing the reaction products with deionized water and ethanol for several times, and drying the reaction products to obtain MoS₂/SnS₂Composite nanosheets;

(3) flake g-C₃N₄Preparation of

Heating urea to 500-600 ℃ at a heating rate of 3-5 ℃/min, preserving heat for 3-4 h, cooling to room temperature, collecting light yellow powder, dissolving and ultrasonically treating the powder, and stripping blocks to obtain flaky g-C₃N₄；

(4) Ternary complex g-C₃N₄/MoS₂/SnS₂Synthesis of (2)

Mixing MoS₂/SnS₂Composite nanosheet and platelet g-C₃N₄Mixing the materials according to a mass ratio of 1-3: 7-9, adding the mixture into deionized water for ultrasonic treatment for 2-4 h, heating the mixture at 120-180 ℃ for 4-6 h, centrifugally dispersing reaction products, washing the reaction products with deionized water and ethanol for several times, and drying the reaction products to obtain a ternary compound g-C₃N₄/MoS₂/SnS₂A nanosheet of (a).

2. The fully two-dimensional ternary complex g-C of claim 1₃N₄/MoS₂/SnS₂The preparation method of the visible light response photocatalyst is characterized in that in the step (1), the mixed solution is transferred to a reaction kettle and then heated to 200-250 ℃.

3. The fully two-dimensional ternary complex g-C of claim 1₃N₄/MoS₂/SnS₂The preparation method of the visible-light-responsive photocatalyst is characterized in that in the steps (1) and (2), the nanosheets are obtained by drying at 70 ℃.

4. The fully two-dimensional ternary complex g-C of claim 1₃N₄/MoS₂/SnS₂The preparation method of the visible light response photocatalyst is characterized in that in the step (3), the urea is placed in a crucible with a cover, and then the crucible is transferred to a high-temperature furnace to be heated to 500-600 ℃.

5. The fully two-dimensional ternary complex g-C of claim 1₃N₄/MoS₂/SnS₂The preparation method of the visible light response photocatalyst is characterized in that the MoS₂/SnS₂Composite nanosheet and platelet g-C₃N₄The mass ratio of (1: 9), (2: 8) and (3: 10).

6. g-C prepared by the preparation method of claim 1₃N₄/MoS₂/SnS₂The visible light is responsive to the photocatalyst.

Technical Field

The invention relates to a visible light responding catalyst, in particular to a full two-dimensional ternary compound g-C₃N₄/MoS₂/SnS₂A visible light response photocatalyst and a preparation method thereof.

Background

Fossil fuels still play an important role in life and industry at present, and annual consumption still shows an increasing trend, and the organic pollutants produced thereby seriously damage the environment and threaten human health. The direct utilization of solar energy for photocatalytic degradation of pollutants is the first choice for dealing with environmental pollution. In this respect, currently, many wide bandgap oxide semiconductor materials with high activity, such as TiO2, SnO2, etc., are studied, and the spectral range of the photocatalytic reaction is limited by ultraviolet light, while the radiation energy of the ultraviolet light only accounts for 4% of the sunlight, which becomes an important factor limiting the large-scale application of the material. Under such a background, the development of a novel catalyst having a visible light response has become a hot spot of research in the field of photocatalysis in recent years. Two-dimensional semiconductor material g-C₃N₄、MoS₂And SnS₂The photocatalyst has received much attention recently as a novel photocatalytic material, because the band gaps of the photocatalyst fall in the visible light region, and the photocatalyst with visible light response is very suitable for being constructed, but the defects of the photocatalyst are all existed. The specific expression is that g-C3N4 has strong oxidizing ability, but the specific surface area is small, and the electron-hole recombination rate is high; MoS₂Has proper forbidden band width, large specific surface and high reactivity, but has low photocatalytic activity per se, and only exposed edges have photocatalytic activity; SnS₂Is a visible light semiconductor photocatalyst, has good photocatalytic performance, but has stronger volatility and self-luminous corrosivity at high temperature, and seriously influences SnS₂Practical application of photocatalysis.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: how to effectively compound three two-dimensional materials provides a full two-dimensional ternary compound g-C₃N₄/MoS₂/SnS₂A visible light response photocatalyst and a preparation method thereof.

The invention solves the technical problems through the following technical scheme, and the invention provides a full two-dimensional ternary complex g-C₃N₄/MoS₂/SnS₂The preparation method of the visible light response photocatalyst comprises the following steps:

(1)MoS₂synthesis of nanosheets

Mixing sodium molybdate hydrate with sodium molybdate hydrate according to the molar ratio of 1-3: 15-25: 1-3: thioacetamide: dissolving hydrated silicotungstic acid in deionized water to prepare a solution with the concentration of 0.1-0.2 mo/L, magnetically stirring the solution until the solution is completely dissolved, heating the mixed solution to 200-250 ℃, keeping the mixed solution for 20-25 h, naturally cooling the mixed solution to room temperature, centrifugally dispersing reaction products, washing the reaction products for a plurality of times by using the deionized water and ethanol to obtain a black precursor, and drying the black precursor to obtain MoS₂Nanosheets;

(2)MoS₂/SnS₂synthesis of composite nanosheets

Mixing MoS₂Dissolving in deionized water, adding tin chloride hydrate and citric acid, standing for 1-2 h, adding thiourea, and magnetically stirring for at least 30min, wherein the weight ratio of the tin chloride hydrate: citric acid: the molar ratio of thiourea is 1-2: 4-6: 7-9, heating the mixed solution to 180-200 ℃, keeping the temperature for 10-14 hours, naturally cooling to room temperature, centrifugally dispersing reaction products, washing the reaction products with deionized water and ethanol for several times, and drying the reaction products to obtain MoS₂/SnS₂Composite nanosheets;

(3) flake g-C₃N₄Preparation of

Heating urea to 500-600 ℃ at a heating rate of 3-5 ℃/min, preserving heat for 3-4 h, cooling to room temperature, collecting light yellow powder, dissolving and ultrasonically treating the powder, and stripping blocks to obtain flaky g-C₃N₄；

(4) Ternary complex g-C₃N₄/MoS₂/SnS₂Synthesis of (2)

Mixing MoS₂/SnS₂Composite nanosheet and platelet g-C₃N₄Mixing the raw materials according to the mass ratio of 1-3: 7-9, adding the mixture into deionized water for ultrasonic treatment for 2-4 h, heating the mixture at 120-180 ℃ for 4-6 h, centrifugally dispersing reaction products, and cleaning the reaction products with deionized water and ethanolWashing for several times and drying to obtain ternary compound g-C₃N₄/MoS₂/SnS₂A nanosheet of (a).

In a preferred embodiment of the present invention, in the step (1), the mixed solution is transferred to a reaction vessel and then heated to 200 to 250 ℃.

In a preferred embodiment of the present invention, the nanosheets are obtained by drying at 70 ℃ in the steps (1) and (2).

In a preferred embodiment of the present invention, in the step (3), the urea is put into a crucible with a cover, and then transferred into a high temperature furnace to be heated to 500 to 600 ℃.

In a preferred embodiment of the present invention, the MoS is₂/SnS₂Composite nanosheet and platelet g-C₃N₄The mass ratio of (A) to (B) is 1:9,2:8 and 3: 10.

g-C prepared by the preparation method₃N₄/MoS₂/SnS₂The visible light is responsive to the photocatalyst.

The energy level structure matched among the three materials is very beneficial to the space separation of photo-generated electrons and holes. In fact, for the design of the composite photocatalyst, energy level matching is the primary condition for achieving charge separation at the surface or interface. This matching generally requires that the conduction band potentials of several materials participating in recombination sequentially rise and the valence band potentials sequentially fall, so as to achieve efficient separation of the photogenerated electrons from the materials with the highest conduction band potential and the holes from the materials with the lowest valence band potential, i.e., electron-hole separation. The three materials can be effectively compounded and overcome the defects and shortcomings of each other through the matched energy level structure design.

Compared with the prior art, the invention has the following advantages: the three units in the compound prepared by the invention are in surface-to-surface contact and effectively compounded, and the compound presents a staggered energy level structure, so that the absorption of visible light is increased, the separation of electron-hole pairs is promoted, the photocatalytic efficiency is improved, the compound is expected to be widely applied to the field of photocatalytic degradation of organic matters, and the compound has a good development prospect.

Drawings

FIG. 1 is a schematic diagram of the energy level matching of the present invention;

FIG. 2 is an XRD pattern of a product made in accordance with the present invention;

FIG. 3 is an XPS characterization of the product obtained in example 2;

FIG. 4 is a SEM and TEM representation of the product prepared by the invention;

FIG. 5 is a photo-catalytic performance test chart of the product prepared by the present invention.

Detailed Description

The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.