阅读说明：本技术 一种铌酸基上硫化物复合材料及其制备方法 (Niobium acid-based sulfide composite material and preparation method thereof ) 是由 宋春风 王振娇 刁新勇 李婷婷 刘庆岭 纪娜 于 2019-09-11 设计创作，主要内容包括：本发明涉及一种铌酸基上硫化物复合材料及制备方法,铌酸基上硫化物复合材料结构式为A<Sub>x</Sub>B<Sub>y</Sub>S<Sub>z</Sub>-H<Sub>4</Sub>Nb<Sub>2</Sub>O<Sub>7</Sub>,其中A、B为Co、Mo、Ni、Cu、Zn、Fe不同金属元素中的一种或两种,其中0＜x＜10,0≤y＜10,0＜z＜10,具体数值根据化合物具体价态决定。称取铌酸锡加入到聚四氟乙烯内衬中,并加入一种或两种可溶性金属盐和硫脲,用水溶解后进行水热反应,得到黑色沉淀物；将黑色沉淀物进行抽滤洗涤,并置于真空干燥箱中,进行干燥,得到A<Sub>x</Sub>B<Sub>y</Sub>S<Sub>z</Sub>-H<Sub>4</Sub>Nb<Sub>2</Sub>O<Sub>7</Sub>复合材料。本发明制备条件低,操作简单,硫化物均匀生长在铌酸表面,为反应提供更多的反应活性位点,充分提高了金属硫化物在催化反应中的反应活性。(The invention relates to a niobium acid group sulfide composite material and a preparation method thereof, wherein the niobium acid group sulfide composite material has a structural formula of A x B y S z ‑H 4 Nb 2 O 7 Wherein A, B is one or two of different metal elements of Co, Mo, Ni, Cu, Zn and Fe, wherein x is more than 0 and less than 10, y is more than 0 and less than 10, z is more than 0 and less than 10, and the concrete formula isThe numerical value is determined according to the specific valence of the compound. Weighing tin niobate, adding the tin niobate into a polytetrafluoroethylene lining, adding one or two soluble metal salts and thiourea, dissolving the metal salts and the thiourea in water, and carrying out hydrothermal reaction to obtain a black precipitate; filtering and washing the black precipitate, placing the black precipitate in a vacuum drying oven, and drying to obtain A x B y S z ‑H 4 Nb 2 O 7 A composite material. The preparation method has the advantages of low preparation conditions and simple operation, and the sulfide uniformly grows on the surface of the niobic acid, so that more reactive sites are provided for the reaction, and the reactivity of the metal sulfide in the catalytic reaction is fully improved.)

1. A composite material of sulfide on niobate base is characterized in that the structural formula is A_xB_yS_z-H₄Nb₂O₇Wherein A, B is one or two of different metal elements of Co, Mo, Ni, Cu, Zn and Fe. Wherein x is more than 0 and less than 10, y is more than or equal to 0 and less than 10, and z is more than 0 and less than 10, and the specific numerical value is generally determined according to the valence state of the compound.

2. The niobate-based sulfide-on-niobate composite material according to claim 1, wherein the metal sulfide is uniformly dispersed in a surface layer of the niobate microsphere.

3. A method of preparing a niobium acid based sulfide composite material as claimed in claim 1, characterized by comprising the steps of:

1) weighing tin niobate, adding the tin niobate into a polytetrafluoroethylene lining, adding one or two soluble metal salts and thiourea, adding a hydrochloric acid solution to adjust the pH value to 0.7-1.0, putting the mixture into a kettle, and reacting to obtain a black precipitate;

2) filtering and washing the black precipitate obtained after the reaction of 1) and placing the black precipitate in a vacuum drying oven for drying to obtain A_xB_yS_z-H₄Nb₂O₇A catalyst.

4. The method as set forth in claim 3, characterized in that the hydrothermal reaction temperature in step 1) is 100-200 ℃ and the reaction time is 2-48 h.

5. The method of claim 3, wherein the metal soluble salt is a molybdate, nitrate, acetate, chloride or sulfate.

6. The method according to claim 3, wherein the mass ratio of the metal salt to the tin niobate is 5:1 to 20:1, and the mass ratio of the thiourea to the metal salt is in the range of 0.2:1 to 2: 1.

7. The method as set forth in claim 3, wherein 0.1 to 0.2mol/L hydrochloric acid solution is added, and the ratio of the volume of hydrochloric acid to the amount of tin niobate added is 50 to 300 mL/g.

8. The method as set forth in claim 3, wherein the drying temperature in the step 2) is 60 ℃ to 120 ℃ for 6h to 12 h.

Technical Field

The invention belongs to the technical field of synthesis of novel catalytic materials, and particularly relates to preparation of a novel microspherical metal sulfide-niobic acid composite material.

Background

Sulfide materials have been extensively studied because they exhibit certain catalytic capabilities in the areas of photolysis of water to produce hydrogen, photocatalytic degradation of dyes, photocatalytic reduction of carbon dioxide, electrocatalysis, and biomass conversion. Sulfide is cheap and is considered as a cheap material which can replace noble metal and be applied to industrial production. The material represented by molybdenum disulfide is a typical transition metal bis-alkyl halide, and adjacent nano sheets are connected together and stacked through weak van der waals interaction to form a sandwich structure, and each unit nano sheet is composed of three atom (S-Mo-S) layers which are covalently bonded.

Transition metal sulfide catalytic materials have also been widely used in hydrodesulfurization, hydrodeoxygenation, hydrodenitrogenation, and other biomass catalytic conversion reactions. The catalytic activity of the molybdenum disulfide material is derived from unsaturated atoms at the edges of the molybdenum disulfide material, and increasing the number of active sites exposed at the edges can increase the catalytic activity of the molybdenum disulfide material. The research shows that the material, whether supported or unsupported, has excellent catalytic activity. And the structure of the material has a great influence on the activity of the material, and the current research focuses on changing the structure and the shape of the material so as to improve the activity of the material.

Niobium-based solid acids are gradually used as materials due to their stronger surface acidity and water resistanceVectors were investigated. Adriana et al synthesized Pb composites with niobium pentoxide as the carrier, as compared to SiO₂A supported catalyst material having a reaction rate of SiO in the hydrodeoxygenation of phenol₂90 times of the carrier. The high activity of the material may be due to Nb⁵⁺/Nb⁴⁺Strong interaction between the oxophilic sites represented by the cations and the molecular oxygen of phenol. However, in recent studies, the metallic phase in the composite material is mostly concentrated on the noble metal, and the non-noble metal composite material based on the niobium-based solid acid is currently less studied.

Disclosure of Invention

In order to explore the composite material of the sulfide with a novel structure and a novel shape and further expand the application range of the niobate-based material, the invention provides a hydrothermal-in-situ composite preparation method for preparing the sulfide-niobate composite material. The preparation method has mild conditions and simple operation, and the prepared niobate-based material has certain application potential in the aspects of photocatalysis and lignin catalytic conversion. And the active metal phase in the composite material is non-noble metal, so that the price is relatively low, and a foundation is laid for the large-scale application of the material.

In order to achieve the purpose, the invention adopts the technical scheme that:

a composite material of sulfide on niobate radical with the structural formula of A_xB_yS_z-H₄Nb₂O₇A, B is one or two of different metal elements of Co, Mo, Ni, Cu, Zn and Fe, wherein x is more than 0 and less than 10, y is more than or equal to 0 and less than 10, z is more than 0 and less than 10, and the specific numerical value is generally determined according to the valence state of a compound;

the niobic acid is a microsphere with the size of 1-5 mu m, and the metal sulfide is uniformly dispersed on the surface layer of the niobic acid microsphere.

The preparation method of the metal sulfide composite material on the niobate base comprises the following steps:

1) weighing tin niobate, adding the tin niobate into a polytetrafluoroethylene lining, adding one or two soluble metal salts and thiourea, adding a hydrochloric acid solution to adjust the pH value to 0.7-1.0, putting the mixture into a kettle, and reacting to obtain a black precipitate;

2) filtering and washing the black precipitate obtained after the reaction of 1) and placing the black precipitate in a vacuum drying oven for drying to obtain A_xB_yS_z-H₄Nb₂O₇A composite material.

The hydrothermal reaction temperature in the step 1) is 100-; the metal soluble salt can be molybdate, nitrate, acetate, chloride or sulfate;

the mass ratio of the metal salt to the tin niobate in the step 1) is 5: 1-20: 1, and the mass ratio of the thiourea to the metal salt is 0.4: 1-2: 1; adding 0.1-0.2 mol/L hydrochloric acid solution, wherein the ratio of the volume of the hydrochloric acid to the addition amount of the tin niobate is 50-300 mL/g

The drying temperature in the step 2) is 60-120 ℃, and the drying time is 6-12 h;

the invention firstly prepares microspherical tin niobate precursor according to literature, and then carries out the steps of hydrothermal-in-situ synthesis and the like to generate the corresponding metal sulfide-niobate composite material. The preparation method adopts thiourea as a sulfur source, and avoids the application of H in the conventional sulfide synthesis method₂And S, the synthesis process is cleaner and safer and is easy to control in the high-temperature vulcanization process.

The metal sulfide-niobic acid composite material prepared by the method can be used for photocatalytic hydrolysis hydrogen production and photocatalytic degradation of dyes, such as rhodamine B.

The specific operation of photocatalytic degradation of rhodamine B is as follows: 0.05g of the composite material and 50mL of rhodamine B solution with the concentration of 20mg/L are added into a reactor, and the mixture is irradiated for 2 hours by a xenon lamp with a 420nm filter. After the irradiation is finished, the absorbance of the solution at 554nm is measured by using an ultraviolet spectrophotometer to determine the degradation rate.

The invention has the following remarkable advantages:

1. the preparation method has low preparation conditions and simple operation, and the sulfide can uniformly grow on the surface of the niobic acid, so that more reactive sites are provided for catalytic reaction, and the reactivity of the metal sulfide in the catalytic reaction can be fully improved.

2. Adopted in the inventionHydrothermal method for forming metal sulfide without using H₂S is subjected to high-temperature vulcanization, the operation is simple, the safety is high, the synthesis difficulty is greatly reduced, and the niobium-based composite material prepared in the invention is not added with any noble metal, so that the material preparation cost is low and the application potential is large.

3. The sulfide-niobate composite material prepared by the invention has good crystallinity and high purity, and the formation of high-purity niobate crystal phase can be obviously observed by XRD.

4. The invention innovatively combines the sulfide and the niobic acid, and widens the application range of the niobium-based solid acid material. The material has a degradation rate of 93.1% in the reaction of degrading rhodamine B through photocatalysis, which is 13 times of that of the common molybdenum disulfide material.

Drawings

FIG. 1 is an X-ray powder diffraction pattern of the materials of the various examples of the invention described below.

Detailed Description

In order to make the present invention more comprehensible, the technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited thereto.