Preparation method of nano oxide film photoelectrode

Abstract

The invention discloses a preparation method of a nano oxide film photoelectrode, and belongs to the technical field of new energy materials, the preparation method of the nano oxide film photoelectrode comprises the following steps: cutting a metal substrate into a proper size, cleaning and drying; placing the dried metal substrate on plasma flames generated by discharging of a high-frequency solid Tesla coil for oxidation treatment; and cooling to obtain the metal oxide film photoelectrode. According to the method, the high-frequency solid Tesla coil is used for rapidly preparing the nano oxide film photoelectrode on the metal substrate, the method has the advantages of being convenient, rapid, efficient and energy-saving, the preparation time of preparing the photoelectrode on the metal substrate can be greatly shortened, and excessive use of chemical reagents can be avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy materials, and specifically relates to a method for preparing a nano-oxide thin film photoelectrode. Background Art

[0002] Photoelectrocatalytic (PEC) water splitting hydrogen production technology uses semiconductor thin-film materials as photoelectrodes to decompose water into hydrogen and oxygen under solar energy. This technology directly converts solar energy into hydrogen and stores energy. Transition metal oxides such as TiO2, Fe2O3, Cu2O, and CuO are the most commonly used photoelectrode (including photoanode and photocathode) materials in PEC water splitting hydrogen production due to their abundant resources and the fact that most materials are non-toxic and harmless.

[0003] Currently, the main preparation technologies for preparing metal oxide photoelectrodes on metal substrates include: inserting a metal sheet into an electrolyte solution, especially a fluorine-containing electrolyte solution, oxidizing the surface of the metal sheet through anodization technology, and then obtaining a metal oxide photoelectrode through high-temperature treatment after several hours; growing a precursor film on a metal substrate through a hydrothermal method or a solvent thermal method. This process usually takes several hours and requires several chemical reagents; then heat-treating the precursor film through a muffle furnace and other heat treatment equipment to convert it into a metal oxide photoelectrode. This process usually also takes several hours; and preparing a metal oxide photoelectrode by directly oxidizing the metal surface through thermal oxidation technology.

[0004] Most of the above methods require prolonged high-temperature heat treatment, the use of multiple chemical reagents, or the use of highly hazardous fluorine-containing solutions. Therefore, there is an urgent need to find more efficient and energy-efficient methods for directly preparing metal oxide photoelectrodes on metal substrates. To address this problem, the present invention provides the following technical solutions. Summary of the Invention

[0005] The present invention aims to provide a method for preparing nano-oxide thin-film photoelectrodes, addressing the existing problems with metal oxide photoelectrodes, which often require prolonged high-temperature heat treatment, the use of multiple chemical reagents, or the use of highly hazardous fluorine-containing solutions. Consequently, there is an urgent need for more efficient and energy-saving methods for directly preparing metal oxide photoelectrodes on metal substrates.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A method for preparing a nano-oxide thin film photoelectrode comprises the following steps: Step 1: Cut the metal substrate into appropriate size, clean and dry it; Step 2: placing the dried metal substrate on a plasma flame generated by a high-frequency solid-state Tesla coil discharge for oxidation treatment; After cooling, a metal oxide thin film photoelectrode is obtained.

[0007] As a further solution of the present invention, the method for cleaning the metal substrate is: ultrasonic cleaning in acetone, ethanol, and distilled water in sequence.

[0008] As a further embodiment of the present invention, the duration of ultrasonic cleaning in each solvent is 4-7 minutes.

[0009] As a further solution of the present invention, the metal substrate is metal titanium, metal tungsten or metal copper.

[0010] As a further embodiment of the present invention, the oxidation treatment time is 1-60 seconds.

[0011] Beneficial effects of the present invention: The present invention uses a high-frequency solid-state Tesla coil to quickly prepare nano-oxide thin film photoelectrodes on a metal substrate, which is convenient, fast, efficient, and energy-saving. It can greatly shorten the preparation time of photoelectrodes on metal substrates and avoid the excessive use of chemical reagents. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention will be further described below with reference to the accompanying drawings.

[0013] Figure 1 is the X-ray diffraction pattern of the prepared titanium dioxide photoanode; Figure 2 a is a scanning electron microscope photograph of titanium metal, and b is a scanning electron microscope photograph of the titanium dioxide photoanode prepared in Example 1; Figure 3 is a linear sweep voltammetric curve of the photoelectrocatalytic water splitting test performed under the three-electrode test configuration and intermittent illumination conditions in Example 1; Figure 4 This is the X-ray diffraction pattern of the copper oxide photocathode prepared in Example 2; Figure 5 a is a scanning electron microscope photo of metallic copper, and b is a scanning electron microscope photo of the prepared copper oxide photocathode; Figure 6 The linear sweep voltammetry curve of the photoelectrocatalytic water splitting test in the three-electrode test configuration and intermittent illumination conditions in Example 2; Figure 7 Schematic diagram of high-frequency solid-state Tesla coil discharge generating plasma flame. DETAILED DESCRIPTION

[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making any creative efforts shall fall within the scope of protection of the present invention.

[0015] A method for preparing a nano-oxide thin film photoelectrode comprises the following steps: Step 1: Cut the metal substrate into appropriate sizes, then ultrasonically clean it in acetone, ethanol, and distilled water for 4-7 minutes, and then dry it naturally. Step 2: Place the dried metal substrate on a plasma flame generated by a high-frequency solid-state Tesla coil (HFSSTC) discharge for oxidation treatment; The processing time is 1-60 seconds. After being removed and cooled, the metal oxide thin film photoelectrode can be obtained.

[0016] The metal substrate can be metal titanium, metal tungsten, metal copper, etc. The high-frequency solid-state Tesla coil (HFSSTC) is a modern, solid-state improvement of the traditional Tesla coil. It replaces the traditional spark gap or vacuum tube with a semiconductor switching device (such as a MOSFET or IGBT), and combines high-frequency resonance technology (hundreds of kHz to MHz) to achieve efficient energy transmission and arc discharge. When the electric field strength formed between the end of the secondary coil and the surrounding environment exceeds the breakdown threshold of air, it ionizes gas molecules in the air, generating a flame-like discharge plasma. For example, when oxygen (O2) molecules in the air are ionized by the discharge of a high-frequency solid-state Tesla coil, highly reactive oxidizing species such as atomic oxygen (O), ozone (O3), and oxygen ions (O⁻, O2⁻) are produced. These particles have extremely strong oxidizing properties and can react rapidly with metal surfaces.

[0017] Based on this principle, metal sheets such as titanium sheets and copper sheets are placed above the high-frequency solid-state Tesla coil plasma flame, and the corresponding metal oxide photoelectrodes can be prepared directly on the surface of the metal sheet within seconds.

[0018] The schematic diagram of the high-frequency solid-state Tesla coil generating a discharge plasma flame is shown in the figure below. Figure 7 As shown, the input voltage is 12-36V and the current is 2-5A. Reference numeral 1 represents the base, 2 represents the cooling fan, 3 represents the support mechanism, 4 represents the heat sink, 5 represents the circuit control system, 6 represents the primary coil, 7 represents the secondary coil, 8 represents the discharge terminal, and 9 represents the plasma flame generated by the discharge. This structure is prior art and will not be described in detail here.

[0019] Example 1 Preparation of titanium dioxide photoanode on titanium substrate S1. Cutting a titanium metal sheet into a rectangular titanium substrate, wherein the titanium metal sheet has a thickness of 0.1 mm, a width of 10 mm, and a length of 20 mm; S2, cleaning the cut titanium substrate; The cleaning method is: Ultrasonic cleaning was performed with acetone, ethanol, and distilled water for 5 minutes in sequence to remove surface oil and organic matter, and then the surface was dried naturally. S3. Place the metal titanium substrate on the plasma flame generated by high-frequency solid-state Tesla coil discharge for oxidation treatment. The treatment time is 10 seconds. After being removed and cooled, the titanium dioxide thin film photoanode can be obtained.

[0020] like Figure 1 As shown, it can be seen from the X-ray diffraction pattern of the prepared titanium dioxide photoanode that the main component of the prepared titanium dioxide photoanode is titanium dioxide.

[0021] like Figure 2 As shown, from the comparison of the scanning electron microscope photos of the prepared titanium dioxide photoelectrode and the metal titanium substrate, it can be seen that the prepared titanium dioxide photoanode is mainly composed of particles with a size of less than 100 nanometers.

[0022] The titanium dioxide photoanode prepared above was used in a photoelectrochemical cell to catalyze water decomposition reaction.

[0023] The prepared nano-titanium dioxide photoanode was inserted into a potassium hydroxide aqueous solution with a molar concentration of 1 mol / L, and a photoelectrocatalytic water splitting test was carried out under a three-electrode test configuration and intermittent illumination conditions. The linear sweep voltammetry curve is shown in FIG. Figure 3 As shown in the figure, it can be seen that the nano-titanium dioxide photoanode has a strong light response when illuminated, indicating that this method can quickly and efficiently prepare nanostructured photoelectrodes.

[0024] Example 2 Preparation of copper oxide (containing cupric oxide and cuprous oxide) photocathode on a metallic copper substrate S1. Cut the copper metal sheet into a rectangular copper substrate, wherein the copper metal sheet has a thickness of 0.1 mm, a width of 10 mm, and a length of 20 mm; S2, cleaning the metal copper substrate; The cleaning method is: Ultrasonic cleaning was performed with acetone, ethanol, and distilled water for 5 minutes in sequence to remove surface oil and organic matter, and then the surface was dried naturally. S3. Place the metal copper substrate on the plasma flame generated by high-frequency solid-state Tesla coil discharge for oxidation treatment. The treatment time is 10 seconds. After being removed and cooled, a copper oxide thin film photocathode can be obtained.

[0025] like Figure 4 As shown, from the X-ray diffraction pattern of the prepared copper oxide photocathode, it can be seen that the main components of the prepared copper oxide photocathode are copper monoxide and cuprous oxide; like Figure 5 As shown, from the comparison of the scanning electron microscope photos of the prepared copper oxide photoelectrode and the metal titanium copper substrate, it can be seen that the prepared copper oxide photocathode is mainly composed of particles with a size of less than 100 nanometers.

[0026] The prepared nano-copper oxide photocathode is used in a photoelectrochemical cell to catalyze water decomposition reaction.

[0027] The nano-copper oxide photocathode prepared above was inserted into a sodium sulfate aqueous solution with a molar concentration of 0.5 mol / L, and a photoelectrocatalytic water splitting test was carried out under a three-electrode test configuration and intermittent illumination conditions. The linear sweep voltammetry curve is shown in FIG. Figure 6 As shown in the figure, it can be seen that the nano-copper oxide photocathode has a strong light response when illuminated, which further shows that this method can quickly and efficiently prepare nanostructured photoelectrodes.

[0028] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a nano-oxide thin film photoelectrode, characterized in that: The steps include: Step 1: Cut the metal substrate into appropriate size, clean and dry it; Step 2: placing the dried metal substrate on a plasma flame generated by a high-frequency solid-state Tesla coil discharge for oxidation treatment; After cooling, a metal oxide thin film photoelectrode is obtained.

2. The method for preparing a nano-oxide thin film photoelectrode according to claim 1, characterized in that: The method for cleaning the metal substrate is: ultrasonic cleaning in acetone, ethanol and distilled water in sequence.

3. The method for preparing a nano-oxide thin film photoelectrode according to claim 2, characterized in that: The duration of ultrasonic cleaning in each solvent ranged from 4 to 7 minutes.

4. The method for preparing a nano-oxide thin film photoelectrode according to claim 1, characterized in that: The metal substrate is metal titanium, metal tungsten or metal copper.

5. The method for preparing a nano-oxide thin film photoelectrode according to claim 1, characterized in that: The oxidation treatment time is 1-60 seconds.

6. Use of the nano-oxide thin film photoelectrode prepared by the preparation method according to any one of claims 1 to 5 in photoelectrocatalytic water decomposition.

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