Two-step rapid electric heating preparation method of nano titanium dioxide photo-anode and application of two-step rapid electric heating preparation method

Abstract

The invention discloses a two-step rapid electric heating preparation method and application of a nano titanium dioxide photo-anode, and belongs to the field of new energy materials, and the preparation steps are as follows: cutting a titanium metal sheet into a rectangle, sequentially carrying out ultrasonic cleaning with acetone, ethanol and distilled water, drying, placing in an electric heating device, electrifying for 20-30 seconds under the voltage of 50-100 volts, and cooling to room temperature to obtain the nano titanium dioxide photo-anode. The first-step electric heating treatment is completed; naturally cooling; and continuously placing in the electric heating device, and electrifying for 20-30 seconds under the voltage of 50-100 volts to finish the second-step electric heating treatment, so as to obtain the nano titanium dioxide photo-anode. According to the method, the nanometer titanium dioxide photo-anode is directly and rapidly grown on the titanium metal sheet in a two-step electric heating mode, the method has the characteristics of convenience and high efficiency, the preparation time of the titanium dioxide photo-anode can be greatly shortened, and excessive use of chemical reagents can be avoided.

Description

Technical Field

[0001] The present invention belongs to the field of new energy materials, and in particular, relates to a two-step rapid electrothermal preparation method of a nano titanium dioxide photoanode and an application thereof. Background Art

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

[0003] Photoelectrocatalytic (PEC) water splitting technology uses semiconductor materials as photoelectrodes to decompose water into hydrogen and oxygen under the drive of solar energy. It is a method of directly converting solar energy into hydrogen energy. Since the oxygen evolution reaction occurring on the photoanode is a kinetically slow process compared to the hydrogen evolution reaction occurring on the photocathode, it is the main limiting factor for water splitting. So far, scientists have made a lot of attempts to develop photoanodes and have achieved considerable results. Titanium dioxide (TiO2), as an important n-type semiconductor material among many transition metal oxides, has become an important candidate for photoanode materials due to its advantages such as high stability, appropriate band edge position, non-toxicity and low cost.

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

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

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

[0007] (3) A titanium-containing solution is deposited onto a substrate such as conductive glass by spin coating technology, and then a titanium dioxide photoanode is obtained through a sol drying and high-temperature heat treatment process (for example, reference ACS Appl. Nano Mater. 2020, 3, 1, 131-137).

[0008] Most of the above methods require long-term high-temperature heat treatment, or the use of multiple chemical reagents, or the use of highly hazardous fluorine-containing solutions. Therefore, it is urgent to find a more efficient and safe method for preparing titanium dioxide photoanodes. Summary of the invention

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

[0010] The purpose of the present invention can be achieved through the following technical solutions:

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

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

[0013] S2. Clean the titanium sheet by ultrasonic cleaning with acetone, ethanol, and distilled water for 10 to 30 minutes in sequence to remove surface oil and organic matter;

[0014] S3. The cleaned titanium sheet is dried at a temperature range of 50°C to 80°C for 4-6 hours;

[0015] S4. The dried titanium sheet is placed in an electric heating device and powered on for 20-30 seconds at a voltage of 50 to 100 volts to complete the first step of the electric heating treatment;

[0016] S5. The titanium sheet and the electric heating device in step S4 are naturally cooled to room temperature;

[0017] S6. Continue to place the cooled titanium metal sheet in the electric heating device, and power on again at a voltage of 50 to 100 volts for 20-30 seconds to complete the second step of electric heating treatment; after completing the two-step electric heating preparation process, the surface of the titanium metal sheet can be oxidized by oxygen in the air due to the action of electric heating to generate a thin layer of nano-titanium dioxide. The titanium metal sheet after electric heating oxidation is the prepared nano-titanium dioxide photoanode, which can be used in solar-driven photoelectric catalytic systems such as photoelectric catalytic water decomposition.

[0018] Furthermore, the electric heating device includes an insulating block, on which two symmetrical metal U-shaped clips are arranged, the open ends of the two metal U-shaped clips are arranged opposite to each other, a graphite felt is arranged between the two metal U-shaped clips, and both ends of the graphite felt are fixed to the inner surface of the metal U-shaped clip by a bolt structure;

[0019] The two closed ends of the metal U-shaped clip are connected by a wire, and a power source and a switch are provided on the wire;

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

[0021] Another object of the present invention is to provide an application of the nano-titanium dioxide photoanode prepared by the above preparation method in the photoelectrochemical cell catalyzing water decomposition reaction. Specifically, the nano-titanium dioxide photoanode prepared by the above preparation method is inserted into a 1 mol / L potassium hydroxide aqueous solution, and the photoelectrocatalytic water decomposition reaction is carried out under a three-electrode test configuration and intermittent lighting conditions.

[0022] Beneficial effects of the present invention:

[0023] The present invention uses a two-step electric heating method to directly and quickly grow a nano titanium dioxide photoanode on a titanium metal sheet, which is convenient and efficient, can greatly shorten the preparation time of the titanium dioxide photoanode, and can avoid excessive use of chemical reagents. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

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

[0026] Figure 2 Scanning electron microscope photos of (a) titanium metal sheet; (b) titanium metal sheet after one-step electric heating; (c) nano-titanium dioxide photoanode prepared by two-step electric heating.

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

[0028] Figure 4 X-ray photoelectron spectroscopy of titanium sheet after two-step electric heating: (a) Characterization of the chemical environment of the Ti element; (b) Characterization of the chemical environment of the O element.

[0029] Figure 5 Linear sweep voltammograms of the titanium sheet after one-step and two-step electroheating in a 1 mol / L potassium hydroxide aqueous solution under three-electrode test configuration and intermittent illumination conditions for photoelectrocatalytic water splitting test.

[0030] In the figure: 1. Insulation block; 2. Metal U-shaped clamp; 3. Graphite felt; 4. Bolt structure; 5. Wire; 6. Power supply; 7. Switch. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] like Figure 1 As shown, the electric heating device used for the electric heating treatment of the present invention comprises an insulating block 1, on which two symmetrical metal U-shaped clips 2 are arranged, the open ends of the two metal U-shaped clips 2 are arranged opposite to each other, a graphite felt 3 is arranged between the two metal U-shaped clips 2, and both ends of the graphite felt 3 are fixed to the inner surface of the metal U-shaped clip 3 by a bolt structure 4;

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

[0034] When in use, the titanium metal sheet is placed on the graphite felt 3 for electric heating treatment.

[0035] Embodiment 1

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

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

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

[0039] S3. The cleaned titanium sheet was dried at 50 ° C for 6 hours;

[0040] S4. Place the dried titanium sheet on Figure 1 In the electric heating device, power is supplied at a voltage of 50 volts for 30 seconds to complete the first step of electric heating treatment;

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

[0042] S6. Place the titanium sheet after the first step of the electrothermal treatment in step S4 on Figure 1In the electric heating device, power is supplied again at a voltage of 50 volts for 30 seconds to complete the second step of electric heating treatment and obtain a nano-titanium dioxide photoanode.

[0043] like Figure 2 As shown, these are scanning electron microscope photos of a titanium metal sheet, a titanium metal sheet after one-step electric heating, and a nano-titanium dioxide photoanode prepared by two-step electric heating. Before electric heating, the surface morphology of the titanium metal sheet is relatively smooth with only a few wrinkles; after one-step electric heating, nanoparticles appear on the surface of the titanium metal sheet; after two-step electric heating, a large number of nano-sized particles appear on the surface of the titanium metal sheet, which is a nano-titanium dioxide thin layer.

[0044] like Figure 3 and Figure 4 Shown are the X-ray photoelectron spectra of the titanium metal sheet after one-step electric heating and two-step electric heating, respectively.

[0045] Embodiment 2

[0046] A two-step rapid electrothermal preparation method for a nano titanium dioxide photoanode is as follows:

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

[0048] S2. Clean the titanium sheet by ultrasonic cleaning with acetone, ethanol, and distilled water for 20 minutes in sequence to remove surface oil and organic matter;

[0049] S3. The cleaned titanium sheet was dried at 65 ° C for 5 hours;

[0050] S4. Place the dried titanium sheet on Figure 1 In the electric heating device, power is supplied at a voltage of 75 volts for 25 seconds to complete the first step of electric heating treatment;

[0051] S5. Make the titanium metal sheet and Figure 1 The electric heating device is cooled naturally to room temperature;

[0052] S6. Place the titanium sheet after the first step of the electrothermal treatment in step S4 on Figure 1 In the electric heating device, power was turned on again at a voltage of 75 volts for 25 seconds to complete the second step of electric heating treatment and obtain a nano-titanium dioxide photoanode.

[0053] Embodiment 3

[0054] A two-step rapid electrothermal preparation method for a nano titanium dioxide photoanode is as follows:

[0055] S1. Cut the titanium sheet into a rectangular shape, the thickness of the titanium sheet is 0.2 mm, the width is 15 mm, and the length is 25 mm;

[0056] S2. Clean the titanium sheet by ultrasonic cleaning with acetone, ethanol, and distilled water for 30 minutes in sequence to remove surface oil and organic matter;

[0057] S3. The cleaned titanium sheet was dried at 80 ° C for 4 hours;

[0058] S4. Place the dried titanium sheet on Figure 1 In the electric heating device, power is supplied at a voltage of 100 volts for 20 seconds to complete the first step of electric heating treatment;

[0059] S5. Make the titanium metal sheet and Figure 1 The electric heating device is cooled naturally to room temperature;

[0060] S6. Place the titanium sheet after the first step of the electrothermal treatment in step S4 on Figure 1 In the electric heating device, power is supplied again at a voltage of 100 volts for 20 seconds to complete the second step of electric heating treatment and obtain a nano-titanium dioxide photoanode.

[0061] application

[0062] The nano-titanium dioxide photoanode prepared by two-step electrothermal treatment in Example 1 was used in a photoelectrochemical cell to catalyze water decomposition. The nano-titanium dioxide photoanode prepared above was inserted into a 1 mol / L potassium hydroxide aqueous solution, and a photoelectrochemical water decomposition test was performed under a three-electrode test configuration and intermittent illumination conditions. The linear sweep voltammetric curve is shown in FIG. Figure 5 As shown. It can be seen that the nano titanium dioxide photoanode has a strong light response when illuminated, and its performance is comparable to that of the photoanode obtained by the main preparation method of titanium dioxide photoanode at present.

[0063] The above specific implementation method part specifically introduces the analytical method involved in the present invention. It should be noted that the above introduction is only to help those skilled in the art better understand the method and ideas of the present invention, rather than limiting the relevant content. Without departing from the principle of the present invention, those skilled in the art may also make appropriate adjustments or modifications to the present invention, and the above adjustments and modifications shall also fall within the scope of protection of the present invention.

Claims

1. A two-step rapid electrothermal preparation method for nano-titanium dioxide photoanode, characterized in that: The specific steps are as follows: S1. Cut the titanium sheet into a rectangular shape; S2. Clean the titanium sheet by ultrasonic cleaning with acetone, ethanol and distilled water for 10 to 30 minutes in sequence; S3. The cleaned titanium sheet is dried under certain temperature conditions; S4. The dried titanium sheet is placed in an electric heating device and powered on for 20-30 seconds at a voltage of 50 to 100 volts to complete the first step of the electric heating treatment; S5. The titanium sheet and the electric heating device in step S4 are naturally cooled to room temperature; S6. The cooled titanium metal sheet is placed in the electric heating device again and powered on again at a voltage of 50 to 100 volts for 20 to 30 seconds to complete the second step of electric heating treatment and obtain the nano titanium dioxide photoanode.

2. The two-step rapid electrothermal preparation method of nano titanium dioxide photoanode according to claim 1, characterized in that: The titanium metal sheet cut in step S1 has a thickness of 0.2 mm, a width of 15 mm, and a length of 25 mm.

3. The two-step rapid electrothermal preparation method of nano titanium dioxide photoanode according to claim 1, characterized in that: Drying parameters in step S3: drying at a temperature range of 50° C. to 80° C. for 4-6 hours.

4. The two-step rapid electrothermal preparation method of nano titanium dioxide photoanode according to claim 1, characterized in that: The electric heating device comprises an insulating block, on which two symmetrical metal U-shaped clips are arranged, the open ends of the two metal U-shaped clips are arranged opposite to each other, a graphite felt is arranged between the two metal U-shaped clips, and both ends of the graphite felt are fixed to the inner surface of the metal U-shaped clip by a bolt structure; The two closed ends of the metal U-shaped clip are connected by a wire, and a power source and a switch are provided on the wire; When in use, the titanium metal sheet is placed on the graphite felt for electric heating treatment.

5. Use of the nano titanium dioxide photoanode prepared according to the preparation method according to any one of claims 1 to 4 in catalyzing water decomposition reaction in a photoelectrochemical cell.

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