Photocatalytic device, preparation method thereof, photocatalytic layer and sterilization equipment

Abstract

The invention provides a photocatalytic device and a preparation method thereof, a photocatalytic layer and sterilization equipment, and relates to the technical field of semiconductor catalysis, and the photocatalytic device comprises a light-emitting element and the photocatalytic layer. The photocatalytic layer is arranged on the light-emitting side of the light-emitting element and comprises a photocatalytic unit, the photocatalytic unit comprises a first component and a second component, the first component comprises graphite phase carbon nitride with introduced structural defects, and the second component is in contact with the first component and is located on the surface of the first component. The material of the second component is a semiconductor material different from that of the graphite phase carbon nitride in the first component, and a heterojunction can be formed on the contact surface between the second component and the first component, so that the photocatalytic activity and the spectral range of the photocatalytic unit can be improved on the basis that the graphite phase carbon nitride with the introduced structure defect can improve the photocatalytic activity and the spectral range of the photocatalytic unit; and a heterojunction is formed between the first component and the second component, so that compounding of photo-induced electrons and holes is further inhibited.

Description

Technical Field

[0001] This application relates to the field of semiconductor catalysis technology, and particularly to a photocatalytic device and a preparation method thereof, as well as a photocatalytic layer and a sterilization device. Background Art

[0002] Among the numerous widely developed photocatalysts, graphitic carbon nitride (g-C3N4) has received increasing research attention due to its advantages such as simple preparation, low cost, and adjustable electronic structure, and has been widely used in the field of photocatalysis.

[0003] However, due to the easy recombination of photo-generated electrons and holes during the transfer process in g-C3N4, the carrier lifetime is short, resulting in a decrease in catalytic activity. At the same time, due to the narrow absorption spectrum of g-C3N4 and weak light absorption ability, it is unable to efficiently utilize sunlight, which limits the further development of g-C3N4 photocatalysts. Summary of the Invention

[0004] In view of this, this application provides a photocatalytic device and a preparation method thereof, as well as a photocatalytic layer and a sterilization device. The solutions are as follows:

[0005] A photocatalytic device includes:

[0006] A light-emitting element for emitting an illumination beam;

[0007] A photocatalytic layer located on the light-emitting side of the light-emitting element. The photocatalytic layer includes photocatalytic units, and each photocatalytic unit includes a first component and a second component;

[0008] The first component includes graphitic carbon nitride with introduced structural defects. The second component is in contact with the first component, located on the surface of the first component, and the material of the second component is a semiconductor material different from the graphitic carbon nitride in the first component. A heterojunction is formed at the contact surface between the second component and the first component;

[0009] The photocatalytic layer is activated by the illumination beam based on the photocatalytic units to achieve sterilization of the environment where the photocatalytic device is located and self-cleaning of the light-emitting element.

[0010] Optionally, the first component is graphitic carbon nitride including a first doping and a second doping;

[0011] The first doping is a cyano group, and the second doping is an oxygen atom to introduce structural defects into the graphitic carbon nitride.

[0012] Optionally, the second component is zinc indium sulfide.

[0013] Optionally, the light-emitting element includes at least one LED;

[0014] The photocatalytic layer is coated on the light-emitting surface of at least some of the at least one LED.

[0015] A sterilization device includes the photocatalytic device described in any one of the above.

[0016] A photocatalytic layer is applied to a photocatalytic device including a light-emitting element. The photocatalytic layer includes photocatalytic units, and each photocatalytic unit includes a first component and a second component;

[0017] The first component includes graphitic carbon nitride introducing structural defects. The second component is in contact with the first component, located on the surface of the first component, and the material of the second component is a semiconductor material different from the graphitic carbon nitride in the first component. A heterojunction is formed at the contact surface between the second component and the first component;

[0018] The photocatalytic layer is activated by the illumination beam of the light-emitting element based on the photocatalytic unit, so as to achieve sterilization of the environment where the photocatalytic device is located and self-cleaning of the light-emitting element.

[0019] A method for preparing a photocatalytic device includes:

[0020] Prepare a photocatalytic layer. The photocatalytic layer includes photocatalytic units, and each photocatalytic unit includes a first component and a second component; the first component includes graphitic carbon nitride introducing structural defects. The second component is in contact with the first component, located on the surface of the first component, and the material of the second component is a semiconductor material different from the graphitic carbon nitride in the first component. A heterojunction is formed at the contact surface between the second component and the first component;

[0021] Provide a light-emitting element, and dispose the photocatalytic layer on the light-emitting side of the light-emitting element. The light-emitting element emits an illumination beam;

[0022] The photocatalytic layer is activated by the illumination beam based on the photocatalytic unit to generate active free radicals, so as to achieve sterilization of the environment where the photocatalytic device is located and self-cleaning of the light-emitting element.

[0023] Optionally, preparing the photocatalytic layer includes:

[0024] Prepare the first component, which is graphitic carbon nitride including first doping and second doping; wherein, the first doping is cyano group and the second doping is oxygen atom to introduce structural defects into the graphitic carbon nitride.

[0025] Form the second component on the surface of the first component to form the photocatalytic layer; wherein, the second component is zinc indium sulfide.

[0026] Optionally, preparing the first component includes:

[0027] Mix urea and ascorbic acid in a first preset ratio to form a first mixture;

[0028] Transfer the first mixture to a crucible and place it in a muffle furnace. Under the atmosphere of air, heat it to a first preset temperature at a preset heating rate and keep it warm for a first preset time to obtain the first component.

[0029] Optionally, forming the second component on the surface of the first component includes:

[0030] Disperse a first preset amount of the first component into a second preset amount of acidic water to obtain a second mixture;

[0031] Disperse zinc chloride anhydrous, thioacetamide and indium(III) chloride tetrahydrate in a second preset ratio into the second mixture and react at a second preset temperature for a second preset time to form the second component on the surface of the first component.

[0032] Compared with the related art, the beneficial effects of the technical solution of the present application are as follows:

[0033] The photocatalytic device includes: a light-emitting element and a photocatalytic layer. The photocatalytic layer is disposed on the light-emitting side of the light-emitting element and is composed of a photocatalytic unit including a first component and a second component. The first component includes graphitic carbon nitride with introduced structural defects. The second component is in contact with the first component and is located on the surface of the first component. Among them, the material of the second component is a semiconductor material different from the graphitic carbon nitride in the first component, and a heterojunction can be formed at the contact surface between the second component and the first component.

[0034] As described above, based on the improvement of the catalytic activity and spectral range of the photocatalytic unit by the structural defects of graphitic carbon nitride in the photocatalytic device, the heterojunction formed between the first component and the second component by the second component is utilized to inhibit the recombination of photogenerated electrons and holes, further enhancing the photocatalytic activity of the photocatalytic layer, so as to effectively solve the problems of fast recombination rate of photogenerated electron-hole pairs and weak light absorption ability of graphitic carbon nitride. Therefore, the photocatalytic layer of the photocatalytic device has strong photocatalytic activity and a wide spectral range, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0036] The structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those who are familiar with this technology to understand and read, and are not used to limit the limited conditions that can be implemented in the present application. Therefore, they do not have technical substance significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present application can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present application.

[0037] Figure 1 It is a schematic structural diagram of a photocatalytic device provided by the present application;

[0038] Figure 2 It is a comparison diagram of the catalytic capabilities of the photocatalytic layer and other different photocatalytic materials in a photocatalytic device provided by the present application;

[0039] Figure 3 It is an SEM diagram of the photocatalytic layer and other different photocatalytic materials in a photocatalytic device provided by the present application;

[0040] Figure 4 It is a flowchart of the preparation method of a photocatalytic device provided by the present application;

[0041] Figure 5 It is a comparison diagram of X-ray diffraction peaks of the photocatalytic layer in a photocatalytic device provided by the present application;

[0042] Figure 6 It is a Fourier transform infrared spectrum diagram of the photocatalytic layer in a photocatalytic device provided by the present application;

[0043] Figure 7Schematic diagram of the synthesis and catalytic process of the photocatalytic layer in a photocatalytic device provided by this application. Detailed implementation manners

[0044] The following will clearly and completely describe the embodiments in this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0045] To make the above objects, features, and advantages of this application more obvious and understandable, the following further details this application in conjunction with the drawings and specific implementation manners.

[0046] As described in the background art section, graphitic carbon nitride (g-C3N4) is a photocatalytic material that has received wide attention. However, due to the easy recombination of photo-generated electrons and holes, as well as its relatively narrow absorption spectrum, etc., the further development of g-C3N4 photocatalysts is restricted.

[0047] Based on the above, this application provides a photocatalytic device, as Figure 1 shown, Figure 1 Schematic diagram of the structure of a photocatalytic device provided by this application. Figure 1 In [diagram], a is a partial enlarged view of the photocatalytic layer in the photocatalytic device. The photocatalytic device includes:

[0048] A light-emitting element 100, and the light-emitting element 100 is used to emit an illumination beam.

[0049] A photocatalytic layer 200, the photocatalytic layer 200 is located on the light-emitting side of the light-emitting element 100, and the photocatalytic layer 200 includes photocatalytic units. The photocatalytic units include a first component 202 ( Figure 1 not shown in [diagram]) and a second component 204.

[0050] The first component 202 includes graphitic carbon nitride with introduced structural defects. The second component 204 is in contact with the first component 202, and the second component 204 is located on the surface of the first component 202. Among them, the material of the second component 204 is a semiconductor material different from the graphitic carbon nitride in the first component 202, and a heterojunction can be formed at the contact surface between the second component 204 and the first component 202. That is to say, the second component 204 is a semiconductor material with a band match with the graphitic carbon nitride in the first component 202, and a heterojunction can be formed at the contact surface between the second component 204 and the first component 202.

[0051] The photocatalytic layer 200 is activated by being irradiated with an illumination beam based on the above-mentioned photocatalytic unit, achieving sterilization of the environment where the photocatalytic device is located and self-cleaning of the light-emitting element 100. That is, the photocatalytic units in the photocatalytic layer 200 can generate electron-hole pairs under the excitation of the illumination beam, thereby triggering a series of redox reactions, converting surrounding molecules such as oxygen and moisture into free radicals with strong oxidation ability (such as hydroxyl radicals, superoxide anions, etc.). These free radicals can react with organic pollutants, decompose them into harmless carbon dioxide and water, keep the surface of the light-emitting element 100 clean, reduce light loss, and maintain efficient light output. At the same time, these free radicals also have strong bactericidal ability, so that the photocatalytic device can be applied in medical, sanitary and other fields and has broad application prospects.

[0052] As can be seen from the above, the first component 202 of the photocatalytic unit in the photocatalytic layer 200 of the photocatalytic device includes graphitic carbon nitride with an introduced defect structure. That is, the first component 202 can include graphitic carbon nitride with structural defects, also known as modified graphitic carbon nitride. Introducing structural defects in graphitic carbon nitride is a strategy that can effectively improve its photocatalytic activity and broaden the absorption spectrum range (i.e., broaden the light response range). Thus, the photocatalytic activity and spectral range of the photocatalytic layer 200 in the photocatalytic device can be effectively improved, having strong photocatalytic activity and a wide absorption spectrum range.

[0053] In addition, the second component 204 of the photocatalytic unit in the photocatalytic layer 200 is located on the surface of the first component 202, and a heterojunction is formed at the contact surface where the second component 204 and the first component 202 are in contact. Therefore, the electrons and holes generated by the photocatalytic unit being activated by the illumination beam can be transmitted between the second component 204 and the first component 202 through the above-mentioned heterojunction, which can further achieve the separation of photo-generated electrons and holes, thereby inhibiting the recombination of photo-generated electrons and holes, enhancing the photocatalytic activity of the photocatalytic layer 200, and improving the photocatalytic performance of the photocatalytic device.

[0054] In summary, in the photocatalytic device described in the present application, the photocatalytic unit of the photocatalytic layer 200 can be composed of graphitic carbon nitride with structural defects (i.e., the first component 202) and a semiconductor material located on the surface of the graphitic carbon nitride (i.e., the second component 204). The semiconductor material can form a heterojunction between the contact surfaces of the two, so that on the basis of improving the catalytic activity and spectral range of the photocatalytic unit due to the structural defects of the graphitic carbon nitride, the heterojunction formed between the first component 202 and the second component 204 by the second component 204 can be utilized to inhibit the recombination of photo-generated electrons and holes, further enhancing the photocatalytic activity of the photocatalytic layer 200, effectively solving problems such as the fast recombination rate of photo-generated electron-hole pairs and weak light absorption ability of graphitic carbon nitride. Therefore, the photocatalytic layer 200 of this photocatalytic device has strong photocatalytic activity and a wide spectral range, and has broad application prospects.

[0055] In an embodiment of the present application, the first component 202 is graphitic carbon nitride including the first doping and the second doping. Among them, the first doping can be a cyano group -CN, and the second doping can be an oxygen atom O to introduce structural defects into the graphitic carbon nitride. It should be noted that in the present application, graphitic carbon nitride including the first doping and the second doping can be abbreviated as COCN.

[0056] In an embodiment of the present application, the second component 204 can be zinc indium sulfide with the chemical formula ZnIn2S4. It should be noted that when these two semiconductor materials, zinc indium sulfide and graphitic carbon nitride, come into contact, due to their different energy band structures, a heterojunction will be formed at the interface. And under light illumination conditions, both zinc indium sulfide and the modified graphitic carbon nitride can absorb photons and generate photo-generated carriers (electrons and holes). Also, because the conduction band position of zinc indium sulfide is more negative than that of graphitic carbon nitride, the photo-generated electrons on the conduction band of zinc indium sulfide can spontaneously transfer to the conduction band of graphitic carbon nitride, and at the same time, the photo-generated holes on the valence band of graphitic carbon nitride can also transfer to the valence band of zinc indium sulfide, so that the photo-generated carriers in the photocatalytic unit can be effectively separated, thereby improving its photocatalytic performance. It should also be noted that in the present application, the photocatalytic unit formed by forming zinc sulfide on the surface of graphitic carbon nitride including a cyano group and oxygen doping can be abbreviated as COCN / ZIS, that is, the photocatalytic unit formed by forming the second component 204 on the surface of the first component 202 can be abbreviated as COCN / ZIS. In addition, zinc indium sulfide can also be abbreviated as ZIS.

[0057] Specifically, as Figure 2 shown, Figure 2Among them, curve 1 is the photocatalytic curve of graphitic carbon nitride, curve 2 is the photocatalytic curve of graphitic carbon nitride with the first doping and the second doping, curve 3 is the photocatalytic curve of zinc indium sulfide, and curves 4 - 8 are the photocatalytic curves of the photocatalytic layer when the doping ratios of the first component 202 in the photocatalytic layer are 30mg, 60mg, 100mg, 200mg, and 300mg respectively. According to Figure 2 it can be known that zinc indium sulfide is formed on the surface of graphitic carbon nitride with structural defects to form a heterojunction at the contact surface between the zinc indium sulfide and the graphitic carbon nitride with structural defects. Compared with the catalytic capabilities of graphitic carbon nitride and graphitic carbon nitride with structural defects, there is a significant improvement. That is to say, the catalytic performance of the photocatalytic layer 200 can be effectively improved. It should be noted that Figure 2 in the above, each of the photocatalytic curves can be the change curve of the methylene blue concentration with time when catalytically degrading methylene blue under LED illumination, so as to characterize the catalytic performance of each photocatalytic material.

[0058] In addition, as Figure 3 shown, Figure 3 in (a) is the SEM (Scanning Electron Microscope) image of graphitic carbon nitride (g-C3N4), (b) is the SEM image of graphitic carbon nitride (COCN) including the first doping and the second doping, (c) is the SEM image of zinc indium sulfide (ZIS), (d) is the partial enlarged view of the SEM image of zinc indium sulfide (ZIS), (e) is the SEM image of the photocatalytic layer (COCN / ZIS), and (f) is the partial enlarged view of the SEM image of the photocatalytic layer (COCN / ZIS). According to Figure 3 it can be known that after the second component 204 is formed on the surface of the first component 202, the surface of the photocatalytic layer 200 can become rougher, so as to form a nanoscale rough surface on the side of the photocatalytic layer 200 facing the light-emitting element 100. Furthermore, total reflection of the illumination beam when irradiating the photocatalytic layer 200 can be reduced, and diffuse reflection can be increased, so that more illumination beams can act effectively on the photocatalytic layer 200, improving the light utilization rate.

[0059] In an embodiment of the present application, the light-emitting element 100 may include at least one LED, and the photocatalytic layer 200 is coated on the light-emitting surface of at least some of the at least one LED. That is, when the light-emitting element 100 includes one LED, the photocatalytic layer 200 is coated on the light-emitting surface of this one LED. When the light-emitting element 100 includes multiple LEDs, according to the design requirements, the photocatalytic layer 200 can be coated on the light-emitting surface of one LED among the multiple LEDs, or can be coated on the light-emitting surfaces of at least two LEDs among the multiple LEDs.

[0060] It can be seen that the light source of the photocatalytic device described in the present application can be an LED. The above-mentioned photocatalytic layer 200 is located on the light-emitting surface of the LED, that is, the surface of the LED. Specifically, the above-mentioned photocatalytic layer 200 can be added to the LED packaging structure. By using the illumination beam emitted by the LED to activate the photocatalytic layer 200, the purpose of killing bacteria and viruses can be achieved, so as to be applicable to places such as medical treatment and food processing that require high hygiene standards. Moreover, adding the above-mentioned photocatalytic layer 200 to the LED packaging structure can also endow the LED with self-cleaning ability, decompose the organic substances and pollutants on its surface, keep the surface of the LED clean, maintain efficient light emission, and extend the service life.

[0061] Based on the photocatalytic device described in any one of the above, the present application further provides a sterilization device, which includes the photocatalytic device described in any one of the above embodiments.

[0062] The present application further provides a photocatalytic layer, which can be applied to the photocatalytic device described in any one of the above embodiments. The photocatalytic device includes a light-emitting element 100, and the photocatalytic layer 200 is disposed on the surface of the light-emitting element 100. The photocatalytic layer 200 includes photocatalytic units, and each photocatalytic unit includes a first component 202 and a second component 204.

[0063] The first component 202 includes graphitic carbon nitride with introduced structural defects, and its chemical formula is g-C3N4. The second component 204 is in contact with the first component 202, and the second component 204 is located on the surface of the first component 202. Among them, the material of the second component 204 is a semiconductor material different from the graphitic carbon nitride in the first component 202, and a heterojunction is formed at the contact surface between the second component 204 and the first component 202. That is to say, the second component 204 is a semiconductor material with a band structure matching that of the graphitic carbon nitride in the first component 202, and a heterojunction can be formed at the contact surface between the second component 204 and the first component 202.

[0064] The photocatalytic layer 200 is activated by being irradiated with an illumination beam based on the above-mentioned photocatalytic unit, realizing sterilization in the environment where the photocatalytic device is located and realizing self-cleaning of the light-emitting element 100. That is, the photocatalytic units in the photocatalytic layer 200 can generate electron-hole pairs under the excitation of the illumination beam, and then trigger a series of redox reactions, converting surrounding molecules such as oxygen and moisture into free radicals with strong oxidation ability (such as hydroxyl radicals, superoxide anions, etc.). These free radicals can react with organic pollutants and decompose them into harmless carbon dioxide and water, keeping the surface of the light-emitting element 100 clean, reducing light loss, and maintaining efficient light emission. At the same time, these free radicals also have strong bactericidal ability, so that the photocatalytic device can be applied to fields such as medical treatment and hygiene, and has broad application prospects.

[0065] It should be noted that the above-mentioned photocatalytic layer 200 is the photocatalytic layer 200 described in any one of the embodiments of the photocatalytic device part, and no detailed introduction to this photocatalytic layer 200 will be given here.

[0066] The present application also provides a method for preparing a photocatalytic device, and this preparation method is used to obtain the photocatalytic device described in any one of the above embodiments. As Figure 4 shown, Figure 4 is a flowchart of a method for preparing a photocatalytic device provided by the present application, and this preparation method includes:

[0067] S1: Prepare the photocatalytic layer 200. The photocatalytic layer 200 includes photocatalytic units, and the photocatalytic units include a first component 202 and a second component 204. Among them, the first component 202 includes graphitic carbon nitride with introduced structural defects, the second component 204 is in contact with the first component 202, and the second component 204 is located on the surface of the first component 202. Among them, the material of the second component 204 is a semiconductor material different from the graphitic carbon nitride in the first component 202, and a heterojunction is formed at the contact surface between the second component 204 and the first component 202. That is to say, the second component 204 is a semiconductor material with a band matching that of the graphitic carbon nitride in the first component 202, and a heterojunction can be formed at the contact surface between the second component 204 and the first component 202.

[0068] S2: Provide a light-emitting element 100, and arrange the photocatalytic layer 200 on the light-emitting side of the light-emitting element 100. The light-emitting element 100 is used to emit illumination light beams.

[0069] The photocatalytic layer 200 is activated by being irradiated with the illumination light beam based on the above-mentioned photocatalytic unit, so as to realize the sterilization of the environment where the photocatalytic device is located and the self-cleaning of the light-emitting element 100. That is, the photocatalytic units in the photocatalytic layer 200 can generate electron-hole pairs under the excitation of the illumination light beam, and then trigger a series of redox reactions, converting surrounding oxygen, water molecules, etc. into free radicals with strong oxidation ability (such as hydroxyl radicals, superoxide anions, etc.). These free radicals can react with organic pollutants and decompose them into harmless carbon dioxide and water, keeping the surface of the light-emitting element 100 clean, reducing light loss, and maintaining efficient light output. At the same time, these free radicals also have strong bactericidal ability, so that this photocatalytic device can be applied to medical, sanitary and other fields and has broad application prospects.

[0070] In an embodiment of the present application, for the above step S1, preparing the photocatalytic layer 200 includes:

[0071] Prepare the first component 202, where the first component 202 is a graphitic carbon nitride including a first doping and a second doping. Among them, the first doping is a cyano group with the chemical formula -CN, and the second doping is an oxygen atom with the chemical formula O, so as to introduce structural defects into the graphitic carbon nitride.

[0072] Form a second component 204 on the surface of the first component 202 to form a photocatalytic layer 200. Among them, the second component 204 is zinc indium sulfide. As Figure 5 and Figure 6 shown, Figure 5 in which a, b, c, and d are the X-ray powder diffraction patterns of g-C3N4, COCN, ZnIn2S4, and COCN / ZIS respectively, Figure 6 in which a, b, c, and d are the Fourier transform infrared spectra of g-C3N4, COCN, ZnIn2S4, and COCN / ZnIn2S4 respectively. According to Figure 5 and Figure 6 it can be known that the X-ray powder diffraction pattern of COCN / ZIS of the photocatalytic layer 200 includes both the characteristics of COCN and the characteristics of ZIS, and no characteristics other than the two appear. And the Fourier transform infrared spectrum of COCN / ZIS of the photocatalytic layer 200 includes both the characteristics of COCN and the characteristics of ZIS, and no characteristics other than the two appear. Therefore, the formation of the second component 204 on the surface of the first component 202 is realized, that is, the second component 204 is successfully set on the surface of the first component 202, and no denaturation of the first component 202 and the second component 204 is caused to form the photocatalytic layer 200.

[0073] It should be noted that when these two semiconductor materials, zinc indium sulfide and graphitic carbon nitride, are in contact, due to their different band structures, a heterojunction will be formed at the interface. And under light illumination conditions, both zinc indium sulfide and graphitic carbon nitride can absorb photons and generate photo-generated carriers. Also, because the conduction band position of zinc indium sulfide is more negative than that of graphitic carbon nitride, the photo-generated electrons on the conduction band of zinc indium sulfide can spontaneously transfer to the conduction band of graphitic carbon nitride, and at the same time, the photo-generated holes on the valence band of graphitic carbon nitride can also transfer to the valence band of zinc indium sulfide, so that the photo-generated carriers in the photocatalytic unit are effectively separated, and thus its photocatalytic performance can be improved. At the same time, as Figure 3 shown, after the second component 204 is formed on the surface of the first component 202, the surface of the photocatalytic layer 200 can become rougher, so as to form a nano-scale rough surface on the side of the photocatalytic layer 200 facing the light-emitting element 100. Furthermore, the total reflection of the illumination beam when irradiating the photocatalytic layer 200 can be reduced, and the diffuse reflection can be increased, so that more illumination beams can act effectively on the photocatalytic layer 200, improving the light utilization rate.

[0074] In one embodiment of the present application, preparing the first component 202 includes:

[0075] Mix urea and ascorbic acid in a first preset ratio to form a first mixture.

[0076] Transfer the first mixture to a crucible, and place it in a muffle furnace. Under an air atmosphere, heat it to a first preset temperature at a preset heating rate, and keep it warm for a first preset time to obtain the first component 202.

[0077] For example, add 15 g to 25 g of urea to 0.007 g to 0.018 g of ascorbic acid, mix to form a first mixture. Transfer the first mixture to a crucible, and place it in a muffle furnace. Under an air atmosphere, heat it at a heating rate of 5 °C / min to 15 °C / min to 450 °C to 550 °C, and keep it warm for 1.5 h to 3 h to obtain the first component 202.

[0078] In one embodiment of the present application, forming the second component 204 on the surface of the first component 202 includes:

[0079] Disperse a first preset amount of the first component 202 into a second preset amount of acidic water to obtain a second mixture. It should be noted that the acidic water can be adjusted to a pH with hydrochloric acid.

[0080] Disperse a second preset ratio of anhydrous zinc chloride, thioacetamide, and indium(III) chloride tetrahydrate into the second mixture, and react at a second preset temperature for a second preset time to form the second component 204 on the surface of the first component 202.

[0081] For example, disperse 30 mg of the first component 202 into 25 ml to 35 ml of acidic water with a pH of 2 to 3 by ultrasonic treatment to obtain a second mixture.

[0082] After that, disperse 131 mg to 140 mg of anhydrous zinc chloride, 145 mg to 150 mg of thioacetamide, and 288 mg to 298 mg of indium(III) chloride tetrahydrate into the second mixture, perform ultrasonic treatment on the second mixture for 25 min to 35 min, then react at 75 °C to 85 °C for 10 h to 14 h, wash the obtained product with anhydrous ethanol and deionized water, and vacuum dry it at 55 °C to 65 °C for 10 h to 14 h to form the second component 204 on the surface of the first component 202, thereby forming a photocatalytic layer including a photocatalytic unit.

[0083] To more clearly understand a method for preparing a photocatalytic device provided by the present application, the following provides a detailed introduction to the preparation method through a specific embodiment.

[0084] 0.012 g of ascorbic acid was added to 20 g of urea and evenly mixed to form a first mixture. Then, the first mixture was placed in a crucible and heated in a muffle furnace under an air atmosphere at a heating rate of 10 °C / min until 500 °C was reached, and then held for 2 hours. After that, it was naturally cooled with the furnace to obtain graphitic carbon nitride doped with the first and second dopants, that is, modified graphitic carbon nitride, denoted as COCN.

[0085] 30.00 mg of COCN obtained in the above step was dispersed into 30 mL of water with a pH of 2.5 (adjusted by hydrochloric acid) by ultrasonic treatment to obtain a second mixture. Then, 136 mg of anhydrous zinc chloride, 150 mg of thioacetamide, and 293 mg of indium(III) chloride tetrahydrate were added to the above second mixture, and after ultrasonic treatment for 30 minutes, the reaction was carried out at 80 °C for 12 hours. It should be noted that stirring was required during this process. Then, the obtained product was washed with anhydrous ethanol and deionized water, and finally vacuum-dried at 60 °C for 12 hours to obtain a photocatalytic layer with a second component 204 on the surface of a first component 202. The amount of COCN was 30.00 mg, which was called a 30-COCN / ZIS composite material, and ZIS was the abbreviation of zinc indium sulfide. The synthesis process and photocatalytic process of the photocatalytic layer 200 are as Figure 7 shown. According to Figure 7 it can be seen that this photocatalytic layer 200 can decompose oxygen and moisture in the air into hydroxyl radicals OH and superoxide radicals O2 - under light irradiation, and degrade methylene blue MB into carbon dioxide CO2 and water H2O.

[0086] As can be seen from the above, the preparation method of the photocatalytic layer 200 of the present application does not require harsh preparation processes, has simple operations, and strong repeatability. In addition, the chemical reagents and equipment used are reasonably priced, easy to obtain, and have strong applicability, making the industrial application value of this photocatalytic device and its photocatalytic layer high and easy to promote and utilize.

[0087] In order to detect the catalytic performance of the prepared photocatalytic layer 200, x-COCN / ZIS samples (x = 30, 60, 100, 200, 300) can be prepared by the above method, where x is the addition amount of COCN, indicating that the addition amounts of COCN are 30 mg, 60 mg, 100 mg, 200 mg, and 300 mg respectively. Based on Figure 2It can be seen that the present application also compares the photocatalytic performances of the prepared photocatalytic layer 200 with those of graphitic carbon nitride, modified graphitic carbon nitride, and zinc indium sulfide. For this purpose, after graphitic carbon nitride, modified graphitic carbon nitride, and zinc indium sulfide are prepared by corresponding preparation methods, methylene blue (MB) can be degraded by using the above different photocatalytic materials. Specifically, an LED can be used as the light source to evaluate the degradation ability of each of the above photocatalytic materials to methylene blue under LED illumination.

[0088] First, 20 mg of the photocatalyst is added to 100 mL of the MB solution. The concentration of the MB solution can be 20 mg / L. After reaching the adsorption equilibrium in the dark environment, it is transferred to a xenon lamp light source for a photocatalytic degradation experiment. The illumination time can be fixed at 60 min. During the illumination process, a certain amount of the supernatant after removing particles is taken out at regular intervals, and the absorbance of the MB solution at 664 nm is obtained by using an ultraviolet-visible spectrophotometer, and the concentration of MB at a certain moment is calculated by conversion, and then the change of its concentration can be obtained, and thus the photocatalytic curves of each photocatalytic material as Figure 2 described can be obtained. Figure 2 In the figure, curve 1 is the photocatalytic curve of graphitic carbon nitride, curve 2 is the photocatalytic curve of graphitic carbon nitride with the first doping and the second doping, curve 3 is the photocatalytic curve of zinc indium sulfide, and curves 4 - 8 are the photocatalytic curves of the photocatalytic layer when the doping ratios of the first component in the photocatalytic layer are 30 mg, 60 mg, 100 mg, 200 mg, and 300 mg, respectively. According to Figure 2 it can be seen that compared with the catalytic abilities of graphitic carbon nitride, modified graphitic carbon nitride, and zinc indium sulfide, the catalytic performance of the photocatalytic layer of the present application has been greatly improved.

[0089] It should be noted that Figure 2 the part to the left of the dashed line in the figure is the time period when the above-mentioned various catalytic materials reach the adsorption equilibrium in the dark environment. It should also be noted that when analyzing the catalytic performances of the above-mentioned various catalytic materials, substances other than methylene blue can also be used, and the present application does not limit this, which depends on the specific situation.

[0090] In this specification, each embodiment is described in a progressive, or parallel, or a combination of progressive and parallel manner. The key points of each embodiment are the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description in the method part.

[0091] It should be noted that in the description of this application, it is to be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be construed as a limitation of this application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be intervening components present at the same time.

[0092] It should also be noted that in this context, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, such that an article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the article or device comprising the above elements.

[0093] The above description of the disclosed embodiments enables those skilled in the art to implement or use this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to the embodiments shown herein, but rather is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photocatalytic device, characterized in that, Comprising: A light-emitting element for emitting an illumination beam; A photocatalytic layer located on the light-emitting side of the light-emitting element, the photocatalytic layer comprising photocatalytic units, and the photocatalytic units comprising a first component and a second component; The first component comprises graphitic carbon nitride with introduced structural defects, the second component is in contact with the first component and located on the surface of the first component, and the material of the second component is a semiconductor material different from the graphitic carbon nitride in the first component, and a heterojunction is formed at the contact surface between the second component and the first component; The photocatalytic layer is activated by the illumination beam based on the photocatalytic units to achieve sterilization of the environment where the photocatalytic device is located and self-cleaning of the light-emitting element.

2. The photocatalytic device according to claim 1, characterized in that, The first component is graphitic carbon nitride including a first doping and a second doping; The first doping is a cyano group, and the second doping is an oxygen atom to introduce structural defects in the graphitic carbon nitride.

3. The photocatalytic device according to claim 1, characterized in that The second component is zinc indium sulfide.

4. The photocatalytic device according to claim 1, wherein The light-emitting element comprises at least one LED; The photocatalytic layer is coated on the light-emitting surface of at least some of the at least one LED.

5. A sterilization device, characterized in that, Comprising the photocatalytic device according to any one of claims 1-4.

6. A photocatalytic layer, characterized in that, Applied to a photocatalytic device comprising a light-emitting element, the photocatalytic layer comprising photocatalytic units, and the photocatalytic units comprising a first component and a second component; The first component comprises graphitic carbon nitride with introduced structural defects, the second component is in contact with the first component and located on the surface of the first component, and the material of the second component is a semiconductor material different from the graphitic carbon nitride in the first component, and a heterojunction is formed at the contact surface between the second component and the first component; The photocatalytic layer is activated by the illumination beam of the light-emitting element based on the photocatalytic units to achieve sterilization of the environment where the photocatalytic device is located and self-cleaning of the light-emitting element.

7. A method for preparing a photocatalytic device, characterized in that, Comprising: Preparing a photocatalytic layer, the photocatalytic layer comprising photocatalytic units, and the photocatalytic units comprising a first component and a second component; the first component comprises graphitic carbon nitride with introduced structural defects, the second component is in contact with the first component and located on the surface of the first component, and the material of the second component is a semiconductor material different from the graphitic carbon nitride in the first component, and a heterojunction is formed at the contact surface between the second component and the first component; Providing a light-emitting element, disposing the photocatalytic layer on the light-emitting side of the light-emitting element, and the light-emitting element emits an illumination beam; The photocatalytic layer is activated by the illumination beam based on the photocatalytic units to achieve sterilization of the environment where the photocatalytic device is located and self-cleaning of the light-emitting element.

8. The preparation method of the photocatalytic device according to claim 7, characterized in that, Preparing the photocatalytic layer includes: Prepare the first component, which is graphitic carbon nitride including a first doping and a second doping; wherein, the first doping is a cyano group and the second doping is an oxygen atom to introduce structural defects into the graphitic carbon nitride. Form the second component on the surface of the first component to form the photocatalytic layer; wherein, the second component is zinc indium sulfide.

9. The method for preparing a photocatalytic device according to claim 8, characterized in that, Preparing the first component includes: Mix a first preset ratio of urea and ascorbic acid to form a first mixture. Transfer the first mixture to a crucible and place it in a muffle furnace. Heat it to a first preset temperature at a preset heating rate in an air atmosphere and keep it warm for a first preset time to obtain the first component.

10. The method for preparing a photocatalytic device according to claim 8, characterized in that, Forming the second component on the surface of the first component includes: Disperse a first preset amount of the first component into a second preset amount of acidic water to obtain a second mixture. Disperse a second preset ratio of anhydrous zinc chloride, thioacetamide, and indium(III) chloride tetrahydrate into the second mixture and react at a second preset temperature for a second preset time to form the second component on the surface of the first component.

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