A method for constructing a semiconductor photoelectrode universal and recycled isotropic pyrolytic graphite conductive current collector

Abstract

The application relates to the field of photoelectric catalysis, in particular to a method for constructing isotropic pyrolytic graphite conductive current collectors which can be universally used and recycled for semiconductor photoelectrodes. The isotropic pyrolytic graphite is used as a conductive base body, and different kinds of semiconductor thin films can be grown on the surface of the isotropic pyrolytic graphite as photoelectrodes by using the advantages of the isotropic pyrolytic graphite such as high work function, high conductivity, corrosion resistance and high temperature resistance. In addition, the semiconductor thin films grown on the base body can be removed by mechanical peeling and other means, the isotropic pyrolytic graphite base body is recycled and reused for growing semiconductor thin film photoelectrodes, and the photoelectrochemical performance test of the photoelectrodes can be carried out in various solutions, and the isotropic pyrolytic graphite conductive current collector still remains stable. The application solves the problems of the traditional conductive base body for photoelectrodes, such as not resistant to high temperature and reducing atmosphere, and the problem of hydrogen embrittlement of the metal base in a high-temperature reducing atmosphere, and the isotropic pyrolytic graphite base body can be recycled.

Description

Technical Field

[0001] This invention relates to the field of photoelectrocatalysis, specifically to a method for constructing a universal and recyclable isotropic pyrolytic graphite conductive current collector with semiconductor photoelectrodes. Background Technology

[0002] Photoelectrocatalytic water splitting holds promise for solving the energy crisis. However, the conductive current collectors in photoelectrodes, a crucial component of photocatalysis, currently have limited options. Traditional conductive current collectors are primarily transparent conductive oxides like FTO and ITO, or opaque metal substrates. However, FTO and ITO suffer severe deformation and decreased conductivity at heat treatment temperatures above 700℃; while metal substrates are prone to hydrogen embrittlement in high-temperature reducing atmospheres. Furthermore, traditional electrodes are easily corroded in strong acid or alkali systems. Specifically, ITO exhibits indium leaching at pH below 5, while metals and FTO undergo chemical reactions. In addition, commonly used copper-based photocathodes often require a high work function transition layer between FTO and the copper-based semiconductor film to form an ohmic contact, accelerate carrier separation, and improve the photo / electrochemical performance of the resulting copper-based semiconductor film. Moreover, current traditional photoelectrode current collectors are difficult to regenerate with consistent semiconductor array films for photoelectrochemical research through recycling, hindering energy conservation, emission reduction, and compliance with green chemistry requirements.

[0003] In conclusion, the development of high-temperature resistant, high-conductivity, corrosion-resistant, high-power-function, and recyclable conductive current collectors is of great significance for the fields of photoelectrocatalysis and green chemistry. This is also an urgent issue that needs to be addressed for the future application of optoelectronic materials in specialized fields and for reducing the cost of commercial applications. Summary of the Invention

[0004] The purpose of this invention is to provide a method for constructing a universal and recyclable isotropic pyrolytic graphite conductive current collector for semiconductor photoelectrodes. This method solves the problems faced by traditional photoelectrode current collectors, such as insensitivity to acids and alkalis, high-temperature deformation and deactivation, hydrogen embrittlement, and inability to be repeatedly recycled. It also enriches the types of conductive substrates in the field of photoelectrocatalysis and promotes the development of green chemistry.

[0005] The technical solution of this invention is:

[0006] A method for constructing a universal and recyclable isotropic pyrolytic graphite conductive current collector with semiconductor photoelectrodes is disclosed. Using isotropic pyrolytic graphite as the conductive substrate, and leveraging its high work function, high conductivity, corrosion resistance, and high temperature resistance, various types of semiconductor thin films are grown on its surface using different synthesis methods to serve as photoelectrodes. Furthermore, after removing the semiconductor thin films grown on the substrate, the isotropic pyrolytic graphite substrate is recycled and reused for growing semiconductor thin film photoelectrodes. The photoelectrochemical performance of the photoelectrodes is tested in various solutions, while the isotropic pyrolytic graphite conductive current collector remains stable.

[0007] The method for constructing a semiconductor photoelectrode that is universal and recyclable isotropic pyrolytic graphite conductive current collector, wherein the isotropic pyrolytic graphite includes pure phase or other element-doped isotropic pyrolytic graphite, and its preparation method is chemical vapor deposition.

[0008] The method for constructing a universal and recyclable isotropic pyrolytic graphite conductive current collector for semiconductor photoelectrodes, wherein the doped isotropic pyrolytic graphite contains one or more non-metallic and metallic elements.

[0009] The method for constructing a universal and recyclable isotropic pyrolytic graphite conductive current collector for semiconductor photoelectrodes uses one or more of nitrogen, boron, and silicon as non-metallic elements, and one or more of zirconium, tantalum, and copper as metallic elements.

[0010] The method for constructing a universal and recyclable isotropic pyrolytic graphite conductive current collector for semiconductor photoelectrodes involves heat-treating the isotropic pyrolytic graphite after the growth of the semiconductor thin film. The conductivity remains unchanged and no deformation occurs. The heat treatment temperature is between 100 and 1500°C, the heat treatment time is between 5 min and 48 h, and the heating rate is between 1 and 30°C / min.

[0011] The method for constructing a universal and recyclable isotropic pyrolytic graphite conductive current collector for semiconductor photoelectrodes allows the photoelectrochemical performance to be tested under strong acid or strong alkali conditions, and the photoelectrode still functions stably.

[0012] The method for constructing a universal and recyclable isotropic pyrolytic graphite conductive current collector for semiconductor photoelectrodes includes various synthesis methods for growing semiconductor thin films on the surface of isotropic pyrolytic graphite, such as electrochemical deposition, magnetron sputtering, atomic layer deposition, hydrothermal deposition, thermal evaporation, or high-temperature chemical vapor deposition.

[0013] The method for constructing a universal and recyclable isotropic pyrolytic graphite conductive current collector for semiconductor photoelectrodes involves growing semiconductor thin films on the surface of isotropic pyrolytic graphite, including metal oxides, metal nitrides, metal borides, and metal oxynitrogen compounds or metal oxysulfur compounds, with a thickness of 1 nm to 20 μm.

[0014] The method for constructing a universal and recyclable isotropic pyrolytic graphite conductive current collector for semiconductor photoelectrodes includes removing the semiconductor thin film grown on the isotropic pyrolytic graphite substrate by means of: sanding, ultrasonic cleaning, acid and alkali etching, cutting, and pasting, and the number of treatments is one or more.

[0015] The method for constructing a universal and recyclable isotropic pyrolytic graphite conductive current collector for semiconductor photoelectrodes involves recycling the isotropic pyrolytic graphite substrate and then regrowing a semiconductor thin film, resulting in a semiconductor thin film photoelectrode with unchanged performance.

[0016] The design concept of this invention is as follows:

[0017] Graphite materials possess high-temperature structural and mechanical stability, along with excellent properties such as high conductivity, high work function, and resistance to strong acids and alkalis, making them ideal materials for fabricating photoelectrode current collectors. However, graphite materials prepared using traditional processes lack airtightness due to their high open porosity, while thin films or bulk materials made from nanomaterials such as graphene are unsuitable as conductive current collectors due to poor mechanical properties and interlayer bonding. This invention discovers that isotropic pyrolytic graphite prepared by chemical vapor deposition simultaneously possesses excellent airtightness, high-temperature stability, mechanical properties, resistance to acid and alkali corrosion, and high work function. Copper-based photocathodes with ohmic contacts can be directly grown on its surface to achieve high work function characteristics, and high-temperature resistant photoelectrode semiconductor films can also be fabricated on its surface, replacing metal current collectors that suffer from hydrogen embrittlement problems under high-temperature reducing atmospheres. More importantly, isotropic pyrolytic graphite has the same structure and properties in any direction and is easy to process. Therefore, by processing away the semiconductor array film on the surface of isotropic pyrolytic graphite, a photoelectrode array film can be prepared again, realizing the recycling of conductive current collectors and maintaining the same photoelectric properties.

[0018] The advantages and beneficial effects of this invention are:

[0019] 1. This invention develops and constructs a universal and recyclable isotropic pyrolytic graphite conductive current collector for semiconductor photoelectrodes, solving the problems of acid and alkali resistance, high-temperature deformation and deactivation, and hydrogen embrittlement faced by traditional photoelectrode current collectors. It enriches the types of conductive substrates in the field of photoelectrocatalysis and promotes the development of electrode materials in photoelectrocatalysis and devices.

[0020] 2. The isotropic pyrolytic graphite used in this invention can maintain its conductivity at room temperature even at high temperatures, which greatly contributes to the development of semiconductor thin film photoelectrodes that require high-temperature processing.

[0021] 3. The isotropic pyrolytic graphite used in this invention can be processed to remove the semiconductor array film on the surface and then used to prepare a photoelectrode film again. This process can be repeated multiple times, and the photoelectrode still has the same photoelectric properties.

[0022] 4. The isotropic pyrolytic graphite used in this invention can reduce the cost of materials and the use of metal consumables through recycling.

[0023] 5. This invention solves the problems of traditional FTO (or ITO) conductive substrates used in photoelectrodes being intolerant to high temperatures and reducing atmospheres, as well as the problem of hydrogen embrittlement of metal substrates in high-temperature reducing atmospheres. At the same time, the isotropic pyrolytic graphite substrate can be reused, enriching the types of conductive substrates in the field of photoelectrocatalysis, and is expected to promote the assembly of new photoelectrodes and the development of green energy chemistry. Attached Figure Description

[0024] Figure 1 The XRD patterns of the obtained isotropic pyrolytic graphite and graphite prepared by conventional process are shown. The horizontal axis 2Theta is the diffraction angle 2θ (degree), and the vertical axis Intensity is the diffraction peak intensity (au).

[0025] Figure 2 Scanning electron microscope (SEM) images of the cross-section of isotropic pyrolytic graphite.

[0026] Figure 3 Scanning electron microscope (SEM) image of the top view of the obtained isotropic pyrolytic graphite.

[0027] Figure 4 The curves showing the change of sheet resistance of isotropic pyrolytic graphite and FTO with temperature are shown. The horizontal axis represents temperature (°C), and the vertical axis represents sheet resistance (milliohms).

[0028] Figure 5 The XRD patterns of the isotropic pyrolytic graphite and the cuprous oxide array films grown by FTO are shown. The horizontal axis 2Theta is the diffraction angle 2θ (degree), and the vertical axis Intensity is the diffraction peak intensity (au).

[0029] Figure 6 Scanning electron microscope (SEM) image of the top view of the isotropic pyrolytic graphite-grown cuprous oxide array film.

[0030] Figure 7Scanning electron microscope (SEM) image of the cross-section of the isotropic pyrolytic graphite-grown cuprous oxide array film.

[0031] Figure 8 The obtained photocurrent polarization curves of isotropic pyrolytic graphite and FTO-grown cuprous oxide array films are shown. The horizontal axis, Potential, represents the potential relative to the reversible hydrogen electrode (V vs. RHE), and the vertical axis, J, represents the current density (mA / cm²). 2 ).

[0032] Figure 9 The XRD pattern of tantalum grown from isotropic pyrolytic graphite is shown. The horizontal axis 2Theta represents the diffraction angle 2θ (degree), and the vertical axis Intensity represents the diffraction peak intensity (au).

[0033] Figure 10 A scanning electron microscope (SEM) image of the top view of the isotropic pyrolytic graphite-grown tantalum metal obtained.

[0034] Figure 11 Scanning electron microscope (SEM) image of the cross section of the isotropic pyrolytic graphite-grown tantalum metal.

[0035] Figure 12 The XRD patterns of the isotropic pyrolytic graphite and tantalum nanorod array films grown from tantalum nanorods are shown. The horizontal axis 2Theta represents the diffraction angle 2θ (degree), and the vertical axis Intensity represents the diffraction peak intensity (au).

[0036] Figure 13 Scanning electron microscope (SEM) image of the top view of the isotropic pyrolytic graphite-grown tantalum nitride nanorod array film.

[0037] Figure 14 Scanning electron microscope (SEM) image of the cross-section of the isotropic pyrolytic graphite-grown tantalum nitride nanorod array film.

[0038] Figure 15 The photocurrent polarization curves obtained after growing tantalum nitride nanorod array films from isotropic pyrolytic graphite and tantalum metal are shown. The horizontal axis, Potential, represents the potential relative to the reversible hydrogen electrode (V vs. RHE), and the vertical axis, J, represents the current density (mA / cm²). 2 ).

[0039] Figure 16 The XRD pattern of the isotropic pyrolytic graphite-grown titanium dioxide nanorod array film is shown. The horizontal axis 2Theta is the diffraction angle 2θ (degree), and the vertical axis Intensity is the diffraction peak intensity (au).

[0040] Figure 17 Scanning electron microscope (SEM) image of the top view of the isotropic pyrolytic graphite-grown titanium dioxide nanorod array film.

[0041] Figure 18 Scanning electron microscope (SEM) image of the cross-section of the isotropic pyrolytic graphite-grown titanium dioxide nanorod array film.

[0042] Figure 19 The obtained isotropic pyrolytic graphite and titanium dioxide thin films deposited on FTO by atomic layer deposition, as well as the photocurrent polarization curves obtained after high-temperature treatment, are shown. The horizontal axis, Potential, represents the potential relative to the reversible hydrogen electrode (Vvs. RHE), and the vertical axis, J, represents the current density (mA / cm²). 2 ).

[0043] Figure 20 The photocurrent polarization curves of the titanium dioxide thin film deposited on isotropic pyrolytic graphite by atomic layer deposition and the titanium dioxide nanorod array thin film regrown after high-temperature treatment are shown. The horizontal axis Potential represents the potential relative to the reversible hydrogen electrode (V vs. RHE), and the vertical axis J represents the current density (mA / cm²). 2 ).

[0044] Figure 21 The photocurrent polarization curves of the obtained isotropic pyrolytic graphite and the cuprous oxide array film grown on the reused isotropic pyrolytic graphite are shown. The horizontal axis, Potential, represents the potential relative to the reversible hydrogen electrode (V vs. RHE), and the vertical axis, J, represents the current density (mA / cm²). 2 ).

[0045] Figure 22 The photocurrent polarization curves of the obtained isotropic pyrolytic graphite and the tantalum nitride nanorod array film grown on the reused isotropic pyrolytic graphite are shown. The horizontal axis, Potential, represents the potential relative to the reversible hydrogen electrode (V vs. RHE), and the vertical axis, J, represents the current density (mA / cm²). 2 ).

[0046] Figure 23 The photocurrent polarization curves of the obtained isotropic pyrolytic graphite and the titanium dioxide nanorod array film grown on the reused isotropic pyrolytic graphite are shown. The horizontal axis, Potential, represents the potential relative to the reversible hydrogen electrode (Vvs. RHE), and the vertical axis, J, represents the current density (mA / cm²). 2 ). Detailed Implementation

[0047] In its specific implementation, this invention provides a method for constructing a reusable and recyclable isotropic pyrolytic graphite conductive current collector for semiconductor photoelectrodes. Using isotropic pyrolytic graphite as the conductive substrate, leveraging its advantages such as high work function, high conductivity, corrosion resistance, and high temperature resistance, various synthetic methods can be used to grow different types of semiconductor thin films on its surface, thereby constructing a recyclable photoelectrode. Isotropic pyrolytic graphite or doped isotropic pyrolytic graphite prepared in various ways is used as the conductive substrate. It is first subjected to ultrasonic treatment, and then different types of semiconductor array thin films are rationally grown on its surface and subjected to heat treatment. Furthermore, the semiconductor array thin films grown on the resulting isotropic pyrolytic graphite substrate can be processed (e.g., mechanical peeling) to remove the semiconductor array thin films, allowing the isotropic pyrolytic graphite substrate to be recycled and reused for growing semiconductor array thin film photoelectrodes again. The photoelectrochemical performance of the electrode is tested in various solutions, and the isotropic pyrolytic graphite conductive current collector remains stable. Specifically, the method is characterized by:

[0048] 1. The isotropic pyrolytic graphite is prepared by chemical vapor deposition. The performance parameters of the isotropic pyrolytic graphite are as follows: work function ≥ 4.9 eV, resistivity at room temperature is (3.72 ± 0.64) × 10⁻⁶. -5 It has a strength of Ω·m, good machinability, compressive strength ≥180MPa, open porosity ≤0.3%, and density ≥1.8×10⁻⁶. 3 kg / m 3 Operating temperature ≤1500℃, etc.

[0049] 2. The doped isotropic pyrolytic graphite mentioned above, wherein the doping elements include non-metallic elements (such as nitrogen, boron, silicon, etc.) or metallic elements (such as zirconium, tantalum, copper, etc.).

[0050] 3. The isotropic pyrolytic graphite undergoes heat treatment, during which its electrical conductivity remains almost unchanged and it does not deform. The heat treatment temperature is between 100 and 1500°C (preferably between 500 and 1000°C), the heat treatment time is between 5 min and 48 h (preferably between 30 min and 12 h), and the heating rate is between 1 and 30°C / min (preferably between 2 and 10°C / min).

[0051] 4. The various solution tests mentioned include various strong acid and strong alkali solutions.

[0052] 5. The methods for growing semiconductor array thin films include: electrochemical deposition, magnetron sputtering, atomic layer deposition, hydrothermal deposition, thermal evaporation, etc.

[0053] 6. The types of semiconductor array thin films grown on the surface include: metal oxides, metal nitrides, metal borides, and various semiconductors such as metal oxynitrides and metal oxysulfides.

[0054] 7. The methods for removing the semiconductor array thin film grown on the isotropic pyrolytic graphite substrate include sanding, ultrasonic cleaning, acid and alkali etching, cutting, and pasting, with sanding and ultrasonic cleaning being preferred, and the treatment can be performed multiple times.

[0055] 8. The semiconductor array film is regrown after the isotropic pyrolytic graphite matrix is ​​recycled, and the performance of the resulting semiconductor array film photoelectrode remains unchanged.

[0056] The present invention will now be further described in detail with reference to embodiments and accompanying drawings.

[0057] Example 1

[0058] In this embodiment, isotropic pyrolytic graphite prepared by chemical vapor deposition was used as the conductive substrate. First, 77.6 mL and 22.4 mL of water were measured, followed by 16 g of copper sulfate (chemical formula CuSO4). After stirring for a period of time, 5 g of sodium hydroxide (chemical formula NaOH) was weighed and stirred again. After the solution cooled to room temperature, an electrochemical deposition method was used, with a Pt sheet as the positive electrode and isotropic pyrolytic graphite as the negative electrode. The deposition current was 3 mA and the deposition time was 4 h. After deposition, the solution was washed with ethanol and deionized water in sequence and dried with nitrogen to obtain a cuprous oxide array film (chemical formula Cu2O) supported by an isotropic pyrolytic graphite substrate, with a thickness of 5 micrometers.

[0059] like Figure 1 As shown, the XRD patterns of isotropic pyrolytic graphite and ordinary graphite are obtained. Compared with ordinary graphite, the (002) diffraction peak of isotropic pyrolytic graphite is stronger, but not sharp. The remaining fine diffraction lines are not obvious, which is consistent with the characteristics of disordered layer structure.

[0060] like Figure 2 As shown, the scanning electron microscope (SEM) image of the cross-section of the isotropic pyrolytic graphite reveals that it is composed of spherical particles and lamellar graphite.

[0061] like Figure 3 As shown, the scanning electron microscope (SEM) image of the top view of isotropic pyrolytic graphite has the same morphology as the top view, indicating that isotropic pyrolytic graphite has the same properties in each direction.

[0062] like Figure 4 As shown, the sheet resistance of isotropic pyrolytic graphite and FTO varies with temperature. The resistance of FTO is three orders of magnitude higher than that of isotropic pyrolytic graphite, and the resistance increases sharply with increasing temperature, while that of isotropic pyrolytic graphite remains unchanged. This indicates that isotropic pyrolytic graphite is an excellent conductive current collector.

[0063] like Figure 5As shown, the XRD patterns of the isotropic pyrolytic graphite and FTO after growing cuprous oxide array films are shown. The appearance of cuprous oxide diffraction peaks indicates that cuprous oxide was successfully deposited on the isotropic pyrolytic graphite and FTO substrates.

[0064] like Figure 6 The image shown is a scanning electron microscope (SEM) image of the top view of the isotropic pyrolytic graphite-grown cuprous oxide array film, which shows that a cone-shaped cuprous oxide array film was obtained.

[0065] like Figure 7 As shown, the scanning electron microscope (SEM) image of the cross-section of the isotropic pyrolytic graphite-grown cuprous oxide array film shows that the prepared cuprous oxide has a thickness of 5 micrometers.

[0066] like Figure 8 As shown, the photocurrent polarization curves of the isotropic pyrolytic graphite and the cuprous oxide array film grown on FTO are obtained. The photocurrent value of the cuprous oxide array film grown on isotropic pyrolytic graphite is 1.5 times that grown on FTO. This is because the high work function of isotropic pyrolytic graphite forms an ohmic contact with cuprous oxide, promoting carrier separation. (Note: The work function of isotropic pyrolytic graphite is 4.9 eV, cuprous oxide is 4.82 eV, and FTO is 4.46 eV.)

[0067] Example 2

[0068] In this embodiment, isotropic pyrolytic graphite prepared by chemical vapor deposition was used as the conductive substrate. A tantalum target was sputtered using magnetron sputtering with a DC power supply under an argon atmosphere. The sputtering pressure was 0.8 Pa, the sputtering power was 30 W, and the sputtering time was 20 minutes, resulting in a tantalum film supported by the isotropic pyrolytic graphite substrate. Using the obtained tantalum film supported by the isotropic pyrolytic graphite substrate as the base, 8.4 mL of a 0.2 M hydrofluoric acid solution was measured and transferred to an 80 mL stainless steel reactor lined with polytetrafluoroethylene. A sample holder was placed inside, and then the tantalum substrate was placed on the sample holder. After sealing the reactor, it was placed in an oven and heated at 180 °C for 12 h. The reaction sample was then removed, washed sequentially with ethanol and deionized water, and dried with nitrogen to obtain an isotropic pyrolytic graphite-supported tantalum pentoxide (Ta₂O₅) nanorod array film. The obtained isotropic pyrolytic graphite-supported tantalum pentoxide nanorod array film was then heat-treated, specifically treated at 1000℃ under ammonia gas for 6 hours with an ammonia flow rate of 50 sccm and a heating rate of 10℃ / min, to obtain an isotropic pyrolytic graphite-supported tantalum nitride (chemical formula Ta3N5) nanorod array film, and its performance was tested in a strong alkaline solution with pH=14.

[0069] like Figure 9As shown, the XRD pattern of the isotropic pyrolytic graphite after the growth of tantalum metal is obtained. The appearance of tantalum diffraction peaks indicates that tantalum metal was successfully sputtered onto the isotropic pyrolytic graphite matrix.

[0070] like Figure 10 As shown, the scanning electron microscope (SEM) image of the top view of the isotropic pyrolytic graphite-grown tantalum metal shows that the sputtered tantalum metal is a dense thin film.

[0071] like Figure 11 As shown in the scanning electron microscope (SEM) image of the cross-section of the isotropic pyrolytic graphite-grown tantalum metal, it can be seen that the thickness of the sputtered tantalum metal is 1 micrometer.

[0072] like Figure 12 As shown, the XRD patterns of the isotropic pyrolytic graphite and tantalum metal after growing tantalum nitride nanorod array films are obtained. The appearance of tantalum nitride diffraction peaks indicates that tantalum nitride was successfully grown on the isotropic pyrolytic graphite and tantalum metal substrates. Moreover, the diffraction peaks of the isotropic pyrolytic graphite remain unchanged, proving that the isotropic pyrolytic graphite can withstand high-temperature reducing atmospheres.

[0073] like Figure 13 The image shown is a scanning electron microscope (SEM) image of the top view of the tantalum nitride nanorod array film grown on isotropic pyrolytic graphite. The results show that a uniform porous tantalum nitride nanorod film array was successfully prepared on the isotropic pyrolytic graphite substrate, and the diameter of the nanorods is 80 nm.

[0074] like Figure 14 The image shows a scanning electron microscope (SEM) image of the cross-section of the isotropic pyrolytic graphite-grown tantalum nitride nanorod array film, which shows that the thickness of the tantalum nitride nanorod array is 500 nm.

[0075] like Figure 15 As shown, the photocurrent polarization curves of the isotropic pyrolytic graphite and the tantalum nitride nanorod array films grown from tantalum metal show similar photocurrent values. Furthermore, the isotropic pyrolytic graphite does not fracture, indicating that it can withstand high temperatures and reducing atmospheres, thus avoiding the problem of hydrogen embrittlement in metals.

[0076] Example 3

[0077] In this embodiment, isotropic pyrolytic graphite prepared by chemical vapor deposition is used as the conductive substrate. Atomic layer deposition (ALD) is employed, using titanium tetraisopropoxide as the titanium source and water as the oxidant, at a reaction temperature of 150°C, to deposit titanium dioxide array films of varying thicknesses. The resulting isotropic pyrolytic graphite-supported amorphous titanium dioxide array films are then heat-treated at 1000°C in an argon atmosphere for 6 hours at a heating rate of 10°C / min to obtain crystalline titanium dioxide array films supported by the isotropic pyrolytic graphite substrate. A titanium dioxide nanorod array film was then grown on the surface of a crystallized titanium dioxide array film supported by an isotropic pyrolytic graphite substrate. First, 13 mL of concentrated hydrochloric acid (37 wt%) and 15 mL of water were measured and stirred for 30 minutes. Then, 440 μL of tetrabutyl titanate was added, and stirring continued for 10 minutes. The solution was then transferred to an 80 mL stainless steel reactor lined with polytetrafluoroethylene (PTFE). The isotropic pyrolytic graphite-supported titanium dioxide array film was placed at an angle against the PTFE inner substrate. After sealing the reactor, it was placed in an oven and heated at 150 °C for 6 hours. The reaction sample was then removed, washed sequentially with ethanol and deionized water, and dried with nitrogen gas to obtain the isotropic pyrolytic graphite-supported titanium dioxide nanorod array film.

[0078] like Figure 16 As shown, the XRD pattern of the isotropic pyrolytic graphite-grown titanium dioxide nanorod array film shows that, in addition to the significant diffraction peaks of isotropic pyrolytic graphite, characteristic peaks of rutile phase titanium dioxide also appear.

[0079] like Figure 17 The image shown is a scanning electron microscope (SEM) image of the top view of the isotropic pyrolytic graphite-grown titanium dioxide nanorod array film, which shows a uniformly distributed titanium dioxide nanorod array with a nanorod diameter of 500 nm.

[0080] like Figure 18 As shown in the scanning electron microscope (SEM) image of the cross-section of the isotropic pyrolytic graphite-grown titanium dioxide nanorod array film, it can be found that the thickness of the obtained titanium dioxide nanorod film array is 4 micrometers.

[0081] like Figure 19 As shown, the obtained isotropic pyrolytic graphite and titanium dioxide thin films deposited on FTO by atomic layer deposition, as well as the photocurrent polarization curves obtained after high-temperature treatment, show that when titanium dioxide of the same thickness is deposited on isotropic pyrolytic graphite, the titanium dioxide grown on isotropic pyrolytic graphite has better interfacial contact due to the better contact between titanium tetraisopropoxide and graphite than that on FTO, resulting in a larger photocurrent value. In addition, the performance of the photoelectrode is further improved after high-temperature treatment, which is beneficial for processing semiconductor array thin films that require high-temperature sintering.

[0082] like Figure 20As shown, the photocurrent polarization curves of the titanium dioxide array film deposited on isotropic pyrolytic graphite by atomic layer deposition and the titanium dioxide nanorod array film regrown after high-temperature treatment demonstrate that the titanium dioxide grown on the surface of isotropic pyrolytic graphite can be used to grow other semiconductor array films after high-temperature treatment, further improving the performance of photoelectrodes.

[0083] Example 4

[0084] In this embodiment, a recyclable photoelectrode is constructed. Specifically, the semiconductor array film on the surface of isotropic pyrolytic graphite with grown semiconductor array film is sanded off with sandpaper. The resulting isotropic pyrolytic graphite is then ultrasonically treated in 1M hydrochloric acid for 10 minutes, rinsed with water, and dried with nitrogen. The experimental procedures in Examples 1, 2, and 3 are repeated to obtain recyclable cuprous oxide array films supported by isotropic pyrolytic graphite substrates, recyclable titanium dioxide nanorod array films supported by isotropic pyrolytic graphite substrates, and recyclable tantalum nitride array films supported by isotropic pyrolytic graphite substrates, respectively.

[0085] like Figure 21 As shown, the photocurrent polarization curves of the obtained isotropic pyrolytic graphite and the recycled isotropic pyrolytic graphite after growing a cuprous oxide array film show that the photocurrent values ​​are basically the same, indicating that isotropic pyrolytic graphite can be used to construct recyclable photoelectrodes.

[0086] like Figure 22 As shown, the photocurrent polarization curves of the obtained isotropic pyrolytic graphite and the reused isotropic pyrolytic graphite after growing tantalum nitride nanorod array films show that the photocurrent values ​​are basically the same, indicating that isotropic pyrolytic graphite can be used to construct recyclable photoelectrodes.

[0087] like Figure 23 As shown, the photocurrent polarization curves of the obtained isotropic pyrolytic graphite and the reused isotropic pyrolytic graphite after growing titanium dioxide nanorod array films show that the photocurrent values ​​are basically the same, indicating that isotropic pyrolytic graphite can be used to construct recyclable photoelectrodes.

[0088] The results of the embodiments show that the present invention can construct recyclable photoelectrodes on isotropic pyrolytic graphite, which solves the problems faced by the current collectors of traditional photoelectrodes, such as insensitivity to acids and alkalis, high-temperature deformation and deactivation, hydrogen embrittlement, and inability to be repeatedly recycled. This enriches the types of conductive substrates in the field of photoelectrocatalysis and promotes the development of green chemistry.

Claims

1. A method of constructing a semiconductor photoelectrode universal and recyclable isotropic pyrolytic graphite conductive current collector, characterized by, Isotropic pyrolytic graphite is used as conductive substrate, and different kinds of semiconductor films are grown on its surface as photoelectrode by various synthesis methods due to its high work function, high conductivity, corrosion resistance and high temperature resistance. In addition, the isotropic pyrolytic graphite substrate is recycled and reused for growing semiconductor film photoelectrode after removing the semiconductor film grown on the substrate, and the photoelectrochemical performance of the photoelectrode is tested in various solutions, while the isotropic pyrolytic graphite conductive current collector remains stable. The performance parameters of the isotropic pyrolytic graphite are as follows: work function ≥ 4.9 eV, room temperature resistivity (3.72 ± 0.64) × 10 -5 Ω·m, compressive strength ≥ 180 MPa, open porosity ≤ 0.3%, density ≥ 1.8 × 10 3 kg / m 3 , working temperature ≤ 1500℃; The semiconductor films grown on the surface of isotropic pyrolytic graphite include metal oxides, metal nitrides, metal borides, and metal oxynitride or metal oxysulfide, and the thickness of the semiconductor film is 1 nm to 20 μm. The performance of the semiconductor film photoelectrode remains unchanged after recycling the isotropic pyrolytic graphite substrate and growing semiconductor film again.

2. The method of constructing a semiconductor photoelectrode versatile and recyclable isotropic pyrolytic graphite conductive current collector according to claim 1, characterized in that, The isotropic pyrolytic graphite includes pure phase or other element-doped isotropic pyrolytic graphite, and is prepared by chemical vapor deposition method.

3. The method of constructing a semiconductor photoelectrode versatile and recyclable isotropic pyrolytic graphite conductive current collector according to claim 2, characterized in that, The doped isotropic pyrolytic graphite includes one or more than two of non-metallic elements and metallic elements.

4. The method of constructing a semiconductor photoelectrode versatile and recyclable isotropic pyrolytic graphite conductive current collector according to claim 3, characterized in that, The non-metallic elements include one or more than two of nitrogen, boron and silicon, and the metallic elements include one or more than two of zirconium, tantalum and copper.

5. The method of constructing a semiconductor photoelectrode versatile and recyclable isotropic pyrolytic graphite conductive current collector according to claim 1, characterized in that, The isotropic pyrolytic graphite after growing semiconductor film is subjected to heat treatment, and its conductivity remains unchanged without deformation. The heat treatment temperature is 100-1500℃, the heat treatment time is 5 min-48 h, and the heating rate is 1-30℃ / min.

6. The method of constructing a semiconductor photoelectrode versatile and recyclable isotropic pyrolytic graphite conductive current collector according to claim 1, characterized in that, The photoelectrochemical performance test is carried out in strong acid or strong alkali environment, and the photoelectrode can still work stably.

7. The method of constructing a semiconductor photoelectrode versatile and recyclable isotropic pyrolytic graphite conductive current collector according to claim 1, characterized in that, The synthesis methods for growing semiconductor film on the surface of isotropic pyrolytic graphite include electrochemical deposition, magnetron sputtering, atomic layer deposition, hydrothermal method, thermal evaporation or high temperature chemical vapor deposition.

8. The method of constructing a semiconductor photoelectrode versatile and recyclable isotropic pyrolytic graphite conductive current collector according to claim 1, characterized in that, The ways for removing the semiconductor film grown on the isotropic pyrolytic graphite substrate include sandpaper polishing, ultrasonic cleaning, acid and alkali etching, cutting and pasting, and the processing times are one or more than two.

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