阅读说明：本技术 二维SiP纳米片作为光催化剂在可见光下光催化固氮的应用 (Application of two-dimensional SiP nanosheet as photocatalyst in photocatalytic nitrogen fixation under visible light ) 是由 元勇军 汤睿 王浩东 沈志凯 于 2021-08-26 设计创作，主要内容包括：本发明公开二维SiP纳米片作为光催化剂在可见光下光催化固氮的应用。本发明二维SiP纳米片光催化剂通过简单的液相超声的方法制备,超声后先通过低速离心去除大尺寸颗粒,进而通过高速离心得到高质量的磷化硅纳米片。所制备的磷化硅纳米片可以有效地应用于光催化固氮,在可见光下将水和氮气转化为氨。本发明的磷化硅纳米片光催化剂具有绿色,稳定,制备快速和工艺简单等优点。(The invention discloses application of a two-dimensional SiP nanosheet as a photocatalyst in photocatalytic nitrogen fixation under visible light. The two-dimensional SiP nanosheet photocatalyst is prepared by a simple liquid-phase ultrasonic method, large-size particles are removed by low-speed centrifugation after ultrasonic treatment, and then high-quality silicon phosphide nanosheets are obtained by high-speed centrifugation. The prepared silicon phosphide nanosheet can be effectively applied to photocatalysis nitrogen fixation, and water and nitrogen are converted into ammonia under visible light. The silicon phosphide nanosheet photocatalyst has the advantages of being green, stable, rapid in preparation, simple in process and the like.)

1. The application of the two-dimensional SiP nanosheet as a photocatalyst in photocatalytic nitrogen fixation under visible light is provided.

2. Use according to claim 1, wherein two-dimensional SiP nanoplates are dispersed in a nitrogen-saturated aqueous solution and nitrogen and water are converted to ammonia under visible light irradiation.

3. Use according to claim 1 or 2, wherein the size of the two-dimensional SiP nanoplates is between 200 and 500 nm.

4. The use of claim 1, wherein the two-dimensional SiP nanoplatelet photocatalyst is prepared by the following method:

taking bulk silicon phosphide as a raw material, taking ethanol as a solvent, carrying out ultrasonic stripping in an ultrasonic cell crushing instrument for 3-12h, and carrying out fractional centrifugation to obtain the required two-dimensional silicon phosphide nanosheet.

5. Use according to claim 4, wherein the mass to volume ratio of bulk silicon phosphide to ethanol is between 0.1 and 10 mg: 1 mL.

6. The use according to claim 4, wherein the temperature of the solution is maintained below 5 ℃ during the sonication of the cell disruptor.

7. The use as claimed in claim 4, wherein the fractional centrifugation is performed by first centrifugation at 2000-4000rpm for 10-20min to remove non-peeled large-sized particles, and then secondary centrifugation at 10000rpm for 5-10min on the upper solution.

Technical Field

The invention belongs to the field of environment-friendly materials, and particularly relates to application of a two-dimensional SiP nanosheet as a photocatalyst in photocatalytic nitrogen fixation under visible light.

Background

With the increasing prominence of the environmental pollution problem, regulations on the use of fossil fuels and the emission of pollutants are becoming stricter. Ammonia has a very important role as an important industrial and agricultural raw material. However, the production mode is mainly the Haber method at present, the method needs to use a large amount of fossil fuels, and simultaneously discharges a large amount of pollutants such as carbon dioxide and the like, and the method is a high-energy-consumption and high-pollution process, so that the method has important significance in exploring a clean and green ammonia synthesis mode.

In recent years, photocatalytic nitrogen fixation technology has become the focus of research. The catalyst converts water and nitrogen into ammonia under the irradiation of sunlight, does not consume fossil energy and does not discharge pollutants, and the whole production process does not involve carbon, so the catalyst is an ideal ammonia synthesis technology. The currently studied photocatalytic nitrogen fixation catalysis can be mainly divided into metal materials, carbon-based materials, metal sulfides, and the like. However, these materials are limited in cost and preparation method, are difficult to apply in large scale, and most of them can only use ultraviolet light, and are rarely used for visible light. Therefore, the development and preparation of the catalytic material which is simple and has visible light response is an important link for promoting the development and application of the photocatalytic nitrogen fixation technology.

Based on the above, the invention provides an application of a two-dimensional SiP nanosheet photocatalyst in photocatalytic nitrogen fixation under visible light. The two-dimensional SiP nanosheet can realize visible light response, and the preparation method is simple to operate, low in cost and high in photocatalytic capacity.

Disclosure of Invention

The first purpose of the invention is to provide the application of the two-dimensional SiP nanosheet as the photocatalyst in the visible light photocatalysis nitrogen fixation aiming at the defects that the existing photocatalytic nitrogen fixation catalyst is complex in preparation and cannot effectively utilize visible light.

The two-dimensional SiP nanosheets are dispersed in a nitrogen-saturated aqueous solution, and nitrogen and water can be converted into ammonia under the irradiation of visible light.

Preferably, the size of the two-dimensional SiP nanosheet is 200-500nm, and the two-dimensional SiP nanosheet has a typical two-dimensional structure.

The two-dimensional SiP nanosheet photocatalyst is prepared by the following method:

taking bulk silicon phosphide as a raw material, taking ethanol as a solvent, carrying out ultrasonic stripping in an ultrasonic cell crushing instrument for 3-12h, and carrying out fractional centrifugation to obtain the required two-dimensional silicon phosphide nanosheet.

Preferably, the mass volume ratio of the bulk silicon phosphide to the ethanol is 0.1-10 mg: 1 mL.

Preferably, the solution temperature is maintained below 5 ℃ during sonication.

Preferably, the fractional centrifugation is performed by first centrifuging at 2000-4000rpm for 10-20min to remove non-peeled large-sized particles, and then centrifuging the upper solution at 10000rpm for 5-10 min.

The invention firstly provides the application of the two-dimensional SiP nanosheet as a photocatalyst in photocatalytic nitrogen fixation, and promotes the development of the non-metal phosphide in the photocatalytic nitrogen fixation technology. In addition, the preparation process of the two-dimensional SiP nanosheet is simple to operate as the preparation process is prepared by an ice bath liquid phase ultrasonic method.

Drawings

FIG. 1 is an X-ray electron diffraction pattern of bulk silicon phosphide SiP before being stripped and silicon phosphide nanosheet SiP-10000 after being stripped according to the present invention.

FIG. 2 is a scanning electron micrograph of a silicon phosphide bulk (a) before exfoliation and a silicon phosphide nanosheet (b) after exfoliation using the present invention.

FIG. 3 is a transmission electron micrograph of a silicon phosphide nanosheet photocatalyst.

FIGS. 4(a) - (b) are photographs of a silicon phosphide bulk before peeling and a silicon phosphide nanosheet after peeling dispersed in an ethanol solution, respectively.

FIG. 5 shows the photocatalytic nitrogen fixation performance of bulk and nanosheets of silicon phosphide.

Detailed Description

The present invention will be described in detail by the following specific examples, but those skilled in the art will appreciate that the following examples are not intended to limit the scope of the present invention, and that any modifications and variations based on the present invention are within the scope of the present invention.

Example 1-1:

adding 0.05g of bulk silicon phosphide material SiP into 100ml of ethanol solution, uniformly stirring, placing in an ultrasonic cell pulverizer, and carrying out ultrasonic treatment for 12 hours, wherein the temperature of the solution is kept below 5 ℃. And after the ultrasonic treatment is finished, centrifuging the solution at 2000rpm for 20min to remove non-stripped large-size particles, centrifuging the upper-layer liquid at 10000rpm for 8min, and collecting precipitates to obtain stripped silicon phosphide nanosheets SiP-10000. From the X-ray electron diffraction image, it was confirmed that the crystal structure of the silicon phosphide after exfoliation was not changed and a good crystal structure was maintained, as shown in fig. 1. The bulk silicon phosphide was very large in size before exfoliation, as shown in fig. 2 (a). The size of the stripped silicon phosphide nanosheet is 200-500nm, as shown in FIG. 2 (b). The stripped silicon phosphide nanosheet presents a typical two-dimensional morphology structure as shown in fig. 3. The bulk silicon phosphide and the silicon phosphide nanosheet SiP-10000 are respectively dispersed in an ethanol solution, and the silicon phosphide nanosheet solution is observed to be yellow as shown in figure 4.

Examples 1 to 2:

adding 0.05g of bulk silicon phosphide material SiP into 100ml of ethanol solution, uniformly stirring, placing in an ultrasonic cell pulverizer, and carrying out ultrasonic treatment for 3 hours, wherein the temperature of the solution is kept below 5 ℃. And after the ultrasonic treatment is finished, centrifuging the solution at 4000rpm for 10min to remove the non-stripped large-size particles, centrifuging the upper-layer liquid at 10000rpm for 5min, and collecting the precipitate to obtain the stripped silicon phosphide nanosheet. The X-ray electron diffraction image can prove that the crystal structure of the silicon phosphide is not changed after stripping, the good crystal structure is kept, and the size of the bulk silicon phosphide before stripping is 200-500 nm.

Examples 1 to 3:

adding 0.05g of bulk silicon phosphide material SiP into 100ml of ethanol solution, uniformly stirring, placing in an ultrasonic cell pulverizer, and carrying out ultrasonic treatment for 10 hours, wherein the temperature of the solution is kept below 5 ℃. And after the ultrasonic treatment is finished, centrifuging the solution at 2000rpm for 20min to remove the non-stripped large-size particles, centrifuging the upper-layer liquid at 10000rpm for 10min, and collecting the precipitate to obtain the stripped silicon phosphide nanosheet. The X-ray electron diffraction image can prove that the crystal structure of the silicon phosphide is not changed after stripping, the good crystal structure is kept, and the size of the bulk silicon phosphide before stripping is 200-500 nm.

Example 2-1:

using the silicon phosphide nanosheet SiP-10000 prepared in example 1-1 as a photocatalyst, 250ml of deionized water and 10mg of the photocatalyst were poured into a glass reactor, nitrogen was introduced into the solution for 30 minutes to saturate the solution with nitrogen, and 1ml of the solution was sampled. The nitrogen fixation performance of the photocatalyst is tested under the irradiation of visible light (lambda is more than 420nm) by taking a 300W xenon lamp as a light source. The solution in the system was taken out 1ml of the solution every 1 hour, centrifuged to remove the precipitate, and the nitrogen content in the solution was measured by the nano-meter reagent spectrophotometry, as shown in FIG. 5. The test was continued for 6 h.

Example 2-2:

in the photocatalyst in the embodiment 2-1, the silicon phosphide nanosheet SiP-10000 prepared in the embodiment 1-1 is changed into bulk silicon phosphide as the photocatalyst, the rest conditions are unchanged, and the photocatalytic nitrogen fixation performance is shown in Table 1.

The above embodiments are not intended to limit the present invention, and the present invention is not limited to the above embodiments, and all embodiments are within the scope of the present invention as long as the requirements of the present invention are met.