Two-step rapid electro-thermal preparation method of nano-titanium dioxide photo-anode and application thereof

Abstract

The application discloses a two-step rapid electrothermal preparation method of a nano-titanium dioxide photoanode and application thereof, and belongs to the field of new energy materials, and the preparation steps are as follows: titanium metal sheets are cut into rectangles, are sequentially cleaned with acetone, ethanol and distilled water through ultrasonic cleaning, are dried, are placed in an electrothermal device, are electrified under a voltage of 50 to 100 volts for 20 to 30 seconds, the first-step electrothermal treatment is completed, are naturally cooled, are continuously placed in the electrothermal device, are electrified again under a voltage of 50 to 100 volts for 20 to 30 seconds, the second-step electrothermal treatment is completed, and the nano-titanium dioxide photoanode is prepared.The application directly and rapidly grows the nano-titanium dioxide photoanode on the titanium metal sheets in a two-step electrothermal mode, has the characteristics of convenience and high efficiency, can greatly shorten the preparation time of the titanium dioxide photoanode, and can avoid excessive use of chemical reagents.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of new energy materials, and particularly relates to a two-step rapid electrothermal preparation method of a nano-titanium dioxide photoanode and application thereof. BACKGROUND

[0002] Reasonably optimizing energy structure, and finding and developing various sustainable green energy systems have become one of the focuses of scholars in the world. As the most abundant clean renewable resource on the earth, how to effectively utilize solar energy has been a research hotspot of scientists. Water is one of the most abundant natural resources on the earth, and is composed of only two elements of hydrogen and oxygen. Only water is produced in the hydrogen combustion process. Therefore, using solar energy to decompose water to prepare "green hydrogen" to realize the storage and conversion of solar energy is one of the ideal ways to achieve the carbon neutralization goal.

[0003] Photoelectrocatalytic (PEC) water splitting technology is a method of directly converting solar energy into hydrogen energy by using a semiconductor material as a photoanode to decompose water into hydrogen and oxygen under the driving of solar energy. Since the oxygen evolution reaction occurring on the photoanode is a kinetic process slower than the hydrogen evolution reaction occurring on the photocathode, it is the main limiting factor of water splitting. So far, scientists have made a lot of attempts in developing photoanodes and have achieved considerable results. As an important n-type semiconductor material among many transition metal oxides, titanium dioxide (TiO2) has become an important candidate for photoanode material due to its advantages of high stability, appropriate band edge position, non-toxicity and low cost.

[0004] At present, the main preparation technologies of titanium dioxide photoanode are as follows:

[0005] (1) A TiO2 precursor film is grown on a conductive glass or titanium metal sheet substrate by a hydrothermal or solvothermal method, which usually takes several hours and needs several chemical reagents; then the precursor film is heat-treated by a muffle furnace or other heat treatment equipment, which also usually takes several hours (for example, the invention patent with the publication number CN115418668A and the literature Nano Lett.2011,11,3026-3033);

[0006] (2) A titanium metal sheet is inserted into a fluorine-containing electrolyte solution, and the surface of the titanium metal sheet is oxidized by an anodization technology, and then a titanium dioxide photoanode is obtained through high-temperature treatment after several hours (for example, the invention patent with the publication number CN116139843A and the literature Electrochimica Acta,2013,107,313-319);

[0007] (3) The solution containing titanium is deposited on a substrate such as conductive glass by a spin coating technique, and then a thin layer of titanium dioxide photoanode is obtained through the drying of the sol and high-temperature heat treatment process (for example, the document ACS Appl. Nano Mater. 2020, 3, 1, 131-137).

[0008] Most of the above methods require long-time high-temperature heat treatment, or the use of multiple chemical reagents, or the use of fluorine-containing solutions with high hazards. Therefore, it is urgent to find a more efficient and safe preparation method of titanium dioxide photoanode. SUMMARY

[0009] The purpose of the present application is to overcome the shortcomings and deficiencies of the prior art, and to provide a two-step rapid electrothermal preparation method of nanometer titanium dioxide photoanode and its application.

[0010] The purpose of the present application can be achieved by the following technical solutions:

[0011] A two-step rapid electrothermal preparation method of nanometer titanium dioxide photoanode, the specific steps are as follows:

[0012] S1. Cut the titanium metal sheet into a rectangular shape, the thickness of the titanium metal sheet is 0.2 mm, the width is 15 mm, and the length is 25 mm;

[0013] S2. Clean the titanium metal sheet, and sequentially ultrasonic clean with acetone, ethanol and distilled water for 10-30 minutes, so as to remove surface oil stains and organic matter, etc.;

[0014] S3. Dry the cleaned titanium metal sheet at a temperature of 50-80℃ for 4-6 hours;

[0015] S4. Place the dried titanium metal sheet in an electrothermal device, and power on for 20-30 seconds under a voltage of 50-100 volts, thereby completing the first step of electrothermal treatment;

[0016] S5. Allow the titanium metal sheet in S4 to cool naturally to room temperature in the electrothermal device;

[0017] S6. Continue to place the cooled titanium metal sheet in the electrothermal device, and power on again for 20-30 seconds under a voltage of 50-100 volts, thereby completing the second step of electrothermal treatment; after completing the two-step electrothermal preparation process, the surface of the titanium metal sheet is oxidized by oxygen in the air to form a thin layer of nanometer titanium dioxide, and the titanium metal sheet after electrothermal oxidation is the prepared nanometer titanium dioxide photoanode, which can be used in solar-driven photoelectrocatalytic systems such as photoelectrocatalytic water splitting.

[0018] Further, the electric heating device comprises an insulating block, two symmetrical metal U-shaped clamps are arranged on the insulating block, the open ends of the two metal U-shaped clamps are oppositely arranged, and a graphite felt is arranged between the two metal U-shaped clamps, and the two ends of the graphite felt are fixed to the inner side surfaces of the metal U-shaped clamps through bolt structures.

[0019] The two closed ends of the metal U-shaped clamps are connected through wires, and a power supply and a switch are arranged on the wires.

[0020] In use, the titanium metal sheet is placed on the graphite felt for electric heating treatment.

[0021] Another object of the present application is to provide the application of the nano-titanium dioxide photo-anode prepared by the above preparation method in the catalytic water decomposition reaction of photo-electrochemical cells, specifically, the nano-titanium dioxide photo-anode prepared by the above preparation method is inserted into a 1 mol / L potassium hydroxide aqueous solution, and the photo-electrocatalytic water decomposition reaction is carried out under the conditions of three-electrode test configuration and intermittent light irradiation.

[0022] The present application has the following beneficial effects:

[0023] The present application uses a two-step electric heating method to directly and quickly grow a nano-titanium dioxide photo-anode on a titanium metal sheet, which has the characteristics of convenience and efficiency, can greatly shorten the preparation time of the titanium dioxide photo-anode, and can avoid excessive use of chemical reagents. BRIEF DESCRIPTION OF DRAWINGS

[0024] The present application will be further described below with reference to the accompanying drawings.

[0025] Figure 1 It is a structural schematic diagram of the electric heating device in the present application.

[0026] Figure 2 It is a scanning electron microscope photograph (a) titanium metal sheet; (b) titanium metal sheet after one-step electric heating; (c) nano-titanium dioxide photo-anode prepared by two-step electric heating.

[0027] Figure 3 It is an X-ray photoelectron spectrum of the titanium metal sheet after one-step electric heating (a) chemical environment characterization of Ti element; (b) chemical environment characterization of O element.

[0028] Figure 4 It is an X-ray photoelectron spectrum of the titanium metal sheet after two-step electric heating (a) chemical environment characterization of Ti element; (b) chemical environment characterization of O element.

[0029] Figure 5 It is a linear sweep voltammetry curve of the photo-electrocatalytic water decomposition test of the titanium metal sheet after one-step electric heating and two-step electric heating in a 1 mol / L potassium hydroxide aqueous solution under the conditions of three-electrode test configuration and intermittent light irradiation.

[0030] In the diagram: 1. Insulating block; 2. Metal U-shaped clamp; 3. Graphite felt; 4. Bolt structure; 5. Wire; 6. Power supply; 7. Switch. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1 As shown, the electrothermal device used for electrothermal treatment in this invention includes an insulating block 1. Two symmetrical metal U-shaped clips 2 are provided on the insulating block 1. The open ends of the two metal U-shaped clips 2 are arranged opposite each other. A graphite felt 3 is provided between the two metal U-shaped clips 2. Both ends of the graphite felt 3 are fixed to the inner surface of the metal U-shaped clips 3 by bolt structure 4.

[0033] The two closed ends of the metal U-shaped clip 3 are connected by a wire 5, and a power supply 6 and a switch 7 are provided on the wire 5;

[0034] In use, the titanium sheet is placed on the graphite felt 3 for electrothermal treatment.

[0035] Example 1

[0036] A two-step rapid electrothermal preparation method for nano-titanium dioxide photoanodes is as follows:

[0037] S1. Cut the titanium sheet into a rectangle with a thickness of 0.2 mm, a width of 15 mm, and a length of 25 mm;

[0038] S2. Clean the titanium sheet by ultrasonically cleaning it with acetone, ethanol, and distilled water for 10 minutes in sequence to remove surface oil and organic matter.

[0039] S3. Dry the cleaned titanium sheet at 50°C for 6 hours;

[0040] S4. Place the dried titanium sheet in... Figure 1 In the electric heating device, the first step of electrothermal treatment is completed by applying 50 volts for 30 seconds.

[0041] S5. Make the titanium sheet from step S4 and... Figure 1 The electric heating device naturally cooled to room temperature;

[0042] S6. Place the titanium sheet after the first step of S4, which has undergone electrothermal treatment, back into the [location / place]. Figure 1The titanium metal sheet is placed in the electric heating device again, and the titanium metal sheet is electrically heated at a voltage of 75 volts for 25 seconds, so that the first step of the electric heating treatment is completed.

[0043] As shown in Figure 2 , the scanning electron microscope photos of the titanium metal sheet, the titanium metal sheet after the first step of the electric heating treatment, and the nano-titanium dioxide photo-anode prepared by the two-step electric heating treatment are shown.

[0044] As shown in Figure 3 and Figure 4 , the X-ray photoelectron spectrograms of the titanium metal sheet after the first step of the electric heating treatment and the titanium metal sheet after the two-step electric heating treatment are shown.

[0045] Example Two

[0046] A two-step rapid electric heating method for preparing a nano-titanium dioxide photo-anode is provided, and the method comprises the following steps:

[0047] S1. The titanium metal sheet is cut into a rectangular shape, and the thickness of the titanium metal sheet is 0.2 mm, the width is 15 mm, and the length is 25 mm.

[0048] S2. The titanium metal sheet is cleaned, and the titanium metal sheet is sequentially cleaned by ultrasonic cleaning for 20 minutes by using acetone, ethanol, and distilled water, so that the surface oil stains and organic matters are removed.

[0049] S3. The cleaned titanium metal sheet is dried at 65 DEG C for 5 hours.

[0050] S4. The dried titanium metal sheet is placed in the electric heating device, and the titanium metal sheet is electrically heated at a voltage of 75 volts for 25 seconds, so that the first step of the electric heating treatment is completed. Figure 1

[0051] S5. The titanium metal sheet in the step S4 and the electric heating device are naturally cooled to room temperature. Figure 1

[0052] S6. The titanium metal sheet after the first step of the electric heating treatment in the step S4 is continuously placed in the electric heating device, and the titanium metal sheet is electrically heated at a voltage of 75 volts for 25 seconds again, so that the second step of the electric heating treatment is completed, and the nano-titanium dioxide photo-anode is obtained. Figure 1

[0053] Example Three

[0054] A two-step rapid electric heating method for preparing a nano-titanium dioxide photo-anode is provided, and the method comprises the following steps:

[0055] S1. The titanium metal sheet is cut into a rectangular shape, and the thickness of the titanium metal sheet is 0.2 mm, the width is 15 mm, and the length is 25 mm.​​​

[0056] S2. Clean the titanium sheet, and sequentially clean it with acetone, ethanol and distilled water for 30 minutes by ultrasonic cleaning, so as to remove surface oil and organic matters;

[0057] S3. Dry the cleaned titanium sheet at 80℃ for 4 hours;

[0058] S4. Place the dried titanium sheet in the electric heating device of Figure 1 , and pass current for 20 seconds under a voltage of 100 volts, so as to complete the first step of electric heating treatment;

[0059] S5. Allow the titanium sheet in S4 to naturally cool to room temperature in the electric heating device of Figure 1 ;

[0060] S6. Continue to place the titanium sheet after the first step of electric heating treatment in S4 in the electric heating device of Figure 1 , and pass current again for 20 seconds under a voltage of 100 volts, so as to complete the second step of electric heating treatment, and obtain the nano-titanium dioxide photo-anode.

[0061] Application

[0062] The nano-titanium dioxide photo-anode prepared by the two-step electric heating in Example 1 is used for water decomposition reaction in photo-electrochemical cell. The nano-titanium dioxide photo-anode prepared above is inserted into 1 mol / L aqueous potassium hydroxide solution, and the photo-electrochemical water decomposition test is carried out under the condition of three-electrode test configuration and intermittent light, and the linear sweep voltammetry curve is shown in Figure 5 . It can be seen that the nano-titanium dioxide photo-anode has strong light response under light, and its performance is comparable to that of the photo-anode prepared by the current main preparation method of titanium dioxide photo-anode.

[0063] The above specific embodiment part specifically introduces the analysis method involved in the present application. It should be noted that the above introduction is only to help the person skilled in the art better understand the method and idea of the present application, and is not a limitation on the related content. The person skilled in the art can also make appropriate adjustments or modifications to the present application without departing from the principles of the present application, and the above adjustments and modifications should also belong to the protection scope of the present application.

Claims

1. A two-step rapid electro-thermal preparation method of nanocrystalline titanium dioxide photoanodes, characterized in that, The specific steps are as follows: S1. Cutting titanium metal sheet into a rectangle; S2. Cleaning the titanium metal sheet, sequentially using acetone, ethanol, distilled water for ultrasonic cleaning for 10-30 minutes; S3. Drying the cleaned titanium metal sheet under certain temperature conditions; S4. Placing the dried titanium metal sheet in an electric heating device, and electrifying for 20-30 seconds under a voltage of 50 to 100 volts, thereby completing the first step of electric heating treatment; S5. Naturally cooling the titanium metal sheet and the electric heating device in step S4 to room temperature; S6. Continuing to place the cooled titanium metal sheet in the electric heating device, and electrifying again for 20-30 seconds under a voltage of 50 to 100 volts, thereby completing the second step of electric heating treatment, and obtaining the nano-titanium dioxide photo-anode; The electric heating device comprises an insulating block, two symmetrical metal U-shaped clamps are arranged on the insulating block, the opening ends of the two metal U-shaped clamps are oppositely arranged, and a graphite felt is arranged between the two metal U-shaped clamps, both ends of the graphite felt are fixed to the inner side surface of the metal U-shaped clamp through a bolt structure; The two closed ends of the metal U-shaped clamp are connected through a wire, and a power supply and a switch are arranged on the wire; In use, the titanium metal sheet is placed on the graphite felt for electric heating treatment.

2. The two-step rapid electro-thermal preparation method of nanometer titanium dioxide photo-anode according to claim 1, characterized in that, The thickness of the titanium metal sheet after cutting in step S1 is 0.2 mm, the width is 15 mm, and the length is 25 mm.

3. The two-step rapid electro-thermal preparation method of nanometer titanium dioxide photo-anode according to claim 1, characterized in that, The drying parameters in step S3 are: drying for 4-6 hours at a temperature range of 50-80°C.

4. Application of the nano-titanium dioxide photo-anode prepared by the preparation method of any one of claims 1-3 in a photoelectrochemical cell catalytic water decomposition reaction.

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