WO2021175304A1

WO2021175304A1 - Plasma driven catalyst reactors and method of preparation thereof

Info

Publication number: WO2021175304A1
Application number: PCT/CN2021/079187
Authority: WO
Inventors: Wai Man Peter LEE; Lok Hang KEUNG; King Ho So; Ka Chun Lee; Ka Kit Yee
Original assignee: Lbs Premium Air Company Limited
Priority date: 2020-03-05
Filing date: 2021-03-05
Publication date: 2021-09-10
Also published as: CN113351010A; WO2021175304A9; TW202135868A

Abstract

A plasma driven catalyst reactor (100) for purifying air, comprising: at least two electrodes (102, 104) for generating a plasma within a plasma zone between the at least two electrodes (102, 104), wherein at least one of the electrodes (102, 104) comprises a dielectric layer (112) and a catalyst layer (114), and wherein a fiber member (108) comprising a catalyst (110) is placed between the electrodes (102, 104) for reducing harmful substances in the plasma zone.

Description

PLASMA DRIVEN CATALST REACTORS AND METHOD OF PREPARATION THEREOF

TECHNICAL FIELD

The present invention relates to non-thermal plasma technology particularly a plasma driven catalyst reactor for purifying air as well as a method of preparation thereof.

BACKGROUND OF INVENTION

Air pollution is a major concern in the world as it can cause adverse health effects. The severity of health hazard depends on exposure level, time of exposure, and nature of air pollutants. Health issues associated with air pollution include nose and throat irritation, asthma, abnormal blood pressure and cancer. Air pollutants include particulate matter (PM) or gaseous droplets found in the air such as mixture of water, dust, dirt, soot, and smoke. On the other hand, gaseous pollutants include volatile organic compounds (VOCs) , ozone, nitrogen dioxide, carbon monoxide and the like.

Non-thermal plasma (NTP) has been demonstrated as an effective approach to decompose gaseous pollutants such as volatile organic compounds (VOCs) , chlorofluorocarbons (CFCs) , and odors. However, it has been found that the plasma treatment alone leads to formation of undesirable by-products such as ozone (O ₃) , and carbon monoxide (CO) . Besides, NTP technology is not useful for removing PM matter and thus its application in air purification is limited.

To reduce the amount of both PM and gaseous pollutants in air especially indoor air, there are currently some advanced air purifiers. In these air purifiers, a HEPA filter and an activated carbon layer are installed together. The HEPA filter removes PM, while the activated carbon layer removes gaseous pollutants. However, there are several drawbacks associated with such an arrangement. First, the use of HEPA filters usually leads to a large pressure drop and thus limits the clean air delivery rate (CADR) . Second, such a hybrid filtration unit is bulky. Third, it has been reported that bacteria can adhere on the carbon particles in the activated carbon layer and results in contamination. Last but not least, said purifiers require regular replacement of HPEA and activated carbon layer and thus increases operational cost.

Therefore, there is an unmet need to develop an air purifying apparatus which is effective in reducing the amount of PM and gaseous pollutants simultaneously.

SUMMARY OF INVENTION

In one aspect of the present invention, there is provided a plasma driven catalyst reactor for purifying air, comprising:

at least two electrodes for generating a plasma within a plasma zone between the at least two electrodes,

wherein at least one of the electrodes comprises a dielectric layer and a catalyst layer, and

wherein a fiber member comprising a catalyst is placed between the electrodes for reducing harmful substances in the plasma zone.

In another aspect of the present invention, there is provided an apparatus comprising at least one said plasma driven catalyst reactor. In particular, the apparatus further comprises

an air inlet and an air outlet allowing air to pass through the plasma driven catalyst reactor; and

a filter placed upstream of the plasma driven catalyst reactor for reducing particulates in the air passing through the plasma driven catalyst.

In a further aspect of the present invention, there is provided a method of preparing said plasma driven catalyst reactor. The method comprises the steps of:

(i) providing at least two electrodes for generating a plasma within a plasma zone between the at least two electrodes, and forming a dielectric layer on at least one of the electrodes;

(ii) forming a catalyst layer on said dielectric layer; and

(iii) placing a fiber member comprising a catalyst between the electrodes.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the present invention are described in more detail below with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram showing a plasma driven catalyst reactor according to an embodiment of the present invention;

Figure 2 is a schematic diagram showing a plasma driven catalyst reactor according to another embodiment of the present invention;

Figure 3 is a schematic diagram showing an apparatus having the plasma driven catalyst reactor schematically shown in Figure 1 according to an embodiment of the present invention;

Figure 4 is a schematic diagram showing steps of preparing a dielectric layer on the electrode according to an embodiment of the present invention;

Figure 5 is a schematic diagram showing steps of preparing a catalyst precursor mixture for forming a catalyst layer according to an embodiment of the present invention;

Figure 6 is a schematic diagram showing steps of coating the catalyst on the electrode according to an embodiment of the present invention; and

Figure 7A shows a scanning electron microscopy (SEM) image of fibers prepared from PAN and 0.5%TiO ₂, Figure 7B shows a SEM image of fibers prepared from PAN and 2%TiO ₂; and Figure 7C shows a SEM image of fibers prepared from PAN and 9%TiO ₂.

DETAILED EMBODIMENT OF INVENTION

The present invention pertains to a plasma driven catalyst reactor which generates a plasma between electrodes for decomposing pathogens, and removing air pollutants in air passing through the plasma driven catalyst reactor, thereby purifying air to improve indoor air quality. It relates to a non-thermal plasma technology based on dielectric-barrier discharge (DBD) , and a similar concept of the technology is described in U.S. Patent No. 9,138,504 and U.S. Patent Application Publication No. 2016/0030622A, the entire disclosures of which are incorporated herein by reference.

In the present invention, at least one of the electrodes of the plasma driven catalyst reactor is preferably coated with a dielectric layer such as a metallic oxide layer, and a catalyst layer. The dielectric layer and the catalyst layer on the electrode together enhance the efficiency on removing pollutants in air. A fiber member containing a catalyst is further placed between the electrodes to facilitate the purification process. The catalyst in the fiber member can be activated by the generated plasma and then decompose the pollutants in air. The fibrous structure of the fiber member provides an increased surface area for the catalytic reaction.

With reference to Figure 1, there is illustrated an embodiment of a plasma driven catalyst (abbreviated as PDC) reactor 100. The PDC reactor 100 has two

electrodes

102, 104 positioned in parallel for generating a plasma within a plasma zone between the

electrodes

102, 104, and a fiber member 108 placed within the plasma zone between and in parallel with the

electrodes

102, 104 for reducing harmful substances in the plasma zone. The

electrodes

102, 104 are connected to a power source 106 particularly an alternating current (AC) power source for providing an AC voltage. A high voltage AC from 3kV to 30kV with frequency ranging from several hundred hertz (Hz) to a few hundred kilo hertz (kHz) particularly from about 0.1 to about 30.0 kilohertz may be applied to generate a plasma inside the PDC reactor 100.

The

electrodes

102, 104 are made of electrically conductive materials and are configured in the form of a mesh. The mesh structure increases surface area for generating plasma. It would be appreciated that other configurations of the electrodes may also be used in the present invention to achieve the same or similar performance as described herein. For example, the

electrodes

102, 104 may be in the form of films, rods, plates or tubes. In an embodiment, the electrodes have zigzag structures. The PDC reactor may have more than two electrodes arranged in parallel with each other, increasing the production of plasma.

Preferably, the

electrodes

102, 104 are spaced apart from each other by a distance of 0.5 mm to 10 mm, or 1 mm to 5 mm, or 1.5 mm to 3 mm. The electrode 102 is coated with a dielectric layer 112. The generated plasma can effectively fill up the space between the electrodes to decompose pathogens in air passing through the space. The efficiency in removing volatile organic compounds (VOCs) is found to be maximized at the abovementioned distance. The dielectric layer 112 partially or wholly covers the surface of the electrode 102 and participates in the generation of plasma. The dielectric layer 112 of the present invention further act as an interfacial layer on the electrode surface. It thus provides a surface for loading functional components such as catalysts or molecules that modify the physical or electrical properties of the electrode 102.

In this embodiment, the dielectric layer 112 contains a cerium oxide. The oxide of cerium may be Ce ₂O ₃, Ce ₃O ₄ or CeO ₂. Preferably, the oxide of cerium is CeO ₂. The dielectric layer 112 can be formed on the surface of the electrode 102 via a metal conversion process, which will be described in detail below. In another embodiment, additional dielectric components may be arranged in contact with the electrode 102 to enhance plasma generation.

On top of the dielectric layer 112, the electrode 102 has an additional catalyst layer 114. In other words, the dielectric layer 112 is sandwiched between the electrode 102 and the catalyst layer 114. The catalyst layer 114 has a surface exposed to the plasma zone. The catalyst layer 114 includes one or more catalysts particularly photocatalysts to degrade pollutants under suitable excitation. The catalyst layer 114 preferably contains titanium oxide which is a promising photocatalyst for minimizing gaseous pollutants and undesirable by-products generated during the plasma generation process. The catalyst can be effectively activated by the plasma generated within the plasma zone. Energetic species generated by the PDC reactor 100 can react with ozone (an undesired by-product) to form oxygen radicals, hydroxyl radicals and hydrogen peroxide in the presence of the catalyst, thereby eliminating or reducing the amount of ozone as well as other pollutants in the air.

It is found that the combination of the dielectric layer containing a cerium oxide and the catalyst layer containing titanium dioxide remarkably increases the efficiency on removing pollutants such as volatile organic compounds in the air.

Referring to Figure 1, the PDC reactor 100 further has a fiber member 108 placed in parallel with the

electrodes

102, 104. The fiber member 108 contains one or more catalysts 110 which further improve the pollutants removal rate. Preferably, the fiber member 108 contains or consists of electrospun fibers (not shown) doped with a predetermined amount of catalyst 110. It would be appreciated that the fiber member 108 has at least one polymer selected from the group consisting of polyvinylidene fluoride (PVDF) , polyacrylonitrile (PAN) , and a combination thereof, and at least one catalyst such as titanium dioxide. In an embodiment, the fiber member is prepared from an electrospinning process with a mixture containing polyacrylonitrile (PAN) and titanium dioxide under suitable conditions for producing nano-sized to micro-sized fibers.

Preferably, the fibers have an average diameter of about 50 nm to about 2000 nm, about 100 nm to about 1000 nm, about 200 nm to about 800 nm, or about 400 nm to 600 nm. The fiber member 108 may contain additives that can modulate the fiber morphology, diameter, thickness and/or density of the fiber layer 108. For example, when the fiber diameter decreases, the fiber member may provide a larger surface area for catalytic reaction to occur, and result in enhanced adsorption and filtration properties of the fiber member. Further, the fibrous porous structure of the fiber member 108 is advantageous as it can act as a filter capturing particulates in the air.

The amount of the catalyst 110 in the fiber member 108 may be about 4%to about 60%by weight, about 10%to about 50%by weight, about 20%to about 40%by weight, or about 50%by weight based on the total weight of the fiber layer 108. In this embodiment, the amount of titanium dioxide is about 50%by weight based on the total weight of the fiber layer 108.

In this embodiment, the catalyst layer 114 and the fiber member 108 contain the same catalyst such as titanium dioxide. It would be appreciated that other catalysts that are suitable for degrading gaseous pollutants are also applicable in the present invention.

Examples include heterojunction photocatalysts that can speed up the activation process. In an alternative embodiment, the catalyst layers and the fiber member may contain different catalysts to purify air.

Accordingly, the PDC reactor 100 according to an embodiment of the present invention has a combined arrangement of a fiber member 108 together with at least one double-coated electrode. When air enters the PDC reactor 100, the plasma generated between the

electrodes

102, 104 will activate the catalyst in the catalyst layer 114 and the fiber member 108 to degrade and remove harmful substances in the air. The discharged air will thus be cleaned. The combination was proved to be effective in improving the removal of gaseous pollutants such as ozone. The PDC reactor 100 can be used with other components, together forming an apparatus.

The PDC reactor according to the present invention may include more than one double-coated electrode, i.e. an electrode coated with both a dielectric layer and a catalyst layer as described above. It will be appreciated that various combinations of electrodes can also be used to form a PDC reactor. For example, a PDC reactor may include two or more double-coated electrodes together with one or more non-coated electrode positioned substantially in parallel with each other.

Figure 2 shows a PDC reactor 200 according to another embodiment of the present invention. The PDC reactor 200 is similar to the PDC reactor 100 as shown in Figure 1, except that the PDC reactor 200 includes two

electrodes

202, 204 independently coated with a

dielectric layer

212a, 212b, and a

catalyst layer

214a, 214b. The

electrodes

202, 204 are connected to a power source 206 to generate a plasma between the

electrodes

202, 204. The catalyst layers 214a, 214b are activated by the plasma to decompose pollutants. The PDC reactor 200 also contains a fiber member 208 placed between and substantially in parallel with the

electrodes

202, 204. The catalyst 210 in the fiber member 208 is activated by the plasma to remove particulate matter in the air.

Referring to Figure 3, there is provided an apparatus 300 of the present invention. The apparatus 300 includes the PDC reactor 100 as described above in a closed arrangement. The apparatus 300 further includes an air inlet 302 and an air outlet 304 allowing air to pass through the PDC reactor 100; and a filter 306 placed upstream of the PDC reactor 100 for eliminating coarse particulates in the air passing through the PDC reactor 100. An electric fan 308 is placed downstream of the PDC reactor 100 to draw air into the air inlet 302 and leave at the air outlet 304 along the direction A. The apparatus 300 may be equipped with one or more sensors, a processor and/or a controller to monitor and control the level of pollutants. The apparatus 300 may further include a display for indicating the level of air pollutants measured before and/or after the plasma treatment.

An experiment was conducted to study the air pollutant removal efficiency by installing an apparatus having the PDC reactor as described above. Particularly, the PDC reactor contains one double-coated electrode and one non-coated electrode. The double-coated electrode has a cerium oxide layer and a TiO ₂ layer. Both of the electrodes were connected with an AC power supply for providing alternating current towards the electrodes. A fiber member containing TiO ₂ doped nanofibers is placed within the plasma zone of the PDC reactor. The PDC reactor is placed in a closed arrangement, together with an electric fan positioned downstream for generating airflow. VOC gas was then injected into the apparatus, and the concentration of the VOC in the apparatus was monitored by a VOC meter. When the concentration of VOC reached equilibrium, the PDC reactor was switched on. After 65 minutes, a final VOC concentration was measured to calculate the air pollutant removal efficiency. Three experiments were conducted with the PDC reactor of the present invention with or without the fiber member. A control experiment was also set up by using bare electrodes, i.e. without coatings, and without fiber member.

Table 1 shows the VOC removal efficiency of the apparatus of the present invention compared to control set-up.

Based on the above experimental results, the VOC removal efficiency of the PDC reactor of the present invention is the highest in the presence of the fiber member. The results suggest that the more TiO ₂ in the plasma zone, the higher VOC removal efficiency can be obtained.

A further experiment was conducted to study the ozone level of air treated with the PDC reactor of the present invention. An ozone monitor was used to measure ozone level in the apparatus as described previously. The PDC reactor was placed next to the ozone meter in the apparatus. Three experiments were conducted with the PDC reactor of the present invention with or without the fiber member. A control experiment was also set up by using bare electrodes, i.e. without coatings, and without fiber member. Initial ozone level was measured before switching on the PDC reactor, and the final ozone level was measured after 10 minutes of treatment. The results are shown in Table 2.

Table 2 shows the ozone removal efficiency of the apparatus of the present invention compared to control set-up.

From the results, less side product (O ₃) was generated from the PDC reactor after treatment with the coated electrode. It is also believed that the coating of the cerium oxide layer enhances the TiO ₂ doping amount. As a result, less O ₃ was detected. The incorporated fiber member of the PDC reactor further suppressed the O ₃ concentration. The results show that TiO ₂ doped fiber in the PDC reactor is useful in suppressing O ₃ generation. Accordingly, the PDC reactor of the present invention is capable of suppressing the release of harmful by-products since the catalyst TiO ₂ is able to generate active species to decompose harmful by-products.

In addition, the provision of a filter member 108 between the

electrodes

102, 104 in the PDC reactor 100 has demonstrated promising effect in filtering air particulates. An experiment was conducted to evaluate the filter efficiency of the PDC reactor of the present invention. Different size of particulate matter (PM) was generated through a particle generator MAG3000. The apparatus 300 was used to collect the generated PM. After 5 minutes injection, the apparatus 300 was sealed and placed at room temperature for 5 minutes to ensure the PM separated equally. The apparatus 300 was connected to a Dust Trak aerosol monitor. A nanofiber filter was placed between the apparatus 300 and a Dust Trak aerosol monitor was provided to filter the PM from the apparatus 300. The initial PM concentration and final PM concentration (after passing through the nanofiber filter) were measured and used to calculate the filter efficiency. The results are shown in Table 3.

Table 3 shows the PM removal efficiency of the apparatus of the present invention compared to control set-up.

Based on the results, the fiber member 108 in the PDC reactor 100 can effectively trap PM. The filter efficiency depends on the fiber diameter, TiO ₂ amount and the choice of polymer. By adjusting the fiber diameter and TiO ₂ amount, different nanofiber filters can be made for different air purifying purposes.

A further experiment was conducted to determine the disinfecting effect of the PDC reactor 100. 1 mL of E. Coli culture solution was added to a LB agar plate. The agar plate was then placed in a closed box. In the closed box, a PDC reactor was placed next to the agar plate. The PDC reactor was switched on for 45 minutes. After that the agar plate was taken out for incubation at 37℃ for 24 hours. The bacteria were enumerated by the conventional plate count method. An agar plate with no treatment was used as control group. The results are shown in Table 4. The percentage reduction of test microorganisms in test tubes with the fiber member was calculated using the below equation:

R%= 100* (A–B) /A

where R is the reduction of test microorganism in percentage, A is the total number of colonies on the control agar plate, and B is the total number of colonies on the PDC-NF treated agar plate.

Table 4 shows the number of bacterial colonies with and without treatment with the PDC reactor.

As shown from the above results, the control group did not show any antibacterial activity while the PDC reactor is effective in reducing and inhibiting bacterial growth. The results show that PDC reactor has disinfecting effect.

Lastly, the present invention pertains to a method of preparing the PDC reactor as described above. The method comprises the steps of

(i) providing at least two electrodes for generating a plasma within a plasma zone between the at least two electrodes, and forming a dielectric layer as described above on at least one of the electrodes;

(ii) forming a catalyst layer as described above on the said dielectric layer; and

(iii) placing a fiber member comprising a catalyst between the electrodes, and the fiber member is as described above.

Preferably, step (i) includes depositing a first mixture containing cerium nitrate on at least one of the electrodes, and annealing to form a cerium oxide coating on the electrode. The first mixture may be deposited on the surface of the electrode by spraying, dipping, brushing, or soaking depending on the material and structure of the electrode. Cerium nitrate on the surface of the electrode can then be converted through oxidation into a cerium oxide under suitable reaction conditions including annealing the electrode at a temperature of or above 200℃ .

Figure 4 illustrates an embodiment of a method of coating an electrode with a dielectric layer. An electrode 402 is dipped in a first mixture 404 containing cerium (III) nitrate Ce (NO ₃) ₃ and an oxidizing agent particularly hydrogen peroxide for about 12 hours at room temperature. Then, the electrode 402 is subjected to furnace at a temperature of or above 200 ℃ for 30 min to form a cerium oxide coating 406 on its surface. The cerium oxide coating 406 acts as both a dielectric layer for assisting plasma generation and an interfacial layer for increasing the amount of catalyst applied thereon.

Preferably, the catalyst layer is formed by sol-gel process. Step (ii) includes depositing a catalyst precursor mixture on the formed dielectric layer, and annealing to form the catalyst layer on the dielectric layer. In an embodiment where the catalyst is titanium dioxide TiO ₂, the catalyst precursor mixture contains titanium isopropoxide.

Figures 5 and 6 illustrate an embodiment of steps of forming a catalyst layer on the dielectric layer after step (i) . Two mixtures, Mixture A and Mixture B, are used to prepare the catalyst precursor mixture 410. Mixture A is prepared by mixing 10 wt%to 20 wt%of Triton X-100, 65 wt%to 85 wt%of cyclohexane, and 0.1 wt%to 5 wt%of water with stirring at room temperature for 10 minutes; and adding 5 wt%to 20 wt%of 1-hexanol to the mixture with stirring at room temperature for 1 hour. Mixture B is prepared by mixing 5 wt%to 10 wt%of acetylacetone, 40 wt%to 60 wt%of 1-hexanol and 30 wt%to 50 wt%of titanium isopropoxide together, and then stirring the mixture for 10 minutes at room temperature. After that, Mixture A is added dropwisely into Mixture B with stirring at room temperature for 90 minutes to obtain the catalyst precursor mixture 410.

As shown in Figure 6, the electrode 402 coated with the dielectric layer 406 in step (i) is dipped into the catalyst precursor mixture 410 for a period of time, and is allowed to dry before calcination at 200 ℃ for 30 minutes. After that, the electrode 402 is subjected to furnace at a temperature of about 500 ℃ for 2 hours to form a catalyst coating 412 on top of the dielectric layer 406. Accordingly, the electrode 402 is coated with both a dielectric layer 406 and a catalyst layer 412.

Turning to step (iii) , it preferably utilizes electrospinning technique to fabricate the fiber member. During an electrospinning process, high voltage is applied to a polymer solution for fabricating fibers. Catalyst can be impregnated into electrospun fibers for participating in the filtration of air pollutants such as VOC pollutants.

Preferably, step (iii) includes mixing a second mixture containing at least one polymer and the catalyst, and electrospinning the second mixture to produce fibers forming the fiber member. The polymer is selected from the group consisting of polyvinylidene fluoride (PVDF) , polyacrylonitrile (PAN) , and a combination thereof and the catalyst is preferably titanium dioxide. A person skilled in the art would appreciate suitable methods to determine the amount of the polymer and catalyst based on the desired fiber diameter and thickness.

Alternatively, other polymers that are suitable in electrospinning process may be used or added to the second mixture. Additional additives which can modulate the electrospun product may be added according to the need, for example additives that can change the fiber properties. Additional catalysts may also be incorporated into the fiber member by adding them into the second mixture before the electrospinning process.

Preferably, the second mixture is prepared by mixing 0.1-20 wt%of TiO ₂ particles, 1-20 wt%of polyacrylonitrile, and 60-98.9 wt%of dimethylformamide. Figures 7A to 7C show 3 microscopic images of fiber members obtained by adding 0.5 wt%TiO ₂, 2 wt%TiO ₂, or 9 wt%TiO ₂ into the second mixture before electrospinning with polyacrylonitrile.

In an embodiment herein, the second mixture is prepared by mixing 9 wt%of TiO ₂ particles, 9 wt%of polyacrylonitrile, and 82 wt%of dimethylformamide. During the electrospinning process, the distance between the needle tip and the collector is adjusted to 15 cm. Feed rate of the second mixture is kept constant as 3 mL/h during the spinning process. The electric field occurred between the needle tip and the collector is thus generated using a high voltage power supply with an applied voltage of 30 kV. The fiber member is thus formed by collecting the electrospun fibers doped with TiO ₂ on a non-woven cotton surface. The inventors found out that the arrangement of the fiber member in the PDC reactor can significantly improve the purifying effect of the reactor in particular more gaseous pollutants can be decomposed under plasma activation.

It would be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated.

Claims

A plasma driven catalyst reactor for purifying air, comprising:

at least two electrodes for generating a plasma within a plasma zone between the at least two electrodes,

wherein at least one of the electrodes is coated with a dielectric layer and a catalyst layer, and

wherein a fiber member comprising a catalyst is placed between the electrodes for reducing harmful substances in the plasma zone.
The plasma driven catalyst reactor of claim 1, wherein the fiber member is made of fibers having an average diameter of about 50 nm to about 2000 nm.
The plasma driven catalyst reactor of claim 1, wherein the fiber member comprises at least one polymer selected from the group consisting of polyvinylidene fluoride (PVDF) , polyacrylonitrile (PAN) , and a combination thereof.
The plasma driven catalyst reactor of claim 1, wherein the fiber member comprises 4%to 60%by weight of the catalyst based on the total weight of the fiber member.
The plasma driven catalyst reactor of claim 1, wherein the catalyst is a photocatalyst.
The plasma driven catalyst reactor of claim 1, wherein the catalyst is titanium dioxide.
The plasma driven catalyst reactor of claim 1, wherein the catalyst layer comprises titanium dioxide.
The plasma driven catalyst reactor of claim 1, wherein the electrodes and the fiber member are placed in parallel with each other.
The plasma driven catalyst reactor of claim 1, wherein the electrodes are connected to an alternating current power source for providing an alternating current voltage of 3 to 30 kilovoltz at a frequency of 0.1 to 30 kilohertz.
The plasma driven catalyst reactor of claim 1, wherein the dielectric layer comprises a cerium oxide.
The plasma driven catalyst reactor of claim 1, wherein the dielectric layer comprises CeO ₂.
The plasma driven catalyst reactor of claim 1, wherein the dielectric layer is coated on the at least one of the electrodes, and the catalyst layer is formed on the dielectric layer with a surface exposed to the plasma zone.
The plasma driven catalyst reactor of claim 1, wherein the electrodes are placed in parallel with and spaced apart from each other by a distance of 0.5 mm to 10 mm.
A method of preparing a plasma driven catalyst reactor of any one of claims 1 to 13, comprising the steps of:

(i) providing at least two electrodes for generating a plasma within a plasma zone between the at least two electrodes, and forming a dielectric layer on at least one of the electrodes;

(ii) forming a catalyst layer on said dielectric layer; and

(iii) placing a fiber member comprising a catalyst between the electrodes.
The method of claim 14, wherein the dielectric layer comprises a cerium oxide.
The method of claim 14, wherein the step (i) comprises depositing a first mixture containing cerium nitrate on at least one of the electrodes, and annealing to form a cerium oxide coating on said electrode.
The method of claim 14, wherein the step (ii) comprises depositing a catalyst precursor mixture on the formed dielectric layer, and annealing to form the catalyst layer on the dielectric layer.
The method of claim 14, wherein the step (iii) comprises mixing a second mixture containing at least one polymer and the catalyst, and electrospinning the second mixture to produce fibers forming the fiber member.
The method of claim 18, wherein the at least one polymer is selected from the group consisting of polyvinylidene fluoride (PVDF) , polyacrylonitrile (PAN) , and a combination thereof.
The method of claim 14, wherein the catalyst is titanium dioxide.
The method of claim 18, wherein the fibers have an average diameter of about 50 nm to about 2000 nm.
The method of claim 14, wherein the fiber member comprises 4%to 60%by weight of the catalyst based on the total weight of the fiber member.
The method of claim 14, wherein the fiber member is placed in parallel with the electrodes.