Photocatalytic hollow-core optical fiber with synchronous side transmission of gas and light and preparation method thereof

Abstract

The present invention discloses a photocatalytic hollow optical fiber for synchronous side transmission of gas and light and a preparation method thereof, which is used for synchronous transmission of light and gas, and comprises an optical fiber core, an optical fiber cladding and a photocatalytic layer; the optical fiber cladding is coated on the outer peripheral side of the optical fiber core, and the photocatalytic layer is coated on the outer peripheral side of the optical fiber cladding; the optical fiber core is a hollow structure, and the two ends of the optical fiber core are respectively a gas input end and a light input end, the gas can enter the optical fiber core through the gas input end, and can pass through the optical fiber core to contact the photocatalytic layer to generate a photocatalytic reduction reaction; the light input end has a transparent sealing part, and the light can pass through the sealing part and enter the optical fiber core through the light input end; the photocatalytic hollow optical fiber disclosed by the present invention changes the traditional internal light transmission mode of optical fiber, and the cladding of the hollow optical fiber with a core and a cladding can simultaneously transmit light and gas, further improving the efficiency of the photocatalytic reduction reaction.

Description

Technical Field

[0001] The present invention relates to the field of photocatalytic optical fibers, and in particular to a photocatalytic hollow optical fiber for synchronous side transmission of gas and light and a preparation method thereof. Background Art

[0002] Energy is the driving force behind human progress. Global annual energy consumption has increased from 17.26 billion tons of coal equivalent in 2010 to 19.92 billion tons of coal equivalent today, with fossil fuels accounting for over 84% of this total. This excessive consumption of fossil fuels has not only led to a global energy crisis but also to environmental problems caused by massive CO2 emissions. Since 2010, global CO2 emissions have exceeded 3 billion tons annually and continue to increase, contributing over 60% to global warming. Various strategies are being adopted globally to mitigate the environmental impact of CO2, including reducing CO2 emissions at the source, capturing and storing CO2, and converting CO2 into renewable hydrocarbon fuels for reuse through electrochemical or photocatalytic technologies.

[0003] Among them, photocatalytic technology uses excess renewable energy solar energy at room temperature and pressure to combine the reduction half-reaction of CO2 conversion with the oxidation half-reaction of H2O at the semiconductor photocatalyst interface to achieve CO2+H2O→C x H y O z The molecular transformation of CO2+H2O→C x H y O z The molecular conversion of provides a practical solution to global energy and environmental problems. This technology is of great significance for promoting CO2 emission reduction and renewable fuel production, as well as the sustainable development of energy, environment and economy.

[0004] In an immobilized photocatalytic CO2 reduction reactor, the photocatalyst is fixed to the surface of a carrier, while H2O and CO2 are in the gas phase. This technology effectively enhances the transmission of light and CO2, improving light energy utilization efficiency, quantum efficiency, CO2 conversion efficiency, and system stability; significantly promoting the development of photocatalytic CO2 reduction technology.

[0005] However, in immobilized photocatalytic CO2 reduction technology, light transmission and capture are key limiting steps in the reaction. Therefore, enhancing the light transmission performance within the catalytic layer and the catalyst's light capture ability to avoid photon loss is key to improving light utilization efficiency, surface charge, and CO2 conversion efficiency. Furthermore, the transport of the reactant (CO2) within the photocatalytic layer and its distribution characteristics at the three-phase reaction interface are important factors that directly influence the kinetics of the catalytic reaction and product selectivity.

[0006] In existing immobilized photocatalytic technology, photocatalytic reduction of CO2 reactions often use luminescent optical fibers and multi-channel ceramic monomers as attachment carriers for photocatalysts.

[0007] Among them, side-emitting optical fibers are widely used. They can effectively enhance light transmission, thereby improving the efficiency of light energy utilization and further improving the efficiency of photocatalytic reduction of CO2. For side-emitting catalytic optical fibers, the photocatalyst is coated on the surface of the optical fiber cladding. When the incident light is transmitted to the interface between the optical fiber cladding and the catalytic layer, because the refractive index of the catalyst is greater than the refractive index of the optical fiber cladding, the incident light is refracted into the catalytic layer, and is transmitted within the catalytic layer to excite the catalyst to produce electron-hole pairs. Light that does not enter the interface between the optical fiber and the catalyst continues to be transmitted along the optical fiber. Since photocatalytic optical fibers generally use multimode optical fibers as the light transmission medium, there are many modes of light transmitted inside the optical fiber, so uniform radiation of light can be obtained across the entire optical fiber surface, achieving uniform photoactivation of the catalyst in space.

[0008] However, the core refractive index of existing side-emitting or light-guiding optical fibers is higher than that of the fiber cladding, resulting in light being trapped within the fiber core. This results in weak light intensity within the fiber cladding, weak light intensity transmitted into the photocatalyst coating on the fiber cladding surface, and weak excitation light intensity for the photocatalyst to photocatalytically reduce CO2. Furthermore, existing side-emitting or light-guiding optical fibers are primarily made of glass or plastic materials, which have high material density. This prevents CO2 from being released from the fiber surface, thereby enhancing the active transmission of CO2 from the inside out of the photocatalytic layer, limiting the improvement of photocatalytic CO2 reduction performance.

[0009] Multi-channel ceramic monomers are used in the development of CO2 transmission to enhance the transmission of CO2 molecules within the photocatalytic layer. The side surfaces of the multi-channel ceramic monomers can release CO2, which can effectively improve the uneven distribution of CO2 in the reactor. At the same time, the multi-channel ceramic monomers have a large specific surface area, which can increase the photocatalytic loading capacity, thereby improving the efficiency of the photocatalytic reaction of CO2 in the reactor. Although multi-channel ceramic monomers have many advantages as mentioned above, they are only suitable for gas transmission and have difficulty in achieving light transmission. In other words, multi-channel ceramic monomers cannot achieve the active transmission and enhancement of light from the inside to the outside of the photocatalytic layer, which reduces the efficiency of light energy utilization and the performance of photocatalytic reduction of CO2.

[0010] Summarizing the current domestic research on light and CO2 transmission media involved in photocatalytic reduction of CO2, it can be seen that existing photocatalytic optical fibers can only perform single light transmission, and multi-channel ceramic monomers can only achieve single CO2 transmission. There are no reports on photocatalytic devices that can simultaneously transmit light and gases (such as CO2, N2, NH3, SO2, etc.) from the inside to the outside of the photocatalytic layer. Summary of the Invention

[0011] The purpose of the present invention is to provide a photocatalytic hollow optical fiber with synchronous side transmission of gas and light and a preparation method thereof, so as to solve the technical problem in the prior art that the transmission medium involved in the photocatalytic reduction reaction cannot simultaneously transmit light and gas, resulting in the inability to improve the efficiency of the photocatalytic reduction reaction.

[0012] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0013] A photocatalytic hollow optical fiber for synchronous side transmission of gas and light, used for synchronous transmission of light and gas, comprises an optical fiber core 1, an optical fiber cladding 2 and a photocatalytic layer 3; the optical fiber cladding 2 is coated on the outer peripheral side of the optical fiber core 1, and the photocatalytic layer 3 is coated on the outer peripheral side of the optical fiber cladding 2; the optical fiber core 1 is a hollow structure, and the two ends of the optical fiber core 1 are respectively a gas input end 4 and a light input end 5, the gas can enter the optical fiber core 1 through the gas input end 4, and can pass through the optical fiber core 1 to contact the photocatalytic layer 3 to undergo a photocatalytic reduction reaction; the light input end 5 has a transparent sealing portion 51, and the light can pass through the sealing portion 51 and enter the optical fiber core 1 through the light input end 5.

[0014] Preferably, the optical fiber cladding 2 is made of a polysulfone / SiO2 / GeO2 composite material, and the polysulfone / SiO2 / GeO2 composite material is prepared from a mixed solution of polysulfone, SiO2 and GeO2 complex formed by uniformly dispersing polysulfone, SiO2 and GeO2 in dichloromethane.

[0015] Preferably, the photocatalytic layer 3 is made of a TiO2 / SiO2 composite material, and the TiO2 / SiO2 composite material is prepared by adding SiO2 particles into TiO2 sol.

[0016] Preferably, the diameter of the optical fiber core 1 is 20 to 500 μm, the thickness of the optical fiber cladding 2 is 100 to 500 μm; and the thickness of the photocatalytic layer 3 is 10 to 30 μm.

[0017] Preferably, the gas is one of CO2, N2, NH3, and SO2 gases.

[0018] The present invention also discloses a method for preparing a photocatalytic hollow-core optical fiber for synchronous side transmission of gas and light, which uses the photocatalytic hollow-core optical fiber as described above, comprising the following steps:

[0019] S1, preparing a polysulfone / SiO2 / GeO2 composite material to obtain raw materials for preparing an optical fiber cladding;

[0020] S2, preparing a TiO2 / SiO2 composite material solution to obtain raw materials for preparing an optical fiber photocatalytic layer;

[0021] S3, using the polysulfone / SiO2 / GeO2 composite material prepared in step S1 to prepare a hollow optical fiber by dry-wet spinning;

[0022] S4, drying the hollow-core optical fiber prepared in step S3, and then sealing one end of the hollow-core optical fiber;

[0023] S5. Immerse the hollow optical fiber sealed at one end in step S4 into a TiO2 / SiO2 composite material solution to cover the surface of the hollow optical fiber with a photocatalytic film to form a photocatalytic layer, and obtain a photocatalytic hollow optical fiber after drying.

[0024] Preferably, step S1 includes the following steps:

[0025] S1.1. Add a predetermined amount of polysulfone to a predetermined amount of dichloromethane, and stir to obtain a polysulfone / dichloromethane mixture; the weight ratio of the polysulfone to dichloromethane is in the range of 1:30 to 1:40;

[0026] S1.2, adding SiO2 particles to the polysulfone / dichloromethane mixture, stirring evenly to obtain a polysulfone / dichloromethane mixture doped with SiO2; the weight ratio of SiO2, polysulfone, and dichloromethane is in the range of 0.1:1:30 to 0.2:1:40;

[0027] S1.3. Add GeO2 particles to the polysulfone / dichloromethane mixture doped with SiO2, and stir evenly to obtain a polysulfone / SiO2 / GeO2 composite material; the weight ratio of GeO2, SiO2, polysulfone and dichloromethane is in the range of 0.1:0.1:1:30 to 0.2:0.15:1:40.

[0028] Preferably, step S2 includes the following steps:

[0029] S2.1. Add titanium isopropoxide to the preheated ethylene glycol, and heat the ethylene glycol / titanium isopropoxide mixed solution while stirring; the weight ratio of ethylene glycol to titanium isopropoxide is in the range of 10:1 to 4:1;

[0030] S2.2. Add citric acid monohydrate to the ethylene glycol / titanium isopropoxide mixed solution and stir until the mixed solution becomes clear. The weight ratio of ethylene glycol, titanium isopropoxide, and citric acid monohydrate is 10:1:8 to 4:1:3.

[0031] S2.3, adding TiO2 powder to the mixed solution obtained in step S2.2, and stirring to obtain a photocatalytic TiO2 sol;

[0032] The weight ratio of the mixed solution obtained in step S2.2 to the TiO2 powder is in the range of 1.0 to 1.6, preferably 1.54;

[0033] S2.4. Add SiO2 particles to the photocatalytic TiO2 sol to obtain a TiO2 / SiO2 composite material solution, which is the raw material for preparing the optical fiber photocatalytic layer; the weight ratio of the photocatalytic TiO2 sol to the SiO2 particles is in the range of 120 to 130, and the preferred weight ratio of the photocatalytic TiO2 sol to the SiO2 particles is 127.

[0034] Preferably, the optical fiber core diameter is 20 to 500 μm; the cladding thickness is 100 to 500 μm; and the photocatalytic layer thickness is 10 to 30 μm.

[0035] The present invention has the following beneficial effects:

[0036] 1. The refractive index of the photocatalytic hollow optical fiber for synchronous side transmission of gas and light disclosed in the present invention increases stepwise from the core to the photocatalytic layer, which changes the light transmission mode inside the traditional optical fiber and overcomes the problem that the light beam in the traditional optical fiber is confined to the core for transmission, resulting in low surface light radiation intensity and transmission depth of the traditional optical fiber; the optical fiber cladding of the present invention not only has high light transmission characteristics and a dense structure, but also has the ability to transmit gas molecules (such as CO2, N2, NH3, SO2, etc.) under appropriate pressure conditions. That is, the cladding of the hollow optical fiber with a core and a cladding can transmit light and gas at the same time, further improving the efficiency of the photocatalytic reduction reaction.

[0037] 2. The main material of the fiber cladding of the photocatalytic hollow optical fiber for synchronous side transmission of gas and light disclosed in the present invention is polysulfone material, which has high light transmittance and gas conductivity. At the same time, the SiO2 and GeO2 particles doped in the fiber cladding have high ultraviolet-visible light transmission performance, thereby enhancing the optical transmission performance of the optical fiber. In addition, since the SiO2 and GeO2 particles have strong mechanical properties, the mechanical strength of the optical fiber is increased.

[0038] 3. The photocatalytic hollow optical fiber with synchronous side transmission of gas and light disclosed in the present invention can realize the synchronous transmission and intensification of light and CO2 in the photocatalytic layer. The light and CO2 molecules transmitted into the photocatalytic layer are directly utilized and converted by TiO2, thereby improving the utilization efficiency and conversion efficiency of light energy and CO2. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to make the purpose, technical solutions and advantages of the invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings, in which:

[0040] Figure 1 This is a schematic diagram of the photocatalytic hollow optical fiber structure of the present invention.

[0041] Figure 2 Schematic diagram of the light and gas transmission paths of the present invention.

[0042] Figure 3 Schematic diagram of the molecular structure of ethylene glycol of the present invention.

[0043] Figure 4 Schematic diagram of the molecular structure of titanium isopropoxide of the present invention.

[0044] Figure 5 Schematic diagram of the molecular structure of citric acid monohydrate of the present invention.

[0045] Figure 6 Schematic diagram of the optical radiation intensity on the optical fiber surface and the relationship between the gas release rate and gas pressure on the optical fiber surface according to an embodiment of the present invention.

[0046] Explanation of the accompanying symbols: 1. optical fiber core; 2. optical fiber cladding; 3. photocatalytic layer; 4. gas input end; 41. gas molecules; 5. light input end; 51. sealing part; 52. light source; 53. light. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0048] It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it does not require further definition or explanation in subsequent figures. In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the figures, or the orientations or positional relationships in which the inventive product is typically placed when in use. These terms are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation, and are therefore not to be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and are not to be construed as indicating or implying relative importance. Furthermore, terms such as "horizontal" and "vertical" do not imply that a component must be absolutely horizontal or overhanging, but rather may be slightly tilted. For example, "horizontal" simply refers to a direction that is more horizontal than "vertical," and does not imply that the structure must be completely horizontal, but rather may be slightly tilted. In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0049] In order to simultaneously realize the synchronous transmission and enhancement of light and gas from the inside to the outside of the photocatalytic layer, the present invention invents a photocatalytic hollow optical fiber for synchronous transmission of light and gas, which solves the technical problem in the prior art that the transmission medium involved in the photocatalytic reduction reaction cannot simultaneously transmit light and gas, resulting in the inability to improve the efficiency of the photocatalytic reduction reaction.

[0050] Of course, the present invention is not limited to the transmission of CO2 gas, and the present invention can also be used for the transmission of light and other gases (such as N2, NH3, SO2, etc.).

[0051] like Figure 1As shown, based on the above technical problems to be solved, the present invention discloses a photocatalytic hollow optical fiber for synchronous side transmission of gas and light, which is used for synchronous transmission of light and gas, including an optical fiber core 1, an optical fiber cladding 2 and a photocatalytic layer 3; the optical fiber cladding 2 is coated on the outer peripheral side of the optical fiber core 1, and the photocatalytic layer 3 is coated on the outer peripheral side of the optical fiber cladding 2; the optical fiber core 1 is a hollow structure, and the two ends of the optical fiber core 1 are respectively a gas input end 4 and a light input end 5, the gas can enter the optical fiber core 1 through the gas input end 4, and can pass through the optical fiber core 1 and contact with the photocatalytic layer 3 to generate a photocatalytic reduction reaction; the light input end 5 has a transparent sealing portion 51, and the light can pass through the sealing portion 51 and enter the optical fiber core 1 through the light input end 5.

[0052] Preferably, the optical fiber cladding 2 is made of a polysulfone / SiO2 / GeO2 composite material, which is prepared from a mixed solution of polysulfone, SiO2 and GeO2 complex formed by uniformly dispersing polysulfone, SiO2 and GeO2 in dichloromethane.

[0053] The polysulfone has a transparent gas-conducting function, which can transmit light and allow gas to pass through.

[0054] The SiO2 mentioned above refers to silicon dioxide, also known as quartz sand in Chinese and Silicon dioxide in English, with a CAS number of 14808-60-7 and a molecular weight of 138.184.

[0055] The GeO2 refers to germanium dioxide, whose English name is Germanium oxide, CAS number is 1310-53-8, and molecular weight is 104.639.

[0056] Preferably, the photocatalytic layer 3 is made of a TiO2 / SiO2 composite material, and the TiO2 / SiO2 composite material is prepared by adding SiO2 particles into TiO2 sol.

[0057] The TiO2 refers to silicon dioxide, the English name is titanium oxide, the CAS number is 12065-65-5, and the molecular weight is 223.598.

[0058] Preferably, the diameter of the optical fiber core 1 is 20 to 500 μm, the thickness of the optical fiber cladding 2 is 100 to 500 μm; and the thickness of the photocatalytic layer 3 is 10 to 30 μm.

[0059] Preferably, the gas is one of CO2, N2, NH3, and SO2 gases.

[0060] like Figure 2As shown, the working process of the photocatalytic hollow optical fiber disclosed in the present invention is: gas molecules 41 are injected from the hollow optical fiber gas input end 4, and light 53 is emitted by the light source 52 and injected through the hollow optical fiber light input end 5. The optical fiber can synchronously transmit light 53 and gas molecules 41. At the same time, under appropriate air pressure, the surface of the optical fiber will radiate light 53 and release gas molecules 41, realizing the synchronous transmission and enhancement of light and gas in the photocatalytic layer, and improving the utilization and conversion performance of light energy and gas.

[0061] The present invention also discloses a method for preparing a photocatalytic hollow-core optical fiber for synchronous side transmission of gas and light, which uses the photocatalytic hollow-core optical fiber as described above, comprising the following steps:

[0062] S1, preparing a polysulfone / SiO2 / GeO2 composite material to obtain raw materials for preparing an optical fiber cladding;

[0063] S2, preparing a TiO2 / SiO2 composite material solution to obtain raw materials for preparing an optical fiber photocatalytic layer;

[0064] S3, using the polysulfone / SiO2 / GeO2 composite material prepared in step S1 to prepare a hollow optical fiber by dry-wet spinning;

[0065] S4, drying the hollow-core optical fiber prepared in step S3, and then sealing one end of the hollow-core optical fiber;

[0066] S5. Immerse the hollow optical fiber sealed at one end in step S4 into a TiO2 / SiO2 composite material solution to cover the surface of the hollow optical fiber with a photocatalytic film to form a photocatalytic layer, and obtain a photocatalytic hollow optical fiber after drying.

[0067] Preferably, the optical fiber core diameter is 20 to 500 μm; the cladding thickness is 100 to 500 μm; and the photocatalytic layer thickness is 10 to 30 μm.

[0068] Preferably, step S1 includes the following steps:

[0069] S1.1. Add a predetermined amount of polysulfone to a predetermined amount of dichloromethane, and stir to obtain a polysulfone / dichloromethane mixture; the weight ratio of the polysulfone to dichloromethane is in the range of 1:30 to 1:40;

[0070] S1.2, adding SiO2 particles to the polysulfone / dichloromethane mixture, stirring evenly to obtain a polysulfone / dichloromethane mixture doped with SiO2; the weight ratio of SiO2, polysulfone, and dichloromethane is in the range of 0.1:1:30 to 0.2:1:40;

[0071] S1.3. Add GeO2 particles to the polysulfone / dichloromethane mixture doped with SiO2, and stir evenly to obtain a polysulfone / SiO2 / GeO2 composite material; the weight ratio of GeO2, SiO2, polysulfone and dichloromethane is in the range of 0.1:0.1:1:30 to 0.2:0.15:1:40.

[0072] Specifically, in step S1.1, the polysulfone is stirred by magnetic stirring until it is uniformly dissolved in dichloromethane.

[0073] Specifically, in step S1.2, the particle size of the SiO2 particles is less than 20 nm, and the SiO2 particles are used to increase the mechanical stability of the cladding.

[0074] Specifically, in step S1.3, the particle size of the GeO2 particles is less than 20 nm. The GeO2 particles have high ultraviolet-visible light transmission performance and are used to adjust the refractive index and ultraviolet-visible light transmission characteristics of the optical fiber packaging material.

[0075] Specifically, in step S1.3, GeO2 particles are added to the polysulfone / dichloromethane mixture doped with SiO2, and then stirred with a magnetic stirrer for 24 to 36 hours to obtain the optical fiber cladding raw material.

[0076] Preferably, step S2 includes the following steps:

[0077] S2.1. Add titanium isopropoxide to the preheated ethylene glycol, and heat the ethylene glycol / titanium isopropoxide mixed solution while stirring; the weight ratio of ethylene glycol to titanium isopropoxide is in the range of 10:1 to 4:1;

[0078] S2.2. Add citric acid monohydrate to the ethylene glycol / titanium isopropoxide mixed solution and stir until the mixed solution becomes clear. The weight ratio of ethylene glycol, titanium isopropoxide, and citric acid monohydrate is 10:1:8 to 4:1:3.

[0079] S2.3, adding TiO2 powder to the mixed solution obtained in step S2.2, and stirring to obtain a photocatalytic TiO2 sol;

[0080] The weight ratio of the mixed solution obtained in step S2.2 to the TiO2 powder is in the range of 1.0 to 1.6, preferably 1.54;

[0081] S2.4. Add SiO2 particles to the photocatalytic TiO2 sol to obtain a TiO2 / SiO2 composite material solution, which is the raw material for preparing the optical fiber photocatalytic layer; the weight ratio of the photocatalytic TiO2 sol to the SiO2 particles is in the range of 120 to 130, and the preferred weight ratio of the photocatalytic TiO2 sol to the SiO2 particles is 127.

[0082] The TiO2 / SiO2 composite material solution can enhance the adhesion strength between the photocatalytic layer and the optical fiber cladding, while inhibiting the recombination of photogenerated electron-hole pairs.

[0083] Specifically, in step S2.1, the preheating temperature of ethylene glycol is 55-65°C, and the ethylene glycol needs to be continuously stirred during heating; after adding titanium isopropoxide, the ethylene glycol / titanium isopropoxide mixed solution is heated to 85-95°C.

[0084] Specifically, the ethylene glycol used in step S2.1 is called Ethylene glycol in English, has a molecular formula of C2H6O2, a molecular weight of 62.068, a CAS number of 107-21-1, and is also known in Chinese as 1,2-ethylene glycol / glycol / ethylene glycol / ethylene glycol. The molecular structure of ethylene glycol is as follows: Figure 3 shown.

[0085] Specifically, the titanium isopropoxide used in step S2.1 is commonly known as tetraisopropyl titanate, and its English name is Titanium (4+) tetrapropan-2-olate. Chemical formula C 12 H 28 O4Ti, molecular weight is 284.215, CAS number is 546-68-9, Chinese alias is: tetraisopropyl titanate / tetraisopropoxy titanium (IV) / tetraisopropoxide titanium / tetraisopropoxy titanium, the molecular structure of titanium isopropoxide is as follows Figure 4 shown.

[0086] Specifically, in step S2.3, the particle size of the TiO2 powder is less than 30 nm, and the stirring time ranges from 3 to 5 hours.

[0087] Specifically, the citric acid monohydrate used in step S2.2 is a natural preservative and food sourness enhancer, and its English name is Citric acid monohydrate, and its molecular formula is C6H 10 O8, molecular weight is 210.139, CAS number is 5949-29-1, Chinese alias is: citric acid / citric acid, the molecular structure of citric acid monohydrate is as follows Figure 5 shown.

[0088] Specifically, in step S2.4, the particle size of the SiO2 particles is less than 20 nm.

[0089] Specifically, in step S4, the prepared hollow-core optical fiber is dried at 110-120°C for 3-5 hours to obtain a hollow-core optical fiber consisting only of a core and a cladding. In order to ensure that the optical fiber has good mechanical strength and gas conductivity, the diameter of the optical fiber core is made to be 20-500 μm, and the cladding thickness is made to be 100-500 μm.

[0090] Specifically, in step S4, one end of the hollow optical fiber is sealed with a mixture of UV glue and SiO2 with a particle size less than 20 nm, and the weight ratio of the UV glue to SiO2 is in the range of 95:5 to 98:2.

[0091] Specifically, in step S5, a coating pulling method is used to immerse the hollow-core optical fiber with only the core and cladding sealed at the port into the raw material of the optical fiber photocatalytic layer, and a photocatalytic film with a thickness of 10 to 30 μm is coated on the surface of the hollow-core optical fiber with only the core and cladding. The film is then dried at 150 to 180°C for 24 to 36 hours to obtain a photocatalytic hollow optical fiber for synchronous transmission of light and gas.

[0092] The gas and light synchronous side transmission photocatalytic hollow optical fiber disclosed in the present invention and its preparation method have the following technical effects:

[0093] The refractive index of the photocatalytic hollow optical fiber disclosed in the present invention for synchronous side transmission of gas and light increases stepwise from the core to the photocatalytic layer. The hollow optical fiber disclosed in the present invention changes the light transmission mode inside the traditional optical fiber, and overcomes the problem that the light beam in the traditional optical fiber is confined to the core for transmission, resulting in low surface light radiation intensity and transmission depth of the traditional optical fiber.

[0094] The main material of the fiber cladding of the photocatalytic hollow optical fiber for synchronous side transmission of gas and light disclosed in the present invention is polysulfone material, which has high light transmittance and gas conduction properties; at the same time, the SiO2 and GeO2 particles doped in the optical fiber cladding have high ultraviolet-visible light transmission performance, thereby enhancing the optical fiber light transmission performance; in addition, since the SiO2 and GeO2 particles have strong mechanical properties, the mechanical strength of the optical fiber is increased.

[0095] Therefore, the optical fiber cladding of the photocatalytic hollow optical fiber for synchronous side transmission of gas and light disclosed in the present invention not only has high light transmission characteristics and a dense structure, but also has the ability to transmit gas molecules (such as CO2, N2, NH3, SO2, etc.) under appropriate pressure conditions. That is, the cladding of the hollow optical fiber with a core and a cladding can simultaneously transmit light and CO2, further improving the efficiency of the photocatalytic reduction reaction.

[0096] In addition, the TiO2 in the photocatalytic layer has photocatalytic properties and can reduce CO2 into organic fuels such as methane and ethanol; the SiO2 doped in the photocatalytic layer can effectively inhibit the recombination of TiO2 photogenerated electron-hole pairs, thereby improving the performance of photocatalytic conversion of CO2.

[0097] Therefore, the photocatalytic hollow optical fiber with synchronous side transmission of gas and light disclosed in the present invention can realize the synchronous transmission and intensification of light and CO2 in the photocatalytic layer, and the light and CO2 molecules transmitted into the photocatalytic layer are directly utilized and converted by TiO2, thereby improving the utilization efficiency and conversion efficiency of light energy and CO2. Example

[0098] This embodiment prepares a photocatalytic hollow-core optical fiber with synchronous side transmission of gas and light according to the following steps:

[0099] S1, preparing a polysulfone / SiO2 / GeO2 composite material to obtain raw materials for preparing an optical fiber cladding;

[0100] S1.1. Add 4 g of polysulfone to 100 g of dichloromethane and stir evenly using magnetic stirring to obtain a polysulfone / dichloromethane mixture;

[0101] S1.2. Add 0.15 g of SiO2 particles with a particle size of 5 nm to the polysulfone / dichloromethane mixture, and stir evenly to obtain a polysulfone / dichloromethane mixture doped with SiO2; the SiO2 particles are used to increase the mechanical stability of the cladding.

[0102] S1.3. Add 0.15 g of GeO2 particles with a particle size of 10 nm to the polysulfone / dichloromethane mixture doped with SiO2, and stir evenly to obtain a polysulfone / SiO2 / GeO2 composite material; GeO2 particles have high ultraviolet-visible light transmission performance and are used to adjust the refractive index and ultraviolet-visible light transmission characteristics of the optical fiber cladding material; after adding GeO2 particles to the polysulfone / dichloromethane mixture doped with SiO2, stir with a magnetic stirrer for 24 to 36 hours to obtain the optical fiber cladding raw material.

[0103] S2, preparing a TiO2 / SiO2 composite material solution to obtain raw materials for preparing an optical fiber photocatalytic layer;

[0104] S2.1. Add titanium isopropoxide to ethylene glycol preheated to 55-65°C. Stir continuously while heating the ethylene glycol. Use 13 mL of ethanol and 3 mL of titanium isopropoxide. Heat the ethylene glycol / titanium isopropoxide mixture to 85-95°C while stirring.

[0105] S2.2. Add 12.6 g of citric acid monohydrate to the ethylene glycol / titanium isopropoxide mixed solution and stir until the mixed solution becomes clear.

[0106] S2.3. Add 20 g of TiO2 powder with a particle size of 15 nm to the mixed solution obtained in step S2.2, and stir for 3 to 5 hours to obtain a photocatalytic TiO2 sol;

[0107] S2.4. Add SiO2 particles to the photocatalytic TiO2 sol to obtain a TiO2 / SiO2 composite material solution, which is the raw material for preparing the optical fiber photocatalytic layer; the TiO2 / SiO2 composite material solution can enhance the adhesion strength between the photocatalytic layer and the optical fiber cladding, and at the same time can inhibit the recombination of photogenerated electron-hole pairs.

[0108] S3. Using the polysulfone / SiO2 / GeO2 composite material prepared in step S1, a hollow optical fiber is prepared by dry-wet spinning, wherein the prepared optical fiber has a core diameter of 100 μm and a cladding thickness of 200 μm;

[0109] S4, drying the hollow-core optical fiber prepared in step S3 at 110-120° C. for 3-5 hours, and sealing one end of the hollow-core optical fiber with a mixture of UV glue and SiO2 with a particle size of less than 20 nm, wherein the weight ratio of the UV glue to the SiO2 is in the range of 95:5-98:2;

[0110] S5. Using the coating pulling method, immerse the hollow optical fiber sealed at one end in step S4 into the TiO2 / SiO2 composite material solution, so that the surface of the hollow optical fiber is covered with a photocatalytic film with a thickness of 15 μm to form a photocatalytic layer, and then dry it at 150-180°C for 24-36 hours to obtain a photocatalytic hollow optical fiber.

[0111] The photocatalytic hollow optical fiber obtained according to the above steps was subjected to a test by inputting CO2 gas at the gas input end and inputting light with a light intensity of 5 mW and a wavelength of 650 nm at the light input end. A 20 cm length of the photocatalytic hollow optical fiber was cut to perform the test.

[0112] The light radiation intensity on the surface of photocatalytic hollow fiber is as follows Figure 6 As shown in Figure a, the surface radiation intensity of the optical fiber of the present invention is much higher than the surface radiation intensity of the traditional side-emitting optical fiber with the same diameter.

[0113] The relationship between the rate of CO2 release from the optical fiber surface and the air pressure is shown in the figure below: Figure 6 As shown in Figure b, the CO2 release rate on the surface of the optical fiber of the present invention is comparable to that of the hollow fiber membrane and multi-channel ceramic monomer with the same diameter.

[0114] The rate of photocatalytic hollow-core fiber CO2 degradation is as follows Figure 6 As shown in Figure c, the conversion rate of the optical fiber of the present invention for 10 mL of CO2 with a concentration of 5000 ppm is 100% in 60 minutes, which is much higher than the conversion rate of CO2 of the same volume and concentration using multi-channel ceramic monomers, traditional side-emitting optical fibers, and hollow fiber membranes as photocatalyst attachment carriers with the same composition and weight.

[0115] The experimental results of this embodiment show that the photocatalytic hollow optical fiber with synchronous side transmission of gas and light disclosed in the present invention can realize the synchronous transmission and enhancement of light and CO2 in the photocatalytic layer, thereby improving the utilization efficiency and conversion efficiency of light energy and CO2.

[0116] It will be understood that the present invention is described through some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. Under the guidance of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. The embodiments described in the present invention are some embodiments of the present invention, not all embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

Claims

1. A photocatalytic hollow-core optical fiber for synchronous side transmission of gas and light, used for synchronous transmission of light and gas, characterized in that: It comprises an optical fiber core (1), an optical fiber cladding (2) and a photocatalytic layer (3); The optical fiber cladding (2) is coated on the outer peripheral side of the optical fiber core (1), and the photocatalytic layer (3) is coated on the outer peripheral side of the optical fiber cladding (2); The optical fiber core (1) is a hollow structure, and the two ends of the optical fiber core (1) are respectively a gas input end (4) and a light input end (5); the gas can enter the optical fiber core (1) through the gas input end (4), and can pass through the optical fiber core (1) to contact the photocatalytic layer (3) to generate a photocatalytic reduction reaction; The light input end (5) has a transparent sealing portion (51), and the light can pass through the sealing portion (51) and enter the optical fiber core (1) through the light input end (5); The optical fiber cladding (2) is prepared from a polysulfone / SiO2 / GeO2 composite material, wherein the weight ratio of GeO2, SiO2, polysulfone and dichloromethane in the polysulfone / SiO2 / GeO2 composite material is in the range of 0.1:0.1:1:30 to 0.2:0.15:1:

40.

2. The photocatalytic hollow-core optical fiber for synchronous side transmission of gas and light according to claim 1, characterized in that: The polysulfone / SiO2 / GeO2 composite material is prepared from a mixed solution of polysulfone, SiO2 and GeO2 formed by uniformly dispersing polysulfone, SiO2 and GeO2 in dichloromethane.

3. The photocatalytic hollow-core optical fiber for synchronous side transmission of gas and light according to claim 1, characterized in that: The photocatalytic layer (3) is prepared from a TiO2 / SiO2 composite material, and the TiO2 / SiO2 composite material is prepared by adding SiO2 particles into TiO2 sol.

4. The photocatalytic hollow-core optical fiber for synchronous side transmission of gas and light according to claim 1, characterized in that: The diameter of the optical fiber core (1) is 20 to 500 μm, the thickness of the optical fiber cladding (2) is 100 to 500 μm; and the thickness of the photocatalytic layer (3) is 10 to 30 μm.

5. The photocatalytic hollow-core optical fiber for synchronous side transmission of gas and light according to claim 1, characterized in that: The gas is one of CO2, N2, NH3, and SO2.

6. A method for preparing a photocatalytic hollow-core optical fiber with synchronous side transmission of gas and light, using the photocatalytic hollow-core optical fiber as claimed in claim 1, characterized in that: The following steps are involved: S1. Prepare a polysulfone / SiO2 / GeO2 composite material to obtain raw materials for preparing optical fiber cladding; in the polysulfone / SiO2 / GeO2 composite material, the weight ratio of GeO2, SiO2, polysulfone and dichloromethane is in the range of 0.1:0.1:1:30 to 0.2:0.15:1:40 S2, preparing a TiO2 / SiO2 composite material solution to obtain raw materials for preparing an optical fiber photocatalytic layer; S3, using the polysulfone / SiO2 / GeO2 composite material prepared in step S1 to prepare a hollow optical fiber by dry-wet spinning; S4, drying the hollow-core optical fiber prepared in step S3, and then sealing one end of the hollow-core optical fiber; S5. Immerse the hollow optical fiber sealed at one end in step S4 into a TiO2 / SiO2 composite material solution to cover the surface of the hollow optical fiber with a photocatalytic film to form a photocatalytic layer, and obtain a photocatalytic hollow optical fiber after drying.

7. The method for preparing a photocatalytic hollow-core optical fiber with synchronous side transmission of gas and light according to claim 6, characterized in that: Step S1 includes the following steps: S1.

1. Add a predetermined amount of polysulfone to a predetermined amount of dichloromethane, and stir to obtain a polysulfone / dichloromethane mixture; the weight ratio of the polysulfone to dichloromethane is in the range of 1:30 to 1:40; S1.2, adding SiO2 particles to the polysulfone / dichloromethane mixture, stirring evenly to obtain a polysulfone / dichloromethane mixture doped with SiO2; the weight ratio of SiO2, polysulfone, and dichloromethane is in the range of 0.1:1:30 to 0.2:1:40; S1.

3. Add GeO2 particles to the polysulfone / dichloromethane mixture doped with SiO2, and stir evenly to obtain a polysulfone / SiO2 / GeO2 composite material; the weight ratio of GeO2, SiO2, polysulfone and dichloromethane is in the range of 0.1:0.1:1:30 to 0.2:0.15:1:

40.

8. The method for preparing a photocatalytic hollow-core optical fiber with synchronous side transmission of gas and light according to claim 6, characterized in that: Step S2 includes the following steps: S2.

1. Add titanium isopropoxide to the preheated ethylene glycol, and heat the ethylene glycol / titanium isopropoxide mixed solution while stirring; the weight ratio of ethylene glycol to titanium isopropoxide is in the range of 10:1 to 4:1; S2.

2. Add citric acid monohydrate to the ethylene glycol / titanium isopropoxide mixed solution and stir until the mixed solution becomes clear. The weight ratio of ethylene glycol, titanium isopropoxide, and citric acid monohydrate is 10:1:8 to 4:1:

3. S2.3, adding TiO2 powder to the mixed solution obtained in step S2.2, and stirring to obtain a photocatalytic TiO2 sol; The weight ratio of the mixed solution obtained in step S2.2 to the TiO2 powder is in the range of 1.0 to 1.6; S2.

4. Add SiO2 particles to the photocatalytic TiO2 sol to obtain a TiO2 / SiO2 composite material solution, which is the raw material for preparing the optical fiber photocatalytic layer; the weight ratio of the photocatalytic TiO2 sol to the SiO2 particles is in the range of 120 to 130.

9. The method for preparing a photocatalytic hollow-core optical fiber for synchronous side transmission of gas and light according to any one of claims 6 to 8, characterized in that: The optical fiber core diameter is 20-500 μm; the cladding thickness is 100-500 μm; and the photocatalytic layer thickness is 10-30 μm.

10. The method for preparing a photocatalytic hollow-core optical fiber with synchronous side transmission of gas and light according to claim 8, characterized in that: In the step S2.3, the weight ratio of the mixed solution obtained in the step S2.2 to the TiO2 powder is 1.54; in the step S2.4, the weight ratio of the photocatalytic TiO2 sol to the SiO2 particles is 127.

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