CN111589439A - A kind of Si, Mo co-doped TiO2/redox graphene composite efficient self-cleaning film and preparation method thereof - Google Patents

Abstract

The invention discloses Si and Mo co-doped TiO₂The efficient self-cleaning film of the redox graphene compound adopts a reasonable film deposition process to improve the film quality so as to enhance the film performance, and the steps of preparing the film are as follows: 1) adding raw materials of tetrabutyl titanate, ethyl orthosilicate, ammonium paramolybdate and GO aqueous solution into a mixed solution of absolute ethyl alcohol, water, ethylene glycol, propylene glycol, acetylacetone and glycerol to prepare a precursor solution; 2) 1.0ml of concentrated hydrochloric acid with the concentration of 35 percent is added into every 100ml of precursor solution; 3) stirring to be uniform and transparent; 4) ultrasonically washing a substrate needing film coating by using a detergent and ethanol; 5) dip coating or spin coating, and drying for 0.5h after each coating; 6) firing at 450 ℃ for 1.0 h; the obtained self-cleaning film has no reduction of light transmission performance and has better light transmittance than pure TiO₂Film significantly enhanced conductivity, photoinduced super-hydrophilicity, photocatalysis and light transmissionThe performance is clear.

Description

Efficient self-cleaning of a Si, Mo co-doped TiO2/redox graphene composite Film and method of making the same

technical field

The invention belongs to the field of environmental purification and relates to a self-cleaning film, in particular to a Si, Mo co-doped TiO ₂ /redox graphene composite high-efficiency self-cleaning film and a preparation method thereof.

Background technique

Self-cleaning is a very important environmental purification technology. Films with self-cleaning properties are usually coated on the surfaces of indoor and outdoor buildings, electrical appliances and medical equipment, etc., to decompose, sterilize and reduce pollution of harmful gases in the environment and pollutants attached to the surface of the film. The effect of the degree of adhesion of the material, so as to purify the environment and so on. Therefore, all countries in the world have extensive research and application of self-cleaning films. TiO ₂ thin films are currently commonly used self-cleaning films due to their good photocatalysis and environmental stability.

Self-cleaning films are usually required to have good photocatalytic properties (decomposing harmful gases and attached pollutants and sterilization), good electrical conductivity (preventing the electrostatic adsorption of pollutants), light-induced super-hydrophilic properties (making some pollutants difficult to Adheres to and lifts over adsorbed water to clean surfaces) and light-transparency properties necessary in some applications (such as window glass). Although TiO2 films have good self-cleaning properties such as photocatalysis, their performance is still limited. Enhancing the photocatalytic performance of _TiO2 powder materials by ion doping or/and composite with graphene (rGO) has been widely studied and applied, and usually has a more significant effect. However, the development of _TiO thin film photocatalytic materials by ion doping or/and composite with graphene (rGO) is rarely studied. Usually some ion doping and composite graphene will lead to the reduction of optical transparency, while studies have shown that a large amount of Si doping can enhance the optical transparency of _TiO2 materials and enhance the photocatalytic performance. Therefore, when the graphene is compounded, some ions (such as Mo, etc.) are selected to be doped and doped with Si, so that the light transmission performance is not reduced. However, there is currently a lack of development of Si-doped TiO ₂ /rGO composite films, and even less development of (Si,Mo)-co-doped TiO ₂ /graphene composite films with good electrical conductivity, light-induced superhydrophilicity and optical transparency. development. In addition, a reasonable thin film deposition process is also beneficial to obtain a uniform and dense thin film with small particle size, thereby enhancing the performance of the thin film.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a kind of Si, Mo co-doped TiO ₂ /redox graphene composite efficient self-cleaning film and preparation method thereof, by doping a large amount of silicon and a trace amount of transition metal molybdenum and compounding graphene, using three The synergistic effect between the species enhances the self-cleaning properties of the TiO ₂ thin film material, the obtained self-cleaning thin film does not reduce the light transmission performance, and has good electrical conductivity, light-induced super-hydrophilicity and light transparency.

For achieving the above object, the technical scheme adopted in the present invention is:

A Si, Mo co-doped TiO ₂ /redox graphene composite efficient self-cleaning film, comprising the following components:

Mo content is 0-1.0at% of the total amount of _TiO2 and _SiO2 , excluding 0;

The content of SiO ₂ is 30 at.% of the total amount of TiO ₂ and SiO ₂ ;

Graphene oxide is 0-0.3 wt.%, excluding 0, of the total amount of _TiO2 and _SiO2 .

A preparation method of Si, Mo co-doped TiO ₂ /redox graphene composite efficient self-cleaning film, comprising the following steps:

1) Add the raw material tetrabutyl titanate, ethyl orthosilicate, ammonium paramolybdate and GO aqueous solution to the mixed solution of absolute ethanol, water, ethylene glycol, propylene glycol, acetylacetone and glycerol to configure the precursor solution ;

The doping amount of Si is 30 at.% of the total amount of TiO ₂ and SiO ₂ , that is, the molar ratio of SiO ₂ /(TiO ₂ +SiO ₂ )=0.3; the doping amount of Mo is 0-1.0 at.% of the total amount of TiO ₂ and SiO ₂ % does not include 0, the mass ratio of rGO/(TiO ₂ +SiO ₂ )=0～0.0030 does not include 0, and the concentration of Ti and Si ions is 0.05mol/l; according to this concentration, the amount of raw materials added per 100ml of solution is: Tetrabutyl titanate 1.19g, ethyl orthosilicate 0.312g; ammonium paramolybdate 0-0.0088g; 1g/ml graphene oxide aqueous solution 5ml, the raw materials are added to the mixed solution and stirred for 5-30min until uniform and transparent;

2) In the precursor solution of every 100ml, add 1.0ml of concentrated hydrochloric acid with a concentration of 35%;

3) Stir for 5-30min until the solution is uniform and transparent;

4) Coat the solution obtained in step 3) on the surface of the clean substrate, dry at 150-200°C for 0.5h after each coating, apply repeatedly for 5-15 times, and then burn at 450°C for 1.0h to obtain self-cleaning film.

Further, in step 1), the mixed solution is obtained by mixing absolute ethanol, water, ethylene glycol, propylene glycol, acetylacetone, and glycerol in a volume ratio of 4:1:3:0.35:1.

Further, in step 4), the substrate to be coated is cleaned by ultrasonic washing with detergent and ethanol.

Further, in step 4), the solution obtained in step 3) is coated on the surface of the clean substrate by dip coating or spin coating.

The beneficial effects of the present invention are:

In the present invention, by doping a large amount of silicon and a trace amount of transition metal molybdenum (Mo) and _compounding graphene (rGO), the (Si, Mo) - The doped TiO ₂ /rGO composite film has good photocatalytic performance, good electrical conductivity, hydrophilicity and light-induced super-hydrophilicity, which is close to the optical transparency performance of pure TiO ₂ film.

In the present invention, the Mo content in the self-cleaning film component is increased from 0 to 1.0 at%, regardless of whether the photocatalytic, conductive and hydrophilic self-cleaning properties of the composite rGO film are enhanced; the Mo content of 0.5 at.% has the best performance Light transparency performance, but 1.0at.% light transparency performance decreased. When the mass ratio of rGO increases from 0 to 0.03wt.%, the photocatalytic, conductive and hydrophilic self-cleaning properties of the Mo-doped film are enhanced, and it is used in occasions where various properties are required, but the light transmission performance is decreased. , more than 0.03wt.%, the self-cleaning performance is enhanced but the appearance color is darker. Although rGO leads to a decrease in optical transparency, the optical transparency of the composite films is still greater than or equal to that of pure _TiO2 films when the Mo content is 0.5 at.% due to the doping of Si.

In the precursor solution prepared by the thin film, anhydrous ethanol and a small amount of water are used as solvents; concentrated hydrochloric acid (HCl, 35%) is used as a reducing agent for graphene oxide; ethylene glycol, propylene glycol, acetylacetone and propylene in a certain proportion are used. Triol is used as a dispersant, which can adjust the viscosity of the solution and maintain the stable and uniform dispersion of the reduced graphene oxide. Acetylacetone is used as a stabilizer to prevent the hydrolysis of the main raw material, butyl phthalate.

If the firing temperature is too low, the organic matter cannot be completely decomposed; Therefore, 450°C is a reasonable firing temperature. The volume ratio of absolute ethanol, ethylene glycol, propylene glycol, acetylacetone, and glycerol is 4:1:3:0.35:1; the composition and ratio of the solution can ensure that the reduced graphene oxide is uniformly dispersed in the precursor solution and Suspended for ~20min to ensure uniform and stable precursor solution during film deposition and drying.

Description of drawings

Figure 1 shows high-resolution SEM micrographs of self-cleaning films with different Si and rGO contents.

Figure 2(a) shows the relationship between the kinetic constant k1 of the photocatalytic degradation of malachite green aqueous solution and the molar ratio of Mo

Figure 2(b) shows the relationship between the kinetic constant k1 of the photocatalytic degradation of naphthol green B aqueous solution and the molar ratio of Mo

Figure 3 is a graph showing the relationship between the resistivity and Mo molar content of the thin films with and without Si and rGO in the present invention

Figure 4(a) is the light transmittance spectrum of the thin film

Figure 4(b) shows the relationship between the optical band gap energy E _g of the film and the molar ratio of Mo

Figure 5(a) is the light transmittance spectrum of the films with and without Si and rGO and various Mo molar ratios in the invention

Figure 5(b) is a graph showing the relationship between the optical band gap energy E _g and the Mo molar ratio of the films with and without Si and rGO and various Mo molar ratios in the invention.

Detailed ways

The present invention will be described in further detail below with reference to specific embodiments, but it is not intended to limit the present invention.

Example 1

Si, Mo co-doped TiO ₂ /redox graphene composite high-efficiency self-cleaning film, graphene is the mass ratio, others are molar ratios, including the following components:

Mo content is 1.0at% of the total amount of _TiO2 and _SiO2 ;

The content of SiO ₂ is 30 at.% of the total amount of TiO ₂ and SiO ₂ ;

Graphene oxide is 0.3 wt.% of the total amount of _TiO2 and _SiO2 ;

Solvent: absolute ethanol;

Dispersants and stabilizers are: ethylene glycol, propylene glycol, acetylacetone and glycerol;

The volume ratio of absolute ethanol, ethylene glycol, propylene glycol, acetylacetone, and glycerol is 4:1:3:0.35:1;

Concentrated hydrochloric acid 1.0vol.% with a concentration of 35%;

The ion concentrations of Ti and Si were 0.05 mol/l. According to this concentration, the amount of raw materials added per 100ml of solution is: tetrabutyl titanate 1.19g; tetraethyl orthosilicate 0.312g; ammonium paramolybdate 0.0088g; graphene oxide aqueous solution (1g/ml) 5ml. After the raw materials are added to the solution, the solution needs to be fully stirred for 5-30 minutes until it is uniform and transparent.

Repeated coating 10 times, and then fired at 450 ℃ for 1.0h.

The film of this example has the highest light-transparency performance, and the photocatalytic, hydrophilic and light-induced superhydrophilicity, and electrical conductivity are all better than those without Si and Mo.

Example 2

The Si,Mo co-doped TiO ₂ /redox graphene composite efficient self-cleaning film includes the following components:

Mo content is 0.5at% of the total amount of _TiO2 and _SiO2 ;

The Si content is 30 at.% of the total amount of TiO ₂ and SiO ₂ ;

Graphene oxide is 0.3 wt.% of the total amount of _TiO2 and _SiO2 ;

Solvent: absolute ethanol;

Dispersants and stabilizers are: ethylene glycol, propylene glycol, acetylacetone and glycerol;

The volume ratio of absolute ethanol, water, ethylene glycol, propylene glycol, acetylacetone and glycerol is 4:1:3:0.5:1;

Concentrated hydrochloric acid 1.0vol.% with a concentration of 35%;

The ion concentrations of Ti and Si were 0.05 mol/l. According to this concentration, the amount of raw materials added per 100ml of solution is: tetrabutyl titanate 1.19g; tetraethyl orthosilicate 0.312g; ammonium paramolybdate 0.0044g; graphene oxide aqueous solution (1g/ml) 5ml. After the raw materials are added to the solution, the solution needs to be fully stirred for 5-30 minutes until it is uniform and transparent.

Repeated coating 10 times, and then fired at 450 ℃ for 1.0h.

The film of this example has high photocatalytic, hydrophilic and light-induced superhydrophilic properties, and does not contain stone

All thin films of graphene, and have better optical transparency than TiO ₂ thin films,

Example 3

The Si,Mo co-doped TiO ₂ /redox graphene composite efficient self-cleaning film includes the following components:

Mo content is 0.75at% of the total amount of _TiO2 and _SiO2 ;

The Si content is 30 at.% of the total amount of TiO ₂ and SiO ₂ ;

Graphene oxide is 0.3 wt.% of the total amount of _TiO2 and _SiO2 ;

Solvent: absolute ethanol;

Dispersants and stabilizers are: ethylene glycol, propylene glycol, acetylacetone and glycerol;

The volume ratio of absolute ethanol, ethylene glycol, propylene glycol, acetylacetone and glycerol is 4:1:3:0.5:1;

Concentrated hydrochloric acid 1.0vol.% with a concentration of 35%;

The ion concentrations of Ti and Si were 0.05 mol/l. According to this concentration, the amount of raw materials added per 100ml of solution is: tetrabutyl titanate 1.19g; tetraethyl orthosilicate 0.312g; ammonium paramolybdate 0.0066g; graphene oxide aqueous solution (1g/ml) 5ml. After the raw materials are added to the solution, the solution needs to be fully stirred for 5-30 minutes until it is uniform and transparent.

Repeated coating 10 times, and then fired at 450 ℃ for 1.0h.

The film of this example has the best photocatalytic, hydrophilic and light-induced superhydrophilic and electrical conductivity properties, but has lower optical transparency than the TiO2 film.

Example 4

Si, Mo co-doped TiO ₂ /redox graphene composite high-efficiency self-cleaning film and preparation method thereof, comprising the following steps:

1) Add the raw material tetrabutyl titanate, ethyl orthosilicate, ammonium paramolybdate and GO aqueous solution to the mixed solution of absolute ethanol, ethylene glycol, propylene glycol, acetylacetone and glycerol to configure the precursor solution. The volume ratio of water ethanol, ethylene glycol, propylene glycol, acetylacetone and glycerol is 4:1:3:0.5:1;

The Si doping amount is 30 at.% of the total amount of TiO ₂ and SiO ₂ , that is, the molar ratio of SiO ₂ /(TiO ₂ +SiO ₂ )=0.3; the Mo doping amount is 1.0 at. % of the total amount of TiO ₂ and SiO ₂ , rGO/(TiO ₂ +SiO ₂ ) mass ratio=0.0030, Ti and Si ion concentrations are 0.05mol/l; according to this concentration, the amount of raw materials added per 100ml of solution is: tetrabutyl titanate 1.19g; 0.312 g of ethyl acetate; 0.0088 g of ammonium paramolybdate; 5 ml of graphene oxide aqueous solution (1 g/ml).

2) 1.0 ml of concentrated hydrochloric acid with a concentration of 35% is added to every 100 ml of precursor solution to prevent the formation of hydroxide and reduce graphene oxide (GO);

3) After fully stirring for 20min to uniform and transparent;

4) The substrates that need to be coated are ultrasonically washed with detergent and ethanol, dip coating or spin coating method, dry at 180°C for 0.5h after each coating, apply repeatedly 10 times, and then bake at 450°C for 1.0h.

The film of this example has the best photocatalysis, hydrophilicity and light-induced superhydrophilicity, electrical conductivity and optical transparency, and has a long service time.

Example 5

Si, Mo co-doped TiO ₂ /redox graphene composite high-efficiency self-cleaning film and preparation method thereof, comprising the following steps:

1) Add the raw material tetrabutyl titanate, ethyl orthosilicate, ammonium paramolybdate and GO aqueous solution to the mixed solution of absolute ethanol, ethylene glycol, propylene glycol, acetylacetone and glycerol to configure the precursor solution. The volume ratio of water ethanol, ethylene glycol, propylene glycol, acetylacetone and glycerol is 4:1:3:0.5:1;

The doping amount of SiO ₂ is 30 at.% of the total amount of TiO ₂ and SiO ₂ , that is, the molar ratio of SiO ₂ /(TiO ₂ +SiO ₂ )=0.3; the doping amount of Mo is 0.5 at.% of the total amount of TiO ₂ and SiO ₂ . %, rGO/(TiO ₂ +SiO ₂ ) mass ratio=0, Ti and Si ion concentrations are 0.05mol/l; according to this concentration, the amount of raw materials added per 100ml of solution is: tetrabutyl titanate 1.19g; Ethyl silicate 0.312g; Ammonium paramolybdate 0.0044g.

2) 1.0 ml of concentrated hydrochloric acid with a concentration of 35% is added to every 100 ml of precursor solution to prevent the formation of hydroxide and reduce graphene oxide (GO);

3) After fully stirring for 5min to uniform and transparent;

4) The substrates that need to be coated are washed with detergent and ethanol ultrasonically, by dip coating or spin coating, drying at 150°C for 0.5h after each coating, repeated coating 15 times, and then fired at 450°C for 1.0h.

The film of this example has high photocatalytic, hydrophilic and light-induced superhydrophilic properties, and does not contain stone

All thin films of graphene, and have better light-transparency properties than TiO ₂ thin films, and have a long use time.

Example 6

Si, Mo co-doped TiO ₂ /redox graphene composite high-efficiency self-cleaning film and preparation method thereof, comprising the following steps:

1) Add the raw material tetrabutyl titanate, ethyl orthosilicate, ammonium paramolybdate and GO aqueous solution to the mixed solution of absolute ethanol, ethylene glycol, propylene glycol, acetylacetone and glycerol to configure the precursor solution. The volume ratio of water ethanol, ethylene glycol, propylene glycol, acetylacetone and glycerol is 4:1:3:0.5:1;

The doping amount of Si is 30 at.% of the total amount of TiO ₂ and SiO ₂ , that is, the molar ratio of SiO ₂ /(TiO ₂ +SiO ₂ )=0.3; the doping amount of Mo is 0.25 at. % of the total amount of TiO ₂ and SiO ₂ , rGO/(TiO ₂ +SiO ₂ ) mass ratio=0.003, Ti and S ion concentrations are 0.05mol/l; according to this concentration, the amount of raw materials added per 100ml of solution is: tetrabutyl titanate 1.19g; 0.312g of ethyl acetate; 0.0022g of ammonium paramolybdate; 5ml of graphene oxide aqueous solution (1g/ml).

2) 1.0 ml of concentrated hydrochloric acid with a concentration of 35% is added to every 100 ml of precursor solution to prevent the formation of hydroxide and reduce graphene oxide (GO);

3) After fully stirring for 30min to uniform and transparent;

4) The substrate to be coated shall be ultrasonically washed with detergent and ethanol, by dip coating or spin coating method, dry at 200°C for 0.5h after each coating, apply repeatedly for 5 times, and then fired at 450°C for 1.0h.

The film of this example has the best photocatalytic, hydrophilic and light-induced super-hydrophilic properties, electrical conductivity, moderate optical transparency, and short usage time.

Figure 1. High-resolution SEM micrographs of self-cleaning films with different Si and rGO contents;

In (a), SiO ₂ /(TiO ₂ +SiO ₂ )=0, rGO/TiO ₂ =0, and Mo content is 0;

(b) SiO ₂ /(TiO ₂ +SiO ₂ )=0.3, rGO/(TiO ₂ +SiO ₂ )=0, Mo content 0;

In (c) SiO ₂ /(TiO ₂ +SiO ₂ )=0.3, rGO/(TiO ₂ +SiO ₂ )=0, Mo content is 0.5at.%,

(d) SiO ₂ /(TiO ₂ +SiO ₂ )=0.3, rGO/(TiO ₂ +SiO ₂ )=0, and the Mo content is 1.0 at.%;

(e) SiO ₂ /(TiO ₂ +SiO ₂ )=0.3, rGO/(TiO ₂ +SiO ₂ )=0.003, and Mo content is 0;

(f) SiO ₂ /(TiO ₂ +SiO ₂ )=0.3, rGO/(TiO ₂ +SiO ₂ )=0.003, Mo content 0.5at.%;

(g) SiO ₂ /(TiO ₂ +SiO ₂ )=0.3, rGO/(TiO ₂ +SiO ₂ )=0.003, Mo content 1.0 at.%

得出的曲线斜率给出，其中，C₀和C是染料溶液光催化前和光催化t小时后的浓度；图2(a)为光催化降解孔雀石绿水溶液的反应动力学常数k1与Mo摩尔比的关系图；图2(b)为光催化降解萘酚绿B水溶液的反应动力学常数k1与Mo摩尔比的关系图。In the present invention, on films with and without Si and graphene, the relationship between the kinetic constant k1 of the photocatalytic degradation of aqueous solutions of malachite green and naphthol green B and the molar ratio of Mo, k1 is determined by the relational formula

The slopes of the resulting curves are given, where C ₀ and C are the concentrations of the dye solution before photocatalysis and after photocatalysis for t hours; Figure 2(a) is the kinetic constant k of the photocatalytic degradation of malachite green aqueous solution versus Mo moles Figure 2(b) shows the relationship between the kinetic constant k1 of the reaction and the molar ratio of Mo in the photocatalytic degradation of the aqueous solution of naphthol green B.

Figure 3 is a graph showing the relationship between the resistivity and Mo molar content of thin films with and without Si and rGO in the present invention. The figures all illustrate that Si-doped films have lower resistivity than pure TiO ₂ films, and both composite graphene (rGO) and Mo-doped films further reduce the resistivity of the films.

The Raman spectrum of the film in Fig. 4(a), the peaks at 146, 399, 517, and 640 cm ^-1 are characteristic peaks of _TiO2 , and the intensity ratio of the 1354 cm ^-1 peak to the 1597 cm ^-1 peak of the GO-containing film is higher than that of the GO film , indicating that graphene oxide GO is reduced. The water contact angles of various films in Fig. 4(b) illustrate that Si-doped films have lower water contact angles (i.e. higher hydrophilicity) than pure _TiO films, composite graphene (rGO) and doped Mo further reduces the water contact angle (ie, enhances hydrophilicity). The water contact angle decreased after UV irradiation, indicating the existence of light-induced superhydrophilicity. Both Si and Mo doping as well as composite graphene lead to photoinduced superhydrophilic enhancement.

The optical spectra of films with and without Si and rGO and various Mo molar ratios in the present invention are shown in Fig. 5(a) and Fig. 5(b); Fig. 5(a) is a light transmittance spectrum diagram; Fig. 5 (b) is the relationship between the optical band gap energy E _g and Mo molar ratio. Figure 5(a) and Figure 5(b) show that Si doping leads to an increase in light transmittance, Mo doping leads to a decrease in light transmittance, and graphene leads to a decrease in optical head rate, but when the Mo content is 0.5at. % still has higher light transmittance than TiO ₂ thin film.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: Modifications or equivalent substitutions are made to the specific embodiments, and any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention shall all be included in the scope of the present claims.

Claims (5)

1. Si and Mo co-doped TiO₂The efficient self-cleaning film of the redox graphene composite is characterized by comprising the following components:

mo content of TiO₂And SiO₂0 to 1.0 at% of the total amount excluding 0;

SiO₂in a content of TiO₂And SiO₂30 at.% of total;

the graphene oxide is TiO₂And SiO₂0-0.3 wt.% of the total, excluding 0.

2. The Si, Mo-codoped TiO of claim 1₂The preparation method of the efficient self-cleaning film of the redox graphene compound is characterized by comprising the following steps of:

1) adding raw materials of tetrabutyl titanate, ethyl orthosilicate, ammonium paramolybdate and GO aqueous solution into a mixed solution of absolute ethyl alcohol, water, ethylene glycol, propylene glycol, acetylacetone and glycerol to prepare a precursor solution;

the doping amount of Si is TiO₂And SiO₂30 at.% of the total, i.e. SiO₂/(TiO₂+SiO₂) The molar ratio is 0.3; the Mo doping amount is TiO₂And SiO₂0 to 1.0 at.% of the total excluding 0, rGO/(TiO)₂+SiO₂) The mass ratio is 0-0.0030 and does not include 0, and the concentration of Ti and Si ions is 0.05 mol/l; according to the concentration, the adding amount of the raw materials in each 100ml of solution is as follows: 1.19g of tetrabutyl titanate and 0.312g of tetraethoxysilane; 0-0.0088g of ammonium paramolybdate; 5ml of 1g/ml graphene oxide aqueous solution, adding the raw materials into the mixed solution, and stirring for 5-30min until the mixture is uniform and transparent;

2) 1.0ml of concentrated hydrochloric acid with the concentration of 35 percent is added into every 100ml of precursor solution;

3) stirring for 5-30min until the solution is uniform and transparent;

4) coating the solution obtained in the step 3) on the surface of the clean substrate, drying for 0.5h at the temperature of 150-200 ℃ after each coating, repeatedly coating for 5-15 times, and then firing for 1.0h at the temperature of 450 ℃ to obtain the self-cleaning film.

3. The Si, Mo co-doped TiO of claim 2₂The preparation method of the efficient self-cleaning film of the redox graphene compound is characterized by comprising the following steps: the mixed solution in the step 1) is prepared from absolute ethyl alcohol, ethylene glycol, propylene glycol, acetylacetone and glycerol according to the volume ratio of 4: 1: 3: 0.35:1 are mixed to obtain the product.

4. The Si, Mo co-doped TiO of claim 2₂The preparation method of the efficient self-cleaning film of the redox graphene compound is characterized by comprising the following steps: and 4) ultrasonically washing the substrate to be coated with the film by using a detergent and ethanol to clean the substrate.

5. The Si, Mo co-doped TiO of claim 2₂The preparation method of the efficient self-cleaning film of the redox graphene compound is characterized by comprising the following steps: step 4) coating the solution obtained in step 3) on the surface of the cleaning substrate by dip coating or spin coating.

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