CN100408166C - AgTO2Visible light response photocatalysis material of type composite oxide and application thereof - Google Patents

Abstract

AgTO₂Visible light response photocatalysis material of type composite oxide, which has the general formula of AgTO₂A photocatalytic material comprising the compound oxide semiconductor shown In the following formula (wherein T represents Al, Ga, In, Cr, Fe, Co, Ni). And can be doped and modified in AgTO₂In the presence of a certain amount of metal, including: alkali metal, alkaline earth metal, transition metal, Ge, Sn, Pb, Sb or Bi, and the doping amount is 0.1-10 wt% by using the oxide, hydroxide, various inorganic salts and organic salts of the above metals as raw materials. The compound oxide semiconductor can be used for photocatalytic decomposition of harmful chemical substances. When the photocatalyst is used as a photocatalytic material for decomposing harmful chemical substances, the photocatalyst is characterized in that: under the irradiation of light including ultraviolet light and visible light, harmful chemical substances can be decomposed and removed efficiently.

Description

AgTO2 Composite Oxide Visible Light Responsive Photocatalytic Material and Its Application

1. Technical field

The invention relates to a photocatalytic material (also known as photocatalyst). Especially visible light-responsive photocatalytic materials, which are AgTO ₂ composite oxide (also known as multi-element metal oxide) semiconductor materials composed of Ag and another metal (common valence is +3) and their applications.

2. Technical background

In the 20th century, the rapid economic growth and the take-off of large-scale industrial production brought negative effects—the earth’s ecological environment is getting worse and worse, and there is a shortage of ore energy such as oil and coal. Needless to say, environmental hormones such as dioxane, pesticides and odorous substances in water and air also threaten people's safe and comfortable life. In the 21st century, governments of various countries have been fully aware of environmental and energy issues, and raised environmental purification, new energy development, energy efficient utilization and conservation to a strategic level that is related to the survival and development of the country. Therefore, related research in this area and Technological development has attracted much attention.

The use of photocatalytic technology to purify the environment is a brand new "green technology". Due to its low energy consumption, it relies almost entirely on solar energy, and the secondary pollution is almost zero (other pollutants are not easily produced during the environmental purification process). It has been paid more and more attention by the governments of various countries, and has become a research hotspot in the academic and industrial circles of various countries.

The photocatalytic material is an oxide semiconductor material. Using the properties of the semiconductor itself, the following reaction can occur under light conditions: when the photocatalytic material absorbs photons exceeding its band gap energy, holes and electrons are generated, and these holes The holes and electrons move from the inside of the catalyst to the surface. Because the holes and electrons have strong oxidation and reduction capabilities, they can oxidize and reduce the chemical substances around them. Here, the important characteristics of oxide semiconductor photocatalytic materials are the size of their bandgap and the energy levels of conduction and forbidden bands. The holes in the valence band of oxide semiconductors have a very strong oxidation ability, which can oxidize electron donors such as water and various organic substances, while the conduction band electrons generated at the same time need to be consumed by reducing oxygen in the air. That is to say, the prerequisite for the photocatalytic material to react is that its energy band structure must match the oxidation potential and reduction potential of the reactants (water, organic matter and oxygen).

Photocatalytic materials can effectively remove harmful substances and sterilize the air under light irradiation: VOCs (volatile organic compounds in the air, including alcohol gases, aldehyde gases, volatile ketone gases, volatile benzene series, etc. Gas), sulfide, nitrogen oxides are directly oxidized and decomposed into carbon dioxide, water or other non-toxic and harmless substances; it can efficiently destroy the cell membranes of various bacteria, coagulate the proteins of various viruses, and achieve the purpose of sterilization. In foreign countries, it has been widely used in homes, office buildings, conference rooms, indoor public places, hospital wards, kindergartens, schools, computer rooms, and automobiles, trains, ships, and aircraft vehicles. At present, titanium dioxide (TiO ₂ ) with stable chemical properties is the main research object, and its wide industrial application is greatly restricted. The main problems include: 1. The quantum yield is low, the overall reaction rate is slow, and it is difficult to process large quantities and High concentration of industrial waste gas and wastewater; 2. Low utilization rate of solar energy. Since the band gap of titanium dioxide is 3.2eV, it can only show activity under the irradiation of ultraviolet rays shorter than 400nm, so it can only absorb and utilize the ultraviolet part of sunlight , cannot absorb visible light, so it can only work outdoors or in places with ultraviolet lamps. The sunlight entering the earth's surface reaches the maximum radiation intensity near the visible wavelength of 500nm, and the energy in the range of visible light with a wavelength of 400-750nm is 43% of the total solar energy. The energy in ultraviolet light with a wavelength below 400nm is about 4%. If the wavelength range absorbed by the material can be expanded to effectively utilize visible light, the efficiency of photocatalytic materials will be significantly improved. Therefore, the development of high-efficiency semiconductor photocatalytic materials with high quantum yields that can be excited by visible light in the solar spectrum is the key to solving the current problems in photocatalytic technology.

3. Contents of the invention

The purpose of the present invention is to develop a series of photocatalytic materials, which can not only absorb ultraviolet light in sunlight, but also absorb visible light, and can efficiently generate photocatalytic reactions. By illuminating the catalyst, it can decompose harmful substances, thereby providing a method for purifying and treating harmful substances. The research group that proposed the present invention has been devoting itself to the research of environmental pollution control, proposed various schemes for the control and control of pollution using photocatalytic materials, and developed a number of inventions.

Technical solution of the present invention is:

1. The general formula is AgTO ₂ composite oxide visible light responsive photocatalytic material, where T represents Al, Ga, In, Cr, Fe, Co, Ni elements, including semiconductor materials AgAiO ₂ , AgGaO ₂ , AgInO ₂ , AgCrO _2. AgFeO ₂ , AgCoO ₂ , AgNiO ₂ .

2. Synthesis method of AgTO ₂ type composite oxide visible light responsive photocatalytic material. Using oxides, hydroxides, various inorganic salts and organic salts of Ag and metal T as raw materials, according to the molar ratio of Ag and metal T 1:1, according to the following preparation method, using different process conditions, prepared Orthorhombic or hexagonal AgTO ₂ :

(1) Ion exchange method: firstly, the corresponding precursor samples LiTO ₂ , NaTO ₂ , KTO ₂ (T=Al, Ga, In, Cr, Fe, Co, Ni) should be synthesized. Li ₂ CO ₃ and T ₂ O ₃ (T=Al, Ga, In, Cr, Fe, Co, Ni) was reacted to prepare LiTO ₂ at a reaction temperature of 500-1200°C (different sintering temperatures were used depending on the precursor material), sintered for 12 hours, and then Mix and grind LiTO ₂ , AgNO ₃ , and KNO ₃ in a certain proportion (dry grinding). After the grinding is completed, transfer the mixed sample to a crucible. Different sintering temperatures) sintered for 12 hours to obtain samples, washed away the soluble matter with distilled water to obtain AgTO ₂ samples, and dried the samples for later use.

(2) Hydrothermal synthesis method: use oxides and hydroxides of Ag and metal T (+3 valence) as raw materials, and put them into the Teflon autoclave liner according to the molar ratio of Ag and metal T in a ratio of 1:1 Add a certain amount of NaOH as an additive, then add a certain amount of water, put the autoclave liner into the autoclave, tighten the lid of the autoclave, keep it warm for 5-20 hours at 120°C-200°C, take it out The samples were then dried for later use.

(3) Sol-gel synthesis method: using soluble salts of Ag and metal T (+3 valence) (including soluble in water or soluble in organic solvents) as raw materials, according to the molar ratio of Ag and metal T 1:1 ratio of raw materials , water or organic matter as a solvent, add an appropriate complexing agent, dry the sol in an oven to become a gel, put the gel in an electric furnace, keep it at 300°C for 3 hours, and then in a reducing atmosphere, heat it at 400°C- Sintering at 1200°C (different sintering temperature according to different materials) for 3-10 hours, different sintering temperature and time can prepare nano AgTO ₂ samples with different particle sizes.

(4) Co-precipitation method: using soluble salts of Ag and metal T (+3 valence) (including soluble in water or organic solvents) as raw materials, according to the molar ratio of Ag and metal T 1:1 ratio of raw materials, water or The organic matter is a solvent, adjusting the pH value to be greater than 10 can cause Ag ⁺ and metal T ions to precipitate, filter out the precipitate, and sinter at 400°C-1200°C (different sintering temperatures are used according to different materials) in an electric furnace under a reducing atmosphere for 3 -12 hours, different sintering temperature and time can prepare nano-AgTO ₂ samples with different particle sizes.

For the method of (1)-(4) described in 2, it is recommended to use (1) ion exchange method, because most of the metal elements T have multiple valences, and the ion exchange method can be used to control the metal element T valence in the precursor sample. The +3 valence also ensures the +3 valence in AgTO ₂ , making its crystal structure controllable and reducing defects inside the crystal.

3. Doping modification method of visible light-responsive photocatalytic material of AgTO ₂ type composite oxide. A certain amount of metal can be doped in AgTO ₂ to realize the modification of properties such as stability and light resistance. These metals include: alkali metals, alkaline earth metals, transition metals, Ge, Sn, Pb, Sb, Bi. The above-mentioned metal oxides, hydroxides, various inorganic salts and organic salts are used as raw materials to realize doping modification, and the doping amount is 0.1%-10% (mass fraction). The preparation process is as follows:

For method (1)-(4) described in 2, divide into three groups and realize by the following methods:

(1) For the ion exchange method, doping is carried out when the precursor sample is prepared, and oxides, hydroxides or simple metals containing doped metals are added to Li ₂ CO ₃ and T ₂ O ₃ (T=Al, Ga , In, Cr, Fe, Co, Ni) mixture, the precursor preparation is carried out, and then the preparation process described in (1) in 2 can be implemented.

(2) For the hydrothermal synthesis method, add oxides, hydroxides or simple metals containing doped metals to the raw materials according to the doping amount, and implement according to the preparation process described in (2) in 2.

(3) For the sol-gel synthesis method and the co-precipitation method, add soluble salts containing doping metals (including soluble in water or soluble in organic solvents) to the raw materials according to the doping amount, according to 2 in (3) (4) ) The preparation process described in can be implemented.

4. Preparation of nano AgTO ₂ , AgTO ₂ doped modified materials.

The particle size range of the samples prepared as described in 2 and 3 is usually 100nm-2000nm. When it is necessary to disperse the material into the paint, paint, or coat and print on the surface of different materials to prepare various films or surface layers, such as Glass, steel plate, plastic, rubber, paper, wood, aluminum plate, ceramics, pottery, cloth, as well as the exterior and interior surfaces of buildings usually require the preparation of nanometer AgTO ₂ and AgTO ₂ doped modified materials. There are many physical or chemical methods, but the method of ball milling is the best. Generally, the sample is ball milled for half an hour to 50 hours, and more than 50 hours may lead to changes in the crystal structure of the material and a decrease in performance. Finally, a powder with a particle size of 10nm-100nm can be obtained, which is also the optimal particle size range of the particles.

5. Preparation of composite materials of AgTO ₂ type composite oxide visible light responsive photocatalytic materials.

(1) Using AgTO ₂ or doped modified materials prepared by 2, 3, 4 as the main material, the following nano-metal particles can be supported (growth) on its surface: Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ru, Co, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Ge, Sn, Pb, Sb, Bi, prepared AgTO ₂ or AgTO ₂ doped The composite material M/AgTO ₂ or M/(AgTO ₂ doped modified material) (M=metal) with hetero-modified material as the main material can further improve the catalytic efficiency, using soluble salts containing the above-mentioned metal elements as raw materials, The loading amount is 1%-10% (mass fraction). The specific method is as follows:

With AgTO ₂ or AgTO ₂ doped modified material as the main material, with Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ru, Co, Ni, Pd, Pt, Cu, Ag, Au , Zn, Cd, Al, Ga, In, Ge, Sn, Pb, Sb, Bi soluble salts are the raw materials of the loading materials, these soluble salts are first dissolved and configured into a solution of a certain concentration, according to the loading ( Generally, a certain volume of solution is measured according to the mass fraction) and ground together with the main material. After grinding, it is placed in an oven for drying, and then the powder is placed in a tube furnace and treated with a suitable atmosphere for a certain period of time. M/AgTO ₂ , M/(AgTO ₂ doped modified material) composite (M=metal).

(2) Using AgTO ₂ or doped modified materials prepared by 2, 3, 4 as the main material, the following nano-metal oxide particles can be supported (grown) on its surface: transition group metal oxides, Al ₂ O ₃ , Ga ₂ O ₃ , In ₂ O ₃ , GeO ₂ , SnO ₂ , PbO, PbO ₂ , Sb ₂ O ₃ , Sb ₂ O ₅ , Bi ₂ O ₃ , Bi ₂ O ₄ , prepared M _x O _y /AgTO ₂ or M _x O _y / (AgTO ₂ doped modified material) composite material (M = metal), which can further improve the catalytic efficiency, using soluble salts of metal elements containing the above oxides as raw materials, with a loading capacity of 1 %-10% (mass fraction). The specific method is as follows:

Using AgTO ₂ or AgTO ₂ doped modified materials as the main material, and soluble salts of transition metals, Al, Ga, In, Ge, Sn, Pb, Sb, Bi as the raw materials of the loading materials, these Soluble salts are dissolved and configured into a solution with a certain concentration. Measure a certain volume of the solution according to the loading capacity (generally by mass fraction) and grind it with the main material. After grinding, put it in an oven for drying, and then put the powder into a tube furnace Treat in a suitable atmosphere for a certain period of time to obtain M _x O _y /AgTO ₂ , M _x O _y /(AgTO ₂ doped modified material) composite materials (M = metal).

6. AgTO ₂ , AgTO ₂ doped modified material, M/AgTO ₂ , M/(AgTO ₂ doped modified material), M _x O _y /AgTO ₂ , M _x O _y /(AgTO ₂ doped modified material material) film preparation method.

The preparation of powder materials into film materials can save the amount of raw materials and expand the application range of materials. For AgTO ₂ , AgTO ₂ doped modified material, M/AgTO ₂ , M/(AgTO ₂ doped modified material), M _x O _y /AgTO ₂ , M _x O _y /(AgTO ₂ doped modified material ) of the thin film, the method is as follows:

(1) The powder prepared by 2, 3, 4, 5 is added with solvent, binder, etc. to make a slurry, and the slurry is directly coated on the substrate by the Doctor Blade Method, and the Sintering at ℃ for 2-5 hours can produce a thin film.

(2) The powders prepared by 2, 3, 4, and 5 can also be prepared by physical methods (evaporation coating, sputtering coating, etc.) to prepare AgTO ₂ , AgTO ₂ doped modified materials, M/AgTO ₂ , M /(AgTO ₂ doped modified material), M _x O _y /AgTO ₂ , M _x O _y /(AgTO ₂ doped modified material) thin film.

(3) It is also possible to use chemical methods, such as the sol-gel method, to prepare AgTO ₂ or AgTO ₂ doped modified material films, and then support (grow) metal or metal oxide nanoparticles on the film surface .

7. Disperse the composite oxide semiconductor photocatalyst materials of the above 2, 3, 4, 5 into coatings and paints, the addition amount is 0.2%-2% (mass fraction), or add different dispersants and solvents, coat Coated or printed on the surface of different materials to prepare various films or surface layers, such as glass, steel plate, plastic, rubber, paper, wood, aluminum plate, ceramics, pottery, cloth surface, the coating amount is 100mg/m ² , so that These materials become environmentally friendly products.

8. Put the powder material or film material prepared in 2, 3, 4, 5, and 6 above into a special environmental purifier for use, and determine the amount of addition as required to achieve environmental purification.

The features of the present invention are:

1. High catalytic efficiency. On the one hand, it is manifested in high visible light photoresponsiveness: the present invention has developed a new type of photocatalytic material that is completely different from the photocatalytic materials developed in the past, because the holes and electrons excited by the photocatalytic material need to be transported from the inside of the catalyst to the surface To be used, some energy needs to be consumed in the transport of holes and electrons, so some narrow bandgap materials (bandgap less than 1.6eV) cannot show high photocatalytic activity, even if they can absorb long-wavelength light , the energy of this part of light can only provide the energy for transporting holes and electrons, but cannot provide the energy for the photocatalytic reaction, and the AgTO ₂ type composite oxide new photocatalytic material developed by the present invention has an energy band gap of 1.6eV In the range of -2.8eV, most of them can strongly absorb visible light, and the wavelength range of light absorption of some materials almost covers the entire visible light part. At the same time, due to its special crystal structure, the energy consumed in transporting holes and electrons is very low. These two reasons determine the high visible light photoresponsiveness of the material and show high catalytic activity.

2. Diversity of preparation methods. Whether a material is practical or not depends on its synthetic method. The feasibility of diversified preparation determines that the material can be prepared from different raw materials, so the production can not be affected by regional differences, and cheaper raw materials can be selected to reduce the production cost. cost. The AgTO ₂ composite oxide novel photocatalytic material developed by the present invention can be prepared by various methods, such as ion exchange method, hydrothermal synthesis method, sol-gel synthesis method, co-precipitation method and the like. According to the different preparation methods, the raw materials can be Ag and another metal oxide, hydroxide, various inorganic salts and organic salts as raw materials.

3. Universal applicability to organic pollutants. It can photocatalytically degrade harmful organic pigments: azo dyes, nitro dyes, sulfur dyes, anthraquinone dyes, etc. It can photocatalytically degrade volatile harmful organic gases: alkanes, alkenes, alkynes, alcohols, aldehydes, ketones, benzene and its homologues, polycyclic aromatic hydrocarbons, halogenated hydrocarbons, etc.

The invention relates to the preparation and application of a novel photocatalytic material AgTO ₂ type composite oxide capable of efficiently absorbing ultraviolet light and visible light contained in sunlight and a composite material thereof. By illuminating the catalyst or the composite material with it as the main material, the VOCs, sulfides, nitrogen oxides in the air or harmful organic substances in the water are directly oxidized and decomposed into carbon dioxide, water or other non-toxic and harmless substances, Thereby, a harmless treatment method for harmful substances is provided.

The AgTO ₂ -type compound oxide semiconductor photocatalytic material (T=Al, Ga, In, Cr, Fe, Co, Ni) of the present invention, as mentioned above, has high catalytic activity in a wide spectrum, and the conditions of use are different. Harsh, can be used durablely, and the service life of the material can be increased by doping and modifying AgTO _2. Further, M/AgTO ₂ , M/(AgTO ₂ doped modified material), M _x O _y can be produced /AgTO ₂ , M _x O _y /(AgTO ₂ doped modified material) composite material (M=metal) and corresponding thin film materials, provide the market with diversified products that meet different needs of industry or life, so the commercialization prospect is broad .

4. Specific implementation

Example 1

Preparation of AgTO ₂ by ion exchange method:

In the present invention, when using the ion exchange method to synthesize AgTO ₂ (T=Al, Ga, In, Cr, Fe, Co, Ni), the raw materials used are as follows (all produced by Sinopharm Chemical Reagent Co., Ltd.): Li ₂ CO ₃ (99.99%), Al ₂ O ₃ (99.99%), Ga ₂ O ₃ (99.9%), In ₂ O ₃ (99.9%), Cr ₂ O ₃ (99.0%), Fe ₂ O ₃ (99.0%), Co ₂ O ₃ (99.0%), NiO (99.0%), AgNO ₃ (99.8%) and KNO ₃ (99.0%). Prepare LiTO ₂ (T=Al, Ga, In, Cr, Fe, Co, Ni) according to the stoichiometric ratio: LiAlO ₂ and LiCoO ₂ are sintered with Li ₂ CO ₃ and Al ₂ O ₃ or Co ₂ O ₃ at 900°C Obtained in 12 hours; LiGaO ₂ , LiInO ₂ , LiCrO ₂ , and LiFeO ₂ are obtained by sintering Li ₂ CO ₃ with Ga ₂ O ₃ , In ₂ O ₃ , Cr ₂ O ₃ , and Fe ₂ O ₃ at 750°C for 12 hours, respectively. ; LiNiO ₂ obtained by sintering Li ₂ CO ₃ and NiO at 650 ° C for 12 hours. The obtained precursor sample was mixed with AgNO ₃ and KNO ₃ in a molar ratio of 1:3:1, and then sintered at 275°C-400°C for 12 hours. After sintering, the sample was taken out for cleaning, and the remaining precipitate was dried at room temperature for later use. The particle size of the powder prepared by the above process is 200nm-1000nm, and it can be crushed with a ball mill to reduce the particle diameter. The particle size is generally 10nm-200nm, and the particle size range with the best effect is 10- 100nm.

Example 2

_M /AgTO ₂ , M _x O _y /AgTO ₂ , M/(AgTO ₂ doped modified material), M _{x O y /} (AgTO ₂ doped Modified material) composite material:

Take several parts of 1g of the AgTO ₂ powder prepared in Example 1, and measure the prepared AgNO ₃ (1g/100ml), Bi(NO ₃ ) ₃ ·5H ₂ O (1g/100ml), Ni(NO ₃ ) ₂ ·6H ₂ O(1g/100ml), Zn(NO ₃ ) ₂ ·6H ₂ O(1g/100ml), H ₂ PtCl ₆ ·6H ₂ O(1g/100ml), RuCl ₃ ·3H ₂ O( 1g/100ml) and other salt solution, mix and grind AgTO ₂ powder with the salt solution for half an hour, and dry in an oven. To prepare M/AgTO ₂ composite material (M = metal), put the powder in a tube furnace for 300-1200°C (different sintering temperatures are used depending on the decomposition temperature of the above-mentioned salts), sintering in an air atmosphere for 3-12 hours, and then sintering in a hydrogen reducing atmosphere for 3-12 hours to obtain M/AgTO ₂ ; To prepare the M _x O _y /AgTO ₂ composite material (M=metal), place the powder in a tube furnace at 300-1200°C (different sintering temperatures are used according to the decomposition temperature of the above-mentioned salts), and sinter in an air atmosphere for 3 -12 hours, M _x O _y /AgTO ₂ is obtained.

For AgTO ₂ doped modified materials, M/(AgTO ₂ doped modified materials) and M _x O _y /(AgTO ₂ doped modified materials) composite materials can be prepared using the above method.

Example 3

Preparation of AgTO ₂ film by Doctor Blade Method and preparation of AgTO ₂ surface coating layer:

When preparing the _AgTO2 thin film, take a small amount of _AgTO2 (T=Al, Ga, In, Cr, Fe, Co, Ni) powder prepared in Example 1, add 2-4 drops of polyvinyl alcohol and acetylacetone each, and mix to prepare Make a slurry, directly coat the slurry on the substrate (20mm×20mm) with the doctor blade method, and sinter at 400°C for 2-5 hours to make a film, weigh the substrate and the film The base sheet can obtain the weight of the film layer, about 10mg-30mg.

When preparing the surface coating layer, take 100mg of AgTO ₂ (T=Al, Ga, In, Cr, Fe, Co, Ni) powder, suspend in 100ml of water or organic solvent, divide the suspension into 3- Spray on the surface of the building material (1m ² ) for 5 times, and anneal at 300-1000°C (different temperature according to the base material) for 30 minutes for each splash, and finally the surface of AgTO ₂ can be prepared on the surface of the building material coating layer.

Example 4

Photocatalytic decomposition of methylene blue (MB) using _AgTO2 :

Utilize 200mg of AgAlO ₂ prepared in Example 1, suspend it in a reactor (75mm in diameter, 35mm in height) filled with about 21.0mg/L of MB aqueous solution 100ml (pH value is about 7), and carry out photocatalytic decomposition of MB reaction. While stirring with a magnetic bar, light was applied from the outside. A 300W Xe lamp was used as the light source, and heat-resistant glass (product of Corning Company) was used as the reactor. To remove thermal effects, a cooling device was placed between the reactor and the Xe lamp to cool the reactor. If an optical filter is inserted between the lamp and the cooling device, only light with a wavelength longer than the filter can be used for irradiation (for example, if a 420nm filter is used, only light with λ≥420nm can pass through). The concentration change due to the photodecomposition of MB can be detected by UV-Vis absorption spectrometer.

As a result, MB was degraded by 95% after 120 minutes under simultaneous irradiation with ultraviolet light and visible light. Under the irradiation of visible light with a wavelength greater than 420nm, after 120 minutes, MB was degraded by 86%. Commercial TiO ₂ (P25, Degussa, Germany) was also used to conduct a comparative experiment under visible light irradiation. After 120 minutes, MB could only degrade up 35%. The results are shown in Table 1.

For AgTO ₂ (T=Ga, In, Cr, Fe, Co, Ni), use the same conditions to carry out the photocatalytic decomposition reaction of MB respectively, and light for a certain time can also achieve the same effect as AgAlO ₂ .

M/AgTO ₂ , M _x O _y /AgTO ₂ (T=Al, Ga, In, Cr, Fe, Co, Ni; M=metal) prepared in Example 2 were used to conduct experiments to obtain better results, and the catalytic efficiency was higher than The increase of AgTO ₂ , especially the efficiency of the composite material loaded with Pt, Ag, Bi ₂ O ₃ increases significantly.

Example 5

Photocatalytic Decomposition of Methylene Blue (MB) Using AgTO ₂ Thin Films:

Utilize the _AgAlO film prepared in Example 3, place it at the bottom of a reactor (25mm × 25mm × 20mm) containing 10ml of 5.0mg/L MB aqueous solution (pH value is about 7), use ultraviolet light and visible light The light irradiation of light irradiation and the light irradiation of the visible light of wavelength greater than 420nm, after 60 minutes, the effect is close to embodiment 4.

Using AgTO ₂ (T=Ga, In, Cr, Fe, Co, Ni) film, and then carrying out the photocatalytic decomposition reaction of MB according to the above experimental conditions, the same effect as that of AgAlO ₂ film can be achieved by light for a certain time.

Example 6

Photocatalytic Decomposition of Alizarin Red (AR) Using AgTO ₂ :

300 mg of AgAlO ₂ prepared in Example 1 was used to suspend it in 100 ml of an AR aqueous solution (pH value of 7-8) of about 16.0 mg/L to carry out the photocatalytic decomposition reaction of AR. Same conditions as above.

As a result, under the irradiation of ultraviolet light and visible light at the same time, 96% of AR was degraded after 120 minutes; under the irradiation of visible light with a wavelength greater than 420nm, 70% of AR was degraded after 120 minutes. The results are shown in Table 1.

For AgTO ₂ (T=Ga, In, Cr, Fe, Co, Ni), the photocatalytic decomposition reaction of AR is carried out under the same conditions, and the same effect as that of AgAlO ₂ can be achieved by light for a certain time.

Using the M/AgTO ₂ , M _x O _y /AgTO ₂ (X=Al, Ga, In, Cr, Fe, Co, Ni; M=metal) composite materials prepared in Example 2 to carry out experiments to obtain better results, catalytic The efficiency is higher than that of AgTO ₂ , especially the efficiency of composite materials loaded with Pt, Ag, Bi ₂ O ₃ is significantly increased.

Example 7

Photocatalytic Decomposition of Alizarin Red (AR) Using AgTO ₂ Thin Films:

Utilize the _AgAlO2 film prepared in Example 3, place it at the bottom of a reactor (25mm×25mm×20mm) filled with 10ml of 5.0mg/L AR aqueous solution (pH value is about 7), use ultraviolet light and visible light The light irradiation and the light irradiation of the visible light of wavelength greater than 420nm, after 60 minutes, the effect is close to that of embodiment 6.

For the thin film of AgTO ₂ (T=Ga, In, Cr, Fe, Co, Ni), the photocatalytic decomposition reaction of AR is carried out according to the above experimental conditions, and the same effect as that of the AgAlO ₂ thin film can be achieved by light for a certain time.

Example 8

Photocatalytic degradation of acetaldehyde pollution gas using _AgTO2 :

300mg of AgAlO prepared in Example ₁ was placed on a glass slide of 24mm × 24mm, then the slide glass was put into a closed system (232cc in volume) with a gas circulation pump, and a certain amount of acetaldehyde solution (40 cc) was injected thereinto. %) to form heavily polluted air containing acetaldehyde gas with a concentration of 1270ppm in the air, irradiate with an Xe lamp without a filter, and circulate the gas with a gas circulation pump. The concentrations of generated CO ₂ and residual pollutants were detected by gas chromatography (GC).

Results Under the condition of irradiation with ultraviolet light and visible light at the same time, after 360 minutes, 1270ppm of acetaldehyde was completely degraded, and the mineralization rate reached 90% in 840 minutes.

Mineralization refers to the transformation of organic matter into harmless substances such as CO ₂ and water. The mineralization rate is obtained by dividing the actual CO ₂ produced by the theoretical CO ₂ that should be generated by the complete decomposition of organic matter. Usually, the powder material has adsorption on gas , so it is impossible to reach 100%.

For AgTO ₂ (T=Ga, In, Cr, Fe, Co, Ni), the photocatalytic decomposition reaction of acetaldehyde is carried out under the same conditions, and the same effect as that of AgAlO ₂ can be achieved by light for a certain time.

Experiments using the M/AgTO ₂ , M _x O _y /AgTO ₂ (T=Al, Ga, In, Cr, Fe, Co, Ni; M=metal) composite materials prepared in Example 2 can obtain better results, The catalytic efficiency is higher than that of AgTO ₂ , especially the efficiency of composite materials loaded with Pt, Ag, Bi ₂ O ₃ is significantly increased.

According to the above results, the AgTO ₂ type composite oxide novel photocatalytic material of the present invention has a wide range of applications. Uses such as: coatings, paint additives, or added to different dispersants and solvents, coated or printed on the surface of different materials to prepare various films or surface layers, such as glass, steel plate, plastic, rubber, paper, wood, Aluminum panels, ceramics, earthenware, fabrics, and exterior and interior surfaces of buildings, work better than titanium dioxide. It can decompose and remove harmful chemical substances under the irradiation of ultraviolet light and visible light. Treatment of high-concentration organic chemical wastewater: as in the above-mentioned embodiment, the added amount is 0.1%-0.3% (mass fraction) of the amount of water to be treated, and the COD removal rate can reach more than 90% through light (ultraviolet light is better); the treatment is high Concentration of organic chemical waste gas: as in the above examples, the usage amount is 1.3mg/cc, after light (ultraviolet light is better), the decomposition rate is 100%, and the mineralization rate is more than 90%. Thin film materials can achieve the same effect with less raw material consumption, composite materials M/AgTO ₂ , M _x O _y /AgTO ₂ (T=Al, Ga, In, Cr, Fe, Co, Ni; M=metal) Better than single AgTO ₂ performance. See Table 1.

Table ₁ AgAlO photocatalytic degradation results of organic pollutants

Claims (3)

1. AgTO ₂ type composite oxide visible light response photocatalytic material, T in the general formula AgTO ₂ represents Al, Ga, In, Cr, Fe, Co or Ni, doping a certain amount of metal in AgTO ₂ constitutes AgTO ₂ doping The material, the metal is selected from alkali metal, alkaline earth metal, Ge or Pb, the metal oxide of the metal is used as the raw material, the doping amount of the metal is 0.1wt%-10wt%, it is characterized in that the AgTO ₂ The surface of the doping material supports nano-metal particles to form a composite material of M/AgTO ₂ doped materials, wherein M is a nano-metal particle, and the nano-metal particle is selected from Ru, Ni, Pt, Ag, Zn or Bi, and the nano-metal particle The loading amount is 1wt%-10wt%. 2. AgTO ₂ type composite oxide visible light response photocatalytic material, T in the general formula AgTO ₂ represents Al, Ga, In, Cr, Fe, Co or Ni, doping a certain amount of metal in AgTO ₂ constitutes AgTO ₂ doping The material, the metal is selected from alkali metal, alkaline earth metal, Ge or Pb, the metal oxide of the metal is used as the raw material, the doping amount of the metal is 0.1wt%-10wt%, it is characterized in that the AgTO ₂ The surface of the doping material supports nano metal oxide particles, the nano metal oxide particles are selected from Sb ₂ O ₃ , Sb ₂ O ₅ , Bi ₂ O ₃ or Bi ₂ O ₄ , and the nano metal oxide particles support The loading is 1wt%-10wt%. 3. The application of AgTO ₂ -type composite oxide visible light-responsive photocatalytic material, characterized in that the AgTO ₂ -type composite oxide visible light-responsive photocatalytic material described in claim 1 or 2 is used as an additive for coatings and paints or building materials and Japanese The surface of the material is used to coat the material, the addition amount of the additive is 0.2wt%-2wt%, and the coating amount of the surface coating material is 100mg/ ^m2 .