KR100844007B1 - The manufacturing method of one-body photoanode - Google Patents

Abstract

A method for manufacturing a one-body photo anode is provided to improve a separate effect of a light catalyst and to fix stably the light catalyst on a supporter by forming a light catalyst on the supporter. A method for manufacturing a one-body photo anode includes a process for forming an oxide layer(12) on a surface of a metal supporter(11) having a function of a light catalyst. The method further includes a process for degreasing a surface of the supporter, a first washing process for washing the degreased surface of the supporter, a process for pickling the supporter having the washed surface, a second washing process for washing the supporter, and a process for processing thermally the supporter under oxidation atmosphere.

Description

The manufacturing method of one-body photoanode

1 is a schematic view showing an embodiment photoanode prepared by the method of the present invention,

  (A) is a cross-sectional view of a photoanode having an oxide layer formed on only one surface thereof,

  (B) is sectional drawing of the photoanode in which the oxide layer was formed in both surfaces.

2 is a schematic structural diagram of an embodiment heat treatment furnace for carrying out the method of the present invention.

3 is a schematic structural diagram of an embodiment anodizing apparatus for implementing the method of the present invention

4 is an embodiment block diagram of the method of the present invention.

5 is an absorption spectrum in the ultraviolet / visible region for photoanode samples.

6 to 8 are X-ray diffraction pattern graphs of the samples of FIG. 5.

9 is a photograph of the surface after washing of Sample 1,

  (A) is 1,000 times the scanning microscope image,

  (B) is 100,000-times scanning microscope image.

10 is a surface photograph after washing of sample 2 and 5% HF pickling,

  (A) is 1,000 times the scanning microscope image,

  (B) is 80,000 times scanning microscope image.

FIG. 11 is a surface photograph after washing of sample 3, pickling 5% HF and heat treatment at 350 ° C. for 1 hour (atmospheric oxidation),

  (A) is 1,000 times the scanning microscope image,

  (B) is 100,000-times scanning microscope image.

12 is a surface photograph after washing of sample 4, 5% HF pickling, anodizing 1 hour and 1 hour 350 ° C. heat treatment (thin film thickness of about 80 nm) in 1% H ₃ PO ₄ ,

  (A) is 1,000 times the scanning microscope image,

  (B) is 100,000-times scanning microscope image.

FIG. 13 shows the surface after washing of sample 5, pickling 5% HF, anodizing in 0.5MH ₃ PO ₄ + 0.14M NaF + 0.1M NaNO ₃ (20V, 1 hour) and heat treatment at 350 ° C. for 1 hour (thin film thickness about 600 nm). As a photo,

  (A) is 1,000 times the scanning microscope image,

  (B) is 80,000 times scanning microscope image.

14 shows the surface after washing of sample 6, 5% HF pickling, anodization (20V, 1 hour) in 0.5MH ₃ PO ₄ + 0.14M NaF + 0.1M NaNO ₃ and heat treatment at 350 ° C. for 5 hours (thin film thickness of about 600 nm). As a photo,

  (A) is 1,000 times the scanning microscope image,

  (B) is 100,000-times scanning microscope image.

15 shows the surface after washing of sample 7, pickling 5% HF, anodizing in 0.5MH ₃ PO ₄ + 0.14M NaF + 0.1M NaNO ₃ (20V, 1 hour) and heat treatment at 450 ° C. for 1 hour (thin film thickness about 700 nm). As a photo,

  (A) is 1,000 times the scanning microscope image,

  (B) is 80,000 times scanning microscope image.

FIG. 16 shows the surface after washing of sample 8, 5% HF pickling, anodization in 0.5MH ₃ PO ₄ + 0.14M NaF + 0.1M NaNO ₃ (20V, 1 hour) and heat treatment at 450 ° C. for 5 hours (thin film thickness of about 600 nm). As a photo,

  (A) is 1,000 times the scanning microscope image,

  (B) is 80,000 times scanning microscope image.

Figure 17 after washing of sample 9, 5% HF pickling, anodic oxidation (30 V, 1 hour) in 0.5 MH ₃ PO ₄ + 0.14 M NaF + 0.1 M NaNO ₃ and heat treatment at 350 ° C. for 1 hour (film thickness about 2,000 nm). As a surface photograph,

  (A) is 1,000 times the scanning microscope image,

  (B) is 80,000 times scanning microscope image.

18 shows the surface after washing of sample 10, pickling 5% HF, anodizing in 0.5MH ₃ PO ₄ + 0.14M NaF + 0.1M NaNO ₃ (30V, 1 hour) and heat treatment at 350 ° C. for 5 hours (thin film thickness of about 618 nm). As a photo,

  (A) is 1,000 times the scanning microscope image,

  (B) is 100,000-times scanning microscope image.

19 shows the surface after washing of sample 11, pickling 5% HF, anodizing in 0.5MH ₃ PO ₄ + 0.14M NaF + 0.1M NaNO ₃ (30V, 1 hour) and heat treatment at 450 ° C. for 1 hour (thin film thickness about 400 nm). As a photo,

  (A) is 1,000 times the scanning microscope image,

  (B) is 80,000 times scanning microscope image.

20, after washing of sample 12, 5% HF pickling, anodization (30V, 1 hour) in 0.5MH ₃ PO ₄ + 0.14M NaF + 0.1M NaNO ₃ and heat treatment at 450 ° C. for 5 hours (film thickness about 2200 nm). As a surface photograph,

  (A) is 1,000 times the scanning microscope image,

  (B) is 80,000 times scanning microscope image.

FIG. 21 is a surface photograph after washing, 5% HF pickling, 0.5 MH ₃ PO ₄ + 0.14 M NaF + 0.1 M NaNO ₃ (20 V, 1 hour) and without heat treatment.

  (A) is 1,000 times the scanning microscope image,

  (B) is 100,000-times scanning microscope image.

FIG. 22 is a surface photograph after washing, 5% HF pickling, 0.5 MH ₃ PO ₄ + 0.14 M NaF + 0.1 M NaNO _{3 after} anodization (30 V, 1 hour) and no heat treatment.

  (A) is 1,000 times the scanning microscope image,

  (B) is 100,000-times scanning microscope image.

FIG. 23 is a graph of EDAX results for the samples of FIG. 5. FIG.

24 is a graph showing the methylene blue photocatalyst resolution of the samples of FIG.

25 is a graph showing the methylene blue photocatalyst resolution according to the commercial Degussa P25 input amount.

                  ((Explanation of symbols for main part of drawing))

           11. Metal Support Layer 12. Metal Oxide Layer

           21. Furnace 31. Counter electrode (cathode)

           32. Electrolytes 33. Anode

The present invention allows photocatalytic materials, which absorb light to generate charge pairs such as electrons and holes, to be formed on the support surface of a metal component having an electron collecting function, thereby overcoming photocatalytic desorption and ultimately The present invention relates to a method for producing a photoanode in which a photocatalyst and a support are integrally bonded, in which photocatalytic activity in response to light is immobilized in a stable state on a support to improve usability.

The rapid industrialization and development of modern society after the Industrial Revolution consisted of fossil fuel as an energy source, but the excessive warming of carbon dioxide caused by the use of fossil fuel not only causes global warming, but also causes various environmental problems. Since the reserves are limited, it is urgent to develop new alternative energy sources.

Therefore, in order to solve various problems caused by the use of fossil fuel as described above and to secure a stable energy source, various studies are being conducted to develop environmentally friendly natural alternative energy sources such as solar, tidal, and wind power. These natural energy sources are very low in energy density, difficult to use immediately, and require large-scale facility investments. Also, current energy levels have low energy conversion rates, which lowers economic efficiency.

The problem of the natural energy sources as described above is a long-term research problem that cannot be solved in a short time, the hydrogen is easy to store, such as fossil fuel, attention has been attracting attention as an energy source hydrogen that can be used immediately as a fuel for automobiles.

Hydrogen can be produced from almost infinite water or organic materials, and there is little pollution except for a very small amount of NO _X during combustion, so that countries around the world can efficiently produce hydrogen and simply store it. It is struggling to develop

The simplest method for producing hydrogen may be a method of electrolyzing water, but the electrolysis method is not only low efficiency, but also requires a separate energy source called electricity, and natural energy Cause The method using solar light also has difficulties in economical use because of its low efficiency at each stage.

In addition to electrolysis, there is a method of obtaining hydrogen by using a photocatalyst. A photocatalyst is a substance having a semiconductor property that can make a large contribution in the environmental purification area such as decomposition of toxic organic substances by converting light energy into chemical energy. As a photocatalyst, a photocatalyst has a characteristic of producing hydrogen by using sunlight or decomposing organic substances, that is, reducing protons (H ⁺ ) and oxidizing organic substances.

The term "photocatalyst" having the above characteristics is used to refer to a catalyst for accelerating a photoreaction. In order to become a photocatalyst, it is necessary to satisfy the conditions as a general "catalyst" and directly participate in the reaction. Not only should it be consumed, but it should also be able to accelerate the reaction rate by providing a different reaction path than the existing photoreaction.

In this case, to accelerate the reaction rate means that the turnover ratio per active site must be greater than '1.0'. To satisfy this condition, the photocatalyst must be optically active. In order to activate the photocatalytic photocatalyst, light energy of more than band energy (or band gap energy, E _g ) is required.

The band energy is the difference between the valence band as the highest energy band occupied by the electron and the conduction band as the lowest energy band not occupied by the electron. Is a forbidden interval that cannot be occupied, and is the minimum energy that can produce an electron / hole pair to participate in the reaction by exciting electrons in the common band.

Photocatalyst materials having such characteristics are generally metal oxides of semiconductor nature, such as tungsten trioxide (WO ₃ ), zinc oxide (ZnO), silicon carbide (SiC), cadmium sulfide (CdS), Although gallium arsenide (GaAs), etc., generally, titania having an anatase structure is used, which is not only excellent in terms of efficiency as a photocatalyst but also relatively inexpensive, and has a smooth supply and no photocorrosion. Because it was confirmed.

However, in the case of titania, hydrogen is hardly generated in terms of relative energy position, and another photocatalytic material designed for hydrogen generation, perovskite, has a problem in that the manufacturing method is complicated and the reproducibility is poor. .

Therefore, as a method for producing hydrogen, photocatalytic materials and photoelectrochemical approaches have been extensively studied. However, hydrogen production using photocatalysts has high efficiency, while electrodes are expensive and electrochemical. Not only is it unstable, but it is difficult to expand its size, and thus the progress is hardly achieved due to various problems.

In general, the present invention is prepared by the photocatalyst in the form of particles or colloidal solutions, and thus, in the field of energy conversion and environmental purification, it is difficult to immobilize when immobilized on a specific support, and many restrictions such as easy detachment after immobilization. This invention was devised to solve all the problems of the conventional photocatalyst. The photocatalyst, which generates charge pairs such as electrons / holes through light absorption, is stably generated on the surface of the support having the electron collecting function, thereby generating hydrogen. It is an object of the present invention to provide a photoanode, that is, a photosensitive electrode in which the photocatalyst oxide and the support are integrally fixed so as to be efficiently generated and used stably in various fields.

The above object of the present invention is achieved by an atmospheric oxidation or anodization reaction.

The integrated photoanode manufactured by the method of the present invention is formed by immobilizing a photocatalyst oxide on a metal support, and is characterized in that hydrogen can be efficiently generated by improving the stability of the photocatalyst.

As described above, the photoanode according to the method of the present invention is a structure in which the photocatalytic material titania is integrally bonded to the surface of the metal titanium (Ti) as a support through atmospheric oxidation or anodization, as shown in FIG. It consists of a plate-shaped metal titanium support 11 and the titanium metal oxide layer 12 formed in at least one surface of both surfaces of the support 11.

That is, since the integrated photoanode is bonded to the support 11 and the oxide layer 12 in a stacked state, the redox reaction is separated by inducing electrons to move in one direction through a Schottky barrier. It can be caused by.

In this case, the metal oxide layer 12 is produced through a method of heat treating the pickled support 11 in an oxygen atmosphere, or electrochemically oxidizing a titanium metal plate using a copper or platinum coil as a counter electrode. The method of the present invention is as follows.

A conductive metal support such as titanium is washed with a detergent, and the washed support is first pickled with 3 to 7 vol.% Of inorganic acid solution such as nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid, or after 40 to 50 vol.% HF, Secondary pickling treatment was performed on a mixed solution of 60 to 70 vol.% HNO ₃ and 25 to ₃₀ vol.% H ₂ O _{2 at} a volume ratio of 1: 1 to 2: 1 to form naturally produced rutile ( Titatia of rutile structure is removed, and the pickling process produces a dangling bond, which is the outermost electron of titanium atoms that are not completely bonded and remain redundant.

At this time, the acid solution used during the first pickling is an inorganic acid, when an organic acid is used, a nonuniform oxide film may be formed during heat treatment. If the concentration of the inorganic acid is less than 3%, the etching of the parasitic oxide film is uneven. If the concentration exceeds 7%, the titanium plate may dissolve.

In addition, the solution for secondary pickling is a mixed solution of inorganic acid and strong oxidizing agent, the nitric acid solution can be used up to twice the volume for hydrofluoric acid and hydrogen peroxide.If this ratio is not reached, the etching of the already formed oxide film is uneven. If the ratio is exceeded, the titanium plate may be dissolved.

After that, as shown in FIG. 2, the oxygen per unit surface area (1 cm 2) of the support to be oxidized at a flow rate of 40 to 60 ml / min in the tubular furnace 21 having conditions capable of adjusting the atmospheric gas and the treatment temperature. Heat treatment at 350-450 DEG C while supplying, or as shown in Figure 3, using a copper or platinum coil as a negative electrode 31 as a counter electrode, phosphoric acid (H ₃ PO ₄ ), sodium fluoride (NaF) and sodium nitrate (NaNO ₃ ) The oxidized surface of titanium, which is the anode 33, is oxidized in an appropriately mixed electrolyte 32, and then subjected to heat treatment in the same manner as above to form the integrated photoanode of the present invention.

At this time, if the amount of oxygen per unit surface area (1 cm 2) of the support supplied to form the oxidation atmosphere during the heat treatment is less than 40ml / min, the oxide layer formation time is delayed and the oxide may be incompletely formed, 60ml If it exceeds / min, no further effect is seen, and in the case of the heat treatment time, it varies depending on the oxygen supply amount, the heat treatment temperature, the support surface area, etc., and generally takes about 1 to 10 hours.

As described above, the method of manufacturing the integrated photoanode of the present invention includes the steps of: degreasing the support; First washing with water; Pickling; Washing with water secondly; It consists of sequential processes such as heat treatment in an oxidizing atmosphere, or heat treatment after anodizing. In the degreasing step, oil and various contaminants on the surface of the support are separated and removed, and in the first washing step, the surface of the support is removed. The remaining separation contaminants and degreasing agents are washed away, and the pickling step removes the parasitic oxide layer on the surface of the support.

In addition, after removing the separated oxide and the acid remaining on the surface of the support in the second washing step to form an appropriate oxide layer in the heat treatment step or anodization process.

At this time, the degreasing treatment and washing step is a process for removing oils and other contaminants adhering to the surface of the material, and degreasing may be performed by using a general detergent, and various other methods such as steam degreasing or solvent or alkali cleaning. If the scale is solid, sand blasting or dye bath treatment may be performed before pickling.

The heat treatment performed after the anodic oxidation is a process for crystallizing the amorphous oxide layer formed by the anodic oxidation with anatase. If the heat treatment temperature is less than 350 ° C., crystallization to the anatase structure is difficult and the temperature exceeds 450 ° C. In this case, a rutile structure may be generated.

In addition, the voltage applied to the positive electrodes 31 and 33 in the anodizing step before heat treatment is suitably in the range of 15 to 35 V. When the voltage is less than 15 V, the generation of oxide becomes irregular, and when the voltage exceeds 35 V, the oxide This is because desorption of the layer is caused, and the time required for anodic oxidation is approximately 2 to 3 hours or less.

At this time, the electrolyte for the anodic oxidation, 13 to 15 parts by weight of sodium fluoride and sodium nitrate each mixed with respect to 100 parts by weight of phosphoric acid, if the content of the sodium fluoride is less than 13 parts by weight may form a tubular oxide film If it exceeds 15 parts by weight, it is transformed into an uneven form, and in the case of sodium nitrate, if the content is less than 13 parts by weight, visible light response may occur, but if it exceeds 15 parts by weight, recombination of the generated charge pairs may be promoted to decrease efficiency. Can be.

According to the above process, an oxide layer having proper photoresist ability can be generated on the surface of titanium, and the oxide layer formed on the surface of titanium, which is a support, serves to generate electrons by receiving sunlight, ultraviolet light, or some visible light. do.

In this case, when the second pickling was performed, the result of observing with an electron microscope showed no difference as compared with the case where only the first pickling was performed or anodized.

Then, the sodium fluoride as the electrolyte used for the anodic oxidation is for supplying the fluorine ions required for producing the titania structure in the form of a tube.

In addition, the phosphate and sodium salts are adsorbed to titania formed on the surface of the support by anodic oxidation. At the time of heat treatment, the phosphate and sodium salts form oxygen vacancies that can be reacted with oxygen to induce visible light regions. This is to obtain a doping effect of nitrogen or phosphorus on the structure.

In other words, the oxygen band which is located below 0.75 to 1.18 eV than the titania conduction band and eventually causes light absorption from the visible light region having a wavelength of about 614 nm, and a new band within the band gap energy of the titania structure by doping with nitrogen or phosphorus component By forming the spacing energy, a response of visible light is caused.

The Schottky barrier created between the metal and the semiconductor oxide is created when the Fermi energy level is in equilibrium when the two materials come in contact, causing electrons in the oxide conduction band to move to the lower equilibrium level when the oxide is illuminated. As a result, the efficiency of use of the photocatalyst is increased by preventing recombination of parasitic charge pairs.

In the case of a photocatalyst, the kind is not limited, but from the viewpoint of price and performance, at present, titania having an anatase structure is most preferred, and a solar spectral region absorbed by nitrogen substitution or the like is The increase in charge pair density results in an increase in the efficiency of the photocatalyst.

The methylene blue dye, which is a kind of dye widely used in the photoactivity investigation study, was decomposed using the integrated photoanode prepared by the method of the present invention as described above. Let's look at an example.

Example 1

An integrated photoanode sample was prepared using a 0.5 mm thick titanium plate having an area of 4 cm ² (2 cm × 2 cm). The preparation conditions are shown in Table 1 below.

division          Atmospheric acidification   Detergent cleaning only  Only detergent cleaning and pickling       350 ℃       450 ℃  1 hours  5 hours  1 hours  5 hours     No treatment    3             -     One       2     Anodic oxidation 20V (1% H ₃ PO ₄ )    4                - 20V (0.5MH ₃ PO ₄ + 0.14M NaF + 0.1M NaNO ₃ )      5      6      7      8 30V (0.5MH ₃ PO ₄ + 0.14M NaF + 0.1M NaNO ₃ )      9      10      11      12

* 'Number' in Table 1 is 'sample number'.

* Detergent wash and 5% HF pickling for numbers 3-12.

20V, 30V; Voltage applied to anodic oxidation.

Absorption spectra (UV / Vis spectroscopy), surface morphology (scanning electron microscope), component analysis (energy dispersion spectroscopy), and crystal structure (X-ray diffractometer) in the ultraviolet / visible region for each of the 12 samples of Table 1 above. ) And the like.

When comparing the absorbance of each sample of Samples 1, 5 and 6, and the typical Titania photocatalyst Degussa P25 products, the Ti metal in the 400 to 500 nm region when only washed, as shown in FIG. The titanium plate, which showed a slight absorption, shows high absorption in the visible region through anodic oxidation and heat treatment, and it can be seen that absorption in the slightly transitioned ultraviolet region also occurs.

In addition, the crystal structure of titania in each sample was analyzed using an X-ray diffractometer. As shown in FIGS. 6 to 8, samples 1 to 5 had anatase with a diffraction angle 2θ at around 25.2 °. On the other hand, in case of samples 6 to 12, there was some amount difference, but it was confirmed that the characteristic peak of anatase appeared clearly.

In addition, the surface shape of the samples was confirmed by using a scanning microscope, and the scanning microscope image photographs of the surfaces of each sample are shown in FIGS. 9 to 22. In the case of Samples 1 and 2, which were washed only or pickled after washing, A smooth surface was observed, and it was confirmed that elliptical grains having a size of about 100 nm were produced in the air-oxidized sample 3, and in the case of sample 4 heat-treated after anodization, the size of the circular grains was reduced to around 10 nm. .

Since no fluoride was used until sample 4, a thin layer of titania layer appeared to be formed. For samples 5 to 8, a tube having a diameter of 80 to 100 nm and a length of 600 to 700 nm was formed. It was confirmed that titania was produced.

In the case of samples 9 to 12, the anodic oxidation voltage was 30 V, and the tube was damaged in a large amount, or when the processing temperature was high, it was formed in the form of a thick thin film without pores, and except for the sample 9, it was confirmed that titania of the anatase structure was produced. There was.

As a result, it can be seen that the anodization voltage plays an important role in the morphology of the thin film, and the formation of the anatase crystal structure is an important variable for the heat treatment temperature and time.

In addition, when looking at the titania, the mass composition of oxygen, and the oxygen / titania element composition ratio of the samples, the process of forming an oxide layer can be confirmed. As shown in FIG. 23, the mass ratio of titania is increased from sample 1 to 12. As the mass ratio of oxygen decreases and the mass ratio of oxygen increases, it can be confirmed that the atomic composition ratio (atomic O / Ti) of oxygen and titania is close to 2 (the atomic ratio between constituent elements of TiO ₂ is O / Ti = 2).

In the case of Sample 12, the thickness of the thin film was about 2.2 μm and the oxygen / titania ratio was calculated to be almost 2 due to the relative harsh conditions. Therefore, it can be estimated that the analytical depth of the X-ray diffractometer is about 2 μm. Relatively, in the case of other samples having a thickness of 1 μm or less, the composition ratio of oxygen and titania element was slightly higher than 1 because the titanium support was included in the X-ray diffraction measurement, but the tube or thin film The composition ratio of oxygen and titania element of the oxide layer is considered to be close to two.

Example 2

Light was irradiated to samples prepared using a solar simulator light source having a spectrum similar to sunlight, and a state in which methylene blue aqueous solution was photoly decomposed by each sample was investigated.

200 mL of aqueous solution containing 10 ppm of methylene blue was placed in a reactor having a volume of about 278 mL (inner diameter 6.34 cm and height 8.8 cm), and the plate-shaped sample prepared in the size of 2 cm x 2 cm was placed at 0.5 cm below the surface of the aqueous solution, and then shot. The light was irradiated to the sample using a simulator, and the absorption rate of 661 nm, which is the main characteristic wavelength peak of methylene blue, was observed at regular time intervals.

That is, as can be seen in Figure 24, compared with the general commercial photocatalyst P25 having a first-order reaction, the sample has a low activity, that is, the '0' order of reaction, which can be described as follows.

In order to compare with 0.2g of P25 powder photocatalyst used, the amount of TiO ₂ formed on the surface of the sample having an area of 4 cm ₂ with TiO ₂ thin film thickness of 1 to 2 μm and TiO ₂ density of 3.9 g / cm ³ was calculated. If you look,

(Amount of TiO ₂ on the plate surface produced)

= (4 × 10 ^-4 m ² ) × {1 (or 2) × 10 ^-6 m} × (3.9 × 10 ⁶ g / m ³ )

= (15.6-31.2) x 10 ^-4 g

= (1.6-3.1) mg

Becomes

That is, it can be estimated that the sample is about 1/100 of the amount of P25 actually used.

In addition, after confirming the difference of the relative amount as described above, when the photocatalytic reaction follows the Langmuir-Hinshelwood reaction formula as shown in Equation 1 below, if the concentration of the substrate is low, that is, 0.2g of P25 In the case of using KC 《1, since r = kC, the reaction rate is first with respect to the concentration, and when the concentration is high, that is, when the sample is used, it is with r = k. Can be explained.

Where r is the reaction rate, k is the rate constant, and C is the concentration of the substrate.

When the photolysis was performed only by the solar simulator, the concentration of methylene blue was almost unchanged. Therefore, the photolysis did not occur naturally.In the case of P25, 0.2 g / 200 mL of the methylene blue had a characteristic characteristic of about 1 hour. It was confirmed that the peak (661 nm) disappeared.

In the case of the prepared samples, about 30% of the samples were removed for 4 hours, and 40% of the samples were decomposed in 3 hours when the samples were decomposed using four samples. The concentration of methylene blue) is large and follows the '0' equation, and the decomposition of the trace amount of harmful substances with low concentration is followed by the first reaction equation, and thus the rapid decomposition tendency can be shown. Is shown in FIG. 25.

25, it can be seen that the smaller the amount of P25 introduced when decomposing methylene blue at the same concentration, the "0" order reaction tendency appears.

As described above, the integrated photoanode manufactured by the method of the present invention can solve the limitation of utilization and manufacturing difficulties of the conventional photocatalytic material in the form of particles or colloids, as well as purifying the environment using photo-stress. And energy conversion capacity is maintained as it is, not only to maximize its utilization, but also ultimately, electrochemical photoanode or electron-hole photovoltaic or independent cell-type positive electrode, environmental application material There is an advantage that can be utilized as such.

Claims (8)

In the method of forming an oxide layer on the surface of the metal support serving as a photocatalyst, Degreasing the surface of the support; Firstly washing the denitrated support; Pickling the first washed support; Second washing the pickled support; A method of manufacturing an integrated photoanode, comprising the step of heat-treating a secondary flushed support under an oxidizing atmosphere. In the method of forming an oxide layer on the surface of the metal support serving as a photocatalyst, Degreasing the surface of the support; Firstly washing the denitrated support; Pickling the first washed support; Second washing the pickled support; Anodizing the secondary flushed support; A method of manufacturing an integrated photoanode, comprising the step of heat-treating an anodized support. The method of claim 1 or 2, wherein the support is one of metal photocatalysts including metal titanium. The method of claim 1 or 2, wherein the pickling step, the washed support, Sedimentation in inorganic acid solution such as nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid of 3-7 vol. Alternatively, the washed support is immersed in a solution of inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid, etc. in _{3 to 7} vol.%, And then 40 to 50 vol.% HF solution, 60 to 70 vol.% HNO ₃ solution, and 25 to 30 vol.% H. _{The 2} O ₂ solution was mixed with a mixture of 40 to 50 vol.% HF solution: 60 to 70 vol.% HNO ₃ solution: 25 to 30 vol.% H ₂ O ₂ solution so that the volume ratio was 1: 1 to 2: 1, respectively. Method of manufacturing an integrated photoanode, characterized in that any one of the step of secondary deposition. The method of claim 1 or 2, wherein the heat treatment step, A method for producing an integrated photoanode, which is carried out in an oxidizing atmosphere of 350 to 450 ° C. The method of claim 5, wherein the oxidizing atmosphere, A method for producing an integrated photoanode, characterized in that it is formed by supplying oxygen per unit surface area (1 cm 2) of a metal support at a flow rate of 40 to 60 ml / min. The method of claim 2, wherein the anodic oxidation step, A copper or platinum coil is used as a cathode 31 as a counter electrode, a mixture of phosphoric acid (H ₃ PO ₄ ), sodium fluoride (NaF), and sodium nitrate (NaNO ₃ ) is used as an electrolyte 32, and a metal support is used as an anode ( 33), wherein a voltage of 15 to 35 V is applied between two electrodes. The method of claim 6, wherein the electrolyte, A method for producing an integrated photoanode, characterized in that 13 to 15 parts by weight of sodium fluoride and sodium nitrate are respectively mixed with respect to 100 parts by weight of phosphoric acid.

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