WO2024053969A1 - Method for manufacturing composite photocatalyst filter activated by oxygen vacancy and air purification filter according thereto - Google Patents

Abstract

The present invention provides a method for manufacturing a composite photocatalyst filter activated by oxygen vacancies, the method comprising: a first step of preparing a Black-WO3 (BW) catalyst by thermally treating tungsten oxide powder under a reducing gas atmosphere at a temperature range of 400 to 600°C; a second step of preparing a Black-TiO2 (BT) catalyst by thermally treating a mixture of titanium dioxide and a reducing agent under an inert gas atmosphere at a temperature range of 200 to 400°C; a third step of forming a composite photocatalyst by combining the prepared BT and BW catalysts; and a fourth step of embedding the composite photocatalyst in filter paper to fabricate a filter, wherein carbon monoxide is removed from the surrounding environment by adsorption onto the filter when the T:W ratio of the composite photocatalyst is between 1:1 and 19:1.

Description

Manufacturing method of composite photocatalyst filter activated with oxygen vacancies and resulting air purification filter

The present invention relates to a method of manufacturing a composite photocatalyst filter activated by oxygen vacancies and the resulting air purifying filter. More specifically, a method of manufacturing a composite photocatalyst filter activated by oxygen vacancies of tungsten oxide and titanium dioxide and the resulting air purification filter. It's about filters.

The generation of environmental pollutants due to industrialization not only causes water and air pollution, but also threatens the destruction of the ecosystem and human health. Accordingly, various studies on the capture and removal of environmental pollutants are being conducted. Conventional methods for removing environmental pollutants include adsorption using high specific surface area materials, thermal oxidation using metal and metal oxide catalysts, and photochemical decomposition using photocatalysts. Adsorption using the high specific surface area material does not convert environmental pollutants into harmless substances, but simply removes them by adsorption, so there is a risk of secondary contamination due to desorption of pollutants in the future, and it has the disadvantage of being difficult to reuse. In contrast, thermal oxidation using metal and metal oxide catalysts can convert environmental pollutants into carbon dioxide and water that are harmless to the human body, but since the thermal oxidation method is carried out at a high temperature of 200℃ or higher, an additional device that can supply heat energy is required. . This limits the practical application of thermal oxidation methods. Unlike these, in the case of photochemical decomposition using a photocatalyst, environmental pollutants can be converted into carbon dioxide and water that are harmless to the human body using light energy, a non-polluting energy source. Unlike other general catalysts, the biggest advantage of photocatalysts is that the reaction can be carried out at room temperature using light energy without requiring an additional energy source.

Photocatalysts can sterilize, antibacterial, and decompose contaminants in the air and solutions, so they can be used in glass, tiles, exterior walls, food, factory interior walls, metal products, water tanks, marine pollution purification, construction materials, mold prevention, UV protection, water purification, and air purification. It is used for a wide range of purposes. The most widely used material as a photocatalyst is titanium dioxide. Titanium dioxide is advantageous from an economic perspective because it can be used semi-permanently. Additionally, since titanium dioxide is a safe material that does not have a negative impact on the environment, there is no concern about secondary pollution when disposed of. Republic of Korea Patent No. 10-1606642 discloses a visible light-responsive photocatalyst with hydrophilic surface modification using polymer materials, but there was a problem of increasing the activity of the photocatalyst.

In order to solve the above problems, the purpose of the present invention is to provide a method for manufacturing a composite photocatalyst filter activated by oxygen vacancies.

Additionally, the purpose is to provide an air purifying filter manufactured according to the above manufacturing method.

In order to achieve the above object, the present invention,

A first step of preparing a Black-WO ₃ (BW) catalyst by heat treating tungsten oxide powder at a temperature range of 400 to 600 ° C. under a reducing gas atmosphere;

A second step of preparing a Black-TiO ₂ (BT) catalyst by heat-treating the powder mixed by adding a reducing agent to titanium dioxide at a temperature range of 200 to 400 ° C. under an inert gas atmosphere;

A third step of forming a composite photocatalyst by bonding the prepared BT and BW catalysts; and

A fourth step of manufacturing a filter by supporting the composite photocatalyst on filter paper,

When the T:W ratio of the composite photocatalyst is 1:1 to 19:1, a method for manufacturing a composite photocatalyst filter activated by oxygen vacancies is provided, which removes carbon monoxide from the surrounding environment during filter adsorption.

In order to achieve the above other objects, the present invention provides an air purifying filter manufactured according to the above manufacturing method.

The manufacturing method of the present invention produces a composite photocatalyst in a simple manner in a relatively short time, and can increase the photoactivity of the tungsten oxide and titanium dioxide composite photocatalyst activated by oxygen vacancies compared to a single catalyst. In addition, the composite photocatalyst produced according to the production method of the present invention has the advantage of improved light absorption and charge separation, and is suitable for removing indoor air pollution due to its high optical activity.

Figure 1 shows catalyst changes as the firing maintenance period increases according to an embodiment of the present invention.

Figure 2 shows the light absorption wavelength range and catalyst color change of tungsten oxide and titanium dioxide improved with oxygen vacancies according to an embodiment of the present invention.

Figure 3 shows TEM images of tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention.

Figure 4 shows XRD of tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention.

Figure 5 shows O 1s

Figure 6 shows W 4f, Ti 2p It was done.

Figure 7 shows a comparison of the removal performance of tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention.

Figure 8 shows a comparison of performance by ratio of tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention.

Figure 9 shows a comparison of the carbon monoxide removal performance of tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention and the carbon monoxide oxidation It shows the carbon dioxide production rate.

Figure 10 shows a comparison of carbon monoxide removal reaction rates of tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention. .

Figure 11 shows the light absorption wavelength region of the composite photocatalyst according to an embodiment of the present invention.

Figure 12 shows the catalyst color of the composite photocatalyst according to an embodiment of the present invention.

Figure 13 shows the carbon monoxide removal and carbon dioxide production rates of a composite photocatalyst containing zeolite according to an embodiment of the present invention.

Figure 14 shows a comparison of carbon monoxide removal reaction rates of a composite photocatalyst containing zeolite according to an embodiment of the present invention.

Figure 15 shows the carbon monoxide removal and carbon dioxide production rates of a composite photocatalyst carbon nanotube filter according to an embodiment of the present invention.

Figure 16 shows a comparison of carbon monoxide removal reaction rates of composite photocatalyst carbon nanotube filters according to an embodiment of the present invention.

Figure 17 shows the carbon monoxide removal rate of the TAW composite photocatalytic filter according to a comparative example of the present invention.

Hereinafter, the present invention will be described in more detail.

According to one aspect of the present invention, a first step of preparing a Black-WO ₃ (BW) catalyst by heat treating tungsten oxide powder at a temperature range of 400 to 600 ° C. under a reducing gas atmosphere;

A second step of preparing a Black-TiO ₂ (BT) catalyst by heat-treating the powder mixed by adding a reducing agent to titanium dioxide at a temperature range of 200 to 400 ° C. under an inert gas atmosphere; A third step of forming a composite photocatalyst by bonding the prepared BT and BW catalysts; And a fourth step of manufacturing a filter by supporting the composite photocatalyst on filter paper, wherein when the T:W ratio of the composite photocatalyst is 1:1 to 19:1, carbon monoxide in the surrounding environment is removed during filter adsorption. A method for manufacturing a composite photocatalyst filter activated by oxygen vacancies is provided.

Tungsten oxide is a catalyst that can be expected to exhibit catalytic activity under visible light irradiation, but it has the disadvantage of low electron transfer and rapid recombination of electrons and holes, which reduces photoactivity. TiO ₂ photocatalyst is non-toxic, harmless to the human body, excellent durability, and abundant resources, so it is a photocatalyst widely applied in photocatalyst technology. However, it has the disadvantage of inducing a photocatalytic reaction only in the ultraviolet region, which is a specific light wavelength.

The filter manufacturing method of the present invention solves the shortcomings of each catalyst and increases the light absorption of the catalyst and improves conductivity by activating oxygen vacancies in the catalyst to increase performance compared to the existing catalyst. In addition, by combining tungsten oxide and titanium dioxide, which have different photocharge movement speeds, or by manufacturing a composite photocatalyst of tungsten oxide and titanium dioxide activated by oxygen vacancies, it is possible to reduce the rapid recombination of electrons and holes and improve charge separation, thereby increasing photoactivity compared to existing ones. there is.

First, the first step will be explained. Tungsten oxide powder is heat-treated in a H ₂ /Ar atmosphere, preferably 10% H ₂ (in Ar balance), at a temperature range of 400 to 600 ℃, more preferably 450 to 550 ℃ to produce Black-WO ₃ (BW) catalyst. manufactures. If heat treatment is performed at a temperature range of 300°C to less than 400°C, oxygen vacancy formation occurs weakly, and if heat treatment is performed below 300°C, oxygen vacancy formation does not occur and the color of the catalyst remains the same. The heat treatment was performed under various conditions and the firing time was 10 to 120 minutes, preferably 10 to 60 minutes, and more preferably 45 to 60 minutes.

Depending on the firing maintenance time, the degree to which oxygen vacancies are activated on the surface of the catalyst varies. The longer the firing time is, the more oxygen vacancies appear on the catalyst surface. However, optimization of the calcination maintenance time is necessary to ensure high performance of catalysts activated with oxygen vacancies. High performance is achieved when the existing catalyst and oxygen vacancies on the surface are in an appropriate ratio. If the firing maintenance time exceeds 120 minutes, oxygen vacancies are strongly formed and the color of the catalyst becomes closer to black, but this is not a condition for excellent carbon monoxide removal performance. In addition, even if oxygen vacancies are weakly formed with a firing holding time of less than 10 minutes, the carbon monoxide removal performance is low.

In addition, as a result of using 10% H ₂ (in Ar balance) gas as a reducing agent and treating WO ₃ using pure Ar gas without using H ₂ gas, oxygen vacancies were not activated, resulting in a color change of the catalyst. There was no improvement in the photocatalytic performance of the intact catalyst.

Next, the second step will be explained. This is a process of forming oxygen vacancies in titanium dioxide using a chemical reduction method. The powder mixed with agate oil by adding a reducing agent to titanium dioxide is placed in an alumina crucible and heat-treated in an Ar atmosphere, preferably in a 100% Ar atmosphere, at a temperature range of 200 to 400 ℃, preferably 250 to 350 ℃, to obtain black- TiO ₂ (BT) catalyst is prepared. The reducing agent of the present invention can be calcium hydride or sodium borohydride, but calcium hydride has the disadvantage of having a long calcination time, so sodium borohydride is most preferable. Heat treatment conditions were set between 10 and 120 minutes, preferably 10 to 60 minutes, and most preferably 45 to 60 minutes. After heat treatment, BT was washed with purified water and ethanol.

Next, the third step will be explained. A composite photocatalyst is formed by combining BT and BW catalysts. The T:W ratio of the composite photocatalyst is 10:0 to 0:10, preferably 1:1 to 19:1, more preferably 1:1 to 9:1, and most preferably 9:1. .

When the T:W ratio of the composite photocatalyst is 1:1 to 9:1, the time for the carbon monoxide concentration in the surrounding environment to reach 0 upon filter adsorption is 3 to 4 hours, and when T:W = 9:1, it takes 3 hours. do.

Next, the fourth step will be explained. The composite photocatalyst is filtered through filter paper to produce a filter, and dried in a dryer for 12 to 24 hours, preferably 12 to 18 hours, preferably 12 to 16 hours, most preferably 12 hours. The filter paper may be made of ceramic, paper, carbon, polymer, fiber, etc.

According to another aspect of the present invention, an air purifying filter manufactured according to a method of manufacturing a composite photocatalytic filter activated with oxygen vacancies is provided.

The thickness of the manufactured filter is 0.25 mm to 27 mm, preferably 0.25 mm to 20 mm, and more preferably 1 mm to 5 mm. In addition, it can be said that CO was removed as CO was converted to CO ₂ depending on the T:W ratio of the photocatalyst included in the air purification filter. CO removal rate can be optimized depending on the T:W ratio.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Meanwhile, illustrations and detailed descriptions of the configuration and its operations and effects that can be easily seen by those with ordinary knowledge in the relevant technical field will be simplified or omitted and will be explained in detail focusing on parts related to the present invention.

<Example>

Example 1 - Fabrication of composite photocatalytic filter

(1) Production of tungsten oxide activated with oxygen vacancies

Commercial WO ₃ was used and fired at 500°C in a 10% H ₂ /Ar gas atmosphere. At this time, the temperature increase rate required for sintering was 10°C/min, and when the final temperature was reached, it was maintained for 50 min. After sintering was completed in a 10% H ₂ /Ar atmosphere, it was naturally cooled to room temperature. The calcined tungsten oxide is Black-WO ₃ (BW).

(2) Production of titanium dioxide activated with oxygen vacancies

2 g of commercial TiO ₂ (P25) and 750 mg of sodium hydroboride (NabH ₄ ) were added and mixed into the agate mortar. The mixed powder was placed in an alumina crucible and fired in a 99.99% Ar atmosphere at 300°C for various times in a 10% H ₂ /Ar atmosphere, and then naturally cooled to room temperature. The fired Black-TiO ₂ (BT) was washed with purified water and ethanol and dried in an oven at 60°C for more than 12 hours.

(3) Fabrication of composite photocatalyst filter

Tungsten oxide and titanium dioxide were mixed in 50 mL of purified water at a constant mass ratio of 50 mg and stirred for 30 minutes. A filter was manufactured by filtering the stirred solution through filter paper (0.45 uM) using a vacuum pump. The manufactured filter was dried in a dryer for more than 12 hours.

Example 2 - Fabrication of composite photocatalytic filter containing zeolite

Tungsten oxide and titanium dioxide were added to 50 mL at a constant mass ratio of 50 mg, and zeolite (1, 5, 10 wt%) was added and stirred together for 30 minutes. The zeolite used here is Zeolite Y (Hydrogen), and it was heat treated at 110°C for 12 hours as a zeolite pretreatment process. A filter was manufactured by filtering the stirred solution through filter paper (0.45 uM) using a vacuum pump.

Example 3 - Production of composite photocatalytic carbon nanotube filter

First, a carbon nanotube filter was produced using multi-walled carbon nanotubes (MWCNT). Carbon nanotubes, which are mainly hydrophobic, were modified to be hydrophilic through surface treatment. Using aqua regia (100 mL) mixed with nitric acid and hydrochloric acid in a ratio of 1:3, 0.5 g of carbon nanotubes were added and stirred for 6 hours. The stirred carbon nanotubes were washed several times with water. The modified carbon nanotubes were dried in an oven at 60 degrees for more than 12 hours.

In order to disperse 50 mg of carbon nanotubes well, they were placed in 80 mL of ethanol and dispersed by ultrasonic waves for 30 minutes, and the well-dispersed carbon nanotubes were filtered using a PVDF 0.22 uM filter. Next, in the same manner as the above filter manufacturing process, the composite photocatalyst solution was filtered over the carbon nanotubes to produce a composite photocatalyst carbon nanotube filter. When the manufactured filter was dried in a dryer for more than 12 hours, only the composite photocatalyst carbon nanotube filter was separated from the PVDF 0.22 uM filter, thereby obtaining a stand-alone composite photocatalyst carbon nanotube filter.

Example 4 - Analysis

(1) Catalyst surface analysis

The change in catalyst color was observed after surface modification of the catalyst. Additionally, in order to determine the light absorption range of the catalyst, it was measured using an analysis device from Shimadzu. Using BaSO4 (Barium sulfate), we first set a standard and measured the light absorption spectrum in the wavelength range from 200 nm to 900 nm in the form of catalyst powder.

In addition, T, W, BT, and BW sample powders were measured using a field emission transmission electron microscope FE-TEM (200kV) for micro-area image observation and component and structure analysis of the ultra-fine areas of the samples.

In addition, in order to analyze the crystal structure, Cu-Kα radiation (40 kV, 30 mA) with a wavelength of 1.5406 Å was applied using PANalytical's EMPUREAN equipment to measure T, W, BT, and BW in powder form.

In addition, in order to measure the composition and components of the surface, Al-Kα (1486.6 eV) was applied using ThermoFisher (NEXSA) equipment to measure T, W, BT, and BW in powder form.

(2) Performance evaluation

The composite photocatalyst filter prepared above was used with an area of 2.5 x 2.5 cm ² . To evaluate the performance of the composite photocatalyst filter, an experiment was conducted to oxidize carbon monoxide, a harmful indoor gas, to carbon dioxide. Before proceeding with the experiment, air was purged while exposed to light for 1 hour to remove carbon attached to the surface of the filter. 0.1% carbon monoxide (CO) and 21% oxygen (O ₂ ) were used in a nitrogen atmosphere. A mixed gas of carbon monoxide and air, each of which had flow rates controlled by a flow controller (MFC), was purged into the photocatalyst reactor by passing it through an impinger containing water. To stabilize the concentration, the reactor was allowed to flow for 30 minutes, and then both sides were blocked and sunlight was applied. The gas in the reactor was sampled at a certain time to confirm the reduction of carbon monoxide and the production of carbon dioxide. The decomposition and production amount of the gas was confirmed by quantifying carbon monoxide and carbon dioxide using GC-FID.

Comparative Example 1 - Production of TiO2/Al2O3[TA]/WO3[W] composite photocatalyst (TAW)

Two types of composite photocatalysts, TA/W-1 and TA/W-1, were manufactured by bonding Al ₂ O ₃ to TiO ₂ . At this time, the concentration of Al ₂ O ₃ is 0.05 to 0.1 M for TA/W-1 and 0.28 to 0.32 M for TA/W-2.

Results and Evaluation

Catalyst surface analysis

Figure 1 shows catalyst changes as the firing maintenance period increases according to an embodiment of the present invention. Referring to Figure 1, the color of samples of tungsten oxide (BW) and titanium dioxide (BT) activated with oxygen vacancies changed. As the firing holding time increased, the color of the sample tended to become darker, and both BW and BT changed to navy blue or black. At a certain temperature, BT-1 and BW-1 were fired for 10 minutes, BT-2 and BW-2 were fired for 50 minutes, and BT-3 and BW-3 were fired for 120 minutes.

Figure 2 shows the light absorption wavelength range and catalyst color change of tungsten oxide and titanium dioxide improved with oxygen vacancies according to an embodiment of the present invention. Referring to FIG. 2, the existing W and T exhibit strong absorption in the UV region, and the samples activated with oxygen vacancies have an expanded wavelength range of light that can be absorbed. As the absorption in the visible and infrared regions was greatly improved, it was confirmed that the catalysts activated with oxygen vacancies had a narrower band gap and were able to absorb light even in the visible light region.

Figure 3 shows TEM images of tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention. Referring to Figure 3, (a) is tungsten oxide (W), (b) is titanium dioxide (T), (c) is tungsten oxide (BW) activated with oxygen vacancies, and (d) is activated with oxygen vacancies. As a titanium dioxide (BT) catalyst, tungsten oxides appeared to have a particle size within about 200 nm, and titanium dioxide appeared to have a particle size within about 50 nm, and there was no change in particle size and shape of the catalysts developed by firing. There was no change in the crystal structure of titanium dioxide before and after treatment, but a new crystalline phase of WO _2.92 was seen in tungsten oxide after treatment.

Figure 4 shows XRD of tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention. Referring to FIG. 4, the intensity of the (002), (020), and (200) portions, which are representative peaks of tungsten oxide, were low and the peaks were wide and broad. It was confirmed that H _x WO ₃ and WO _3-X phases existed through treatment with a tungsten oxide catalyst.

Figure 5 shows O 1s Figure 6 shows W 4f, Ti 2p It was done. Referring to Figures 5 and 6, the O 1s binding energy of BT has moved to a lower energy side compared to T, which means that the Ti-O peak has moved to a lower energy side and treatment to create oxygen vacancies has resulted in the formation of hydroxyl on the surface of BT. This is because the peak of Ti-OH was generated as the group was formed. Additionally, BW moved to higher energy than W. Additionally, it was observed that the Ti 2p binding energy shifted to a lower energy for BT compared to T, which is a phenomenon seen as the formation of Ti ⁺³ in BT. In addition, in W 4f, the binding energy of BW moves to a higher energy side compared to W, and the intensity is lower and wider than that of W, resulting in a broad peak. This is due to the formation of H _x WO ₃ and W ^{+ 5} in BW. .

Comparison of carbon monoxide removal performance of catalysts according to firing holding time

Figure 7 shows a comparison of the removal performance of tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention. Referring to Figure 7, Figure 7 (a) compares the carbon monoxide removal performance of T and BT, and Figure 7 (b) compares the carbon monoxide removal performance of W and BW, comparing the existing catalysts (T and W ) This is the result of an experiment to remove carbon monoxide, a harmful indoor gas, to evaluate the performance of the catalyst activated with oxygen vacancies. When the experiment was conducted under the same conditions with different types of catalysts, the results were as follows. Compared to the existing catalyst, the optical performance of the developed catalyst was improved. In particular, BT-2 increased the carbon monoxide removal reaction rate by about 5 times compared to T. Additionally, performance also differed depending on the catalyst treated with different firing holding times. It was confirmed that the improved optical performance of the catalyst activated by oxygen vacancies had a more efficient effect for air purification, such as carbon monoxide removal, compared to existing catalysts.

Composite photocatalyst filter optimization experiment for carbon monoxide removal

Based on the above results, BT-2 and BW-2, which had relatively excellent performance, were determined, and composite photocatalysts of T, W, BT, and BW were manufactured and performance evaluated. A synergistic effect was seen when two types of catalysts were combined and combined rather than single material T and W catalysts. First, in order to find an appropriate ratio, two catalysts were tested and compared under various ratio conditions. Figure 8 shows a comparison of performance by ratio of tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention. Referring to Figure 8, when overall T is 90% and W is 10% (TW90 in (a), BT/W90 in (b), T/BW90 in (c), BT/BW90 in (d)), showed the best performance.

Figure 9 shows a comparison of the carbon monoxide removal performance of tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention and the carbon monoxide oxidation The carbon dioxide production rate is shown, and Figure 10 shows the removal of carbon monoxide by tungsten oxide (W), titanium dioxide (T), tungsten oxide (BW) activated with oxygen vacancies, and titanium dioxide (BT) catalysts according to an embodiment of the present invention. This shows a comparison of reaction speeds. Referring to Figures 9 and 10, compared to the existing T and W composite photocatalyst (TW), the performance when BT and BW catalysts are bonded together has improved, especially carbon monoxide removal of the T/BW composite photocatalyst filter. The reaction speed was improved by about 8 times more than T and about 2 times compared to TW.

Figure 11 shows the light absorption wavelength region of the composite photocatalyst according to an embodiment of the present invention. Referring to Figure 11, the intensity of the absorption zone was also different for each catalyst. Performance was improved due to complexation with a catalyst activated by oxygen vacancies, and the following catalysts were found to be effective for air purification, such as removal of carbon monoxide, a harmful indoor gas.

Composite photocatalyst filter experiment with zeolite

From the above results, the optimized composite photocatalyst (T/BW) was selected, a certain amount of zeolite (1, 5, and 10 wt%) was added, and a carbon monoxide experiment was conducted under the same conditions. Figure 13 shows the carbon monoxide removal and carbon dioxide production rate of the composite photocatalyst containing zeolite according to an embodiment of the present invention, and Figure 14 shows the carbon monoxide removal reaction rate of the composite photocatalyst containing zeolite according to an embodiment of the present invention. This shows a comparison. Referring to Figure 13, the removal performance rate decreased compared to when zeolite was not included, but as the amount of zeolite increased, the carbon dioxide production rate increased. This means that zeolite has excellent adsorption power as a representative feature, and due to this feature, there is a possibility that carbon monoxide and carbon dioxide are adsorbed while purging gas in the early stages of the experiment. Referring to Figure 14, the removal reaction rate was similar when the zeolite content was 1, 5, and 10 wt%, but was higher by about 0.07 k (h ^-1 ) at 5 wt%.

Composite photocatalyst carbon nanotube filter experiment for carbon monoxide removal

From the above results, the optimized composite photocatalyst (T/BW) was used and applied to the carbon nanotube filter. The same method was used, and this is the result of the experiment when the same composite photocatalyst was used but a different filter substrate was used. Figure 15 shows a comparison of carbon monoxide removal reaction rates of a composite photocatalyst containing zeolite according to an embodiment of the present invention. Referring to (a) of FIG. 15, carbon monoxide was consistently removed linearly rather than non-linearly. Referring to (b) of FIG. 15, the carbon dioxide production rate increased as carbon monoxide was removed. A characteristic of carbon nanotubes is their gas adsorption capacity, so a higher carbon dioxide production rate can be observed compared to carbon monoxide removal compared to when carbon nanotubes are not used.

Figure 16 shows a comparison of carbon monoxide removal reaction rates of composite photocatalyst carbon nanotube filters according to an embodiment of the present invention. Referring to FIG. 16, even when a carbon nanotube filter is used, the catalyst's optical activity is outstanding and the carbon monoxide removal performance shows a removal efficiency of over 80% and a reaction rate of about 0.6 k (h ^-1 ) in 3 hours.

TAW composite photocatalyst filter experiment for carbon monoxide removal

Figure 17 shows the carbon monoxide removal rate of the TAW composite photocatalytic filter according to a comparative example of the present invention. Referring to FIG. 17, the performance of each prepared TA/W catalyst was significantly lower than that of TW or T/BW described in this study, with about 20-25% of carbon monoxide removed.

The foregoing has described, rather broadly, the features and technical advantages of the present invention to enable a better understanding of the claims described below. Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing its technical idea or essential features. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modified forms derived from the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

Claims (4)

A first step of preparing a Black-WO ₃ (BW) catalyst by heat treating tungsten oxide powder at a temperature range of 400 to 600 ° C. under a reducing gas atmosphere; A second step of preparing a Black-TiO ₂ (BT) catalyst by heat-treating the powder mixed by adding a reducing agent to titanium dioxide at a temperature range of 200 to 400 ° C. under an inert gas atmosphere; A third step of forming a composite photocatalyst by bonding the prepared BT and BW catalysts; and A fourth step of manufacturing a filter by supporting the composite photocatalyst on filter paper, A method of manufacturing a composite photocatalyst filter activated with oxygen vacancies, characterized in that carbon monoxide in the surrounding environment is removed during filter adsorption when the T:W ratio of the composite photocatalyst is 1:1 to 19:1. According to clause 1, A method of manufacturing a composite photocatalyst filter activated by oxygen vacancies, characterized in that the reducing gas atmosphere in the first step is 0.5 to 20% H ₂ . According to clause 1, A method of manufacturing a composite photocatalyst filter activated by oxygen vacancies, characterized in that the reducing agent in the second step is a hydrogenated alkali metal and an alkaline earth metal. An air purifying filter manufactured by the manufacturing method according to any one of claims 1 to 3.

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