CN113828291A - A kind of composite photocatalyst with full spectrum absorption characteristics and preparation method thereof - Google Patents

Abstract

Translated fromChinese

本发明公开了一种具有全光谱吸收特性的复合光催化剂，包括TiO₂、g‑C₃N₄和Bi₂Se₃。本发明还公开了其制备方法，先将TiO₂纳米片和双氰胺超声分散于超纯水中，搅拌并加热直至水分蒸干，将所得产物在高温下焙烧获得TiO₂@g‑C₃N₄复合纳米片；然后通过采用液相沉积法或固相烧结法来制备Bi₂Se₃并原位沉积于TiO₂@g‑C₃N₄复合纳米片的表面之上，获得最终产物。通过本发明方法所制备的复合光催化剂材料，不仅具有优异的光催化性能，而且光学稳定性良好。利用不同包覆厚度的g‑C₃N₄来改善TiO₂与Bi₂Se₃的能带过度，不仅促进了可见光的吸收，而且可以提供更多的活性位点；与Bi₂Se₃的复合不仅将光催化剂的吸收光谱拓展至近红外区域，而且加强了光生电子‑空穴的分离与输运效率，其光催化效率得到了极大的提高。

The invention discloses a composite photocatalyst with full spectrum absorption characteristics, comprising TiO₂ , g-C₃ N₄ and Bi₂ Se₃ . The invention also discloses a preparation method thereof. First, TiO₂ nanosheets and dicyandiamide are ultrasonically dispersed in ultrapure water, stirred and heated until the water evaporates to dryness, and the obtained product is calcined at high temperature to obtain TiO₂ @g-C₃ ._N4 composite nanosheets; then Bi₂ Se₃ was prepared by liquid deposition or solid phase sintering and deposited in situ on the surface of TiO₂ @g‑C₃ N₄ composite nanosheets to obtain the final product. The composite photocatalyst material prepared by the method of the present invention not only has excellent photocatalytic performance, but also has good optical stability. Using g‑C₃ N₄ with different coating thicknesses to improve the energy band transition of TiO₂ and Bi₂ Se₃ not only promotes the absorption of visible light, but also provides more active sites; the composite with Bi₂ Se₃ It not only expands the absorption spectrum of the photocatalyst to the near-infrared region, but also strengthens the separation and transport efficiency of photogenerated electron-holes, and its photocatalytic efficiency has been greatly improved.

Description

Composite photocatalyst with full-spectrum absorption characteristic and preparation method thereof

Technical Field

The invention belongs to the field of photocatalysis, and particularly relates to a composite photocatalyst with a full-spectrum absorption characteristic and a preparation method thereof.

Background

Bi of graphene-like layered structure₂Se₃It is considered to be one of the most promising topological insulator materials due to its simple band structure, energy-blown-body band gap much larger than room temperature. The topological insulator is a novel quantum material state discovered in recent years, and has great application prospect in the aspects of energy-consumption-free transmission, spintronics, quantum computers and the like. The novel quantum surface state of the topological insulator can realize high-mobility non-dissipative electrical transmission, thereby creating a perfect conductive channel. Although of narrow band gap, Bi₂Se₃(0.3eV) TiO may be added₂The spectrum absorption range of the light source is expanded to a near infrared regionThe overall photocatalytic performance is not significantly improved. This is because Bi₂Se₃Can not react with TiO₂The band gap matching of the two-phase alternating current-direct current converter forms type II band edge connection, which is not beneficial to the separation and the transportation of photo-generated charges. Therefore, based on the band structure theory, this patent is in Bi₂Se₃With TiO₂Is added with one g-C₃N₄And the band gap connecting layer is used as a matching transition between the two layers. g-C₃N₄As a visible light photocatalyst having excellent properties, not only has a suitable oxidation-reduction potential (CB: -0.52 eV; VB: 1.88eV), but also it reacts with Bi₂Se₃The Fermi level connection between the two can play a role in band edge reforming. In the multi-level composite heterostructure, each unit layer plays its own role and influences each other, g-C₃N₄Not only used as TiO₂And Bi₂Se₃The band gap transition layer can be used as a sensitizing layer of visible light; and the topological insulator Bi₂Se₃Then as a near infrared absorption layer, the heterogeneous interface and topological surface state thereof promote the rapid separation and transportation of photo-generated charges.

Although the topological insulator Bi₂Se₃The related photocatalyst has been reported a little, but most cases do not add an energy band transition layer, let alone Bi is not considered₂Se₃The problem of matching with the substrate bonding, although increasing the light absorption problem, is not ideal for carrier transport efficiency, resulting in low overall photocatalytic efficiency. In addition, these processes generally involve organic solvents and harmful by-products, and in most cases the reaction processes are very difficult to control and the yields are also not high.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a composite photocatalyst which has excellent photocatalytic performance and excellent stability and has full spectrum absorption characteristics and a preparation method thereof.

The technical scheme is as follows: the composite photocatalyst with full-spectrum absorption characteristic comprises TiO₂、g-C₃N₄And Bi₂Se₃(ii) a The TiO is₂And Bi₂Se₃The mass ratio of (A) to (B) is 100: 1-9; the g to C₃N₄In TiO₂The thickness of the nano sheet surface coating is 1-5 nm.

The preparation method of the composite photocatalyst with the full-spectrum absorption characteristic comprises the following steps:

(1) adding TiO into the mixture₂Dispersing the nano-sheets and dicyandiamide in ultrapure water by ultrasonic, stirring and heating until the water content is evaporated to dryness, and roasting the obtained product at high temperature to obtain TiO₂@g-C₃N₄Composite nanosheets;

(2) preparation of Bi by using a liquid phase deposition method or a solid phase sintering method₂Se₃And deposited in situ on TiO₂@g-C₃N₄And (4) obtaining a final product on the surface of the composite nanosheet.

Further, in the step (1), the high temperature is 530 ℃ and 580 ℃, and the roasting time is 2-3 h.

Further, in the step (2), the liquid phase deposition method comprises the following specific steps:

(11) firstly preparing bismuth nitrate pentahydrate, nitrilotriacetic acid and ascorbic acid into a bismuth chelating solution, and then preparing TiO₂@g-C₃N₄Ultrasonically dispersing the composite nano-sheets therein;

(12) under the condition of stirring, taking a certain amount of ammonia water, adjusting the pH value of the solution to 9, and adding a sodium selenosulfate solution in a stoichiometric ratio;

(13) keeping the temperature of the solution at 55-85 ℃, and continuously stirring for 30-120min at the temperature;

(14) under the ultrasonic condition, respectively cleaning the solid precipitate for several times by using absolute ethyl alcohol and ultrapure water until the pH value is neutral;

(15) the washed product was placed in a vacuum drying oven and dried under vacuum.

Further, in the step (11), the mass ratio of the bismuth nitrate pentahydrate to the nitrilotriacetic acid to the ascorbic acid is 2:2: 1.

Further, in the step (15), the temperature of the vacuum drying is 70-80 ℃, and the drying time is 24-30 h.

Further, in the step (2), the solid-phase sintering method comprises the following specific steps:

(21) firstly TiO is added₂@g-C₃N₄Uniformly dispersing the composite nano sheet, the nano selenium powder and the nano bismuth powder, and mechanically grinding;

(22) putting the ground mixed powder material into a corundum crucible, and putting the corundum crucible into a tubular furnace protected by inert gas;

(23) sintering at high temperature under the protection of inert gas, keeping the temperature at the heating rate of 5 ℃/min, and naturally cooling to room temperature.

Further, in the step (21), the molar ratio of the nano selenium powder to the nano bismuth powder is 3: 2; the sum of the mass of the nano selenium powder and the nano bismuth powder is TiO₂@g-C₃N₄1-10% of the composite nano sheet.

Further, in the step (21), the grinding time is 30-120 min.

Further, in the step (23), the high temperature is 650-.

Has the advantages that: compared with the prior art, the invention has the following remarkable advantages:

1. the process flow is simple, complex equipment is not needed, the cost of raw materials is low, no pollution is caused to the environment, and the yield of the photocatalyst is gram-level;

2. the g-C can be controlled by adjusting the addition amount of dicyandiamide₃N₄The coating thickness of (a);

3. the invention innovatively utilizes g-C of different cladding thicknesses₃N₄To improve TiO₂And Bi₂Se₃The energy band of the active site is excessive, so that the absorption of visible light is promoted, and more active sites can be provided;

4. and Bi₂Se₃The composite not only expands the absorption spectrum of the photocatalyst to a near infrared region, but also enhances the separation and transportation efficiency of photoproduction electrons and holes, and greatly improves the photocatalytic efficiency.

5. Can adjust Bi₂Se₃With TiO₂The mass ratio of (a) to (b) optimizes photocatalytic performance.

6. Can be adjusted by adjusting g-C₃N₄The thickness of the coating layer is used for optimizing the photocatalytic performance, and the preparation method has certain universality;

7. the composite photocatalyst material prepared by the method has excellent photocatalytic performance and good optical stability.

Drawings

FIG. 1 is a graph showing the photocatalytic hydrogen production performance of a nanocomposite prepared according to theembodiment 1 as a photocatalyst for 5 hours;

FIG. 2 shows the preparation of the nanocomposite as a photocatalyst according to the embodiment of example 1, and TiO used therein₂TEM images of the nanoplates;

FIG. 3 is a TEM image of a nanocomposite prepared according to the scheme of example 1 as a photocatalyst;

FIG. 4 is a graph showing the spectral absorption of the nanocomposite prepared according to the embodiment of example 1 as a photocatalyst.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings.

Example 1

Firstly, ultrasonically dispersing 1.0g of titanium dioxide nanosheet and 1.0g of dicyandiamide in 100ml of ultrapure water, continuously heating and stirring at 90 ℃ until the water is evaporated to dryness, placing the obtained mixed powder in a corundum boat, covering the corundum boat with a corundum cover, and then placing the corundum boat in an electric furnace for roasting at 550 ℃ for 3 hours to obtain TiO₂@g-C₃N₄Composite nanosheets; then the obtained TiO is mixed₂@g-C₃N₄The composite nano-sheet is ultrasonically dispersed in 100ml of bismuth chelate solution (containing 0.01 mol.l bismuth nitrate)^-1) Adding ammonia water dropwise until pH is 9, and adding 0.1 mol/l^-1Na of (2)₂SeSO₃7ml of the solution, continuously stirring for 90min at the temperature of 75 ℃, obtaining a product in a centrifugal mode after the reaction is finished, and ultrasonically treating the product by using absolute ethyl alcohol and ultrapure waterWashing for several times until the pH value in the centrifugal washing liquid is neutral; finally, the obtained product was dried in a vacuum oven at 70 ℃ for 24 h. After the drying is finished, the TiO is obtained₂@g-C₃N₄@Bi₂Se₃A composite photocatalyst material.

Example 2

Firstly, ultrasonically dispersing 1.0g of titanium dioxide nanosheet and 1.0g of dicyandiamide in 100ml of ultrapure water, continuously heating and stirring at 90 ℃ until the water is evaporated to dryness, placing the obtained mixed powder in a corundum boat, covering the corundum boat with a corundum cover, and then placing the corundum boat in an electric furnace for roasting at 550 ℃ for 3 hours to obtain TiO₂@g-C₃N₄Composite nanosheets; then the obtained TiO is mixed₂@g-C₃N₄The composite nano-sheet is ultrasonically dispersed in 100ml of bismuth chelate solution (containing 0.005 mol.l bismuth nitrate)^-1) Adding ammonia water dropwise until pH is 9, and adding 0.1 mol/l^-1Na of (2)₂SeSO₃3.5ml of solution, continuously stirring for 90min at 75 ℃, obtaining a product in a centrifugal mode after the reaction is finished, and ultrasonically cleaning the product for several times by using absolute ethyl alcohol and ultrapure water until the pH value in the centrifugal cleaning solution is neutral; finally, the obtained product was dried in a vacuum oven at 70 ℃ for 24 h. After the drying is finished, the TiO is obtained₂@g-C₃N₄@Bi₂Se₃A composite photocatalyst material.

According to the method of example 1, example 2 except that Bi₂Se₃With TiO₂The mass ratio of (A) to (B) is 3: 100, and in the preparation of example 1, Bi₂Se₃With TiO₂The mass ratio of (A) to (B) is 6: 100.

example 3

Firstly, ultrasonically dispersing 1.0g of titanium dioxide nanosheet and 0.5g of dicyandiamide in 100ml of ultrapure water, continuously heating and stirring at 90 ℃ until the water is evaporated to dryness, placing the obtained mixed powder in a corundum boat, covering the corundum boat with a corundum cover, and then placing the corundum boat in an electric furnace for roasting at 550 ℃ for 3 hours to obtain TiO₂@g-C₃N₄Composite nanosheets; then the obtained TiO is mixed₂@g-C₃N₄CompoundingThe nano-sheet is ultrasonically dispersed in 100ml of bismuth chelate solution (containing 0.01 mol.l bismuth nitrate)^-1) Adding ammonia water dropwise until pH is 9, and adding 0.1 mol/l^-1Na of (2)₂SeSO₃7ml of the solution, continuously stirring for 90min at 75 ℃, obtaining a product in a centrifugal mode after the reaction is finished, and ultrasonically cleaning the product for a plurality of times by using absolute ethyl alcohol and ultrapure water until the pH value in the centrifugal cleaning solution is neutral; finally, the obtained product was dried in a vacuum oven at 70 ℃ for 24 h. After the drying is finished, the TiO is obtained₂@g-C₃N₄@Bi₂Se₃A composite photocatalyst material.

According to the method of example 1, example 3 differs by g-C₃N₄In TiO₂The coating thickness of the nanosheet surface layer is 3-5 nm, and in the preparation process of example 1, g-C₃N₄In TiO₂The coating thickness of the nanosheet surface layer is 8-10 nm.

Example 4

Firstly, ultrasonically dispersing 1.0g of titanium dioxide nanosheet and 1.0g of dicyandiamide in 100ml of ultrapure water, continuously heating and stirring at 90 ℃ until the water is evaporated to dryness, placing the obtained mixed powder in a corundum boat, covering the corundum boat with a corundum cover, and then placing the corundum boat in an electric furnace for roasting at 550 ℃ for 3 hours to obtain TiO₂@g-C₃N₄Composite nanosheets; then the obtained TiO is mixed₂@g-C₃N₄The composite nano-sheet is ultrasonically dispersed in 100ml of bismuth chelate solution (containing 0.01 mol.l bismuth nitrate)^-1) Adding ammonia water dropwise until pH is 9, and adding 0.1 mol/l^-1Na of (2)₂SeSO₃7ml of the solution, continuously stirring for 90min at 85 ℃, obtaining a product in a centrifugal mode after the reaction is finished, and ultrasonically cleaning the product for a plurality of times by using absolute ethyl alcohol and ultrapure water until the pH value in the centrifugal cleaning solution is neutral; finally, the obtained product was dried in a vacuum oven at 70 ℃ for 24 h. After the drying is finished, the TiO is obtained₂@g-C₃N₄@Bi₂Se₃A composite photocatalyst material.

According to the method of example 1, example 4 except that Bi₂Se₃Is heavyProduct temperature 85 ℃ and in the preparation of example 1, Bi₂Se₃Deposition temperature of 75 ℃.

Example 5

Firstly, ultrasonically dispersing 1.0g of titanium dioxide nanosheet and 1.0g of dicyandiamide in 100ml of ultrapure water, continuously heating and stirring at 90 ℃ until the water is evaporated to dryness, placing the obtained mixed powder in a corundum boat, covering the corundum boat with a corundum cover, and then placing the corundum boat in an electric furnace for roasting at 550 ℃ for 3 hours to obtain TiO₂@g-C₃N₄Composite nanosheets; then the obtained TiO is mixed₂@g-C₃N₄And uniformly mixing the composite nano sheet for 24 hours, 0.053g of nano selenium powder and 0.209g of nano bismuth powder, continuously grinding for 30min, placing the obtained mixed powder in a tube furnace, and roasting at the high temperature of 650 ℃ for 15 hours under the protection of high-purity argon. After the roasting is finished, the TiO is obtained₂@g-C₃N₄@Bi₂Se₃A composite photocatalyst material.

According to the method of example 1, example 5 except that Bi₂Se₃Is prepared by direct solid-phase sintering, and in the preparation process of example 1, Bi is₂Se₃Is prepared by liquid phase deposition.

Example 6

Firstly, ultrasonically dispersing 1.0g of titanium dioxide nanosheet and 1.0g of dicyandiamide in 100ml of ultrapure water, continuously heating and stirring at 90 ℃ until the water is evaporated to dryness, placing the obtained mixed powder in a corundum boat, covering the corundum boat with a corundum cover, and then placing the corundum boat in an electric furnace for roasting at 550 ℃ for 3 hours to obtain TiO₂@g-C₃N₄Composite nanosheets; then the obtained TiO is mixed₂@g-C₃N₄And uniformly mixing the composite nano-sheets for 24 hours, 0.053g of nano-selenium powder and 0.209g of nano-bismuth powder, continuously grinding for 30min, placing the obtained mixed powder in a tube furnace, and roasting at the high temperature of 650 ℃ for 24 hours under the protection of high-purity argon. After the roasting is finished, the TiO is obtained₂@g-C₃N₄@Bi₂Se₃A composite photocatalyst material.

According to the method of example 5, example 6 except that Bi₂Se₃Has a sintering time of 24h, whereas in the preparation of example 5, Bi₂Se₃The sintering time of (2) was 15 h.

The method for testing the photocatalytic hydrogen production performance comprises the following specific steps:

the photocatalytic water splitting performance is tested on an on-line photocatalytic system of Beijing Powley Labsolar-III AG, the model of a light source is PLS-SXE300, and the light source is provided with an AM 1.5G light filter, and the intensity of the light filter is equivalent to one sunlight. Before testing, 5mg of photocatalyst is dispersed in a mixed solution containing 70ml of ultrapure water and 30ml of methanol, and ultrasonic treatment is carried out for 30min to ensure that the catalyst is uniformly dispersed, the distance between a light source and the liquid level is about 10cm, and the irradiation area is about 10cm². The whole photocatalysis process is carried out at room temperature, and ethylene glycol cooling liquid (-5 ℃) is introduced in the whole process to eliminate the influence caused by the heat of the light source. The platinum is loaded on the surface of the catalyst by an in-situ light deposition method, namely, a certain amount of chloroplatinic acid solution (the mass ratio of the platinum to the catalyst is 3 percent) is added into the mixed solution. The carrier gas of the whole system is high-purity argon, and the flow rate is 6.0 ml/min^-1And is calibrated by a Beijing seven-star CS200 type flow rate controller. After the photocatalyst generates hydrogen under illumination, the hydrogen is brought into a gas chromatograph by carrier gas after a certain time, and online qualitative and quantitative detection is carried out. The model of gas chromatography is GC9790, produced by Fuli Zhejiang, and the detector is a thermal conductivity cell

And (3) a molecular sieve.

The performance test result of the composite photocatalyst material is shown in figure 1 (example 1), and the figure clearly shows that the photocatalyst provided by the invention has excellent photocatalytic hydrogen production performance which reaches 45 mmol-g^-1·h^-1。

As shown in FIG. 4, via Bi₂Se₃Modified TiO₂The absorption range of the light of the nano-sheet is expanded from an ultraviolet light waveband to a near-infrared waveband, and the nano-sheet completely has the characteristic of full-spectrum absorption.

Claims (10)

Translated fromChinese

1.一种具有全光谱吸收特性的复合光催化剂，其特征在于，包括TiO₂、g-C₃N₄和Bi₂Se₃；所述TiO₂与Bi₂Se₃的质量比为100:1-9；所述g-C₃N₄在TiO₂纳米片表面包覆的厚度为1～5nm。1. A composite photocatalyst with full spectrum absorption characteristics, characterized in that, comprising TiO₂ , gC₃ N₄ and Bi₂ Se₃ ; the mass ratio of the TiO₂ to Bi₂ Se₃ is 100:1-9 ; The thickness of the gC₃ N₄ coating on the surface of the TiO₂ nanosheet is 1-5 nm.2.一种权利要求1所述的具有全光谱吸收特性的复合光催化剂的制备方法，其特征在于，包括如下步骤：2. the preparation method of the composite photocatalyst with full spectrum absorption characteristic as claimed in claim 1, is characterized in that, comprises the steps:(1)将TiO₂纳米片和双氰胺超声分散于超纯水中，搅拌并加热直至水分蒸干，将所得产物在高温下焙烧获得TiO₂@g-C₃N₄复合纳米片；(1) ultrasonically dispersing TiO₂ nanosheets and dicyandiamide in ultrapure water, stirring and heating until the water evaporates to dryness, and roasting the resulting product at high temperature to obtain TiO₂ @gC₃ N₄ composite nanosheets;(2)通过采用液相沉积法或固相烧结法来制备Bi₂Se₃并原位沉积于TiO₂@g-C₃N₄复合纳米片的表面之上，获得最终产物。(2) The final product is obtained by preparing Bi₂ Se₃ by liquid deposition method or solid phase sintering method and in-situ deposition on the surface of TiO₂ @gC₃ N₄ composite nanosheets.3.根据权利要求2所述的具有全光谱吸收特性的复合光催化剂的制备方法，其特征在于，步骤(1)中，所述高温为530-580℃，焙烧时间为2-3h。3 . The method for preparing a composite photocatalyst with full spectrum absorption characteristics according to claim 2 , wherein in step (1), the high temperature is 530-580° C., and the calcination time is 2-3 h. 4 .4.根据权利要求2所述的具有全光谱吸收特性的复合光催化剂的制备方法，其特征在于，步骤(2)中，所述液相沉积法的具体步骤如下：4. the preparation method of the composite photocatalyst with full spectrum absorption characteristic according to claim 2, is characterized in that, in step (2), the concrete steps of described liquid deposition method are as follows:(11)先将五水硝酸铋、氨基三乙酸和抗坏血酸配制成铋的螯合溶液，然后将TiO₂@g-C₃N₄复合纳米片超声分散于其中；(11) bismuth nitrate pentahydrate, aminotriacetic acid and ascorbic acid are first prepared into a chelating solution of bismuth, and then TiO₂ @gC₃ N₄ composite nanosheets are ultrasonically dispersed therein;(12)在搅拌的条件下，取一定量的氨水，调节以上溶液的pH至9，并加入化学计量比的硒代硫酸钠溶液；(12) under the condition of stirring, get a certain amount of ammoniacal liquor, adjust the pH of above solution to 9, and add the sodium selenosulfate solution of stoichiometric ratio;(13)将溶液的温度保持在55-85℃，并在温度下持续搅拌30-120min；(13) keep the temperature of the solution at 55-85 ° C, and continue stirring for 30-120 min at the temperature;(14)在超声的条件下，利用无水乙醇和超纯水分别清洗以上固体沉淀物数次，至pH值为中性；(14) under the condition of ultrasonic, utilize dehydrated alcohol and ultrapure water to wash above solid sediments several times respectively, to pH value is neutral;(15)将洗净的产物放于真空干燥箱中，真空干燥。(15) Put the washed product in a vacuum drying oven and vacuum dry.5.根据权利要求4所述的具有全光谱吸收特性的复合光催化剂的制备方法，其特征在于，步骤(11)中，所述五水硝酸铋、氨基三乙酸和抗坏血酸的质量比为2:2:1。5. the preparation method of the composite photocatalyst with full spectrum absorption characteristic according to claim 4, is characterized in that, in step (11), the mass ratio of described bismuth nitrate pentahydrate, aminotriacetic acid and ascorbic acid is 2: 2:1.6.根据权利要求4所述的具有全光谱吸收特性的复合光催化剂的制备方法，其特征在于，步骤(15)中，所述真空干燥的温度为70-80℃，干燥时间为24-30h。6 . The method for preparing a composite photocatalyst with full spectrum absorption characteristics according to claim 4 , wherein in step (15), the temperature of the vacuum drying is 70-80° C., and the drying time is 24-30h. 7 . .7.根据权利要求2所述的具有全光谱吸收特性的复合光催化剂的制备方法，其特征在于，步骤(2)中，所述固相烧结法的具体步骤如下：7. The preparation method of the composite photocatalyst with full spectrum absorption characteristic according to claim 2, is characterized in that, in step (2), the concrete steps of described solid-phase sintering method are as follows:(21)先将TiO₂@g-C₃N₄复合纳米片、纳米硒粉、纳米铋粉分散均匀，机械研磨；(21) First disperse the TiO₂ @gC₃ N₄ composite nanosheets, nano-selenium powder, and nano-bismuth powder uniformly, and grind them mechanically;(22)将研磨好的混合粉体材料放入刚玉坩埚中，并置入有惰性气体保护的管式炉里；(22) Put the ground mixed powder material into the corundum crucible, and put it into a tube furnace protected by an inert gas;(23)在惰性气体的保护下，高温烧结，升温速率为5℃/min，并持续保温，然后自然冷却至室温。(23) Under the protection of inert gas, sintering at high temperature, the heating rate is 5°C/min, and the temperature is maintained continuously, and then it is naturally cooled to room temperature.8.根据权利要求7所述的具有全光谱吸收特性的复合光催化剂的制备方法，其特征在于，步骤(21)中，所述纳米硒粉与纳米铋粉的摩尔配比为3：2；所述纳米硒粉与纳米铋粉的质量之和为TiO₂@g-C₃N₄复合纳米片的1％～10％。8. The method for preparing a composite photocatalyst with full-spectrum absorption characteristics according to claim 7, wherein in step (21), the molar ratio of the nano-selenium powder to the nano-bismuth powder is 3:2; The sum of the mass of the nano-selenium powder and the nano-bismuth powder is 1% to 10% of the TiO₂ @gC₃ N₄ composite nanosheet.9.根据权利要求7所述的具有全光谱吸收特性的复合光催化剂的制备方法，其特征在于，步骤(21)中，所述研磨时间为30-120min。9 . The method for preparing a composite photocatalyst with full-spectrum absorption characteristics according to claim 7 , wherein in step (21), the grinding time is 30-120 min. 10 .10.根据权利要求7所述的具有全光谱吸收特性的复合光催化剂的制备方法，其特征在于，步骤(23)中，所述高温为650-950℃，烧结时间为15-20h，保温时间为15-20h。10 . The method for preparing a composite photocatalyst with full spectrum absorption characteristics according to claim 7 , wherein in step (23), the high temperature is 650-950° C., the sintering time is 15-20 h, and the holding time is 15-20 h. 11 . 15-20h.

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