Photocatalyst film and manufacturing method therefor

Abstract

The present invention relates to a photocatalyst film and a manufacturing method therefor. According to the present invention, the photocatalyst film of the present invention can provide an inexpensive and eco-friendly photocatalyst. In addition, the photocatalytic film of the present invention can exhibit excellent adhesion and durability, and may be attached by using, as a substrate, glass, fluorine-doped tin oxide (FTO), aluminum foil, titanium foil, stone, and wood.

Description

Photocatalytic film and method for producing the same

[0001] The present invention relates to a photocatalyst film and a method for producing the same.

[0002] Urbanization and industrialization are leading to increased air pollution, negatively impacting the environment and human health. Volatile organic compounds (VOCs) are a general term for organic compounds that readily evaporate into the atmosphere and are often emitted artificially from industries, transportation, and households. VOCs are a major air pollutant that causes respiratory diseases in humans and exacerbates global problems such as tropospheric ozone formation and the greenhouse effect. A significant effort is being made to remove VOCs using various methods, including thermal decomposition, adsorption, non-thermal plasma, and catalytic / photocatalytic oxidation. Among these, photocatalysis, which derives the energy required for chemical reactions from light, is an environmentally friendly technology, but its development is still in progress.

[0003] Graphitic carbon nitride (g-C3N4) is an inexpensive, environmentally friendly material with electronic and optical properties favorable for photocatalysis. It also exhibits high activity in hydrogen production, carbon dioxide conversion, and photodegradation of pollutants. However, graphitic carbon nitride has poor dispersibility in water and organic solvents, and it is difficult to adhere and fix to various substrates, hindering its commercialization.

[0004] One object of the present invention is to provide a photocatalyst film.

[0005] Another object of the present invention is to provide a method for manufacturing the photocatalyst film.

[0006] In order to achieve the above object, the present invention provides a photocatalyst film comprising graphite carbon nitride, an organic compound hydrogen-bonded with the graphite carbon nitride, a polymer bonded to an amine group of the graphite carbon nitride, and a crosslinking agent crosslinking the polymer.

[0007] In addition, the present invention provides a method for producing a photocatalyst film, including the steps of preparing graphite carbon nitride, preparing a photocatalyst coating solution containing the graphite carbon nitride, and applying the photocatalyst coating solution to a substrate to produce a photocatalyst film.

[0008] According to the present invention, the photocatalyst film of the present invention can provide an inexpensive and environmentally friendly photocatalyst. Furthermore, the photocatalyst film of the present invention can have excellent adhesive strength and durability, and can be bonded to substrates such as glass, fluorine-doped tin oxide (FTO), aluminum foil, titanium foil, stone, and wood.

[0009] Figure 1 is a flow chart of a method for manufacturing a photocatalyst film according to an embodiment of the present invention.

[0010] Figure 2 is a schematic diagram of a method for manufacturing a photocatalyst film according to an embodiment of the present invention.

[0011] Figure 3 is a scanning electron microscope (SEM) image of a photocatalyst film according to an embodiment of the present invention.

[0012] Figure 4 is a scanning electron microscope image of the surface and cross-section of a photocatalyst film according to an embodiment of the present invention.

[0013] Figure 5 is an X-ray diffraction analysis (XRD) graph of an embodiment according to the present invention.

[0014] Figure 6 is a schematic diagram illustrating the arrangement of graphite carbon nitride nanosheets according to an embodiment of the present invention.

[0015] Figure 7 is an infrared spectroscopy (FT-IR) spectrum graph of an embodiment according to the present invention.

[0016] Figure 8 shows the results of a water contact angle experiment of an example according to the present invention.

[0017] Figure 9 is a thermogravimetric analysis graph of an example according to the present invention.

[0018] Figure 10 is a schematic diagram explaining the photocatalytic film formation mechanism of an embodiment according to the present invention.

[0019] Figure 11 is an image showing a photocatalyst film according to an embodiment of the present invention applied to several substrates.

[0020] Figure 12 is a schematic diagram illustrating the reaction between a photocatalyst film and a substrate according to an embodiment of the present invention.

[0021] Figure 13 shows the results of a tape adhesion test of a photocatalyst film of an example of the present invention.

[0022] Figure 14 shows the results of an adhesion test under ultrasonic conditions of a photocatalyst film according to an example of the present invention.

[0023] Figure 15 is an ultraviolet-visible absorption spectrum of an embodiment according to the present invention.

[0024] Figure 16 is an electron paramagnetic resonance (EPR) graph of an embodiment according to the present invention.

[0025] Figure 17 is an infrared spectroscopy (FT-IR) spectrum for determining the effect of light irradiation of an embodiment according to the present invention.

[0026] Figure 18 shows the results of rhodamine B decomposition according to an example of the present invention.

[0027] Figure 19 is a graph showing the evaluation of acetaldehyde and toluene decomposition according to an example of the present invention.

[0028] Figure 20 is a graph showing the calculation of mineralization into carbon dioxide (CO2) according to an embodiment of the present invention.

[0029] Figure 21 is an image confirming the regeneration capability of an embodiment according to the present invention.

[0030] Figure 22 shows the results of an acetaldehyde and toluene decomposition cycle experiment according to an example of the present invention.

[0031] Figure 23 is an image of the regeneration characteristic analysis of an embodiment according to the present invention.

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The present invention can be modified in various ways and can take various forms, and thus specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, but should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention. In describing each drawing, similar reference numerals are used to indicate similar components. In the attached drawings, the dimensions of structures are shown larger than actual size to ensure clarity of the present invention.

[0033] While terms like "first" and "second" may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component."

[0034] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0035] Meanwhile, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning within the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0036]

[0037] Figure 1 is a flow chart of a method for manufacturing a photocatalyst film according to an embodiment of the present invention.

[0038] Referring to FIG. 1, the method may include a step of preparing a first composition by mixing graphite carbon nitride, glycol, and a radical polymerization monomer (S110); a step of preparing a second composition by adding a cross-linking agent to the first composition (S120); a step of forming a coating film by applying the second composition to a substrate (S130); and a step of curing the coating film (140).

[0039] In the step (S110) of preparing a first composition by mixing the above graphite carbon nitride, glycol, and radical polymerization monomer, the graphite carbon nitride and the glycol can hydrogen bond, and an amine group of the graphite carbon nitride and a vinyl group of the radical polymerization monomer can chemically bond to form a radical polymerization chain.

[0040] In the step (S130) of forming a coating film by applying the second composition to a substrate, the second composition may be applied to the substrate by a method including at least one selected from the group consisting of dip coating, spin coating, roll coating, spray coating, bar coating, and aerosol coating.

[0041] In one embodiment, the curing may be performed at 70 to 120° C. for 6 to 36 hours. In one embodiment, the curing may be performed at about 80 to 100° C. for about 8 hours. When the curing temperature exceeds about 120° C. or is less than about 70° C., the adhesion between the photocatalyst film and the substrate may be reduced, and the strength of the photocatalyst film may be reduced.

[0042] In the step (140) of curing the coating film, the radical polymerization chain can be crosslinked by the crosslinking agent, and the graphite carbon nitride can be laminated and arranged by the crosslinking.

[0043] In one embodiment, the graphite carbon nitride may be commercially available graphite carbon nitride, and may be prepared by manufacturing the graphite carbon nitride.

[0044] In one embodiment, the glycol may be ethylene glycol.

[0045] In one embodiment, the radical polymerization monomer may be acrylamide.

[0046] In one embodiment, the crosslinking agent may be citric acid.

[0047] In one embodiment, the graphite carbon nitride and the radical polymerization monomer can be mixed in a weight ratio of 1 to 6:1.

[0048] In one embodiment, the glycol and the radical polymerization monomer may be mixed in a weight ratio of 1 to 7:1.

[0049] In one embodiment, the radical polymerization monomer and the crosslinking agent may be mixed in a weight ratio of 0.3 to 1:1. In one embodiment, the radical polymerization monomer and the crosslinking agent may be mixed in a weight ratio of 0.6:1.

[0050]

[0051] The photocatalyst film of the present invention can be manufactured by the above manufacturing method, and the photocatalyst film can include graphite carbon nitride and a polymer material chemically bonded to the graphite carbon nitride.

[0052] In one embodiment, the polymer material may include a radical polymerization chain that binds to the graphite carbon nitride and a linker that crosslinks the radical polymerization chain.

[0053] In one embodiment, the vinyl group of the polymer material and the amine group of the graphite carbon nitride may react to form the radical polymerization chain between the polymer material and the graphite carbon nitride, and the radical polymerization chain may be crosslinked by a chemical bond between the amine group of the polymer material and the linker. In addition, the graphite carbon nitride may be arranged in a stacked manner by the crosslinking of the radical polymerization chain.

[0054] In one embodiment, the graphite carbon nitride may be in the form of nanosheets.

[0055] In one embodiment, the polymer may include, but is not limited to, one or more selected from the group consisting of polyacrylamide, polymethacrylamide, and polyvinylamine. In one embodiment, polyacrylamide may be used as the polymer. The vinyl group of the polyacrylamide may polymerize with the graphite carbon nitride, and the amine group of the polyacrylamide may be bonded to the linker to crosslink.

[0056] In one embodiment, the linker may include, but is not limited to, one or more selected from the group consisting of citric acid, acetic acid, methacrylic acid, maleic acid, and succinic acid. In one embodiment, citric acid may be used as the crosslinking agent.

[0057] In one embodiment, the graphite nitride may further include a glycol bonded with hydrogen.

[0058] In one embodiment, the glycol may include, but is not limited to, one or more selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, tylenetriethylene glycol, butylene glycol, and tetramethylene ether glycol. In one embodiment, the organic compound may be ethylene glycol.

[0059] In one embodiment, the photocatalytic film may include a hydroxyl group or an amine group.

[0060] In one embodiment, the photocatalyst film can be bonded to the substrate by bonding with a functional group formed on the substrate. In one embodiment, the hydroxyl group or amine group bonded to the photocatalyst film can bond to the substrate through hydrogen bonding or ligand-metal bonding. The photocatalyst film can be applied to various substrates through the hydrogen bonding or ligand-metal bonding.

[0061] In one embodiment, the substrate may include, but is not limited to, one or more selected from the group consisting of glass, metal foil, polymer, transparent conductive oxide, paper, wood, and stone.

[0062]

[0063] In one embodiment, the average thickness may be 100 to 300 μm.

[0064] In one embodiment, the photocatalytic film can photodecompose pollutants under visible light. In one embodiment, the photocatalytic film can photodecompose rhodamine B, acetaldehyde, and toluene under visible light.

[0065] In one embodiment, the photocatalytic film can absorb moisture in the air to form reactive oxygen species (ROS). ㆍOH, O2ㆍ - , HO2ㆍ, 1ROS including O2 and H2O2 can decompose carbon intermediates, thereby increasing the lifespan of the photocatalytic film.

[0066]

[0067] Hereinafter, to aid understanding of the present invention, examples will be given in detail. However, the following examples are intended only to illustrate the scope of the present invention and are not intended to limit its scope. These examples are provided to more fully explain the present invention to those of average skill in the art.

[0068]

[0069] <Manufacturing Example 1> Manufacturing of graphite carbon nitride

[0070] A slurry was prepared by adding 3 g each of cyanuric acid and melamine to water. The slurry was transferred to an autoclave reactor, stirred for about 60 minutes, and then heat-treated at about 100°C for about 4 hours to form a reactant. The reactant was cooled to room temperature and centrifuged to obtain a white precipitate. The precipitate was washed several times with water and then dried in an oven at about 80°C for about 12 hours. The dried precipitate was heat-treated in a furnace at about 550°C for about 4 hours at a heating rate of about 3.0°C / min to obtain yellow graphite carbon nitride.

[0071]

[0072] <Example 1> Photocatalyst film

[0073] Figure 2 is a schematic diagram of a method for manufacturing a photocatalyst film according to an embodiment of the present invention. The photocatalyst film was manufactured according to Figure 2.

[0074] The graphite carbon nitride powder and acrylamide prepared in Example 1 were added to about 20 ml of an ethylene glycol solution, and the mixture was stirred slowly for about 24 hours to prepare a first mixture. The graphite carbon nitride and acrylamide were added to the ethylene glycol solution at a weight ratio of about 3:1. A photocatalyst coating solution was prepared by adding citric acid to the first mixture. Citric acid was added so that the acrylamide and citric acid had a weight ratio of about 0.6:1. The photocatalyst coating solution was coated on a substrate and cured at about 80 to 100°C for about 12 hours to prepare a photocatalyst film.

[0075]

[0076] <Example 2> Photocatalyst film

[0077] A photocatalyst film was manufactured in the same manner as in Example 2, except that the ethylene glycol and acrylamide were mixed in a weight ratio of about 1.3:1.

[0078]

[0079] <Comparative Example 1>

[0080] A photocatalyst film was manufactured in the same manner as in Example 1, except that the citric acid was not added.

[0081]

[0082] <Experimental Example 1> Structural characteristics of photocatalyst films

[0083] Fig. 3 is a scanning electron microscope (SEM) image of graphite carbon nitride according to Manufacturing Example 1 of the present invention. Fig. 3 is an image of graphite carbon nitride manufactured in Manufacturing Example 1 taken by SEM, and it was confirmed that the graphite carbon nitride is in the form of an irregular nanosheet.

[0084] Figure 4 is a scanning electron microscope image of the surface and cross-section of a photocatalyst film according to Example 1 of the present invention. Figure 4 confirms that the surface of the photocatalyst film is uniform and smooth. The cross-sectional image of the photocatalyst film confirms that Example 1 has an average thickness of approximately 212 μm. Furthermore, it is confirmed that the graphite carbon nitride is evenly arranged.

[0085] FIG. 5 is an X-ray diffraction analysis (XRD) graph of Examples 1 to 2, Preparation Example 1, and Comparative Example 1 according to the present invention. Preparation Example 1 has two characteristic XRD peaks at about 27.3˚(002) and 13.8˚(100), which are peaks related to the interlayer heterocyclic stacking and in-plane stacking aspects of conjugated aromatic units. Examples 1, 2, and Comparative Example 1 were similar to the XRD peak shape of Preparation Example 1, except that the peak at about 27.3˚(002) was reduced. This is because the interlayer stacking unit was rearranged after copolymerization with polyacrylamide molecules. The rearrangement is schematically represented in FIG. 6. In FIG. 5, Example 2 had a (100) plane shifted to about 16.4˚, which means that the (100) plane was compressed.

[0086] Figure 7 is an infrared spectroscopy (FT-IR) spectrum graph of an example according to the present invention. Manufacturing Example 1 is 1200 to 1600 and 810 cm -1 It was confirmed that the acrylic monomer had peaks at 3348 and 3160 cm. Each peak corresponds to the stretching vibration and out-of-plane bending vibration of the aromatic carbon nitride heterocycle. It was confirmed that Examples 1, 2, and Comparative Example 1 had different peaks from the acrylic monomer. The acrylic monomer had peaks at 3348 and 3160 cm. -1 It has two peaks at 961 and 988 cm, which correspond to the stretching asymmetric and symmetric modes of the amide (NH2). -1The peaks correspond to the =CH2 and =CH bending modes, respectively. Examples 1 and 2 correspond to about 961 and 988 cm -1 It was confirmed that the peak disappeared, which is because the vinyl group (CH=CH2) was converted to a saturated carbon chain. Through this, it was confirmed that polyacrylamide was formed in Examples 1, 2, and Comparative Example 1. In addition, Examples 1, 2, and Comparative Example 1 showed a peak of about 810 cm due to copolymerization of polyacrylamide and graphite carbon nitride. -1 The external bending vibration of carbon nitride was reduced. Examples 1 and 2 were about 1725 cm -1 It was confirmed that the polyacrylamide had a C=O stretching vibration peak, indicating that citric acid remained even after the curing process. Through Figure 7, it was confirmed that the radical copolymerization reaction between polyacrylamide and graphite carbon nitride occurred well. In addition, it can be expected that the polyacrylamide has an amide functional group, which will help improve the wettability and reactive oxygen species (ROS) generation of the graphite carbon nitride film.

[0087]

[0088] <Experimental Example 2> Surface characteristics of photocatalyst film

[0089] Figure 8 shows the results of a water contact angle experiment of an example according to the present invention. The water contact angle of Comparative Example 1 was approximately 46.4°, confirming that it was a hydrophilic surface. The water contact angle of Example 1 was approximately 93.0°, confirming that it was a hydrophobic surface. This indicates that the polyacrylamide chains of Comparative Example 1 still existed and did not chemically react. On the other hand, Example 1 changed into a hydrophobic surface due to a reaction between citric acid and the amine group in the polyacrylamide chain or a condensation reaction. This suggests that the surface of a graphite carbon nitride film can be changed to have hydrophilic or hydrophobic properties so that it can selectively react with volatile organic compounds.

[0090]

[0091] <Experimental Example 3> Thermogravimetric analysis of photocatalyst film

[0092] Figure 9 is a thermogravimetric analysis graph of an example according to the present invention. In Comparative Example 1, thermal decomposition proceeded in four stages. The first weight loss (about 34 to 145 °C, about 14.6% weight loss) was due to evaporation of absorbed moisture, as the amide group contained in polyacrylamide can absorb moisture. The second weight loss (about 145 to 335 °C, about 23.3% weight loss) was confirmed to be due to dissociation of hydrogen bonds between ethylene glycol and graphitic carbon nitride and decomposition of the ethylene glycol. The third weight loss (about 334 to 470 °C, about 22.9% weight loss) was due to thermal decomposition of polyacrylamide, which also has the same decomposition temperature as pure polyacrylamide. The fourth weight loss (about 470 to 700 °C, about 39.4% weight loss) was due to thermal decomposition of graphitic carbon nitride. Example 1 underwent thermal decomposition in five stages. The first weight loss (about 30 to 144°C, about 13.3% weight loss) was due to evaporation of absorbed moisture. The second weight loss (about 150 to 323°C, about 32.8% weight loss) was due to thermal decomposition of ethylene glycol. It was confirmed that the addition of citric acid caused thermal decomposition of ethylene glycol at a lower temperature than in Comparative Example 1. The third weight loss (about 325 to 448°C, about 17.5% weight loss) was due to thermal decomposition of citric acid. In Example 1, two strong peaks occurred at about 450 to 690°C, which were peaks for thermal decomposition of polyacrylamide and graphite carbon nitride, respectively. This was presumed to be because polyacrylamide and graphite carbon nitride were arranged in a layered manner. Based on the analysis of Fig. 8, the formation mechanism of the photocatalyst film is shown in Fig. 10. In Fig. 10, the molecular weight (n) is 350 to 1100 g / mol.

[0093]

[0094] <Experimental Example 4> Application of photocatalyst film substrate

[0095] Figure 11 is an image showing a photocatalytic film of an embodiment of the present invention applied to various substrates. Through Figure 11, it was confirmed that the photocatalytic film can be applied to glass slides, fluorine-doped tin oxide (FTO), Plexiglas, titanium foil, granite, and wood. The photocatalytic film possesses hydroxyl and amine groups at its terminals, allowing it to be applied to various substrates through hydrogen bonding or ligand-metal interactions.

[0096] Figure 12 is a schematic diagram illustrating the reaction between the photocatalyst film and the substrate of an embodiment of the present invention. The hydroxyl groups and amine groups of the photocatalyst film can react with the -OH functional groups of the substrate and adhere to the substrate. The surface of the glass substrate has -OH functional groups, and the main component of granite is silica, which has Si-OH functional groups. In addition, most wood is cellulose with many -OH functional groups. Therefore, the -OH functional groups contained in the glass substrate, stone, and wood combined with the hydroxyl groups and amine groups of the photocatalyst film and adhered as shown in Figure 11. The photocatalyst film can also have adhesion to Al foil and Ti foil substrates, due to the ligand-metal interaction including Si-O, Si-N, Al-O, and Al-N. Figure 12 confirmed that the photocatalyst film can adhere to various substrates.

[0097] Figure 13 shows the results of a tape adhesion test of the photocatalyst film of Example 1 of the present invention. The adhesion test was performed according to ASTM 4214-97. After forming the photocatalyst film of Example 1 on a glass substrate, a tape was applied on the photocatalyst film. The surface of the tape was swept with an eraser to ensure good adhesion of the tape. After removing the tape, the surface of the photocatalyst film was visually observed. As shown in Figure 13, the photocatalyst film of Example 1, which underwent an adhesion test, did not experience peeling, confirming excellent adhesion between the substrate and the photocatalyst film.

[0098] Figure 14 shows the results of an adhesion test under ultrasonic conditions for a photocatalyst film according to an example of the present invention. The glass substrate on which the photocatalyst film of Example 1 was formed was immersed in a toluene solution and then ultrasonicated. Toluene was selected as the solvent because it is a common aromatic indoor air pollutant. In Example 1, no peeling of the photocatalyst film from the substrate was observed even under ultrasonic treatment, confirming the excellent durability and adhesiveness of the photocatalyst film.

[0099]

[0100] <Experimental Example 5> Photocatalytic properties of photocatalytic films

[0101] Figure 15 is an ultraviolet-visible absorption spectrum of an example according to the present invention. In Figure 15, Preparation Example 1, Comparative Example 1, and Example 1 were found to transmit visible light. Preparation Example 1 was confirmed to have an absorption threshold associated with an aromatic π-conjugated system at approximately 444 nm. It was confirmed that the absorption thresholds of Comparative Example 1 and Example 1 were red-shifted by approximately 7 and 11 nm, respectively, compared to Preparation Example 1. This confirmed that polyacrylamide improves the optical absorption of the photocatalyst film. In addition, it was confirmed that Example 1 and Comparative Example 1 showed improved light absorption compared to Preparation Example 1 in the wavelength range of approximately 445 to 800 nm. Through a comparison of the absorption thresholds of Example 1 and Comparative Example 1, it was confirmed that citric acid can improve the light harvesting of the photocatalyst film. Through Figure 15, it was confirmed that the photocatalyst film enhances light absorption in the visible light range, and it was assumed that this was due to various additional functional groups with unpaired electrons, such as -COOH, -OH, and -NHx, which are responsible for n-π* absorption in the visible light range.

[0102] Figure 16 is an electron paramagnetic resonance (EPR) graph of an example according to the present invention. The intensity of the graph increases as the number of unpaired electrons increases. Preparation Example 1 exhibited a single Lorenz line at a magnetic field of approximately 3440 to 3550 G, which is due to unpaired electrons in the π-conjugated aromatic ring. The EPR peak intensity of Comparative Example 1 was higher than that of Comparative Example 1 and Example 1. This is due to the amino functional group of polyacrylamide. The EPR intensity of Example 1 was due to the cross-linking of polyacrylamide and citric acid and the reaction of unpaired electrons. Although the EPR intensity of Example 1 was lower than that of Comparative Example 1, it was confirmed to be much higher than that of Preparation Example 1. A photocatalyst film with unpaired electrons is very advantageous for a photocatalytic reaction.

[0103] Figure 17 is an FT-IR spectrum for determining the effect of light irradiation in Example 1 according to the present invention. The photocatalyst film was left for about 180 minutes under conditions of a light density of about 100 mW / cm2 and an air mass of about 1.5 global (AM about 1.5G, one-sun). The photocatalyst film exposed to light under the above conditions was compared with the photocatalyst film not exposed to light. The degree of oxidation of the graphite carbon nitride within the photocatalyst film was determined through changes in the chemical bonding of the photocatalyst film according to the light conditions. Figure 17 confirmed that there was no change in the bonding of the graphite carbon nitride, polyacrylamide, and citric acid according to light irradiation. This confirmed that the photocatalyst film had a non-oxidizing sequence.

[0104] Figure 18 shows the results of rhodamine B decomposition in Example 1 according to the present invention. The photocatalyst film of Example 1 was immersed in a high-concentration rhodamine B (RhB) solution (about 10,000 mg / L) for about 15 minutes. The surface of Example 1 immersed in the rhodamine B solution changed to pink, the color of rhodamine B. RhB was decomposed in the pink-colored Example 1 under visible light illumination (λ > 400 nm) for about 10 minutes. These results confirmed that the photocatalyst film had excellent photocatalytic properties in the visible light range.

[0105] Figure 19 is a graph showing the acetaldehyde and toluene decomposition evaluation of an example according to the present invention. The decomposition evaluation evaluated the decomposition ability of the photocatalyst film under the conditions of about 150 ppmv of acetaldehyde and about 50 ppmv of toluene under visible light (λ > 400 nm) irradiation. In Figure 19, acetaldehyde and toluene did not undergo photodecomposition under visible light. Example 1 decomposed about 70% of acetaldehyde and about 60% of toluene when irradiated with light for about 3 to 4 hours.

[0106] Figure 20 is a graph showing the calculation of the mineralization of carbon dioxide (CO2) according to an example of the present invention. Photocatalysts can form carbon intermediates during the decomposition of pollutants, and these carbon intermediates can cause the deactivation of the photocatalyst. These carbon intermediates can be converted to carbon dioxide, allowing the performance of the photocatalyst to be evaluated by determining the amount of carbon dioxide generated. The mineralization efficiencies of acetaldehyde and toluene were calculated using Equations 1 and 2 below.

[0107] [Formula 1]

[0108] Mineralization efficiency = Δ[CO2] / (2 Х [C2H4O]0) Х 100)

[0109] [Formula 2]

[0110] Mineralization efficiency = Δ [CO2] / (7 Х [C7H8]0) Х 100)

[0111] In the above Equations 1 and 2, Δ [CO2] represents the change in CO2 concentration, [C2H4O]0 represents the acetaldehyde concentration, and [C2H4O]0 represents the toluene concentration. According to Equations 1 and 2, the mineralization efficiency of the photocatalyst film of Example 1 was calculated to be about 68% and about 59%, respectively. This means that the carbonaceous intermediate was effectively converted into carbon dioxide.

[0112]

[0113] <Experimental Example 6> Lifetime characteristics of photocatalyst films

[0114] Figure 21 is an image confirming the regeneration ability of the photocatalyst film of Example 1 according to the present invention. From Figure 19, it was determined that the lifespan of the photocatalyst film of Example 1 was about 3 hours for acetaldehyde decomposition and about 4 hours for toluene decomposition. From Figure 21, it was confirmed that the surface of the photocatalyst had turned brown due to the carbon intermediate. The browning of the surface was due to the carbon intermediate, which means that the photocatalyst film had reached the end of its lifespan. The photocatalyst film whose lifespan had reached the end was left in indoor air under general indoor lighting without any treatment. After 3 days, it was confirmed that the surface color of the photocatalyst film had recovered, indicating that the carbon intermediate had disappeared.

[0115] Figure 22 shows the results of a cycle experiment on the acetaldehyde and toluene decomposition of the photocatalyst film of Example 1 according to the present invention. One cycle consisted of a step of decomposing acetaldehyde and toluene using the photocatalyst film and a step of allowing the photocatalyst film to stand to induce regeneration. The photocatalyst film of Example 1 decomposed acetaldehyde and toluene by approximately 61% and approximately 55%, respectively, in the third cycle experiment.

[0116] Figure 23 is an image of the regeneration characteristics analysis of Example 1 according to the present invention. In order to identify the factor inducing the regeneration characteristics of the photocatalyst film, the photocatalyst film whose lifespan has expired was left indoors and in a dryer. The photocatalyst film left indoors for 5 days was regenerated again, but the photocatalyst film left in a dryer was not regenerated. Through this, it was determined that the self-regeneration characteristics of the photocatalyst film were due to water vapor absorbed by the functional group of polyacrylamide. Therefore, the photocatalyst film absorbs the incident photons and generates electron-hole pairs that react with water molecules adsorbed on the polyacrylamide, thereby generating ㆍOH, O2ㆍ - , HO2ㆍ, 1 Carbonaceous intermediates were continuously decomposed by generating reactive oxygen species such as O2 and H2O2.

[0117]

[0118] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. Graphite carbon nitride; A polymer material chemically bonded to the above graphite carbon nitride; The above polymer material is, A radical polymerization chain bonded to the above graphite carbon nitride; and A photocatalyst film comprising a linker that crosslinks the radical polymerization chain.

2. In paragraph 1, A photocatalyst film in which a vinyl group of the polymer material and an amine group of the graphite carbon nitride are combined to form a radical polymerization chain between the polymer material and the graphite carbon nitride.

3. In paragraph 1, A photocatalyst film in which the radical polymerization chain is crosslinked by a chemical bond between the amine group of the polymer material and the linker.

4. In paragraph 3, A photocatalyst film in which the above graphite carbon nitride is laminated and arranged by crosslinking of the radical polymerization chain.

5. In paragraph 1, The above graphite carbon nitride is a photocatalytic film in the form of nanosheets.

6. In paragraph 1, A photocatalyst film, wherein the polymer comprises at least one selected from the group consisting of polyacrylamide, polymethacrylamide, and polyvinylamine.

7. In paragraph 1, A photocatalyst film, wherein the linker comprises at least one selected from the group consisting of citric acid, acetic acid, methacrylic acid, maleic acid, and succinic acid.

8. In paragraph 1, A photocatalyst film further comprising a glycol bonded with the above graphite nitride.

9. In paragraph 8, A photocatalyst film, wherein the glycol comprises at least one selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, tylenetriethylene glycol, butylene glycol, and tetramethylene ether glycol.

10. In paragraph 1, The above photocatalyst film is a photocatalyst film containing a hydroxyl group or an amine group.

11. In paragraph 1, The above photocatalyst film is a photocatalyst film that is bonded to the substrate by combining with a functional group formed on the substrate.

12. In paragraph 10 or 11, A photocatalyst film in which a hydroxyl group or an amine group bonded to the photocatalyst film is bonded to the substrate through a hydrogen bond or a ligand-metal bond.

13. In paragraph 11, A photocatalytic film, wherein the substrate comprises at least one selected from the group consisting of glass, metal foil, polymer, transparent conductive oxide, paper, wood, and stone.

14. In paragraph 1, A photocatalyst film having an average thickness of 100 to 300 ㎛.

15. In paragraph 1, The above photocatalytic film is a photocatalytic film that photodecomposes pollutants under visible light.

16. In paragraph 1, The above photocatalytic film is a photocatalytic film that absorbs moisture in the air and forms reactive oxygen species (ROS).

17. A step of preparing a first composition by mixing graphite carbon nitride, glycol, and radical polymerization monomer; A step of preparing a second composition by adding a crosslinking agent to the first composition; A step of forming a coating film by applying the second composition to a substrate; and A method for manufacturing a photocatalyst film, comprising a step of curing the above coating film.

18. In paragraph 17, In the step of manufacturing the first composition, A method for producing a photocatalyst film, wherein the above graphite carbon nitride and the above glycol are hydrogen bonded.

19. In paragraph 17, In the step of manufacturing the first composition, A method for manufacturing a photocatalyst film, wherein an amine group of the above graphite carbon nitride and a vinyl group of the above radical polymerization monomer are chemically bonded to form a radical polymerization chain.

20. In paragraph 19, The step of curing the above coating film is: A method for producing a photocatalyst film, wherein the radical polymerization chain is crosslinked by the crosslinking agent.

21. In paragraph 17, A method for producing a photocatalyst film, wherein the above graphite carbon nitride and the radical polymerization monomer are mixed in a weight ratio of 1 to 6:

1.

22. In paragraph 17, A method for producing a photocatalyst film, wherein the glycol and the radical polymerization monomer are mixed in a weight ratio of 1 to 7:

1.

23. In paragraph 17, A method for producing a photocatalyst film, wherein the radical polymerization monomer and the crosslinking agent are mixed in a weight ratio of 0.3 to 1:

1.

24. In paragraph 17, A method for manufacturing a photocatalyst film, wherein the second composition is applied to a substrate by a method including at least one selected from the group consisting of dip coating, spin coating, roll coating, spray coating, bar coating, and aerosol coating.

25. In paragraph 17, A method for manufacturing a photocatalyst film, wherein the above curing is performed at 70 to 120°C for 6 to 36 hours.

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