A filtering component based on carbon quantum dot particles

Abstract

This application relates to the field of air purification, and provides a filtering component based on carbon quantum dot particles. The component includes an outer frame structure, a bottom cover, a photocatalyst particle layer, a carbon quantum dot particle layer, a glass layer, an activated carbon layer, and a first light source. The outer frame structure is a container with one end open, having a top wall and a side wall. The bottom cover is the bottom lid of the outer frame structure, with a through hole on it. The activated carbon layer is fixedly arranged on the side of the bottom cover close to the top wall. A carbon quantum dot particle layer is fixedly arranged on one side of the glass layer, and a photocatalyst particle layer is fixedly arranged on the side of the carbon quantum dot particle layer away from the glass layer. The glass layer is obliquely fixed to the side wall, and the side of the glass layer with the photocatalyst particle layer is close to the bottom cover. The glass layer is in close contact with the side wall. An air extraction hole is arranged on the side wall, between the glass layer and the activated carbon layer. The first light source is fixedly arranged on the side wall between the activated carbon layer and the glass layer. The present invention improves the utilization rate of the light field by the photocatalyst particles, and has a relatively high purification efficiency.

Description

Technical Field

[0001] This application relates to the field of air purification. Specifically, it relates to a filtering component based on carbon quantum dot particles. Background Art

[0002] Photocatalytic air purifiers are common air purification products. Through mechanical filtration and photocatalytic reactions, particulate pollutants and organic gas pollutants in the air, such as formaldehyde, can be removed to achieve the purpose of purifying the air. The purification efficiency of photocatalytic air purifiers is an important measurement index. The higher the air purification efficiency, the more pollutants are removed per unit time, and the shorter the time required to remove a certain amount of pollutants.

[0003] The core component of a photocatalytic air purifier is the filtering component. Generally, the air to be purified enters through the air inlet, and particulate pollutants are filtered out by materials such as activated carbon. The air after primary purification reaches near the photocatalyst particles. Under the irradiation of ultraviolet light, photocatalytic reactions occur between the photocatalyst particles and oxygen, water molecules, organic gas pollutants, etc. in the air, and finally the toxic organic gas pollutants are converted into non-toxic carbon dioxide and water, achieving the purification effect. Specifically, when ultraviolet light irradiates on the surface of the photocatalyst particles, the photon energy causes the electrons in the valence band of the photocatalyst particles to transition to the conduction band, leaving holes in the valence band, that is, generating photogenerated electrons and photogenerated holes. The progress of the photocatalytic reaction depends on the photogenerated electrons and photogenerated holes. Therefore, the utilization rate of the light field by the photocatalyst particles in the photocatalytic reaction is very crucial.

[0004] The existing methods for improving the purification efficiency of the filtering component are to prepare photocatalyst particles with smaller sizes, increase the specific surface area of the photocatalyst particles, or increase the number of photocatalyst particles. However, by simply increasing the number of photocatalyst particles and reducing the particle size to increase the specific surface area to generate more photogenerated electrons and photogenerated holes, after reaching a certain level, the increase reaches saturation and cannot be further improved, ignoring the importance of the utilization rate of the light field in the photocatalytic reaction.

[0005] In summary, the existing filtering component has a low utilization rate of the light field, generates fewer photogenerated electrons and photogenerated holes, has a weak photocatalytic reaction intensity, and a low air purification efficiency. Summary of the Invention

[0006] The purpose of the present invention is to provide a filtering component based on carbon quantum dot particles to solve the problems in the prior art that the filtering component has a low utilization rate of the light field, generates fewer photogenerated electrons and photogenerated holes, has a weak photocatalytic reaction intensity, and a low air purification efficiency.

[0007] To achieve the above object, the technical concept of the present invention is as follows: A carbon quantum dot particle layer is disposed between the glass layer and the photocatalyst particle layer. The carbon quantum dot particles have a small particle size, so that they can be fully irradiated even on the side of the photocatalyst particles away from the light source, improving the utilization rate of the light field. The improvement of the utilization rate of the light field includes the following two aspects. The first aspect is to improve the absorption of the light field by the photocatalyst particles. Specifically, due to the upconversion performance, the photocatalyst particles can absorb visible light and convert long-wavelength visible light into short-wavelength ultraviolet light. The ultraviolet light acts on the photocatalyst particles to generate photoexcited electrons and photoexcited holes, that is, the photocatalyst particles can utilize visible light to generate photoexcited electrons and photoexcited holes, improving the utilization rate of the photocatalyst particles in the visible light band and ultimately enhancing the air purification efficiency. The second aspect is to improve the utilization rate of the photoexcited electrons and photoexcited holes generated by the photocatalyst particles. Specifically, adjacent carbon quantum dot particles are in contact with each other to form an electron transfer channel, enabling the photoexcited electrons to migrate between the photocatalyst particles, so that the concentrations of the photoexcited electrons on each photocatalyst particle tend to be the same, and the intensity of the photocatalytic reaction on each photocatalyst particle is the same. This avoids the situation where the photocatalyst particles with a strong photocatalytic reaction cannot further increase the intensity of the photocatalytic reaction because the concentration of reactants around the photocatalyst particles cannot meet the requirements due to the large amount of reactants needed; it also avoids the situation where the photocatalyst particles with a weak photocatalytic reaction waste a lot of photocatalytic reactants around them because they cannot fully carry out the photocatalytic reaction. Therefore, the carbon quantum dot particles enable the "sharing" of photoexcited electrons between the photocatalyst particles, improving the utilization rate of photoexcited electrons and photoexcited holes, thereby enhancing the intensity of the photocatalytic reaction on the photocatalyst particles and improving the purification efficiency.

[0008] The present application provides a filtering component based on carbon quantum dot particles. The filtering component includes an outer frame structure, a bottom cover, a photocatalyst particle layer, a carbon quantum dot particle layer, a glass layer, an activated carbon layer, and a first light source. The materials of the outer frame structure and the bottom cover are hard and opaque materials, such as cemented carbide, etc. The outer frame structure is a container with one end open, and the container has a top wall and a side wall. The bottom cover is the bottom lid of the outer frame structure, and the bottom cover and the outer frame structure are fixedly connected by means of screw connection or bonding. There are a plurality of through holes on the bottom cover for allowing the air to be purified to flow in.

[0009] The material of the activated carbon layer is activated carbon cotton, which has a porous structure and is used to adsorb particulate pollutants and some gaseous pollutants in the air, preliminarily purifying the air to be purified. The thickness of the activated carbon layer is greater than 2 cm. The longer the distance that the air to be purified passes through the activated carbon layer, the more particulate pollutants and gases are adsorbed, thus enabling effective primary purification of the air. The activated carbon layer is fixedly arranged on one side of the bottom cover close to the top wall. The activated carbon layer and the bottom cover may or may not be in contact. Preferably, the distance between them is 0.5 - 1.0 cm, so that the debris pollutants blocked by the bottom cover do not contact the activated carbon layer, avoiding the pollution of the activated carbon layer by the debris pollutants.

[0010] The material of the glass layer is glass. The carbon quantum dot particle layer is composed of 2 - 3 layers of carbon quantum dot particles, and the photocatalyst particle layer is composed of photocatalyst particles. Specifically, it is composed of 1 - 2 layers of photocatalyst particles. The material of the photocatalyst particles is one of TiO2, ZrO2, ZnO, and WO3. One side of the glass layer is fixedly provided with the carbon quantum dot particle layer, and the side of the carbon quantum dot particle layer away from the glass layer is fixedly provided with the photocatalyst particle layer. The photocatalyst particle layer is used to carry out photocatalytic reactions under the action of light to purify the air; the carbon quantum dot particle layer is used to convert long-wavelength visible light into short-wavelength ultraviolet light, which is then absorbed by the photocatalyst particles for photocatalytic reactions, improving the utilization rate of the light field. Specifically, the particle size of the photocatalyst particles is 50 - 200 nm, and the particle sizes of the photocatalyst particles can be the same or different; the photocatalyst particles do not contact each other, and the spacing is 100 - 200 nm, so that the carbon quantum dot particles on the side away from the light source can be fully irradiated, thus converting more visible light into ultraviolet light, improving the utilization rate of the light field and the photocatalytic efficiency. The particle size of the carbon quantum dot particles is 2 - 8 nm, and the adjacent carbon quantum dot particles may or may not contact each other. Preferably, the adjacent carbon quantum dot particles contact each other.

[0011] The glass layer is fixedly arranged on the side wall obliquely. Specifically, the inclined angle can be any angle, but it is necessary to ensure that the side of the glass layer provided with the photocatalyst particle layer is close to the bottom cover. The glass layer is in close contact with the side wall, and there is no gap between the glass layer and the side wall. They can be fixedly bonded through an adhesive. The thickness of the glass layer can be in the order of millimeters or centimeters. Preferably, the thickness of the glass layer is 0.1 - 0.3 cm, which can provide an effective supporting effect for the photocatalyst particle layer and the carbon quantum dot particle layer, and will not make the overall component too heavy. The first light source is arranged on the side wall between the activated carbon layer and the glass layer. The first light source is an ultraviolet-visible light source. The photocatalyst particles absorb ultraviolet light, and the carbon quantum dot particles absorb visible light, convert the visible light into ultraviolet light, improve the utilization rate of the light field by the photocatalyst particles, and improve the air purification efficiency.

[0012] There are air extraction holes provided on the side wall. The air extraction holes are arranged between the glass layer and the activated carbon layer and are used for external air extraction, so as to form a negative pressure between the glass layer and the activated carbon layer, enabling the surrounding air to enter from the side of the activated carbon layer. Preferably, the air extraction holes are arranged at the end of the glass layer farther away from the activated carbon layer, and the distance from the farther end of the glass layer is less than 1 cm. More preferably, the direction of the air extraction holes is perpendicular to the plane where the glass layer is located. In this way, the initially purified air will not be directly discharged from the air extraction holes between the glass layer and the activated carbon layer, but will form a circulation between the glass layer and the activated carbon layer, so that the interaction time between the air and the photocatalyst particles and carbon quantum dot particles is longer, thereby enhancing the intensity of the photocatalytic reaction and improving the air purification efficiency.

[0013] Furthermore, a noble metal protrusion is fixedly arranged on the side of the photocatalyst particles away from the carbon quantum dot particle layer. The material of the noble metal protrusion is gold or silver. Under the action of the optical field, a local surface plasmon resonance phenomenon occurs on the noble metal protrusion, localizing the optical field near it, making the interaction between the photocatalyst particles and the optical field stronger, thereby enhancing the intensity of the photocatalytic reaction and improving the air purification efficiency.

[0014] Even further, a second light source is fixedly arranged on the top wall or side wall of the side of the glass layer away from the activated carbon layer. The second light source is a visible light source. The light emitted by the second light source irradiates on the side of the glass layer away from the photocatalyst particle layer. The visible light passes through the glass layer and irradiates on the carbon quantum dot particle layer, and is absorbed by the carbon quantum dot particles and converted into ultraviolet light. The ultraviolet light acts on the photocatalyst particles to generate photogenerated electrons and photogenerated holes. In this way, more photogenerated electrons and photogenerated holes can be generated, improving the intensity of the photocatalytic reaction and the air purification efficiency. Preferably, the connection line between the second light source and the first light source is perpendicular to the glass layer, so that the light emitted by the second light source can fully irradiate on the carbon quantum dot particle layer, making the interaction between the optical field and the carbon quantum dot particle layer stronger, thereby enhancing the intensity of the photocatalytic reaction and improving the air purification efficiency.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: A carbon quantum dot particle layer is provided between the glass layer and the photocatalyst particle layer to improve the utilization rate of the light field. The improvement in the utilization rate of the light field mainly refers to enhancing the absorption of the light field by the photocatalyst particles and the utilization rate of the photogenerated electrons and holes generated by the photocatalyst particles. First, by utilizing the upconversion characteristics of the photocatalyst particles, visible light that cannot be directly absorbed by the photocatalyst particles is converted into ultraviolet light that can be absorbed by the photocatalyst particles, thereby enhancing the absorption of the light field by the photocatalyst particles and enabling the photocatalyst particles to generate more photogenerated electrons and holes. Second, adjacent carbon quantum dot particles are in contact with each other, enabling photogenerated electrons to migrate between the photocatalyst particles, so that the concentration of photogenerated electrons on each photocatalyst particle tends to be consistent, and the intensity of the photocatalytic reaction on each photocatalyst particle is the same; this avoids the situation where the photocatalyst particles with a stronger photocatalytic reaction require more reactants and the reactant concentration around the photocatalyst particles cannot be satisfied, resulting in the inability to further enhance the intensity of the photocatalytic reaction; it also avoids the situation where the photocatalyst particles with a weaker photocatalytic reaction cannot fully carry out the photocatalytic reaction and there are more photocatalytic reactants around, causing waste; therefore, through the carbon quantum dot particles, the photogenerated electrons between the photocatalyst particles are "shared", improving the utilization rate of photogenerated electrons and holes, thereby enhancing the intensity of the photocatalytic reaction on the photocatalyst particles and improving the purification efficiency. Description of the Drawings

[0016] Figure 1 Schematic diagram of a filtering component based on carbon quantum dot particles provided by the present invention;

[0017] Figure 2 Schematic diagram of the photocatalyst particle layer, carbon quantum dot particle layer, and glass layer in a filtering component based on carbon quantum dot particles provided by the present invention;

[0018] Figure 3 Schematic diagram of the principle of carbon quantum dot particles converting visible light into ultraviolet light in a filtering component based on carbon quantum dot particles provided by the present invention;

[0019] Figure 4 Schematic diagram of electron transfer between photocatalyst particles and carbon quantum dot particles in a filtering component based on carbon quantum dot particles provided by the present invention.

[0020] Reference numerals: 1 - outer frame structure; 2 - bottom cover; 3 - glass layer; 4 - carbon quantum dot particle layer; 5 - photocatalyst particle layer; 6 - activated carbon layer; 7 - first light source; 8 - second light source. Detailed Embodiments

[0021] In order to make the implementation process of the present invention clearer, the following will be described in detail with reference to the accompanying drawings.

[0022] The present invention provides a filtering component based on carbon quantum dot particles, as Figure 1 and Figure 2 shown. The filtering component includes an outer frame structure 1, a bottom cover 2, a glass layer 3, a carbon quantum dot particle layer 4, a photocatalyst particle layer 5, an activated carbon layer 6, and a first light source 7. The materials of the outer frame structure 1 and the bottom cover 2 are hard and opaque materials, such as cemented carbide, etc. The outer frame structure 1 is a container with one end open, which has a top wall and a side wall, and the shape of the container can be any shape. Preferably, the shape of the container is one of a cylinder and a cuboid, and such conventional shapes are convenient for preparation. The bottom cover 2 is the bottom cover of the outer frame structure 1, that is, the shape and size of the bottom cover 2 match those of the opening of the outer frame structure 1, and the bottom cover 2 and the outer frame structure 1 are fixedly connected by a threaded connection or an adhesive method. There are a plurality of through holes on the bottom cover 2 for allowing the air to be purified to flow in. Specifically, the through directions of the through holes can be the same or different. The thicknesses of the bottom cover and the container are both less than 8 mm, so that the filtering component will not be too heavy. The thickness of the bottom cover 2 and the thickness of the container wall can be the same or different. Preferably, the inner diameter of the through hole is less than 3 mm, so that the bottom cover can block larger particulate pollutants and sundries and can better protect the internal structure.

[0023] The material of the activated carbon layer 6 is activated carbon cotton, and the activated carbon cotton has a porous structure and is used for adsorbing particulate pollutants and some gaseous pollutants in the air to preliminarily purify the air to be purified. The thickness of the activated carbon layer 6 is greater than 2 cm. The greater its thickness, the longer the distance that the air to be purified passes through the activated carbon layer 6, and the more particulate pollutants and gases are adsorbed, so that the air can be effectively purified at the primary stage. The activated carbon layer 6 is fixedly arranged on one side of the bottom cover 2 close to the top wall. The activated carbon layer 6 and the bottom cover 2 may or may not be in contact. Preferably, the distance between the two is 0.5 - 1.0 cm, so that the sundry pollutants blocked by the bottom cover 2 do not contact the activated carbon layer 6, avoiding the pollution of the activated carbon layer 6 by the sundry pollutants. The activated carbon layer 6 is fixedly connected to the side wall of the outer frame structure 1 including. Specifically, it can be fixedly connected by adhesion. The material of the glass layer 3 is glass, the carbon quantum dot particle layer 4 is composed of 2 - 3 layers of carbon quantum dot particles, and the photocatalyst particle layer 5 is composed of photocatalyst particles. Specifically, it is composed of 1 - 2 layers of photocatalyst particles, and the material of the photocatalyst particles is one of TiO2, ZrO2, ZnO, and WO3.

[0024] On one side of the glass layer 3, a carbon quantum dot particle layer 4 is fixedly arranged, and on the side of the carbon quantum dot particle layer 4 away from the glass layer 3, a photocatalyst particle layer 5 is fixedly arranged. The photocatalyst particle layer 5 is used for performing a photocatalytic reaction under the action of light to purify the air; the carbon quantum dot particle layer 4 is used for converting long-wavelength visible light into short-wavelength ultraviolet light, which is then absorbed by the photocatalyst particles for the photocatalytic reaction to improve the utilization rate of the light field. Specifically, as Figure 3As shown, visible light irradiates on carbon quantum dot particles. The carbon quantum dot particles absorb visible light. Multiple photons cause electrons to transition from the valence band to the conduction band, or the photons first transition from the ground state to a metastable state and then are excited from the metastable state to the ground state, and finally return to the ground state in the form of radiation, so that long-wavelength photons with lower energy can be converted into short-wavelength photons with higher energy, achieving upconversion. More specifically, under the irradiation of the light field, the carbon quantum dot particles can convert visible light that cannot be utilized by the photocatalyst particles into ultraviolet light that can be utilized by the photocatalyst particles, resulting in more photogenerated electrons and photogenerated holes in the photocatalyst particles, increasing the intensity of the photocatalytic reaction, and further improving the purification efficiency. Preferably, the particle size of the photocatalyst particles is 50 - 200 nm. The particle sizes of the photocatalyst particles can be the same or different. When the particle sizes of the photocatalyst particles are the same, it is convenient for preparation. When the particle sizes of the photocatalyst particles are different, since the central wavelengths of the light absorbed by the photocatalyst particles with different particle sizes are different, the central wavelengths of the light absorbed by the photocatalyst particles with different particle sizes are not exactly the same, which improves the utilization rate of the light source by the photocatalyst particles, makes the intensity of the photocatalytic reaction stronger, and the air purification efficiency higher. The photocatalyst particles do not contact each other, and the distance between them is 100 - 200 nm. In this way, the carbon quantum dot particles on the side far from the light source can be fully irradiated, so as to convert more visible light into ultraviolet light, improve the utilization rate of the light field, and increase the photocatalytic efficiency.

[0025] The particle size of the carbon quantum dot particles is 2 - 8 nm. The particle sizes of the carbon quantum dot particles can be the same or different. The adjacent carbon quantum dot particles can contact each other or not contact each other. Preferably, the adjacent carbon quantum dot particles contact each other, which can improve the utilization rate of the photogenerated electrons and photogenerated holes generated by the photocatalyst particles. Specifically, the adjacent carbon quantum dot particles contact each other, such as Figure 4As shown, the carbon quantum dot particles can simultaneously act as electron acceptors and donors, that is, an electron transfer channel is formed, enabling the photo-generated electrons to migrate between the photocatalyst particles, so that the concentration of photo-generated electrons on each photocatalyst particle tends to be consistent, and the intensity of the photocatalytic reaction on each photocatalyst particle is the same. This avoids the situation where the photocatalyst particles with a strong photocatalytic reaction cannot further improve the intensity of the photocatalytic reaction because the reactant concentration around the photocatalyst particles cannot meet the need for more reactants; it also avoids the situation where the photocatalyst particles with a weak photocatalytic reaction cause waste because they cannot fully carry out the photocatalytic reaction and there are more photocatalytic reactants around. Therefore, through the carbon quantum dot particles, the photo-generated electrons between the photocatalyst particles are "shared", improving the utilization rate of photo-generated electrons and photo-generated holes, thereby enhancing the intensity of the photocatalytic reaction on the photocatalyst particles and improving the purification efficiency. The above carbon quantum dot particles are carbon quantum dot particles with upconversion properties prepared by any method, such as: a microwave method using isophorone diisocyanate as a single carbon source, a one-step hydrothermal method using bovine serum albumin and folic acid as carbon sources, a one-step hydrothermal method using water hyacinth as a carbon source, an electrochemical method, and so on. The carbon quantum dot particles in the present invention include carbon quantum dot particles containing doping elements.

[0026] The glass layer 3 is fixedly inclined on the side wall. Specifically, the inclined angle can be any angle, but it is necessary to ensure that the side of the glass layer 3 provided with the photocatalyst particle layer 5 is close to the bottom cover 2. The glass layer 3 is in close contact with the side wall, and there is no gap between the glass layer 3 and the side wall. They can be fixedly bonded by an adhesive, so as to form an effective seal and prevent gas exchange on both sides of the glass layer 3. Compared with non-inclined setting, the surface area of the glass layer 3 is larger, that is, more carbon quantum dot particles and photocatalyst particles can be provided. The thickness of the glass layer 3 can be on the order of millimeters or centimeters. Preferably, the thickness of the glass layer is 0.1 - 0.3 cm, which can provide an effective supporting effect for the photocatalyst particle layer 5 and the carbon quantum dot particle layer 4 without making the overall component too heavy. The first light source 7 is arranged on the side wall between the activated carbon layer 6 and the glass layer 3. Preferably, the position of the first light source 7 and the positions of the two farthest end points on the glass layer 3 form an isosceles triangle, and the first light source 7 is located at the vertex of the isosceles triangle. In this way, the light emitted by the first light source can be normally incident on the photocatalyst particle layer 5 and the carbon quantum dot particle layer 4 after propagating in a straight line, so that the photocatalyst particles and the carbon quantum dot particles are fully irradiated, thereby generating more photo-generated electrons and photo-generated holes in the photocatalyst particles and improving the air purification efficiency. The first light source 7 is an ultraviolet-visible light source. The photocatalyst particles absorb ultraviolet light, and the carbon quantum dot particles absorb visible light and convert the visible light into ultraviolet light, improving the utilization rate of the light field by the photocatalyst particles and improving the air purification efficiency. The carbon quantum dot particles and the photocatalyst particles can be prepared by spin coating or deposition methods.

[0027] An air extraction hole is provided on the side wall of the outer frame structure 1. The air extraction hole is arranged between the glass layer 3 and the activated carbon layer 6 and is used to connect with an external air extraction device, so as to form a negative pressure between the glass layer 3 and the activated carbon layer 6, enabling the surrounding air to enter from the side of the activated carbon layer 6 away from the bottom cover 2. Preferably, the air extraction hole is arranged at the end of the glass layer 3 farther from the activated carbon layer 4, and the distance from the air extraction hole to the farther end of the glass layer 3 is less than 1 cm. More preferably, the direction of the air extraction hole is perpendicular to the plane where the glass layer 3 is located. In this way, the preliminarily purified air will not be directly discharged from the air extraction hole between the glass layer 3 and the activated carbon layer 6. That is, the velocity direction of the air entering from the activated carbon layer 6 is different from the velocity direction of the air extracted from the air extraction hole, and the air will form a circulation between the glass layer 3 and the activated carbon layer 6. More preferably, the penetration directions of the through holes on the bottom cover 2 are different. Specifically, the direction of the through hole is inclined towards the end of the glass layer 3 close to the activated carbon layer 6, that is, the upper end of the through hole is closer to the lower end of the glass layer 3 than the lower end, and the farther the through hole is from the lower end of the glass layer 3, the greater the distance between the upper and lower ends of the through hole, that is, the greater the inclination angle. The penetration direction of the through hole with the smallest inclination angle forms a 45-degree angle with the plane where the bottom cover 2 is located. Due to the greater wind resistance, the flow rate of the formed air circulation is smaller, so that the interaction time between the air and the photocatalyst particles and carbon quantum dot particles is longer, the photocatalytic reaction is more sufficient, and the purification efficiency is higher. Since the inclination angles of the through holes are different, air circulations with different flow rates and rotation radii can be formed, enabling any position on the glass layer 3 to be in full contact with the air circulation. This easily makes the intensity of the photocatalytic reaction on each photocatalyst particle consistent, thereby avoiding the low purification efficiency caused by insufficient resource utilization due to locally weak or strong photocatalytic reaction intensity on the photocatalyst. Therefore, the air purification efficiency of the filtering component of the present invention is relatively high.

[0028] Further, a noble metal protrusion is fixedly arranged on the side of the photocatalyst particle layer 5 away from the carbon quantum dot particle layer 4. The noble metal protrusion can be prepared by magnetron sputtering or electron beam deposition. The particle size of the noble metal protrusion is less than two-thirds of the corresponding photocatalyst particle size, so as to ensure that the coverage of the noble metal protrusion will not cause a sharp reduction in the contact area between air and photocatalyst particles. The material of the noble metal protrusion is gold or silver. Under the action of the optical field, local surface plasmon resonance occurs on the noble metal protrusion, and a strong electric field is generated on the surface of the noble metal protrusion, that is, the noble metal protrusion localizes the optical field near it, making the interaction between the photocatalyst particles and the optical field stronger, thereby enhancing the intensity of the photocatalytic reaction and improving the air purification efficiency. In addition, since the noble metal protrusions are not uniformly arranged on the photocatalyst particles, the strong electric field near the noble metal protrusions polarizes the photocatalyst particles, and the photo-generated electrons inside the polarized photocatalyst particles are more likely to be distributed on the surface of the photocatalyst particles, thereby avoiding the recombination rate of photo-generated electrons and photo-generated holes inside the photocatalyst particles, so that more generated photo-generated electrons and photo-generated holes participate in the photocatalytic reaction, that is, the noble metal protrusions reduce the recombination rate of photo-generated electrons and photo-generated holes and improve the utilization rate of photo-generated electrons and photo-generated holes generated by the photocatalyst particles. Therefore, the setting of the noble metal protrusions can further improve the utilization rate of the optical field by the filter component, and further improve the air purification efficiency.

[0029] Furthermore, tetrapod-like zinc oxide whiskers are doped in the photocatalyst particle layer 5. Zinc oxide is a common semiconductor catalyst. The tetrapod-like zinc oxide whiskers are micro-nano structures of zinc oxide, with four nano-sized needles. The length of the needles is about 10 - 60 μm, and the diameter is about 500 nm - 10 μm. Such a structure can, on the one hand, scatter the optical field, making the optical field generated by the first light source 7 irradiate more uniformly on the photocatalyst particles and carbon quantum dot particles. The tetrapod-like structure has an irregular shape, so that the sides of the photocatalyst particles and carbon quantum dot particles that were not originally irradiated by the optical field are irradiated by light, which enhances the contact area between the optical field and the photocatalyst particles and carbon quantum dot particles, enables the photocatalytic reaction to proceed fully, improves the utilization efficiency of the optical field, and thus improves the air purification efficiency; on the other hand, the tetrapod-like structure can adsorb air near it, making the contact between the air and the photocatalyst particles and carbon quantum dot particles more sufficient. That is, the setting of the tetrapod-like zinc oxide whiskers makes the contact between the optical field and air and the photocatalyst particles and carbon quantum dot particles more sufficient at the same time, the intensity of the photocatalytic reaction is greater, and the reaction proceeds more fully, thereby improving the air purification efficiency. The preparation of the tetrapod-like zinc oxide whiskers can refer to the articles named "Preparation of Tetrapod-Like Zinc Oxide Whiskers by Direct Oxidation of Zinc Vapor", "New Technology for the Preparation of Tetrapod-Like Zinc Oxide Whiskers", "Preparation of Tetrapod-Like Zinc Oxide Whiskers by High-Temperature Oxidation of Metallic Zinc", and "Preparation and Application of Tetrapod-Like Zinc Oxide Whiskers".

[0030] Furthermore, a second light source 8 is fixedly arranged on the top wall or the side wall of the glass layer 3 away from the activated carbon layer 6. The second light source 8 is a visible light source, and the light emitted by the second light source 8 irradiates on the side of the glass layer 3 away from the photocatalyst particle layer 5. The visible light passes through the glass layer 3 and irradiates on the carbon quantum dot particle layer 4, and is absorbed by the carbon quantum dot particles and converted into ultraviolet light. The ultraviolet light acts on the photocatalyst particles to generate photo-generated electrons and photo-generated holes, so that more photo-generated electrons and photo-generated holes can be generated, the intensity of the photocatalytic reaction can be improved, and the air purification efficiency can be improved. Preferably, the connection line between the centers of the second light source 8 and the first light source 7 is perpendicular to the glass layer 3, so that the light emitted by the second light source 8 can fully irradiate on the carbon quantum dot particle layer 4, making the interaction between the light field and the carbon quantum dot particle layer 4 stronger, thereby enhancing the intensity of the photocatalytic reaction and improving the air purification efficiency.

[0031] During application, the filtering component can be directly placed in the environment to be used by connecting an air extraction device through the air extraction hole, or can be fixedly installed as a filtering part for use in conjunction with an air purifier. Specifically, when the filtering component is used in conjunction with an air purifier, an air extraction device needs to be connected at the air extraction hole, and the extracted gas is finally discharged through the air outlet hole. It is also necessary to fix the filtering component inside the air purifier so that the air to be purified flows in from the side of the bottom cover 2 away from the activated carbon layer 6. During use, the air extraction device is fixedly connected to the outer side of the air extraction hole, which can be fixedly connected by adhesion or by using a flange ring, etc. During use, the light source and the air extraction device are both in a working state. The air to be purified flows in through the through holes on the bottom cover 2, and is initially purified through the activated carbon layer 6 to remove particulate pollutants and some gaseous pollutants. The gas after preliminary purification forms a circulation between the glass layer 3 and the activated carbon layer 6, and fully undergoes a photocatalytic reaction with the photocatalyst particles and carbon quantum dot particles. Finally, the purified air is extracted through the air extraction hole. Specifically, during the photocatalytic reaction process, photons act on the photocatalyst particles and carbon quantum dot particles. The photocatalyst particles generate photo-generated electrons and photo-generated holes under the excitation of ultraviolet light for the photocatalytic reaction; the carbon quantum dot particles, under the irradiation of visible light, utilize the upconversion property to convert visible light into ultraviolet light, enabling the photocatalyst particles to utilize more light field energy for the photocatalytic reaction. In addition, the carbon quantum dot particles also play a role in "sharing" the photo-generated electrons between the photocatalyst particles, avoiding the decrease in catalytic efficiency caused by the uneven distribution of the photocatalytic reaction intensity. Therefore, the filtering component of the present invention improves the utilization rate of the light field by enhancing the absorption of the photocatalyst particles for the light field and improving the utilization rate of the photo-generated electrons and photo-generated holes generated by the photocatalyst particles, thereby improving the air purification efficiency. Further, during use, the air extraction rate of the air extraction device can be changed, that is, pulsed air extraction is performed. When the air extraction rate is large, the air adsorbed by the tetrapod-shaped zinc oxide whiskers can be desorbed, and when it is small, the zinc oxide whiskers adsorb air for purification. In this way, the process of adsorption and desorption is completed in a cycle, improving the utilization rate of the air, and further improving the air purification efficiency.

[0032] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A filtering component based on carbon quantum dot particles, characterized in that, The filtering component includes an outer frame structure, a bottom cover, a photocatalyst particle layer, a carbon quantum dot particle layer, a glass layer, an activated carbon layer, and a first light source. The outer frame structure is a container with one end open, the container has a top wall and side walls, the bottom cover matches the shape and size of the opening of the outer frame structure, the bottom cover is the bottom lid of the outer frame structure, there are through holes on the bottom cover, the activated carbon layer is fixedly arranged on one side of the bottom cover close to the top wall, the carbon quantum dot particle layer is fixedly arranged on one side of the glass layer, the carbon quantum dot particle layer is composed of 2 - 3 layers of carbon quantum dot particles, adjacent carbon quantum dot particles are in contact with each other, the photocatalyst particle layer is fixedly arranged on the side away from the glass layer of the carbon quantum dot particle layer, the photocatalyst particle layer is doped with tetrapod-like zinc oxide whiskers, the glass layer is inclined and fixedly arranged on the side wall, the side of the glass layer provided with the photocatalyst particle layer is close to the bottom cover, the glass layer is in close contact with the side wall, there is an air extraction hole on the side wall, the air extraction hole is arranged between the glass layer and the activated carbon layer, the air extraction hole is close to the glass layer, the direction of the air extraction hole is perpendicular to the plane where the glass layer is located, the first light source is fixedly arranged on the side wall, and the first light source is arranged between the activated carbon layer and the glass layer.

2. The filter component based on carbon quantum dot particles according to claim 1, characterized in that The photocatalyst particle layer is composed of photocatalyst particles, and the material of the photocatalyst particles is one of TiO2, ZrO2, ZnO, and WO3.

3. The filter component based on carbon quantum dot particles according to claim 2, characterized in that The particle size of the photocatalyst particles is 50 - 200 nm.

4. The filter component based on carbon quantum dot particles according to claim 3, characterized in that, The particle size of the carbon quantum dot particles is 2 - 8 nm.

5. The filter component based on carbon quantum dot particles according to claim 4, wherein, Noble metal protrusions are fixedly arranged on the side of the photocatalyst particles away from the carbon quantum dot particle layer.

6. The filter component based on carbon quantum dot particles according to claim 5, characterized in that, A second light source is arranged on the top wall or the side wall, the second light source is a visible light source, and the first light source is an ultraviolet-visible light source.

7. The filtering component based on carbon quantum dot particles according to any one of claims 1-6, characterized in that, The position of the first light source and the positions of the two farthest endpoints of the glass layer form an isosceles triangle, and the first light source is located at the vertex of the isosceles triangle.

8. The filter component based on carbon quantum dot particles according to any one of claims 1-6, characterized in that, The material of the activated carbon layer is activated carbon cotton, and the thickness of the activated carbon layer is greater than 2 cm.

9. The filtration component based on carbon quantum dot particles according to any one of claims 1-6, characterized in that The shape of the container is one of a cylinder and a cuboid.

10. The filter component based on carbon quantum dot particles according to any one of claims 1-6, characterized in that, There are multiple through holes on the bottom cover, and the bottom cover and the outer frame structure are fixedly connected by a threaded connection or an adhesive method.

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