TWI633935B - Immobilized conductive material-cnt/tio2 photocatalyst and manufacturing method thereof - Google Patents

Abstract

A mixed crystal phase doped titanium dioxide fixed photocatalyst comprising a conductive plastic and a carbon nanotube comprises an immobilized photocatalyst, a carbon nanotube material and a conductive material. The conductive material and the carbon nanotube material are doped on the immobilized photocatalyst to obtain a doped titanium dioxide immobilized photocatalyst, and the doped titanium dioxide immobilized photocatalyst is fixed on a substrate. The carbon nanotube is a monofunctional carbon nanotube, and the functionalized carbon nanotube comprises a carboxylated carbon nanotube, a ruthenium chloride carbon nanotube or a mixture thereof. The doped titanium dioxide immobilized photocatalyst is additionally added with a surfactant.

Description

Mixed crystal phase titanium dioxide immobilized photocatalyst doped with conductive material and carbon nanotube and manufacturing method thereof

The present invention relates to a doped conductive material (for example, polyaniline, PANi) and carbon nanotubes (CNT, carbon nano-tube) or mixed crystal phase titanium dioxide [TiO ₂ ] immobilized photocatalyst [photocatalyst] The invention relates to a method for manufacturing a mixed photocatalyst of a doped conductive material and a carbon nanotube, and a method for producing the same, for degrading diethyl phthalate (DEP).

Conventional carbon nanotube/titanium dioxide composite photocatalyst material and preparation method thereof, for example, the nano carbon tube/titanium dioxide composite photocatalyst and the preparation method thereof of the Republic of China Patent Publication No. I436945, which discloses a nano carbon tube/titanium dioxide composite The photocatalyst manufacturing method comprises: preparing a carbon nanotube; surface modifying the carbon nanotube to obtain a modified carbon nanotube, and the modified carbon nanotube forms a surface graft or a functionalized group; The modified carbon nanotube is added with a titanium precursor to form a composite photocatalyst. The composite photocatalyst degrades bisphenol A under visible light.

Another conventional nano carbon tube/titanium dioxide composite photocatalyst material and a preparation method thereof, for example, a method for preparing a photocatalyst with a titanium dioxide/nanocarbon tube structure and a photocatalyst filter network patent for visible light absorption under the Republic of China Patent Publication No. I410275 It discloses a photocatalyst preparation method comprising the steps of: [a] providing a substrate; [b] forming a plurality of carbon nanotubes a surface of the substrate; [c], providing a titanium supply source and an oxygen supply source; and [d] forming at least one titanium dioxide layer on the surface of the plurality of carbon nanotubes. No. I410275 discloses a photocatalyst filter network comprising: a substrate, a plurality of carbon nanotubes, and a titanium dioxide layer. The plurality of carbon nanotubes are located on the surface of the substrate, and one end thereof is connected to the surface of the substrate, and the titanium dioxide layer is coated on the surface of the plurality of carbon nanotubes. The photocatalyst filter is a photocatalyst filter for visible light absorption, and its titanium dioxide layer has high distribution uniformity, so that it has a high photodecomposition effect.

Another conventional nano carbon tube/titanium dioxide composite photocatalyst material and a preparation method thereof, such as the ternary ternary MWNT-SiO2-TiO2 nano composite photocatalyst material of the Republic of China Patent No. I354578 and a preparation method thereof, which discloses a The ternary MWNT-SiO2-TiO2 nanocomposite photocatalyst material and its preparation method were used to prepare ternary MWNT-SiO2-TiO2 nanocomposite photocatalyst material by sol-gel method. First, a SiO2-TiO2 precursor and a MWNT suspension were prepared, and the MWNT suspension was added to the SiO2-TiO2 precursor to prepare a MWNT-SiO2-TiO2 gel. Then, an acid catalyst is added to the MWNT-SiO2-TiO2 gel to form a black MWNT-SiO2-TiO2 gel, which is subjected to aging, drying, grinding and calcining steps to form the ternary MWNT-SiO2-TiO2 of the present invention. Composite photocatalyst material.

Another conventional nano carbon tube/titanium dioxide composite photocatalyst material and a method for fabricating the same, such as the titanium oxide/single-walled carbon nanotube composites of US-A-9,078,942, which discloses a titanium dioxide/single-walled nanometer. The carbon nanotube [TiO2/SWCNTs] composite photocatalyst material is coated on a membrane filter and a ceramic article, and the titanium dioxide/single-walled carbon nanotube composite photocatalyst material is used for purifying water or air.

However, conventional carbon nanotube/titanium dioxide composite photocatalyst materials still need to improve their own material properties in order to properly upgrade the composite carbon nanotubes. Photocatalytic ability with titanium dioxide materials to degrade various common emerging environmental pollutants such as diethyl phthalate (DEP, commonly known as plasticizer) or other environmental pollutants.

In short, the conventional carbon nanotube/titanium dioxide composite photocatalyst material must have the need to dope other materials to further improve its photocatalytic properties. The foregoing state of the art of the present invention is not limited to the scope of the present invention by reference to the state of the art and the state of the art.

In view of the above, in order to meet the above technical problems and needs, the present invention provides a mixed crystal phase titanium dioxide immobilized photocatalyst doped with a conductive material and a carbon nanotube, and a method for manufacturing the same, which comprises a conductive material and a carbon nanotube The material is doped into an immobilized photocatalyst to obtain a doped titanium dioxide immobilized photocatalyst, so that the photocatalytic degradation efficiency and the manufacturing cost and time can be greatly improved compared with the conventional composite photocatalyst material and the manufacturing method thereof.

The main object of the present invention is to provide a mixed crystal phase titanium dioxide immobilized photocatalyst doped with a conductive material and a carbon nanotube, and a method for manufacturing the same, which comprises doping a conductive material and a carbon nanotube material on an immobilized photocatalyst, A doped titanium dioxide immobilized photocatalyst is obtained to achieve the purpose of improving the photocatalytic degradation efficiency.

In order to achieve the above object, a method for manufacturing a mixed crystal phase titanium dioxide immobilized photocatalyst comprising a conductive material and a carbon nanotube according to a preferred embodiment of the present invention comprises: preparing a carbon nanotube solution; and adding a titanium source precursor material to The carbon nanotube solution is formed to form a titanium source precursor and a carbon nanotube mixed solution; preparing a conductive material solution; The conductive material solution is added to the titanium source precursor and the carbon nanotube mixed solution to form a photocatalyst solution.

In the preferred embodiment of the invention, the titanium source precursor material is titanium isopropoxide.

In a preferred embodiment of the invention, the carbon nanotube is a monofunctional carbon nanotube, and the functionalized carbon nanotube comprises a carboxylated carbon nanotube, a ruthenium chloride carbon nanotube or a mixture thereof.

The conductive material of the preferred embodiment of the invention is a polyaniline material, a polypyrrole material, a polythiophene material or a mixture thereof.

In the preferred embodiment of the present invention, the conductive material solution is additionally added with a surfactant.

In a preferred embodiment of the invention, the photocatalyst solution is added to nitric acid to form a photocatalyst gel.

In order to achieve the above object, the mixed crystal phase titanium dioxide immobilized photocatalyst of the doped conductive material and the carbon nanotube of the preferred embodiment of the present invention comprises: an immobilized photocatalyst, which is a titanium dioxide immobilized photocatalyst, and the immobilized photocatalyst has a a first predetermined content; a carbon nanotube material having a second predetermined content; and a conductive material having a third predetermined content; wherein the conductive material and the carbon nanotube material are doped to the immobilization The photocatalyst is used to obtain a doped titanium dioxide immobilized photocatalyst, and the doped titanium dioxide immobilized photocatalyst is fixed on a substrate.

In a preferred embodiment of the invention, the carbon nanotube is a monofunctional carbon nanotube, and the functionalized carbon nanotube comprises a carboxylated carbon nanotube, a ruthenium chloride carbon nanotube or a mixture thereof.

The conductive material of the preferred embodiment of the invention is a polyaniline material, a polypyrrole material, a polythiophene material or a mixture thereof.

The doped titanium dioxide immobilization in a preferred embodiment of the invention The photocatalyst is additionally added with a surfactant.

1‧‧‧first photocatalytic material

1'‧‧‧Electrical materials

1a‧‧‧CNT-COOH material

1b‧‧‧CNT-COOH/TiO ₂ material

10‧‧‧Photocatalyst solution

100‧‧‧Substrate

2‧‧‧Second photocatalyst material

2a‧‧‧CNT-COCl material

2b‧‧‧CNT-COCl/TiO ₂ material

3‧‧‧The third photocatalyst material

1(a) to 1(e): a mixed photocatalyst of a doped conductive material and a carbon nanotube in a preferred embodiment of the present invention is selected to be [PANi-CNT-COCl/TiO ₂ and Schematic diagram of the interaction of two materials, PANi-CNT-COOH/TiO ₂ .

Fig. 2 is a schematic view showing the addition of a surfactant to a photocatalyst-immobilized photocatalyst of a doped conductive material and a carbon nanotube in a preferred embodiment of the present invention.

Fig. 3 is a schematic view showing the reaction mechanism between the photocatalyst and the sunlight generated by the doped conductive material and the carbon nanotube mixed phase of the preferred embodiment of the present invention.

Figure 4: The doped conductive material and the carbon nanotube mixed phase of the preferred embodiment of the present invention are selected as photocatalyst gels, and are formed on the substrate by a sol-gel method. Schematic diagram.

Fig. 5 is a schematic view showing the photocatalyst solution prepared by the doped conductive material and the carbon nanotube mixed crystal phase titanium dioxide fixed photocatalyst in the preferred embodiment of the present invention, and formed on the substrate by hydrothermal method under low temperature and high pressure. .

In order to fully understand the present invention, the preferred embodiments of the present invention are described in detail below, and are not intended to limit the invention.

The mixed crystal phase titanium dioxide immobilized photocatalyst of the doped conductive material and the carbon nanotube of the preferred embodiment of the present invention and the manufacturing method thereof are applicable to various technical fields related to the doped carbon nanotube/titanium dioxide composite photocatalyst, and the related art The field is within the spirit and technical scope of the invention. The conductive material (for example: polyaniline or polyaniline-containing material) and the carbon nanotube used in the preferred embodiment of the present invention can be widely taken from conductive materials and nanometers. Carbon tube related preparation techniques, but are not intended to limit the invention.

In the preferred embodiment of the present invention, the doped conductive material and the carbon nanotube mixed phase titanium dioxide immobilized photocatalyst comprise an immobilized photocatalyst, a carbon nanotube material (CNT) and a conductive material. For example, the carbon nanotube material may be selected from a monofunctional carbon nanotube material, and the conductive material is a polyaniline material (Polyaniline, PANi), a polypyrrole material, a polythiophene material. [Polythiophene] or various mixtures thereof.

The mixed crystal phase titanium dioxide immobilized photocatalyst of the present invention increases the conductivity by adding the functionalized carbon nanotubes and polyaniline (conductive plastic material) to prolong the time of recombination of electrons and holes, and mixes the mixture The crystalline phase titanium dioxide immobilized photocatalyst produces a red shift to the visible range. The invention utilizes the addition of the functionalized carbon nanotubes to increase the surface area of the photocatalyst and reduce the hydrophobicity of the TiO ₂ , so that it is not easy to agglomerate, thereby having better surface characteristics and increasing its conductivity to allow electrons. There are more free path movements to extend the electron-hole pair recombination time to allow the holes to fully react with H ₂ O, OH- on the photocatalyst surface to form hydroxyl radicals, thereby increasing the photocatalytic degradation efficiency. The invention also utilizes the addition of polyaniline to enable the photocatalyst to be effectively red-shifted to visible light, and the polyaniline is a conductive material, which can also increase the conductivity of the photocatalyst to prolong the electron-hole pair recombination time.

In another preferred embodiment of the present invention, the doped conductive material and the carbon nanotube mixed phase titanium dioxide immobilized photocatalyst comprise an immobilized photocatalyst, a carbon nanotube material, a conductive material and a surfactant (SDS, Sodium Dodecyl Sulfate]. The mixed crystal phase titanium dioxide immobilized photocatalyst of the present invention has the good distribution property of the photocatalyst on a substrate by adding the surfactant. The invention also increases the hydrophilicity between the photocatalyst and the material by adding the surfactant, so that the additive material and the photocatalyst can be uniformly dispersed, and has a strong bonding force, so that the photocatalyst is fixed in visible light. Photocatalysis is carried out under the environment to degrade DEP in water.

The method for manufacturing a mixed crystal phase titanium dioxide immobilized photocatalyst doped with a conductive plastic and a carbon nanotube according to a first preferred embodiment of the present invention comprises: preparing a carbon nanotube solution. For example, an isopropanol solution and a functionalized CNT (for example, 15 minutes) are mixed and oscillated by an ultrasonic oscillator for a predetermined time (for example, 15 minutes), so that the functionalized CNT is uniformly dispersed in In solution. The functionalized carbon nanotube material comprises a carboxylated carbon nanotube (CNT-COOH), a ruthenium chloride carbon nanotube [CNT-COCl] or a mixture thereof.

The method for manufacturing a mixed crystal phase titanium dioxide immobilized photocatalyst comprising a conductive plastic and a carbon nanotube according to a first preferred embodiment of the present invention comprises: a titanium source precursor material (eg, titanium isopropoxide, TTIP) The carbon nanotube solution is added to form a titanium source precursor and a carbon nanotube mixed solution. For example, TTIP is added to the carbon nanotube solution and oscillated using an ultrasonic oscillator for a predetermined period of time (eg, 15 minutes) such that the TTIP is uniformly dispersed in the solution.

The method for manufacturing a mixed crystal phase titanium dioxide immobilized photocatalyst doped with a conductive plastic and a carbon nanotube according to the first preferred embodiment of the present invention comprises: preparing a conductive material solution. For example, an appropriate amount of aniline hydrochloric acid (for example: 0.26 g, 0.52 g or 1.04 g) is dissolved in a nitric acid solution (for example, 70 mL of 0.4 M HNO ₃ ) to prepare a first conductive material solution, that is, an aniline solution; An appropriate amount of ammonium persulfate [ASP] (for example: 0.57 g, 1.14 g or 2.28 g) is dissolved in a nitric acid solution (for example, 10 mL of 0.4 M HNO ₃ ) to prepare a second conductive material solution, that is, an ammonium persulfate solution. .

The method for manufacturing a mixed crystal phase titanium dioxide immobilized photocatalyst doped with a conductive plastic and a carbon nanotube according to the first preferred embodiment of the present invention comprises: adding the first conductive material solution and the second conductive material solution to the titanium The source precursor is mixed with a carbon nanotube to form a first photocatalyst solution. For example, placing the titanium source precursor and the carbon nanotube mixed solution a magnetic stirrer is placed in an ice bath at about 4 ° C, and the first conductive material solution is added to be stirred at a high speed for a predetermined time (for example, 1 hour), and the second conductive material solution is also slowly used by a dropper device. The first photocatalyst solution was completed by dropping and stirring for several hours until the color of the solution was changed from transparent to dark green with metallic luster.

In another preferred embodiment of the present invention, a method for manufacturing a mixed crystal phase titanium dioxide immobilized photocatalyst comprising a conductive plastic and a carbon nanotube comprises: adding the first photocatalyst solution to nitric acid to form a first photocatalyst gel. For example, the first photocatalyst solution is placed on a magnet stirrer, and a nitric acid solution (for example, 80 mL of 0.4 M HNO ₃ ) is added, and stirred at a high speed for several hours to a gel form, that is, the first photocatalyst gel is completed. .

In addition, the method for manufacturing a mixed crystal phase titanium dioxide immobilized photocatalyst doped with a conductive plastic and a carbon nanotube according to a second preferred embodiment of the present invention comprises: preparing a carbon nanotube solution. For example, an isopropanol solution and a functionalized CNT (for example, 15 minutes) are mixed and oscillated by an ultrasonic oscillator for a predetermined time (for example, 15 minutes), so that the functionalized CNT is uniformly dispersed in In solution. The functionalized carbon nanotube material comprises a carboxylated carbon nanotube (CNT-COOH), a ruthenium chloride carbon nanotube [CNT-COCl] or a mixture thereof.

The method for manufacturing a mixed crystal phase titanium dioxide immobilized photocatalyst comprising a conductive plastic and a carbon nanotube according to a second preferred embodiment of the present invention comprises: a titanium source precursor material (eg, titanium isopropoxide, TTIP) The carbon nanotube solution is added to form a titanium source precursor and a carbon nanotube mixed solution. For example, TTIP is added to the carbon nanotube solution and oscillated using an ultrasonic oscillator for a predetermined period of time (eg, 15 minutes) such that the TTIP is uniformly dispersed in the solution.

The method for manufacturing a mixed crystal phase titanium dioxide immobilized photocatalyst doped with a conductive plastic and a carbon nanotube according to a second preferred embodiment of the present invention comprises: preparing a conductive material solution, and adding the surfactant to the conductive material solution. For example, an appropriate amount of aniline hydrochloric acid (for example, 0.26 g, 0.52 g, or 1.04 g) is dissolved in a nitric acid solution (for example, 70 mL of 0.4 M HNO ₃ ) and an aqueous surfactant solution (for example, 3 CMC SDS) to prepare a a first conductive material/surfactant solution, that is, a surfactant-containing aniline solution; and then, an appropriate amount of ammonium persulfate [ASP] (for example, 1.14 g) is dissolved in a nitric acid solution (for example, 10 mL of 0.4 M HNO ₃ ) and interfacial activity. The aqueous solution is prepared to form a second conductive material/surfactant solution, that is, a surfactant-containing ammonium persulfate solution.

The method for manufacturing a mixed crystal phase titanium dioxide immobilized photocatalyst doped with a conductive plastic and a carbon nanotube according to a second preferred embodiment of the present invention comprises: the first conductive material/surfactant solution and the second conductive material/ The surfactant solution is added to the titanium source precursor and the carbon nanotube mixed solution to form a second photocatalyst solution. For example, the titanium source precursor and the carbon nanotube mixed solution are placed on a magnet stirrer and placed in an ice bath at about 4 ° C, and the first conductive material/surfactant solution is added to stir at a high speed. For a predetermined time (for example, 1 hour), the second conductive material/surfactant solution is also slowly dropped by a dropper device and stirred for several hours until the color of the solution changes from transparent to dark green with metallic luster. That is, the second photocatalyst solution is completed.

In another preferred embodiment of the present invention, a method for fabricating a mixed crystal phase titanium dioxide immobilized photocatalyst comprising a conductive plastic and a carbon nanotube comprises: adding the second photocatalyst solution to nitric acid to form a second photocatalyst gel. For example, the second photocatalyst solution is placed on a magnet stirrer, and a nitric acid solution (for example, 80 mL of 0.4 M HNO ₃ ) is added, and stirred at a high speed for several hours to gel, that is, the second photocatalyst gel is completed. .

1(a) to 1(e) show that the doped conductive material and the carbon nanotube mixed phase of the preferred embodiment of the present invention are selected from two types of materials [PANi-CNT-COOH/ Schematic diagram of the interaction between TiO ₂ and PANi-CNT-COCl/TiO ₂ ]. Referring to FIGS. 1(a), 1(b) and 1(d), the doped conductive material and the carbon nanotube mixed crystal phase titanium dioxide immobilized photocatalyst according to the preferred embodiment of the present invention are selected to be one. a first photocatalyst material 1 [PANi-CNT-COOH/TiO ₂ ] which forms a CNT-COOH material 1a from a CNT material, and further forms a CNT-COOH/TiO ₂ material 1b from the CNT-COOH material 1a, and The CNT-COOH/TiO ₂ material 1b re-forms the first photocatalyst material 1. Referring to Figures 1(a), 1(c) and 1(e), the doped conductive material and the carbon nanotube mixed crystal phase titanium dioxide immobilized photocatalyst according to a preferred embodiment of the present invention are selected to be a second photocatalyst material 2 [PANi-CNT-COCl/TiO ₂ ], which forms a CNT-COCl material 2a from a CNT material, and further forms a CNT-COCl/TiO ₂ material 2b from the CNT-COCl material 2a, and then The second photocatalyst material 2 is formed by the CNT-COCl/TiO ₂ material 2b.

FIG. 2 is a schematic view showing the addition of a photocatalyst-added photocatalyst to a mixed-phase titanium dioxide doped conductive material and a carbon nanotube according to a preferred embodiment of the present invention. Referring to FIG. 2, in the preferred embodiment of the present invention, the doped conductive material and the carbon nanotube mixed phase titanium dioxide immobilized photocatalyst are selected to add the surfactant to form a third photocatalyst material 3.

FIG. 3 is a schematic view showing a reaction mechanism between a doped conductive material and a carbon nanotube mixed phase titanium dioxide immobilized photocatalyst and a solar light according to a preferred embodiment of the present invention. Referring to FIG. 3, a first photocatalyst material 1 of the preferred embodiment of the present invention is doped with a conductive material 1', and the first photocatalyst material 1 reacts with sunlight, and the first photocatalyst is displayed. The anatase phase of material 1 is converted to the rutile crystal phase.

Figure 4 is a view showing a preferred embodiment of the present invention, a doped conductive material and a carbon nanotube mixed crystal phase titanium dioxide immobilized photocatalyst selected into a photocatalyst gel, and formed on a substrate by a sol-gel coating method. Schematic diagram. Referring to FIG. 4, a preferred embodiment of the present invention selects a substrate 100 comprising a glass material, an activated carbon material, a cerium oxide material, and polymerization. Materials, carbon fiber materials, high-porosity ceramic materials, stainless steel materials or polymeric fiber materials, such as: cotton fibers or carbonized cotton fibers (CCFs). A photocatalyst solution 10 is spin-coated on the substrate 100 to carry out the immobilization technique of the sol-gel method. The immobilization technique of the sol-gel method includes a dip coating method, an ink jet method, a spray coating method, or a spin coating method.

For example, in a preferred embodiment of the invention, polypropylene particles (PP), polyethylene (polythene, PE), polyvinyl alcohol (PVA) or polyaniline (PANI) are selected.

FIG. 5 is a schematic view showing the photocatalyst solution prepared by the doped conductive material and the carbon nanotube mixed crystal phase titanium dioxide fixed photocatalyst in the preferred embodiment of the present invention, and formed on the substrate by hydrothermal method under low temperature and high pressure. . Referring to FIG. 5, the mixed crystal phase titanium dioxide immobilized photocatalyst of the doped conductive material and the carbon nanotube of the preferred embodiment of the present invention is selected by a hydrothermal coating method.

In another preferred embodiment of the present invention, the doped conductive plastic and the carbon nanotube mixed phase titanium dioxide immobilized photocatalyst may be optionally added with an oxidant (for example: hydrogen peroxide, H ₂ O ₂ ) to effectively enhance its catalytic degradation. effect.

The foregoing preferred embodiments are merely illustrative of the invention and the technical features thereof, and the techniques of the embodiments can be carried out with various substantial equivalent modifications and/or alternatives; therefore, the scope of the invention is subject to the appended claims. The scope defined by the scope shall prevail. The copyright limitation of this case is used for the purpose of patent application in the Republic of China.

Claims (10)

A method for manufacturing a mixed crystal phase titanium dioxide immobilized photocatalyst doped with a conductive material and a carbon nanotube, comprising: preparing a carbon nanotube solution, wherein the carbon nanotube solution comprises a carbon nanotube material, and the naphthalene The carbon nanotube material is a monofunctional carbon nanotube; a titanium source precursor material is added to the carbon nanotube solution to form a titanium source precursor and a carbon nanotube mixed solution; preparing a conductive material solution And adding the conductive material solution to the titanium source precursor and the carbon nanotube mixed solution to form a photocatalyst solution. The method of claim 1, wherein the titanium source precursor material is titanium isopropoxide. The method of claim 1, wherein the functionalized carbon nanotube comprises a carboxylated carbon nanotube, a ruthenium chloride carbon nanotube or a mixture thereof. The method of claim 1, wherein the conductive material is a polyaniline material, a polypyrrole material, a polythiophene material or a mixture thereof. The method of claim 1, wherein the conductive material solution is additionally added with a surfactant. According to the method of claim 1, wherein the photocatalyst solution is added to nitric acid to form a photocatalyst gel. A mixed crystal phase titanium dioxide immobilized photocatalyst doped with a conductive material and a carbon nanotube, comprising: an immobilized photocatalyst, which is a titanium dioxide immobilized photocatalyst, and the immobilized photocatalyst has a first predetermined content; one nano carbon a tube material having a second predetermined content, and the carbon nanotube material is a monofunctional carbon nanotube tube; and a conductive material having a third predetermined content and adding a conductive material solution to the a titanium source precursor and a carbon nanotube mixed solution; The conductive material and the carbon nanotube material are doped on the immobilized photocatalyst to obtain a doped titanium dioxide immobilized photocatalyst, and the doped titanium dioxide immobilized photocatalyst is fixed on a substrate. The titanium dioxide-immobilized photocatalyst according to claim 7, wherein the functionalized carbon nanotube comprises a carboxylated carbon nanotube, a ruthenium chloride carbon nanotube or a mixture thereof. The titanium dioxide-immobilized photocatalyst according to claim 7, wherein the conductive material is a polyaniline material, a polypyrrole material, a polythiophene material or a mixture thereof. The titanium dioxide immobilized photocatalyst according to claim 7, wherein the doped titanium dioxide immobilized photocatalyst is additionally added with a surfactant.