阅读说明：本技术 一种绣花球状Ta3N5/MoS2异质结光催化材料及其制备方法 (Embroidered spherical Ta3N5/MoS2Heterojunction photocatalytic material and preparation method thereof ) 是由 裴浪 元勇军 钟家松 于 2019-08-02 设计创作，主要内容包括：本发明公开一种绣花球状Ta_3N_5/MoS_2异质结光催化材料及其制备方法。呈现出绣花球状,Ta_3N_5纳米棒被均匀的包裹在二维MoS_2层间,且Ta_3N_5与MoS_2之间形成紧密接触的异质结；MoS_2与Ta_3N_5的比例为0.2～1mmol:40mg。本发明将前驱体溶液过夜搅拌操作使得最终制备得到的Ta_3N_5/MoS_2异质结构呈绣花球状。相比于原始的Ta_3N_5,本发明中最优配比的Ta_3N_5/MoS_2异质结光催化剂其光催化产氢速率提高了22倍左右。(The invention discloses an embroidered spherical Ta 3 N 5 /MoS 2 A heterojunction photocatalytic material and a preparation method thereof. Exhibit an embroidered spherical shape, Ta 3 N 5 The nano-rods are uniformly wrapped in the two-dimensional MoS 2 between layers and Ta 3 N 5 And MoS 2 a heterojunction in close contact with the substrate; MoS 2 And Ta 3 N 5 The ratio of (B) to (C) is 0.2-1 mmol:40 mg. The invention leads the precursor solution to be stirred overnight so as to finally prepare the obtained Ta 3 N 5 /MoS 2 The heterostructure is in an embroidered spherical shape. Compared to the original Ta 3 N 5 In the present inventionTa of optimum composition 3 N 5 /MoS 2 The photocatalytic hydrogen production rate of the heterojunction photocatalyst is improved by about 22 times.)

1. Embroidered spherical Ta₃N₅/MoS₂A heterojunction photocatalytic material characterized by exhibiting an embroidered spherical shape, Ta₃N₅The nano-rods are uniformly wrapped in the two-dimensional MoS₂Between layers and Ta₃N₅and MoS₂With a heterojunction in close contact.

2. An embroidered spherical Ta as claimed in claim 1₃N₅/MoS₂A heterojunction photocatalytic material characterized by MoS₂And Ta₃N₅The ratio of (B) to (C) is 0.2-1 mmol:40 mg.

3. An embroidered spherical Ta as claimed in claim 1 or 2₃N₅/MoS₂The preparation method of the heterojunction photocatalytic material is characterized by comprising the following steps of:

Dissolving sodium molybdate serving as a molybdenum source and thiourea serving as a sulfur source in deionized water, fully stirring until the sodium molybdate and the thiourea are completely dissolved, and then adding a certain amount of Ta₃N₅Nano-rod powder to obtain a precursor solution;

The molar ratio of sodium molybdate to thiourea is 1: 2-4;

Sodium molybdate and Ta₃N₅The adding amount ratio of (1) is 0.2-1 mmol:40 mg;

Step (2), stirring the precursor solution at room temperature for 12-24 hours;

Step (3), placing the uniformly mixed precursor solution into a polytetrafluoroethylene inner container of a hydrothermal kettle, sealing, reacting at the temperature of 180-220 ℃ for 20-24 hours to obtain a grey brown suspension, respectively centrifuging by using deionized water and ethanol, cleaning the product for a plurality of times, and drying to obtain the embroidered spherical Ta₃N₅/MoS₂A heterojunction photocatalytic material.

Technical Field

The invention belongs to the field of photocatalysis materials in inorganic nonmetallic energy conversion materials, and particularly relates to an embroidered spherical Ta₃N₅/MoS₂Heterojunction photocatalytic material and method of manufacturing the sameA preparation method.

Background

Energy is the subject of civilization forever, and hydrogen energy is regarded as one of the most potential new energy sources in the century as a high-efficiency clean renewable energy source. The preparation of hydrogen by decomposing water with a semiconductor photocatalyst is a green technology integrating solar energy capture, conversion and storage, and is called holy grail in the inorganic photochemical research field. Noble metals, represented by Pt, are currently the most excellent hydrogen evolution catalytic materials, but their expensive price and very limited reserves severely limit their application in large-scale industry. Therefore, the development of a cheap high-activity photocatalyst with abundant reserves for efficiently photocatalytic decomposing water to produce hydrogen is an important research topic in the field of solar energy-hydrogen energy conversion.

Novel oxynitrides and nitrides have a narrower band gap and enhanced conductivity as compared with corresponding oxides, and have recently been favored in studies on photocatalytic water splitting. In particular tantalum nitride (Ta)₃N₅) The material has an ideal band gap value (2.1 eV) and a proper band edge position, and the theoretical STH conversion efficiency can reach 15.9 percent, so that the material is one of the main attack systems in the international field of solar photoelectrocatalysis hydrogen production at present. From 2003 onwards, on a global scale, Ta₃N₅The material of the photo-anode used as the photoelectrochemistry decomposition water battery is gradually the research hotspot. However, despite Ta₃N₅Has the potential of full hydrolysis, but has very low photocatalytic hydrogen production activity. The cause thereof, Ta₃N₅The further promotion of the hydrogen production activity is severely restricted by the insufficient photo-generated charge separation capability. Thus, Ta is strengthened₃N₅Photogenerated charge separation is the key driving the application of the photogenerated charge separation in the field of photocatalysis. For an effective photocatalytic system, it is often necessary to support a co-catalyst on the surface of the catalyst in addition to a semiconductor as a main photocatalyst for absorbing light energy to generate electron-hole pairs. In general, the promoter may act as a trap for electrons or holes to accelerate the separation of electron-hole pairs in the host photocatalyst. At the same time, suitable cocatalysts may sometimes also act as active sites for the catalytic reaction to reduce oxidation or elseOverpotential in the original reaction improves the rate of the photocatalytic reaction. Two-dimensional MoS₂Is a non-noble metal cocatalyst which is researched more at present, and researches show that the two-dimensional MoS₂can be used as a hydrogen evolution cocatalyst, provides a proper hydrogen evolution active site and reduces a hydrogen evolution reaction barrier. In addition, as an important two-dimensional graphene-like semiconductor material, two-dimensional MoS₂The nano sheet has large specific surface area, adjustable band gap and good adsorption performance, and can be used for various semiconductors (CdS and TiO)₂、p-Si、g-C₃N₄etc.) to facilitate separation of the photo-generated electron-hole pairs. Thus, combining the above considerations, through a two-dimensional MoS₂And Ta₃N₅The guiding assembly and reasonable optimization of the invention are the Ta₃N₅/MoS₂Preparation method of heterojunction photocatalytic material, and strengthening Ta is very likely to be realized₃N₅Separating photo-generated charges and improving the photocatalytic hydrogen production activity.

Disclosure of Invention

It is an object of the present invention to overcome Ta₃N₅The defect of insufficient photo-generated charge separation, provides a Ta with high charge separation efficiency, high hydrogen production activity and stability₃N₅/MoS₂A heterojunction photocatalytic material.

Embroidered spherical Ta₃N₅/MoS₂Heterojunction photocatalytic material exhibiting a spherical embroidered shape, Ta₃N₅the nano-rods are uniformly wrapped in the two-dimensional MoS₂Between layers and Ta₃N₅And MoS₂A heterojunction in close contact with the substrate; MoS₂And Ta₃N₅The ratio of (B) to (C) is 0.2-1 mmol:40 mg.

The preparation method comprises the following steps:

Dissolving sodium molybdate serving as a molybdenum source and thiourea serving as a sulfur source in deionized water, fully stirring until the sodium molybdate and the thiourea are completely dissolved, and then adding a certain amount of Ta₃N₅And (5) obtaining a precursor solution by using the nanorod powder. The molar ratio of sodium molybdate to thiourea used was 1: 2 to 4. Sodium molybdate and Ta₃N₅Is added in an amount of 0.2 to1mmol:40mg。

And (2) stirring the precursor solution at room temperature for 12-24 hours.

Step (3), placing the uniformly mixed precursor solution into a polytetrafluoroethylene inner container of a hydrothermal kettle, sealing, reacting at the temperature of 180-220 ℃ for 20-24 hours to obtain a grey brown suspension, respectively centrifuging by using deionized water and ethanol, cleaning the product for a plurality of times, and drying to obtain the embroidered spherical Ta₃N₅/MoS₂A heterojunction photocatalytic material.

The invention has the following innovation points:

Embroidery spherical Ta in the invention₃N₅/MoS₂Heterostructures can effectively capture sunlight, provide a high specific surface area, and expose a rich array of active sites.

Ta with matched band structure in the invention₃N₅And MoS₂The constructed heterojunction photocatalyst can effectively accelerate photo-generated charges from Ta₃N₅Transfer to MoS₂Thereby reducing photo-generated charge at Ta₃N₅And (4) recombination in a bulk phase. Benefit from MoS₂Coating of three-dimensional structures, Ta in the present invention₃N₅The photocatalyst shows good stability in a reaction system. The invention leads the precursor solution to be stirred overnight so as to finally prepare the obtained Ta₃N₅/MoS₂The heterostructure is in an embroidered spherical shape.

In the presence of methanol as a hole sacrificial agent, compared to the original Ta₃N₅Ta of optimum proportion in the invention₃N₅/MoS₂The photocatalytic hydrogen production rate of the heterojunction photocatalyst is improved by about 22 times.

Drawings

FIG. 1 is an embroiled spherical Ta prepared in example 1 of the present invention₃N₅/MoS₂Scanning electron microscope image of heterojunction photocatalytic material.

FIG. 2 is an embroiled spherical Ta prepared in example 1 of the present invention₃N₅/MoS₂Transmission electron microscopy of the heterojunction photocatalytic material.

FIG. 3 is an embroiled spherical Ta prepared in example 1 of the present invention₃N₅/MoS₂Ultraviolet diffuse reflectance spectrum of the heterojunction photocatalytic material.

FIG. 4 is an embroiled spherical Ta prepared in example 1 of the present invention₃N₅/MoS₂The hydrogen production performance efficiency of the heterojunction photocatalytic material under visible light is shown.

FIG. 5 is an embroiled spherical Ta prepared in accordance with example 1 of the present invention₃N₅/MoS₂a steady state fluorescence spectrum of the heterojunction photocatalytic material.

FIG. 6 is Ta prepared according to comparative example 1 of the present invention₃N₅/MoS₂Scanning electron microscopy of the heterojunction photocatalytic material.

Detailed Description

the invention will be further described with reference to the following figures and examples, without limiting the scope of the invention:

Comparative example 1:

(1) Accurately weighing 1mmol of sodium molybdate and 4mmol of thiourea, dissolving in deionized water, stirring completely, and adding 0.04g of Ta₃N₅And (4) nanorod powder.

(2) For comparison, the precursor solution is directly placed in a polytetrafluoroethylene inner container of a hydrothermal kettle without long-time stirring, the mixture is sealed and then reacts at 220 ℃ for 20 hours to obtain a final suspension, the final suspension is respectively centrifuged by deionized water and ethanol, a product is washed for a plurality of times and then dried to obtain Ta₃N₅/MoS₂A material.

From FIG. 6, it can be seen that Ta prepared in comparative example without long stirring₃N₅/MoS₂the material does not exhibit an embroidered spherical shape, Ta₃N₅Nanorods and two-dimensional MoS₂In a freely dispersed state, thereby suggesting Ta₃N₅Nanorods and two-dimensional MoS₂There is no good heterojunction contact formed between them.