阅读说明：本技术 g-C3N4/In2Se3复合光催化剂及其制备方法和应用 (g-C3N4/In2Se3Composite photocatalyst and preparation method and application thereof ) 是由 张淑敏 张世英 李中付 许凯强 于 2020-04-29 设计创作，主要内容包括：本发明涉及一种g-C<Sub>3</Sub>N<Sub>4</Sub>/In<Sub>2</Sub>Se<Sub>3</Sub>复合光催化剂及其制备方法和应用。该方法包括以下步骤：1)将薄片状g-C<Sub>3</Sub>N<Sub>4</Sub>溶解于溶剂中形成悬浮液；2)加入铟源至所述悬浮液中并搅拌至溶解；3)继续往所述悬浮液中加入硒源和还原剂,搅拌并按照10-15℃/min加热至210-290℃,回流0-1h,之后在-5到5℃下冷却得到所述g-C<Sub>3</Sub>N<Sub>4</Sub>/In<Sub>2</Sub>Se<Sub>3</Sub>复合光催化剂。该方法获得了具有自极化能力的g-C<Sub>3</Sub>N<Sub>4</Sub>/In<Sub>2</Sub>Se<Sub>3</Sub>二维-二维超薄复合光催化剂。此外本发明还包括上述方法制备得到的g-C<Sub>3</Sub>N<Sub>4</Sub>/In<Sub>2</Sub>Se<Sub>3</Sub>复合光催化剂及其应用。(The invention relates to a g-C 3 N 4 /In 2 Se 3 A composite photocatalyst and a preparation method and application thereof. The method comprises the following steps: 1) mixing flakes g-C 3 N 4 Dissolving in a solvent to form a suspension; 2) adding an indium source to the suspension and stirring until dissolved; 3) continuously adding a selenium source and a reducing agent into the suspension, stirring, heating to 210-290 ℃ at a speed of 10-15 ℃/min, refluxing for 0-1h, and then cooling at a temperature of-5 to 5 ℃ to obtain the g-C 3 N 4 /In 2 Se 3 A composite photocatalyst is provided. The method obtains g-C with self-polarization capability 3 N 4 /In 2 Se 3 A two-dimensional-two-dimensional ultrathin composite photocatalyst. In addition, the invention also comprises g-C prepared by the method 3 N 4 /In 2 Se 3 A composite photocatalyst and application thereof.)

1. g-C₃N₄/In₂Se₃The preparation method of the composite photocatalyst is characterized by comprising the following steps:

1) mixing flakes g-C₃N₄Dissolving in a solvent to form a suspension;

2) according to said g-C₃N₄/In₂Se₃In the composite photocatalyst₂Se₃And g-C₃N₄Adding an indium source into the suspension at a theoretical molar mass ratio of 1-10: 100, and stirring until the indium source is dissolved;

3) continuously adding a selenium source and a reducing agent into the suspension, stirring, heating to 210-290 ℃ at a speed of 10-15 ℃/min, refluxing for 0-1h, and then cooling at a temperature of-5 to 5 ℃ to obtain the g-C₃N₄/In₂Se₃A composite photocatalyst is provided.

2. The production method according to claim 1, wherein in step 1), the flake g is prepared-C₃N₄Dissolving in triethylene glycol solvent to form suspension; then heating and distilling under the protection of nitrogen atmosphere to remove water.

3. The production method according to claim 1, wherein in step 2), the indium source is one or both of indium chloride and indium nitrate.

4. The production method according to claim 1, wherein in step 3), the selenium source is selenium powder; and/or the reducing agent is sodium borohydride or hydrazine hydrate; and/or continuously adding the selenium source into the suspension according to the mol ratio of the indium source to the selenium source of 2-3: 3.

5. The method as claimed in claim 1, wherein in step 3), the selenium source and the reducing agent are added to the suspension, stirred and heated at 10-15 ℃/min to 210-290 ℃ and refluxed for 0-1h, and then cooled at-5 to 5 ℃ to obtain the g-C₃N₄/In₂Se₃A composite photocatalyst is provided.

6. The production method according to claim 1, wherein in step 1), the flake g-C₃N₄Is prepared by the following steps:

s1, mixing g-C₃N₄Heating the precursor to 500-520 ℃ at the speed of 10-15 ℃/min, and calcining to obtain primary calcined g-C₃N₄(ii) a The g to C₃N₄The precursor is selected from one or more of urea, dicyandiamide, melamine, cyanamide and thiourea;

s2, calcining the primary g-C₃N₄Heating to 500-520 ℃ at the speed of 5-8 ℃/min for secondary calcination to obtain the flaky g-C₃N₄。

7. The method according to claim 1, wherein in step 1), the mixture is subjected toThe flake form g-C₃N₄Dissolving in solvent, and ultrasonic treating for 30-120min to obtain suspension.

8. The method according to claim 1, wherein in step 2), the g-C is adjusted to₃N₄/In₂Se₃In the composite photocatalyst₂Se₃And g-C₃N₄Adding the indium source into the suspension in a theoretical molar mass ratio of 1-10: 100, and stirring for 30-60min until dissolution.

9. g-C prepared by the preparation method of any one of claims 1-8₃N₄/In₂Se₃A composite photocatalyst is provided.

10. g-C as claimed in claim 9₃N₄/In₂Se₃The composite photocatalyst is applied to the aspect of photocatalytic hydrogen production.

Technical Field

The invention relates to the field of nano photocatalysis, in particular to g-C₃N₄/In₂Se₃A composite photocatalyst and a preparation method and application thereof.

Background

In the present society, energy and environmental problems are two major problems that need to be solved urgently. Scientists are not left with the power to explore new energy to replace traditional fossil energy to deal with energy and environmental crisis. Among numerous new energy sources (solar energy, biomass energy, tidal energy, wind energy, nuclear energy and the like), solar energy is the most ideal clean energy source, has the advantages of inexhaustibility, safety, economy, cleanness and the like, and attracts great interest of scientific researchers. The problem of energy shortage faced by human society can be alleviated by converting solar energy into chemical energy. Photocatalytic hydrogen production is a technology for converting solar energy into hydrogen energy, however, the key of photocatalytic hydrogen production is a photocatalyst, and the photocatalysts developed at present are various in types, but the problem of low photocatalytic hydrogen production efficiency exists. Graphite phase carbon nitride (g-C)₃N₄) Is a relatively high-efficiency organic semiconductor photocatalyst which is just discovered in recent years, is favored by people due to the advantages of simple preparation method, cheap raw materials, no toxicity, no harm and the like, but g-C₃N₄The defects of easy recombination of photon-generated carriers, limited light absorption capacity and the like still exist, so that the two problems of improving the light absorption capacity and the recombination of the photon-generated carriers tend to greatly improve the g-C₃N₄The photocatalytic hydrogen production performance.

The method is an effective method for solving the problem that the compound is compounded with a narrow-bandgap semiconductor with self-polarization capability to form a compact heterojunction structure. Indium selenide is (In)₂Se₃) The IIIA-VIA type chalcogenide compound has a plurality of crystal forms and different electronic structures, is a very promising semiconductor material, and is endowed with self-polarization capability due to an asymmetric atom arrangement structure. When light irradiates the semiconductor, photo-generated carriers are generated to form a built-in electric field, and the separation of the photo-generated carriers is promoted.

Disclosure of Invention

Therefore, based on the background of the above studies, to solve how to obtain g-C with self-polarization capability₃N₄/In₂Se₃The invention provides a two-dimensional-two-dimensional ultrathin composite photocatalyst, and provides g-C₃N₄/In₂Se₃A composite photocatalyst and a preparation method and application thereof.

The invention provides a g-C₃N₄/In₂Se₃The preparation method of the composite photocatalyst comprises the following steps:

1) mixing flakes g-C₃N₄Dissolving in a solvent to form a suspension;

2) according to said g-C₃N₄/In₂Se₃In the composite photocatalyst₂Se₃And g-C₃N₄Adding an indium source into the suspension at a theoretical molar mass ratio of 1-10: 100, and stirring until the indium source is dissolved;

3) continuously adding a selenium source and a reducing agent into the suspension, stirring, heating to 210-290 ℃ at a speed of 10-15 ℃/min, refluxing for 0-1h, and then cooling at a temperature of-5 to 5 ℃ to obtain the g-C₃N₄/In₂Se₃A composite photocatalyst is provided.

Further, in step 1), the flake g-C is formed₃N₄Dissolving in triethylene glycol solvent to form suspension; then heating and distilling under the protection of nitrogen atmosphere to remove water.

Further, in the step 2), the indium source is one or two of indium chloride and indium nitrate.

Further, in step 3), the selenium source is selenium powder; and/or the reducing agent is sodium borohydride or hydrazine hydrate; and/or continuously adding the selenium source into the suspension according to the mol ratio of the indium source to the selenium source of 2-3: 3.

Further, in the step 3), the selenium source and the reducing agent are continuously added into the suspension, stirred and heated to 210-290 ℃ at the speed of 10-15 ℃/min and refluxed for 0-1h, and then cooled at the temperature of-5 to 5 ℃ to obtain the g-C₃N₄/In₂Se₃A composite photocatalyst is provided.

Further, in step 1), the flake-like g-C₃N₄Is prepared by the following steps:

s1, mixing g-C₃N₄Heating the precursor to 500-520 ℃ at the speed of 10-15 ℃/min, and calcining to obtain primary calcined g-C₃N₄(ii) a The g to C₃N₄The precursor is selected from one or more of urea, dicyandiamide, melamine, cyanamide and thiourea;

s2, calcining the primary g-C₃N₄Heating to 500-520 ℃ at the speed of 5-8 ℃/min for secondary calcination to obtain the flaky g-C₃N₄。

Further, in step 1), the flake g-C is subjected to₃N₄Dissolving in solvent, and ultrasonic treating for 30-120min to obtain suspension.

Further, in step 2), according to said g-C₃N₄/In₂Se₃In the composite photocatalyst₂Se₃And g-C₃N₄Adding the indium source into the suspension in a theoretical molar mass ratio of 1-10: 100, and stirring for 30-60min until dissolution.

The invention also provides g-C prepared by the preparation method₃N₄/In₂Se₃A composite photocatalyst is provided.

The invention also provides the above-mentioned g-C₃N₄/In₂Se₃The composite photocatalyst is applied to the aspect of photocatalytic hydrogen production.

Compared with the prior art, the invention has the advantages that: mixing flakes g-C₃N₄Dissolved in a solvent to form a suspension, g-C₃N₄Is in the form of flake to form flake g-C₃N₄/In₂Se₃Providing a substrate for the composite photocatalyst, and then preparing the composite photocatalyst according to the g-C₃N₄/In₂Se₃In the composite photocatalyst₂Se₃And g-C₃N₄Theoretical molar mass ofAdding an indium source into the suspension in a ratio of 1-10: 100 and stirring until the indium source is dissolved, g-C₃N₄Has negative charge, positive charge and mutual attraction of positive and negative charges, and is beneficial to loading indium at g-C₃N₄Then, a selenium source and a reducing agent are continuously added into the suspension, the mixture is stirred and heated to 210-290 ℃ at the speed of 10-15 ℃/min, the growth speed of the indium selenide on the graphite-phase carbon nitride is controlled by controlling the reaction temperature rise speed and the temperature, and the size and the thickness of the indium selenide growth are controlled by controlling the liquid phase reflux time to obtain the two-dimensional-two-dimensional ultrathin g-C₃N₄/In₂Se₃The composite photocatalyst is then cooled at-5 to 5 ℃, and g-C can be rapidly cooled under the low-temperature condition₃N₄/In₂Se₃Composite photocatalyst avoids g-C₃N₄/In₂Se₃The shape of the composite photocatalyst is changed, so that the final two-dimensional-two-dimensional ultrathin g-C can be obtained₃N₄/In₂Se₃Composite photocatalyst, In₂Se₃And g-C₃N₄Ultra-thin g-C with thickness within about 10nm₃N₄And ultra-thin In₂Se₃The composite photocatalyst is of a heterojunction structure, has the advantages of the heterojunction structure, and can further improve the separation efficiency of photo-generated carriers by establishing a polarization electric field inside, so that the photocatalytic efficiency is greatly improved.

Drawings

The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and not to be construed as limiting the invention in any way, and in which:

FIG. 1 shows the sheets g to C of example 1 of the present invention₃N₄A TEM image;

FIG. 2 shows g-C obtained in example 1 of the present invention₃N₄/In₂Se₃SEM picture of the composite photocatalyst;

FIG. 3 shows g-C obtained in example 1 of the present invention₃N₄/In₂Se₃XRD pattern of the composite photocatalyst;

FIG. 4 shows g-C obtained in example 1 of the present invention₃N₄/In₂Se₃A TEM image of the composite photocatalyst;

FIG. 5 shows g-C obtained in example 1 of the present invention₃N₄/In₂Se₃An infrared image of the composite photocatalyst;

FIG. 6 shows g-C obtained in example 1 of the present invention₃N₄/In₂Se₃The hydrogen production performance of the composite photocatalyst is compared with the hydrogen production performance of the catalysts obtained in comparative examples 1 and 2.

Detailed Description

The present embodiment provides a g-C₃N₄/In₂Se₃The preparation method of the composite photocatalyst comprises the following steps:

1) g to C₃N₄Heating the precursor to 500-520 ℃ at the speed of 10-15 ℃/min, and calcining to obtain primary calcined g-C₃N₄(ii) a The g to C₃N₄The precursor is selected from one or more of urea, dicyandiamide, melamine, cyanamide and thiourea;

2) subjecting said primary calcination g-C₃N₄Heating to 500-520 ℃ at the speed of 5-8 ℃/min for secondary calcination to obtain the flaky g-C₃N₄；

3) Mixing flakes g-C₃N₄Dissolving in solvent, and performing ultrasonic treatment for 30-120min to obtain suspension;

4) according to said g-C₃N₄/In₂Se₃In the composite photocatalyst₂Se₃And g-C₃N₄Adding an indium source into the suspension at a theoretical molar mass ratio of 1-10: 100, and stirring for 30-60min until dissolution; the indium source is one or two of indium chloride and indium nitrate;

5) continuously adding a selenium source and a reducing agent into the suspension according to the molar ratio of the indium source to the selenium source being 2-3: 3, stirring, heating to 210-290 ℃ at the speed of 10-15 ℃/min, refluxing for 0-1h, and cooling at the temperature of-5 to 5 ℃ to obtain the g-C₃N₄/In₂Se₃A composite photocatalyst is provided. The selenium source is selenium powder; and/or the reducing agent is sodium borohydride or hydrazine hydrate. The dosage of the reducing agent is 0.05mL-0.15 mL. Some embodiments further continue refluxing for 0-1h after heating to the temperature of 210-290 ℃ and then cooling at-5 to 5 ℃ to obtain the g-C₃N₄/In₂Se₃A composite photocatalyst; some embodiments provide the g-C by heating to the temperature of 210-290 ℃ and directly cooling at-5 to 5 DEG C₃N₄/In₂Se₃A composite photocatalyst is provided.

In this embodiment, the flake g-C is incorporated in step 3)₃N₄Dissolving in triethylene glycol solvent to form suspension; then heating and distilling under the protection of nitrogen atmosphere to remove moisture; the triethylene glycol solvent has a low boiling point if it contains water, so that the removal of water enables the temperature to rise to 210-290 ℃ after the selenium source and the reducing agent are added subsequently. The solvent in this embodiment may also be a high boiling point solvent such as oleylamine solvent, glycerin, and the like.

The specific embodiment also comprises g-C prepared by the preparation method₃N₄/In₂Se₃A composite photocatalyst is provided.

This embodiment also includes the above-mentioned g-C₃N₄/In₂Se₃The composite photocatalyst is applied to the aspect of photocatalytic hydrogen production.

To further illustrate the preparation methods proposed in this embodiment, the following examples are given.