Photocatalytic material as well as preparation method and application thereof

Abstract

The invention relates to a photocatalytic material as well as a preparation method and application thereof. The photocatalytic material contains titanium dioxide, the ratio of the surface Ti < 3 + > content to the surface Ti < 4 + > content measured by an XPS method is (1: 19)-(19: 1), and in an ultraviolet-visible diffuse reflection spectrum, the absorbancy to light with the wavelength of 760 nm is 0.20-2.0, the absorbancy to light with the wavelength of 800 nm is 0.25-1.8, and the absorbancy to light with the wavelength of 850 nm is 0.25-1.7. According to the present invention, the photocatalytic material has advantages of simple manufacturing method, significantly improved long wavelength light response value, and the like.

Description

Technical Field

[0001] The present invention relates to the field of photocatalysis technology. Specifically, it relates to a photocatalytic material, a manufacturing method thereof, and an application thereof. Background Art

[0002] Among all semiconductor metal oxide catalysts, TiO2 not only has high catalytic activity, but also has the advantages of low cost, non-toxicity, and high stability. It is the most promising photocatalyst. TiO2 is an n-type semiconductor and has three crystal forms: anatase, rutile, and brookite. Among them, the rutile form has the highest thermodynamic stability. Anatase and brookite phase titanium oxides can be transformed into the rutile phase after calcination at a high temperature of 600 - 800 °C. The band gaps of rutile, anatase, and brookite phase titanium oxides are 3.02 eV, 3.20 eV, and 3.14 eV respectively, and the anatase phase titanium oxide has the highest photocatalytic activity.

[0003] However, due to its relatively large band gap (3.0 - 3.2 eV), titanium oxide can only respond to ultraviolet light, and ultraviolet light only accounts for 5% of the solar energy. Therefore, its practical application is greatly limited. In addition, the relatively high recombination rate of photo-generated electron-hole pairs in TiO2 also restricts its application in photocatalysis technology. Therefore, there is an urgent need to develop a TiO2 catalyst with high visible light photocatalytic activity.

[0004] Among many methods, halogen doping can effectively improve the photocatalytic performance of TiO2, and has the advantages of low cost and simple preparation method. Halogen doping can enhance the visible light absorption ability of TiO2 and promote the separation of photo-generated charges. Halogen-doped TiO2 includes F doping, Cl doping, Br doping, and I doping. Among them, F-doped and I-doped TiO2 have relatively high visible light photocatalytic performance and are easy to prepare, and are popular research objects. In contrast, there are fewer preparation methods for Cl-doped and Br-doped TiO2, and their visible light photocatalytic activity is low. It is difficult to prepare Cl-doped and Br-doped TiO2 catalysts with high visible light photocatalytic activity by simple methods.

[0005] F doping of TiO2 will enhance its surface acidity and visible light absorption ability, although it will not significantly change its band gap. In F-doped TiO2, F - can replace O atoms. Due to the charge compensation effect between F - and Ti 4+ , it will promote the formation of Ti 3 + . The existence of Ti 3+ can inhibit the recombination of photo-generated electron-hole pairs in TiO2. In addition, F doping can also increase the annealing temperature for the transformation of anatase phase TiO2 to rutile phase. I doping has a different mechanism of action from F doping. I5+ and Ti 4+ have almost the same radius. In terms of atomic radius matching, Ti 4+ can be easily replaced by I 5+ . I doping can change the band gap of titanium oxide and also inhibit the recombination of photo-generated electron-hole pairs. Through first-principles calculations, it is speculated that in I-doped TiO2, its light absorption range extends from ultraviolet to the visible light region, which is due to the hybridization of the 5p orbitals of I 5s with the O 2P and Ti 3d orbitals in titanium oxide.

[0006] Zheng Yafang et al. provided a preparation method of nitrogen-halogen co-doped TiO2 in "Study on the Preparation and Photocatalytic Performance of Nitrogen-Halogen Co-Doped Nano-TiO2", which was prepared by the sol-gel method. First, 17 mL of tetrabutyl titanate and 59.5 mL of absolute ethanol were measured with a measuring cylinder to obtain a mixed solution A. After stirring at a medium speed for 10 min on a magnetic stirrer, the A solution was poured into a separatory funnel for later use. 59.5 mL of absolute ethanol, 6.8 mL of deionized water, and 6.8 mL of glacial acetic acid were measured with a measuring cylinder and poured into a three-necked flask in sequence to obtain a mixed solution B. A certain amount of doping reagents used, namely ammonium fluoride, ammonium chloride, ammonium bromide, and ammonium iodide, were added to the B solution. The water temperature was set at 25 °C, and the B solution was mechanically stirred in a constant temperature water bath until it was evenly mixed, and then the pH of the B solution was adjusted to ≤ 3 with concentrated nitric acid. Still under the condition of mechanical stirring at 25 °C in the water bath, the A solution in the separatory funnel was dropped into the B solution at a speed of 1 drop / second. After the dropping was completed, stirring was continued for 1 hour. The sol was filled into a conical flask, and the mouth of the flask was sealed with plastic wrap and left at room temperature until it gelled. After gelling, it was dried at 80 °C for 20 hours in an electrothermal blast drying oven. The obtained sample was ground into powder and calcined at a certain temperature in a box-type resistance furnace for 2 hours to obtain the co-doped titanium dioxide photocatalyst powder. The results of ultraviolet-visible diffuse reflectance spectroscopy analysis showed that the nitrogen-fluorine doped photocatalyst had the strongest response to visible light; the performance test showed that the performance was the best when the doping amount was 0.15. At this time, the dark adsorption removal rate of the nitrogen-fluorine doped photocatalyst for methylene blue was 48.3%, and the total removal rate was 79.4%. However, the visible light catalytic activities of other doped photocatalysts were very poor, and the total removal rate of methylene blue was always less than 20%, and the visible light activities of the nitrogen-chlorine, nitrogen-bromine, and nitrogen-iodine doped photocatalysts changed little with the change of the doping amount.

[0007] CN1259129C discloses a bromine-doped photocatalytic polycrystalline material exhibiting photocatalytic activity under visible light conditions, belonging to the field of inorganic nanophotocatalytic materials. The material is composed of the following three elements: titanium, oxygen, and bromine, with the weight percentages being: titanium at 54.55%-59.90%, oxygen at 35.45%-40.00%, and bromine at 0.10%-10.00%. Bromine exists in the photocatalytic polycrystalline material in both non-bonded and bonded forms. When bonded, bromine and titanium form Ti-Br chemical bonds within the crystal lattice of the photocatalytic crystal material; when non-bonded, bromine is intercalated within the interstitial spaces of the photocatalytic crystal material. Bromine doping reduces the material's original bandgap to a level that can utilize visible light (400-800nm). Because the material possesses a bandgap wide enough to be excited by visible light irradiation, it achieves full-band absorption of visible light and exhibits high catalytic activity under visible light. Summary of the Invention

[0008] The inventors of the present invention discovered that after a photocatalyst precursor is mixed with a salt containing a dopable element in a solution, the element to be doped can be doped into the photocatalyst precursor lattice under vacuum ultraviolet light irradiation, and at the same time form defects and doping that are beneficial to visible light response and promote the separation of photogenerated electrons and holes.

[0009] Specifically, the present invention relates to the following aspects.

[0010] 1. A photocatalytic material comprising titanium dioxide, wherein the surface Ti 3+ Content and surface Ti 4+ The content ratio is 1:19-19:1 (preferably 1:4-4:1), and in its ultraviolet-visible diffuse reflectance spectrum, the absorbance of light with a wavelength of 760nm is 0.20-2.0 (preferably 0.30-1.8), the absorbance of light with a wavelength of 800nm is 0.25-1.8 (preferably 0.35-1.6), and the absorbance of light with a wavelength of 850nm is 0.25-1.7 (preferably 0.35-1.5).

[0011] 2. The photocatalytic material according to any of the preceding or following aspects is in any solid form selected from particles, powders, plates, strips and heteromorphic shapes (preferably solid particle form), and / or is a solid or hollow solid.

[0012] 3. The photocatalytic material according to any of the preceding or following aspects, comprising 80 wt% or more (preferably 80-99.9 wt% or 85-99.5 wt%) of titanium dioxide, based on the total weight of the photocatalytic material, and / or the titanium dioxide is anatase, rutile or a mixture thereof, and / or the surface TiO2 measured by XPS method is3+ The content is 5%-95% (preferably 20%-80%), and the surface Ti measured by XPS method 4+ The content is 5%-95% (preferably 20%-80%), and / or, after the O1s peak of its XPS measurement is fitted, the content of oxygen vacancy O V The content of the peak is 10%-80% (preferably 15%-60%), and / or, the mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.2-7 wt% (preferably 0.5-5 wt%), and / or, the surface hydroxyl content measured by infrared spectroscopy is 0.03-3 mmol / g (preferably 0.05-1.5 mmol / g), and / or, the particle size distribution range measured by SEM method is 5-150 nm (preferably 10-110 nm) or the average particle size is 20-85 nm (preferably 30-70 nm), and / or, the surface Ti after being washed 10 times with deionized water at 100 °C in a cycle 3+ The content loss rate is less than 2% (preferably less than 1%).

[0013] 4. The photocatalytic material described in any aspect above or below further includes at least one doping element, such as at least one doping element selected from Group VIIA elements of the periodic table (preferably F) and at least one of Group VA elements of the periodic table (preferably N and P), preferably at least one doping element selected from N and F, and based on the total weight of the photocatalytic material, the content of the doping element (calculated as an element) is 0.01-15 wt% (preferably 0.01-10 wt% or 0.1-5 wt%).

[0014] 5. The photocatalytic material described in any aspect above or below, wherein the doping is surface doping, and / or, the F doping is substitutional oxygen doping or a mixture of interstitial doping and substitutional oxygen doping (preferably substitutional oxygen doping), and / or, the N doping includes lattice doping and interstitial doping, wherein the proportion of the lattice doping in the total doping is 80-20% (preferably 70-30%), the proportion of the interstitial doping in the total doping is 20-80% (preferably 30-70%), and the sum of the two is 100%.

[0015] 6. A manufacturing method of a photocatalytic material, comprising the following steps:

[0016] 1) Provide a photocatalytic material precursor covered with a liquid,

[0017] 2) Irradiate the photocatalytic material precursor with rays having a wavelength of less than 200 nm (preferably 100-200 nm or 120-200 nm) (preferably vacuum ultraviolet light) to obtain the photocatalytic material.

[0018] 7. The manufacturing method according to any one of the foregoing or following aspects, wherein the operating conditions of the irradiation include: the operating temperature is -50 - 95 °C (preferably 10 - 70 °C), the operating pressure is 0 - 1 MPaG (preferably 0 - 0.1 MPaG), the lower limit of the duration is 0.1 h (preferably 1 h, 2 h or 3 h), and the upper limit of the duration is 120 h (preferably 60 h, 36 h, 20 h, 15 h or 10 h).

[0019] 8. The manufacturing method according to any one of the foregoing or following aspects, wherein the photocatalytic material precursor is selected from any one of the forms of particles, powders, plates, strips and shaped molded bodies, preferably in the form of particles, and / or, the photocatalytic material precursor is a material capable of undergoing a photochemical reaction under the action of light or its precursor (preferably selected from at least one of sulfide-based photocatalytic materials and their precursors, metal oxide-based photocatalytic materials and their precursors, carbon nitride-based photocatalytic materials and their precursors, metal oxygen-containing salts and their precursors, and composites of these photocatalytic materials and their precursors, particularly preferably selected from at least one of TiO2, ZrO2, ZnO, BiVO4, WO3, SnO2, and composites of these photocatalytic materials and their precursors, more preferably selected from at least one of titanium dioxide and its precursors), and / or, the liquid is insoluble in the photocatalytic material precursor (preferably selected from at least one of water, esters and alcohols, especially water).

[0020] 9. The manufacturing method according to any one of the foregoing or following aspects, wherein based on the total weight of the photocatalytic material precursor, the photocatalytic material precursor contains 80 wt% or more (preferably 80 - 99.9 wt% or 85 - 99.5 wt%) of titanium dioxide, and / or, the titanium dioxide is anatase type, rutile type or a mixture of both, and / or, the photocatalytic material precursor is in the form of solid particles, and the particle size distribution range measured by SEM of the solid particles is 5 - 150 nm (preferably 10 - 110 nm) or the average particle size is 20 - 85 nm (preferably 30 - 70 nm).

[0021] 10. The manufacturing method according to any one of the foregoing or following aspects, wherein the irradiation is carried out under the condition of stirring the photocatalytic material precursor covered by the liquid, and / or, the irradiation is carried out in an inert gas atmosphere, preferably under the condition of inert gas flow or nitrogen gas flow aeration, and / or, the irradiation dose of the irradiation is 0.01 - 50 W / g (preferably 0.1 - 20 W / g), and / or, the irradiation power of the ray is 0.01 - 200 W (preferably 0.01 - 50 W).

[0022] 11. The manufacturing method described in any of the above or following aspects, wherein the coverage depth of the liquid is 0.0001-200 mm (preferably 0.01-120 mm or 0.5-80 mm), and / or the liquid further includes at least one doping element, such as at least one doping element selected from the elements of Group VIIA of the Periodic Table (preferably F) and the elements of Group VA of the Periodic Table (preferably at least one of N and P), preferably at least one doping element selected from N and F, and / or the mass ratio of the liquid to the photocatalytic material precursor is 1-10000:1 (preferably 2-5000:1, further preferably 5-1000:1), and / or the liquid is replaced by an inert gas (such as nitrogen).

[0023] 12. The manufacturing method according to any of the preceding or following aspects, wherein the amount of the doping element (calculated as element) is 0.01-1000 wt% (preferably 0.1-200 wt%) based on the total weight of the photocatalytic material precursor, and / or the doping elements are used in combination (such as N and F in combination), and / or the liquid contains multiple (such as two or three) doping elements, and / or one or more doping elements are introduced into the liquid at one time or in multiple steps, and / or one or more doping elements are introduced into the liquid before, simultaneously with or after irradiating the photocatalytic material precursor with the radiation, and / or step 2) is repeated multiple times (such as 2-4 times), and between two adjacent steps 2), one or more doping elements are introduced into the liquid, and / or the doping element is used in the form of a precursor, and / or the precursor of the doping element is soluble in the liquid.

[0024] 13. The manufacturing method according to any one of the preceding or following aspects further comprises the step of irradiating the photocatalytic material precursor with ultraviolet light having a wavelength of 200-400 nm.

[0025] 14. The manufacturing method described in any of the preceding or following aspects, wherein the irradiation dose of the ultraviolet light is 0.01-200w / g (preferably 0.1-50w / g), and / or the irradiation power of the ultraviolet light is 0.1-1000W (preferably 1-200W), and / or the lower limit of the duration of the ultraviolet light irradiation is 0.5h (preferably 1h, 2h or 3h), and the upper limit of the duration of the ultraviolet light irradiation is 120h (preferably 60h, 36h, 20h, 15h or 10h), and / or the ratio of the ultraviolet light to the radiation is 1:1-30:1 (preferably 3:1-20:1), and / or the irradiation of the ultraviolet light and the irradiation of the radiation are carried out synchronously, successively or alternately.

[0026] 15. The manufacturing method described in any of the foregoing or following aspects further includes the steps of solid-liquid separation, washing (optional), and drying the photocatalytic material.

[0027] 16. The manufacturing method described in any of the foregoing or following aspects, wherein the operating conditions for drying include: the drying temperature is 30 - 150 °C (preferably 35 - 120 °C, more preferably 40 - 90 °C), the drying time is 0.1 - 80 h (preferably 1 - 15 h), and / or the photocatalytic material is not subjected to heat treatment at a temperature above 300 °C (preferably above 200 °C).

[0028] 17. The manufacturing method described in any of the foregoing or following aspects includes the following steps:

[0029] Mixing the liquid (preferably water) with the photocatalytic material precursor (preferably titanium dioxide) under the conditions of aeration and stirring with an inert gas stream to obtain the photocatalytic material precursor covered with the liquid.

[0030] Adding the precursor of the first doping element to the photocatalytic material precursor covered with the liquid under the conditions of aeration and stirring with an inert gas stream to obtain a first raw material mixture.

[0031] Irradiating (first irradiation) vacuum ultraviolet light on the first raw material mixture under the conditions of aeration and stirring with an inert gas stream to obtain a first product mixture.

[0032] Performing solid-liquid separation, washing (optional), and drying the first product mixture to obtain the photocatalytic material.

[0033] 18. The manufacturing method described in any of the foregoing or following aspects, wherein the mass ratio of the photocatalytic material precursor to the liquid is 1:1 - 10000 (preferably 1:2 - 5000, more preferably 1:5 - 1000), the mass ratio of the photocatalytic material precursor to the precursor of the first doping element is 1:0.01 - 10 (preferably 1:0.05 - 5, more preferably 1:0.1 - 2), and the duration of the first irradiation is 0.1 - 120 h (preferably 0.5 - 60 h, more preferably 1 - 36 h).

[0034] 19. The manufacturing method described in any of the foregoing or following aspects further includes the following steps:

[0035] Adding the precursor of the second doping element to the first product mixture to obtain a second raw material mixture.

[0036] Irradiating (second irradiation) vacuum ultraviolet light on the second raw material mixture under the conditions of aeration and stirring with an inert gas stream to obtain a second product mixture.

[0037] Solid-liquid separate, wash (optional), and dry the second product mixture to obtain the photocatalytic material.

[0038] 20. The manufacturing method according to any of the foregoing or following aspects, wherein the mass ratio of the first product mixture (calculated based on the photocatalytic material precursor) to the precursor of the second doping element is 1:0.0001 - 0.3 (preferably 1:0.0003 - 0.15), and the duration of the second irradiation is 0.1 - 40 h (preferably 0.5 - 15 h, more preferably 1 - 10 h).

[0039] 21. A photocatalytic article (such as photocatalytic particles, a photocatalytic plate, or a photocatalytic film) comprising the photocatalytic material according to any of the foregoing or following aspects or a photocatalytic material manufactured by the manufacturing method according to any of the foregoing or following aspects.

[0040] 22. A conversion method (such as a method for treating a gas containing VOCs), comprising the step of irradiating a raw material to be converted (such as a gas containing VOCs) with light in the presence of the photocatalytic material according to any of the foregoing or following aspects, a photocatalytic material manufactured by the manufacturing method according to any of the foregoing or following aspects, or the photocatalytic article according to any of the foregoing or following aspects.

[0041] 23. The method according to any of the foregoing or following aspects, wherein the gas containing VOCs contains formaldehyde, and the content of formaldehyde in the gas containing VOCs is 1 - 10000 ppm (preferably 2 - 1000 ppm, more preferably 5 - 500 ppm).

[0042] 24. The method according to any of the foregoing or following aspects, wherein the wavelength of the light is 100 - 3000 nm (preferably 150 - 2000 nm), and / or the irradiation dose of the light is 0.0001 - 10000 kW / m 3 (preferably 0.005 - 1000 kW / m 3 ).

[0043] 25. The method according to any of the foregoing or following aspects, wherein the operating conditions of the irradiation include: the operating temperature is -50 - 95 °C (preferably 10 - 70 °C), the operating pressure is 0 - 1 MPaG (preferably 0 - 0.5 MPaG), the duration is 0.1 - 2000 h (preferably 0.2 - 200 h), and the volumetric space velocity is 0.01 - 1,000,000 h -1 (preferably 0.1 - 200,000 h -1 ). Detailed Description

[0044] The following is a detailed description of the specific embodiments of the present invention. It should be noted, however, that the scope of protection of the present invention is not limited by these specific embodiments, but is determined by the appended claims.

[0045] All publications, patent applications, patents, and other references mentioned in this specification are hereby incorporated by reference in their entirety. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0046] When this specification uses prefixes such as "well-known to those skilled in the art", "prior art", or similar terms to introduce materials, substances, methods, steps, devices, or components, etc., the objects introduced by such prefixes cover those commonly used in the art at the time when this application is filed, but also include those that are not commonly used at present but will become commonly recognized in the art as suitable for similar purposes.

[0047] In the context of the present invention, all numerical values of parameters (e.g., quantities or conditions) should be understood to be modified by the term "about" in all cases, whether or not "about" actually appears before the numerical value.

[0048] In the context of the present invention, without particularly clear circumstances, the various devices adopted in the present invention may use structures conventionally selected in the art, and there are no particular limitations.

[0049] In the context of the present invention, the so-called "substantially" means that deviations that are acceptable or considered reasonable to those skilled in the art are allowed, such as deviations within ±5%, within ±2%, within ±1%, within ±0.5%, or within ±0.1%.

[0050] In the context of the present invention, a scanning electron microscope is used to statistically analyze the particle size distribution range or the average particle size. The model of the scanning electron microscope (SEM) is Hitachi S-4800. The secondary electron resolution of this device is 1.4 nm (1 kV) and 1.0 nm (15 kV). The electron gun is a cold field emission electron source, and the magnification is 20 - 800,000. The catalyst powder to be tested is adhered to the conductive adhesive, compacted, and then sputter-coated with gold to make a sample for testing, so as to observe the surface structure of the catalyst and measure the particle size. The particle size is measured and statistically analyzed by NanoMeasurer software.

[0051] In the context of the present invention, surface Ti 3+ and Ti 4+ The measurement methods for content, loss rate, oxygen vacancies, and doping types are X-ray Photoelectron Spectroscopy (XPS).

[0052] XPS is an elemental analysis technique. When X-rays with a certain energy irradiate the surface of a sample and interact with the substance to be measured, electrons with characteristic energy can be emitted from the sample to be measured. This process can be expressed by the following formula:

[0053] hγ = E k + E b + E r

[0054] hγ: Energy of the X photon; E k : Energy of the photoelectron; E b : Binding energy of the electron; E r : Recoil energy of the atom. Among them, E r is very small and can be ignored. It can analyze the chemical composition of the sample. The incident beam of X-ray photoelectron spectroscopy is X-rays, which interact with the atoms on the surface of the sample, causing the electrons in the inner shell of the atoms in the sample to be excited and ionized, so that the composition and structure information of all elements except H and He in the sample can be obtained.

[0055] According to the measurement method of the present invention, the X-ray photoelectron spectrometer is Thermo Fisher Multilab2000, with a Mg / Al dual anode as the X-ray source, the vacuum degree in the analysis chamber is 5×10 -10 mbar, and the vacuum degree is obtained by two turbomolecular pumps; the equipment detector is a single-channel electron multiplier; the electron energy analyzer is a hemispherical sector analyzer; after the sample is gently ground and pressed into a tablet, a flat, uniform and compact sample is obtained and sent into the analysis chamber for testing. XPS is used to analyze the elemental composition, valence state and doping method of the product, etc. Combining with literature information, the element type and valence state information can be judged according to the position and line shape of the peak. For example, the peak near 530 eV usually corresponds to the O1s electron energy level, and the asymmetric Gaussian line shape indicates that it is composed of multiple oxygen bonding states superimposed. At this time, the content information of O corresponding to different existence states can be obtained by fitting; for example, after fitting the O1s of a certain titanium oxide, peaks of 532.2, 531.2, and 530.2 eV are obtained. Combining with literature information, the three peaks correspond to adsorbed oxygen (O a ), oxygen vacancy (O v ), and lattice oxygen (O L ), respectively. The same method can also obtain the peaks of Ti 3+ and Ti 4+ . According to the peak area, the contents of Ti 3+ and oxygen vacancy (O v) Proportion of equivalent active sites. The peaks near 399 eV and 699 eV correspond to F 1s and N 1s respectively. After peak deconvolution of the two, the signal peaks of interstitial doping and substitutional oxygen doping can be obtained respectively. For the F element, the peaks of interstitial doping and substitutional oxygen doping are located near 685.3 eV and 687.8 eV respectively, while for N, the peaks of interstitial doping and substitutional oxygen doping are located near 399.3 eV and 396.0 eV respectively.

[0056] In the context of the present invention, the measurement method of the percentage of mass loss is thermogravimetric analysis, and the thermogravimetric analysis of the sample is carried out on a PE 2400II type thermogravimetric analyzer of Perkin Eliner in the United States. Experimental conditions: N₂ atmosphere, the test temperature range is 50 - 400 °C, the heating rate is 10 °C / min, and the weight of the test sample is 10 ± 1 mg.

[0057] In the context of the present invention, the surface hydroxyl content is measured by infrared spectroscopy. When infrared light irradiates an object, it can cause the covalent bonds within the molecules of the substance to vibrate or rotate. The infrared light absorbed during vibration has a specific wavelength, so infrared spectroscopy can obtain information such as skeletal vibrations and surface groups. The sample is tested with an Agilent Cary630 type infrared spectrometer, and the wavelength range is 400 - 4000 cm -1 , before the test, the powder sample is mixed and ground evenly with KBr at a ratio of 1:200, and directly pressed into a uniform and transparent thin film using a tablet press for testing, and the step size is set to 2 cm -1 , and the background is subtracted with KBr.

[0058] In the context of the present invention, the absorbance of the photocatalyst to light of different wavelengths is measured by solid ultraviolet-visible diffuse reflectance spectroscopy. Ultraviolet-visible diffuse reflectance absorption spectroscopy is an important technique for analyzing the electronic structure of semiconductor photocatalysts, and the electronic structure of semiconductor photocatalysts is closely related to the photocatalytic activity. The sample is placed in the integrating sphere of a spectrophotometer (UV-2600, Shimadzu Corporation, Japan), BaSO₄ is used as a reference, the excitation wavelength is set to 200 - 900 nm, and the scanning speed is 1000 nm / min.

[0059] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, and the pressure is gauge pressure.

[0060] In the context of the present invention, any two or more embodiments or aspects of the present invention can be arbitrarily combined, and the technical solutions formed thereby belong to a part of the original public content of this specification and also fall within the protection scope of the present invention.

[0061] According to an embodiment of the present invention, it relates to a photocatalytic material. According to the present invention, the photocatalytic material can exhibit chemical reaction catalytic performance under light irradiation.

[0062] According to an embodiment of the present invention, the photocatalytic material contains titanium dioxide. Preferably, based on the total weight of the photocatalytic material, the photocatalytic material contains 80 wt% or more (preferably 80 - 99.9 wt% or 85 - 99.5 wt%) of titanium dioxide. Here, the titanium dioxide is anatase type, rutile type, or a mixture of both.

[0063] According to an embodiment of the present invention, the surface Ti measured by XPS method of the photocatalytic material 3+ content ratio to the surface Ti 4+ content is 1:19 - 19:1 (preferably 1:4 - 4:1). More specifically, the surface Ti measured by XPS method of the photocatalytic material 3+ content is generally 5% - 95% (preferably 20% - 80%), and its surface Ti measured by XPS method 4+ content is generally 5% - 95% (preferably 20% - 80%).

[0064] According to an embodiment of the present invention, the content of the surface oxygen vacancy O peak measured by XPS of the photocatalytic material V is 10% - 80% (preferably 15% - 60%).

[0065] According to an embodiment of the present invention, in the ultraviolet - visible diffuse reflectance spectrum of the photocatalytic material, the absorbance at a wavelength of 760 nm is 0.20 - 2.0 (preferably 0.30 - 1.8), the absorbance at a wavelength of 800 nm is 0.25 - 1.8 (preferably 0.35 - 1.6), and the absorbance at a wavelength of 850 nm is 0.25 - 1.7 (preferably 0.35 - 1.5). For the photocatalytic material according to the present invention, its utilization rate of visible light and even infrared light is high, and the light response is greatly improved compared with the original titanium oxide.

[0066] According to an embodiment of the present invention, the photocatalytic material is any one form selected from particles, powders, plates, strips, and shaped molded bodies (preferably in particle form). Optionally, the photocatalytic material can be a solid or hollow solid.

[0067] According to one embodiment of the present invention, the mass loss percentage of the photocatalytic material measured by thermogravimetric analysis at 300 °C is 0.2 - 7 wt% (preferably 0.5 - 5 wt%). This measurement indicates that the photocatalytic material of the present invention contains a certain degree of thermally volatile components; without being limited by any theory, the inventors of the present invention believe that these thermally volatile components may be caused by hydroxyl groups or bound water on the photocatalytic material, etc. As evidence, according to the present invention, the surface hydroxyl group content of the photocatalytic material measured by infrared spectroscopy is generally 0.03 - 3 mmol / g (preferably 0.05 - 1.5 mmol / g).

[0068] According to one embodiment of the present invention, the particle size distribution range of the photocatalytic material measured by SEM is 5 - 150 nm (preferably 10 - 110 nm) or the average particle size is 20 - 85 nm (preferably 30 - 70 nm).

[0069] According to one embodiment of the present invention, after the photocatalytic material is washed 10 times with deionized water circulation at 100 °C, the surface Ti 3+ content loss rate is less than 2% (preferably less than 1%). This measurement shows that on the surface of the photocatalytic material of the present invention, Ti 3+ is bonded in the form of chemical bonds, thereby showing strong resistance to cyclic washing performance.

[0070] According to one embodiment of the present invention, the photocatalytic material may further include various doping elements or any combination thereof commonly used in the art when manufacturing photocatalytic materials, such as at least one doping element selected from Group VIIA elements of the periodic table (preferably F) and Group VA elements of the periodic table (preferably at least one of N and P), preferably at least one doping element selected from N and F. Here, as the dosage, for example, based on the total weight of the photocatalytic material, the content of the doping element (calculated as an element) is generally 0.01 - 15 wt% (preferably 0.01 - 10 wt% or 0.1 - 5 wt%). According to the present invention, other elements are successfully doped into the photocatalytic precursor, and at the same time, a certain number of other valence state metal cations, oxygen vacancies, heterojunctions, and hydroxyl groups are generated, making the material have visible light or even infrared light response.

[0071] For the F, N-doped titanium oxide according to the present invention, F is doped into the titanium oxide lattice structure in the form of substituting oxygen, N is interstitial doping and lattice doping, and Ti 3+ and oxygen vacancies are generated; F doping can promote the separation of photo-generated electron-hole pairs; the introduction of Ti 3+ can form an oxidation-reduction cycle of Ti 3+ / Ti 4+ ion pairs, improving the oxidation-reduction performance of the catalyst.

[0072] According to an embodiment of the present invention, in the photocatalytic material, the doping is surface doping. Herein, the so-called surface doping means that the doping element is substantially distributed on the surface of the photocatalytic material or within a depth range of about 3 nm from the surface.

[0073] According to a preferred embodiment of the present invention, in the photocatalytic material, when F doping is included, the F doping is substitutional oxygen doping, or a mixture of interstitial doping and substitutional oxygen doping, preferably substitutional oxygen doping. Alternatively, when N doping is included, the N doping generally includes lattice doping and interstitial doping. Preferably, the proportion of the lattice doping in the total doping is 80 - 20% (preferably 70 - 30%), and the proportion of the interstitial doping in the total doping is 20 - 80% (preferably 30 - 70%), and the sum of the two is 100%.

[0074] According to an embodiment of the present invention, it relates to a method for manufacturing a photocatalytic material. According to the present invention, the manufacturing method can be used to manufacture the photocatalytic material as described above in the present invention.

[0075] According to an embodiment of the present invention, the method for manufacturing the photocatalytic material includes step 1): providing a photocatalytic material precursor covered by a liquid. According to the present invention, preferably, the photocatalytic material precursor is in solid form, not in liquid form or in a dissolved state.

[0076] According to an embodiment of the present invention, the photocatalytic material precursor is selected from any one of the forms of particles, powders, plates, strips, and shaped bodies, preferably in the form of particles. By way of example, the particle size distribution range measured by the SEM method of the particles is 5 - 150 nm (preferably 10 - 110 nm) or the average particle size is 20 - 85 nm (preferably 30 - 70 nm). If the particle size is too large, the specific surface area is small, and the loading amount of fluorine per unit weight is low, resulting in a decrease in its activity; if the particle size is too small, the volume fraction of the atoms located on the particle surface becomes higher, and the surface energy increases, resulting in poor stability of the generated active sites, thus affecting its reaction activity; in addition, too small a particle size will also make it difficult for the catalyst to settle, resulting in difficulty in its separation.

[0077] According to an embodiment of the present invention, the photocatalytic material precursor is a material or its precursor that can undergo a photochemical reaction under the action of light, preferably selected from at least one of sulfide-based photocatalytic materials and their precursors, metal oxide-based photocatalytic materials and their precursors, carbon nitride-based photocatalytic materials and their precursors, metal oxygen-containing salts and their precursors, and composites of these photocatalytic materials and their precursors, particularly preferably selected from at least one of TiO2, ZrO2, ZnO, BiVO4, WO3, SnO2, and composites of these photocatalytic materials and their precursors, and more preferably selected from at least one of titanium dioxide and its precursors. Preferably, based on the total weight of the photocatalytic material precursor, the photocatalytic material precursor contains 80 wt% or more (preferably 80-99.9 wt% or 85-99.5 wt%) of titanium dioxide. As the titanium dioxide, it can be anatase type, rutile type, or a mixture of both.

[0078] According to an embodiment of the present invention, the liquid is insoluble in the photocatalytic material precursor, preferably selected from at least one of water, esters, and alcohols, especially water.

[0079] According to the present invention, the photocatalytic material precursor is covered by the liquid. To achieve the technical effects of the present invention, the liquid forms at least a liquid film on the surface of the photocatalytic material precursor, preferably forming a continuous liquid surface. The present invention discovers that if the liquid only infiltrates or wets the photocatalytic material precursor or its surface, doping will not be successful and it will not have visible light or even infrared light absorption. This may be because the amount of wetting liquid is small and it dries up after volatilization, making it difficult for the doped fluorine compound to present an ionic state and unable to generate active components participating in doping. For this reason, preferably, the covering depth of the liquid (also known as the liquid film thickness) is generally 0.0001-200 mm, preferably 0.01-120 mm or 0.5-80 mm.

[0080] According to an embodiment of the present invention, the manufacturing method of the photocatalytic material includes step 2): irradiating the photocatalytic material precursor with rays having a wavelength of less than 200 nm to obtain the photocatalytic material. Preferably, the wavelength of the rays is 100-200 nm or 120-200 nm, and more preferably vacuum ultraviolet light (VUV) containing 150-190 nm; if the wavelength is too short, the cost of ultraviolet light will increase significantly and it is not easy to scale up, and if the wavelength is too long, the energy of the ultraviolet light will decrease and it cannot effectively excite the reactants to generate free radicals. According to an embodiment of the present invention, the operating conditions of the irradiation include: the operating temperature is -50-95 °C (preferably 10-70 °C), and the operating pressure is 0-1 MPaG (preferably 0-0.1 MPaG).

[0081] According to an embodiment of the present invention, the lower limit of the duration of the irradiation is generally 0.1 h (preferably 1 h, 2 h or 3 h), and the upper limit of the duration of the irradiation is generally 120 h (preferably 60 h, 36 h, 20 h, 15 h or 10 h). If the time is too short, the reaction is incomplete and the doping effect is poor. If the time is too long, as the reaction proceeds, the intermediate products or by-products increase continuously, the reaction tends to equilibrium, and no more beneficial effects will be produced on the product, resulting in waste.

[0082] According to an embodiment of the present invention, in order to make the irradiation more uniform, the irradiation is carried out under the condition of stirring the photocatalytic material precursor covered by the liquid. According to the present invention, the stirring can be carried out in any manner conventionally known in the art without particular limitation. For example, the stirring rate is generally 10 - 1000 rpm.

[0083] According to an embodiment of the present invention, the irradiation is carried out in an inert gas atmosphere, preferably under the condition of inert gas flow or nitrogen gas flow aeration (such as the aeration rate is 0.01 - 10 L / min / g). For this purpose, the liquid is preferably replaced with an inert gas (such as nitrogen). After the inert gas replaces the dissolved oxygen in the liquid, it is beneficial to the formation of the active component Ti 3+ formation.

[0084] According to an embodiment of the present invention, the irradiation dose of the irradiation is generally 0.01 - 50 W / g (preferably 0.1 - 20 W / g). In addition, the irradiation power of the ray is generally 0.1 - 200 W (preferably 1 - 50 W).

[0085] According to an embodiment of the present invention, the liquid may further include various doping elements or any combination thereof commonly used in the art when manufacturing photocatalytic materials, such as at least one doping element selected from the elements of Group VIIA of the periodic table (preferably F) and the elements of Group VA of the periodic table (preferably at least one of N and P), preferably at least one doping element selected from N and F. As the dosage, for example, based on the total weight of the photocatalytic material precursor, the dosage of the doping element (calculated as an element) is generally 0.01 - 1000 wt% (preferably 0.1 - 200 wt%). According to the present invention, the doping elements can be used in multiple combinations (such as N and F in combination), and thus the liquid may contain multiple (such as two or three) doping elements.

[0086] According to a preferred embodiment of the present invention, the liquid includes at least one of the elements of Group VIIA of the periodic table as a doping element. As the element of Group VIIA of the periodic table, F is preferred. The inventors of the present invention have found that when fluorine is doped, it is very beneficial to the generation of Ti 3+etc., which is conducive to the progress of the photocatalytic reaction. For this purpose, as an example of the dosage, based on the total weight of the photocatalytic material precursor, the dosage of the Group VIIA element of the periodic table (in terms of the element) is generally 0.01-1000 wt% (preferably 0.1-200 wt%).

[0087] According to an embodiment of the present invention, the mass ratio of the liquid to the photocatalytic material precursor is required to be at least such that the photocatalytic material precursor is covered by the liquid, and there is no particular limitation, but it is generally 1-10000:1 (preferably 2-5000:1, more preferably 5-1000:1).

[0088] According to an embodiment of the present invention, based on the total weight of the photocatalytic material precursor, the dosage of the doping element (in terms of the element) is generally 0.01-1000 wt% (preferably 0.1-200 wt%). Of course, depending on different doping elements, this dosage can be appropriately changed, which is not difficult for those skilled in the art.

[0089] According to an embodiment of the present invention, one or more of the doping elements are introduced into the liquid in one step or in multiple steps. For example, one or more of the doping elements can be introduced into the liquid before, simultaneously with, or after irradiating the photocatalytic material precursor with the ray. More specifically, step 2) can be repeated multiple times (such as 2-4 times), and preferably, one or more of the doping elements are introduced into the liquid between two adjacent step 2).

[0090] According to an embodiment of the present invention, the doping element as described above is generally used in the form of a precursor. Preferably, the precursor of the doping element is soluble in the liquid, preferably soluble or easily soluble in water. As the precursor, any compound that is used as a precursor of the doping element in the art can be used. Specifically, for example, at least one selected from lithium fluoride, sodium fluoride, potassium fluoride, potassium hydrogen fluoride, sodium hydrogen fluoride, lithium hydrogen fluoride, ammonium fluoride, and ammonium phosphate can be cited.

[0091] According to an embodiment of the present invention, the manufacturing method further includes a step of irradiating the photocatalytic material precursor with ultraviolet light having a wavelength of 200-400 nm. As an example, the ratio of the ultraviolet light to the ray is 1:1-30:1 (preferably 3:1-20:1).

[0092] According to an embodiment of the present invention, the irradiation dose of the ultraviolet light is generally 0.01-200 w / g (preferably 0.1-50 w / g). Additionally, the irradiation power of the ultraviolet light is generally 0.1-1000 W (preferably 1-200 W). Moreover, the conversion efficiency of the ultraviolet light is generally 0.1-80% (preferably 1-60%).

[0093] According to an embodiment of the present invention, the lower limit of the duration of the ultraviolet light irradiation is 0.1 h (preferably 1 h, 2 h, or 3 h), and the upper limit of the duration of the ultraviolet light irradiation is 120 h (preferably 60 h, 36 h, 20 h, 15 h, or 10 h). Additionally, the irradiation of the ultraviolet light and the irradiation of the rays can be carried out synchronously, successively, or alternately, without any particular limitation.

[0094] According to an embodiment of the present invention, the manufacturing method further includes the steps of solid-liquid separation, washing (optional), and drying the photocatalytic material.

[0095] According to an embodiment of the present invention, the solid-liquid separation can be carried out in any manner conventionally known in the art, such as centrifugal separation or filtration, etc., without any particular limitation.

[0096] According to an embodiment of the present invention, the washing is an optional step, and the washing can be carried out in any manner conventionally known in the art, such as washing with water once or multiple times, etc., without any particular limitation.

[0097] According to an embodiment of the present invention, the operating conditions for drying include: the drying temperature is 30-150 °C (preferably 35-120 °C, more preferably 40-90 °C), and the drying time is 0.1-80 h (preferably 1-15 h).

[0098] According to an embodiment of the present invention, the photocatalytic material is not subjected to heat treatment at a temperature above 300 °C (preferably above 200 °C). The inventors of the present invention have found that high-temperature calcination may remove the doped fluorine or oxidize Ti 3+ , resulting in a decrease in the visible light and infrared light photocatalytic activity of the photocatalytic material.

[0099] According to an embodiment of the present invention, the manufacturing method includes the following steps:

[0100] Under the conditions of aeration and stirring in an inert gas stream, the liquid (preferably water) is mixed with the photocatalytic material precursor (preferably titanium dioxide) to obtain the photocatalytic material precursor covered with the liquid.

[0101] Under the conditions of aeration and stirring with an inert gas stream, a precursor of a first doping element is added to the photocatalytic material precursor covered with the liquid to obtain a first raw material mixture.

[0102] Under the conditions of aeration and stirring with an inert gas stream, the first raw material mixture is irradiated with vacuum ultraviolet light (first irradiation) to obtain a first product mixture.

[0103] The first product mixture is subjected to solid-liquid separation, washing (optional) and drying to obtain the photocatalytic material.

[0104] According to an embodiment of the present invention, the mass ratio of the photocatalytic material precursor to the liquid is generally 1:1 - 10000 (preferably 1:2 - 5000, more preferably 1:5 - 1000), and the mass ratio of the photocatalytic material precursor to the precursor of the first doping element is generally 1:0.01 - 10 (preferably 1:0.05 - 5, more preferably 1:0.1 - 2). Additionally, the duration of the first irradiation is generally 0.1 - 120 h (preferably 0.5 - 60 h, more preferably 1 - 36 h).

[0105] According to an embodiment of the present invention, the manufacturing method further includes the following steps:

[0106] A precursor of a second doping element is added to the first product mixture to obtain a second raw material mixture. <l

[0107] Under the conditions of aeration and stirring with an inert gas stream, the second raw material mixture is irradiated with vacuum ultraviolet light (second irradiation) to obtain a second product mixture.

[0108] The second product mixture is subjected to solid-liquid separation, washing (optional) and drying to obtain the photocatalytic material.

[0109] According to the present invention, the second doping element may be the same as or different from the first doping element, preferably different, and can be freely selected from the doping elements described in the present specification as above, without particular limitation. Preferably, a plurality of doping elements are used in combination, especially N and F are used in combination, whereby the liquid may contain a plurality of (such as two or three) doping elements.

[0110] According to an embodiment of the present invention, the mass ratio of the first product mixture (calculated based on the photocatalytic material precursor) to the precursor of the second doping element is generally 1:0.0001 - 0.3 (preferably 1:0.0003 - 0.15). Additionally, the duration of the second irradiation is generally 0.3 - 20 h (preferably 0.5 - 15 h, more preferably 1 - 10 h).

[0111] According to an embodiment of the present invention, there is also provided a photocatalytic article (such as photocatalytic particles, a photocatalytic plate or a photocatalytic film), which comprises the photocatalytic material described in any aspect of the foregoing or following of this specification.

[0112] According to an embodiment of the present invention, there is also provided a conversion method, such as a method for treating a gas containing VOCs.

[0113] According to an embodiment of the present invention, the gas containing VOCs may contain formaldehyde. Preferably, the content of formaldehyde in the gas containing VOCs is 1-10000 ppm (preferably 2-1000 ppm, more preferably 5-500 ppm).

[0114] According to the present invention, the conversion method includes the step of irradiating a raw material to be converted (such as a gas containing VOCs) with light in the presence of the photocatalytic material described in any aspect of the foregoing or following of this specification or the photocatalytic article described in any aspect of the foregoing or following of this specification.

[0115] According to an embodiment of the present invention, the wavelength of the light is 100-3000 nm (preferably 150-2000 nm). Additionally, the irradiation dose of the light is 0.0001-10000 kW / m 3 (preferably 0.005-1000 kW / m 3 ).

[0116] According to an embodiment of the present invention, the operating conditions of the irradiation include: the operating temperature is -50-90 °C (preferably 10-70 °C), the operating pressure is 0-1 MPaG (preferably 0-0.5 MPaG), the duration is 0.1-2000 h (preferably 0.2-200 h), and the volumetric space velocity is 0.01-1,000,000 h -1 (preferably 0.1-200,000 h -1 ).

[0117] Examples

[0118] The present invention will be further described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0119] Example 1

[0120] At room temperature, take a cylindrical quartz glass reaction vessel with a square bottom (side length 80 mm), a height of 90 mm, and a total volume of about 0.6 L. Place it on a magnetic stirrer, add a magnetic stir bar, pour 0.4 L of pure water into the container (the liquid level height is about 62 mm), continuously stir at 200 rpm, and simultaneously introduce nitrogen into the bottom of the container at a gas flow rate of 50 ml / min; then add 1.0 g of anatase titanium dioxide with a particle size in the range of 20 - 70 nm and an average particle size of 40.2 nm to the container, continuously stir and introduce gas until the titanium dioxide is evenly mixed with water to obtain a first raw material mixture; use the MLI - 1000 ArF laser from the German company MLase to irradiate the first raw material mixture from top to bottom. This laser can output vacuum ultraviolet light with a wavelength of 193 nm (maximum power 6 W, power adjustable). Adjust the spot size and shape through a beam expander to match the inner surface of the reaction vessel, and use a beam analyzer (PM10X laser power meter from Coherent, USA) to test and adjust the output spot power, and adjust the spot power acting on the solution surface to 2 W. At this time, the titanium dioxide is evenly mixed with water, the particles are randomly dispersed in water, the average coverage depth of the liquid is 31 mm, and the irradiation dose is 2 W / g. Irradiate and react for 24 hours to obtain a first product mixture. Subsequently, turn off the light source, stop stirring and introducing gas; after natural sedimentation for a period of time, remove the supernatant, filter, wash the sample several times with distilled water, and dry it at 60 °C for 6 hours to obtain the product.

[0121] The test results of ultraviolet - visible diffuse reflectance absorption spectrum show that the absorbance at a wavelength of 760 nm is 0.64, the absorbance at 800 nm is 0.66, and the absorbance at 850 nm is 0.69.

[0122] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, perform peak fitting on O1s and Ti 2p in combination with the literature. After O 1s peak fitting, peaks corresponding to lattice oxygen (O L ), oxygen vacancy (O V ), and adsorbed oxygen (O a ) are obtained. O 总 = O a + O v + O L . Calculate to obtain O v / O 总 = 35.3%, and before the reaction, O v / O 总 = 2.1%; after Ti 2p peak fitting, peaks of Ti 4+ and Ti 3+ are obtained. (Ti 3+ / Ti total ) content is 38.2%, and Ti 4+ (Ti 4+ / Ti total) The content is 61.8%, and the surface Ti 3+ content and the surface Ti 4+ content ratio is 0.618. Before reaction, the Ti 3+ content is 0. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.95%, the surface hydroxyl group content measured by infrared spectroscopy is 0.43 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 39.8 nm respectively. After washing 10 times with deionized water at 100 °C in a cycle, the surface Ti 3+ content loss rate is 0.4%.

[0123] Weigh 1.5 g of embedding agent 812 resin, 0.72 g of DDSA, 1.32 g of MNA, and 0.10 g of DP - 30, and mix them evenly in sequence. Then embed the above catalyst in an embedding tube and cure it at 60 °C for 48 h. After trimming the sample block, perform ultra - thin sectioning (ultra - microtome, UC - 6, Leica Microsystems GmbH, Germany), set the section thickness to 10 nm, and perform TEM - EELS (JEOL JEM - ARM200F, Japan) testing on the obtained sections. The test results show that Ti 3+ is mainly distributed within about 3 nm from the surface of titanium oxide particles, and no Ti 3+ is found inside the particles.

[0124] This material is suitable for VOCs treatment. Taking the degradation of formaldehyde as an example, the usage method of this material is described below.

[0125] Take 16 ml of ethanol, add 0.4 g of the catalyst in Example 1, and stir to disperse the sample into ethanol to obtain a catalyst suspension. Take 4 slides (10 cm × 4 cm), evenly drip the suspension onto the slides, and dry them in an oven at 60 °C. A uniform catalyst film is formed on the slides. During the activity evaluation experiment, place the slides into an acrylic glass reactor of about 0.8 L (20 cm × 10 cm × 4 cm), and introduce a gas containing 100 ppm of formaldehyde. After the formaldehyde gas and the catalyst reach adsorption - desorption equilibrium, turn on the light source. The light source is the PL - X300DF high - performance simulated sunlight xenon lamp of Bofilai Company (150 W), and the wavelength covers light from 300 - 2500 nm. Use the company's CUT600nm filter to filter out light below 600 nm, leaving only visible and infrared light above 600 nm. The change in the formaldehyde concentration in the reactor is continuously monitored using an infrared photoacoustic spectrometer. Denote the formaldehyde concentration at adsorption equilibrium before turning on the light as C0, and the real - time formaldehyde concentration in the reactor after turning on the light as C. C / C0 is the change rate of the formaldehyde concentration with time, and the removal rate is 85.2% after 90 min.

[0126] Example 2

[0127] Adjust the spot power acting on the solution to 3 W, and keep the other conditions the same as in Example 1. At this time, the irradiation dose is 3 W / g. The sample analysis and formaldehyde degradation test methods are also the same as in Example 1.

[0128] The test results of ultraviolet-visible diffuse reflection absorption spectroscopy show that the absorbance at a wavelength of 760 nm is 0.67, the absorbance at 800 nm is 0.69, and the absorbance at 850 nm is 0.72.

[0129] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the spectral peak shape, after fitting, peaks corresponding to lattice oxygen (O L ), oxygen vacancies (O V ), and adsorbed oxygen (O a ) are obtained. Calculate O v / O 总 = 41.3%; after fitting, peaks of Ti 4+ and Ti 3+ are obtained. The content of (Ti 3+ / Ti total ) is 42.6%, the content of Ti 4+ (Ti 4+ / Ti total ) is 57.4%. The ratio of the surface Ti 3+ content to the surface Ti 4+ content is 0.742. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 1.13%. The surface hydroxyl content measured by infrared spectroscopy is 0.47 mmol / g. The particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 40.3 nm respectively. The surface Ti 3+ content loss rate after 10 times of deionized water circulation washing at 100 °C is 0.53%.

[0130] The TEM-EELS test results show that Ti 3+ is mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of Ti 3+ is not found inside the particles.

[0131] The formaldehyde concentration test shows that the removal rate is 87.4% after 90 min.

[0132] Example 3

[0133] Add 0.3 g of sodium fluoride to the first raw material mixture in Example 1 to obtain the first raw material mixture of this example, and keep the other conditions the same. The sample analysis and formaldehyde degradation test methods are also the same as in Example 1.

[0134] The test results of ultraviolet-visible diffuse reflectance absorption spectrum show that the absorbance at a wavelength of 760 nm is 0.68, the absorbance at 800 nm is 0.69, and the absorbance at 850 nm is 0.71.

[0135] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancies (O V ), and adsorbed oxygen (O a ) are obtained. The ratio of O V / O 总 is calculated to be 44.2%; after fitting, the peaks of Ti 4+ and Ti 3+ are obtained. The content of (Ti 3+ / Ti total ) is 46.1%, and the content of Ti 4+ (Ti 4+ / Ti total ) is 53.9%. The ratio of the surface Ti 3+ content to the surface Ti 4+ content is 0.855; the fluorine element is 1.20% and is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 1.52%. The surface hydroxyl content measured by infrared spectroscopy is 0.33 mmol / g. The particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 39.4 nm respectively. The loss rate of the surface Ti 3+ content after washing 10 times with deionized water at 100 °C is 0.46%.

[0136] The TEM-EELS test results show that fluorine elements and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of fluorine and Ti 3+ is not found inside the particles.

[0137] The formaldehyde concentration test shows that the removal rate is 92.2% after 90 min.

[0138] Example 4

[0139] After adding titanium oxide in Example 1, 0.7 g of sodium fluoride is then added as the first raw material mixture of this example, and the other conditions are the same. The sample analysis and formaldehyde degradation test methods are also the same as those in Example 1.

[0140] The test results of ultraviolet-visible diffuse reflectance absorption spectrum show that the absorbance at a wavelength of 760 nm is 0.76, the absorbance at 800 nm is 0.77, and the absorbance at 850 nm is 0.79.

[0141] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, peaks corresponding to lattice oxygen (O L ), oxygen vacancies (O V ), and adsorbed oxygen (O a ) are obtained. Calculate O V / O 总 = 49.6%; after fitting, peaks of Ti 4+ and Ti 3+ are obtained. The content of (Ti 3+ / Ti total ) is 57.1%, and the content of Ti 4+ (Ti 4+ / Ti total ) is 42.9%. The ratio of the surface Ti 3+ content to the surface Ti 4+ content is 1.331; the fluorine element is 1.39% and is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 1.71%. The surface hydroxyl content measured by infrared spectroscopy is 0.41 mmol / g. The particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 39.1 nm respectively. The surface Ti 3+ content loss rate after washing 10 times with deionized water at 100 °C is 0.57%.

[0142] The TEM - EELS test results show that the fluorine element and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of fluorine and Ti 3+ is not found inside the particles.

[0143] The formaldehyde concentration test shows that the removal rate is 95.3% after 90 min.

[0144] Example 5

[0145] Replace sodium fluoride in Example 4 with ammonium fluoride as the first raw material mixture in this example, and the other conditions are the same. The sample analysis and formaldehyde degradation test methods are also the same as those in Example 1.

[0146] The test results of ultraviolet - visible diffuse reflectance absorption spectroscopy show that the absorbance at a wavelength of 760 nm is 0.77, the absorbance at 800 nm is 0.80, and the absorbance at 850 nm is 0.82.

[0147] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, peaks corresponding to lattice oxygen (O L ), oxygen vacancies (O V ), and adsorbed oxygen (O a ) are obtained. Calculate O V / O 总= 47.5%; After fitting, Ti 4+ and Ti 3+ peaks were obtained. The content of (Ti 3+ / Ti total ) was 48.2%, and the content of Ti 4+ (Ti 4+ / Ti total ) was 51.8%. The ratio of the surface Ti 3+ content to the surface Ti 4+ content was 0.93; the fluorine element was 0.53% and it was substitutional oxygen doping; the nitrogen element content was 0.62%. The N doping included lattice doping and interstitial doping, and the proportions of lattice doping and interstitial doping in the total doping were 49.6% and 50.4% respectively. The mass loss percentage measured by thermogravimetric analysis at 300 °C was 1.48%. The surface hydroxyl content measured by infrared spectroscopy was 0.34 mmol / g. The particle size distribution range and average particle size measured by SEM were 20 - 70 nm and 39.7 nm respectively. The surface Ti 3+ content loss rate after 10 times of washing with deionized water at 100 °C for 10 times was 0.02%.

[0148] The TEM - EELS test results showed that fluorine, nitrogen, and Ti 3+ were mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of fluorine, nitrogen, and Ti 3+ was not found inside the particles.

[0149] The formaldehyde concentration test showed that the removal rate was 98.4% after 90 min.

[0150] Example 6

[0151] After adding titanium oxide in Example 2, 0.7 g of ammonium fluoride was then added as the first raw material mixture of this example, and the other conditions were the same. The sample analysis and formaldehyde degradation test methods were also the same as those in Example 1.

[0152] The test results of ultraviolet - visible diffuse reflectance absorption spectroscopy showed that the absorbance at a wavelength of 760 nm was 0.83, the absorbance at 800 nm was 0.85, and the absorbance at 850 nm was 0.86.

[0153] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, peaks corresponding to lattice oxygen (O L ), oxygen vacancy (O V ), and adsorbed oxygen (O a ) were obtained. It was calculated that O V / O 总 = 51.8%; After fitting, peaks of Ti 4+ and Ti 3+ ) were obtained, (Ti3+ / Ti total ) content is 52.1%, Ti 4+ (Ti 4+ / Ti total ) content is 47.9%, surface Ti 3+ content and surface Ti 4+ content ratio is 1.09; fluorine element is 0.64% and is substitutional oxygen doping; nitrogen element content is 0.81%, N doping includes lattice doping and interstitial doping, and the proportions of lattice doping and interstitial doping in the total doping are 54.2% and 45.8% respectively. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 1.69%, the surface hydroxyl content measured by infrared spectroscopy is 0.41 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 40.5 nm respectively, and the surface Ti 3+ content loss rate after 10 times of deionized water circulation washing at 100 °C is 0.09%.

[0154] TEM - EELS test results show that fluorine, nitrogen and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of fluorine, nitrogen and Ti 3+ is not found inside the particles.

[0155] Formaldehyde concentration test shows that the removal rate is 99.1% after 90 min.

[0156] Example 7

[0157] Change the irradiation time of the first raw material mixture in Example 3 to 0.5 hours, and keep the other conditions unchanged. The sample analysis and formaldehyde degradation test methods are also the same as those in Example 1.

[0158] The test results of ultraviolet - visible diffuse reflectance absorption spectrum show that the absorbance at a wavelength of 760 nm is 0.54, the absorbance at 800 nm is 0.56, and the absorbance at 850 nm is 0.59.

[0159] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancy (O V ) and adsorbed oxygen (O a ) are obtained. Calculate O v / O 总 = 24.1%; after fitting, the peaks of Ti 4+ and Ti 3+ are obtained. Ti 3 + (Ti 3+ / Ti total ) content is 30.8%, Ti4+ (Ti 4+ / Ti total ) content is 69.2%, and the ratio of the surface Ti 3+ content to the surface Ti 4+ content is 0.445; the fluorine element is 0.22%, and it is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300°C is 0.48%, the surface hydroxyl content measured by infrared spectroscopy is 0.31 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 39.1 nm respectively, and the surface Ti 3+ content loss rate after 10 times of deionized water circulation washing at 100°C is 0.32%.

[0160] The TEM - EELS test results show that the elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of fluorine and Ti 3+ is not found inside the particles.

[0161] The formaldehyde concentration test shows that the removal rate is 76.3% after 90 min.

[0162] Example 8

[0163] Change the irradiation time of the first raw material mixture in Example 3 to 120 hours, and keep the other conditions unchanged. The sample analysis and formaldehyde degradation test methods are also the same as those in Example 1.

[0164] The test results of ultraviolet - visible diffuse reflectance absorption spectroscopy show that the absorbance at a wavelength of 760 nm is 0.52, the absorbance at 800 nm is 0.53, and the absorbance at 850 nm is 0.55.

[0165] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancy (O V ), and adsorbed oxygen (O a ) are obtained. Calculate O V / O 总 = 22.9%; after fitting, the peaks of Ti 4+ and Ti 3+ are obtained. (Ti 3+ / Ti total ) content is 33.4%, Ti 4+ (Ti 4+ / Ti total ) content is 66.6%, and the ratio of the surface Ti 3+ content to the surface Ti 4+The ratio of the content is 0.502; the fluorine element is 0.33%, and it is for substituting oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.71%, the surface hydroxyl content measured by infrared spectroscopy is 0.36 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 38.7 nm respectively, and the surface Ti after 10 times of deionized water circulation washing at 100 °C 3+ The content loss rate is 0.56%.

[0166] The TEM-EELS test results show that the elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and no fluorine and Ti 3+ are found inside the particles.

[0167] The formaldehyde concentration test shows that the removal rate is 80.6% after 90 min.

[0168] Example 9

[0169] Replace the nano-titanium oxide in Example 3 with particles having a particle size in the range of 10 - 40 nm and an average particle size of 20.2 nm, and the other conditions are the same. The sample analysis and formaldehyde degradation test methods are also the same as those in Example 1.

[0170] The test results of ultraviolet-visible diffuse reflectance absorption spectroscopy show that the absorbance at a wavelength of 760 nm is 0.58, the absorbance at 800 nm is 0.61, and the absorbance at 850 nm is 0.63.

[0171] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancies (O V ), and adsorbed oxygen (O a ) are obtained. It is calculated that O[[ID=3l]] V / O 总 == 26.4%, and before the reaction, O v / O 总 == 2.4%; after fitting, the peaks of Ti 4+ and Ti 3+ are obtained. (Ti 3+ / Ti total ) is 47.8%, the content of Ti 4+ (Ti 4+ / Ti total ) is 52.2%, the ratio of the surface Ti 3 + content to the surface Ti 4+ content is 0.916, and before the reaction, Ti 3+The content is 0; the fluorine element is 1.17%, and it is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 1.36%. The surface hydroxyl content measured by infrared spectroscopy is 0.34 mmol / g. The particle size distribution range and average particle size measured by SEM are 10 - 40 nm and 20.4 nm respectively. After washing 10 times with deionized water at 100 °C in a cycle, the surface Ti 3+ content loss rate is 0.91%.

[0172] The TEM-EELS test results show that the elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and no fluorine and Ti 3+ are found inside the particles.

[0173] The formaldehyde concentration test shows that the removal rate is 77.6% after 90 min.

[0174] Example 10

[0175] Replace the nano-titanium oxide in Example 3 with particles having a particle size in the range of 60 - 100 nm and an average particle size of 81.4 nm, and the other conditions remain the same. The sample analysis and formaldehyde degradation test methods are also the same as in Example 1.

[0176] The test results of ultraviolet-visible diffuse reflectance absorption spectroscopy show that the absorbance at a wavelength of 760 nm is 0.56, the absorbance at 800 nm is 0.58, and the absorbance at 850 nm is 0.59.

[0177] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancies (O V ), and adsorbed oxygen (O a ) are obtained. Calculate O V / O 总 = 30.2%. Before the reaction, O v / O 总 = 2.3%; after fitting, the peaks of Ti 4+ and Ti 3+ are obtained. The content of Ti 3+ (Ti 3+ / Ti total ) is 46.9%; the content of Ti 4+ (Ti 4+ / Ti total ) is 53.1%. The surface Ti 3+ content and the surface Ti 4+The ratio is 0.883; fluorine element is 1.22%, and it is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 1.29%, the surface hydroxyl content measured by infrared spectroscopy is 0.31 mmol / g, the particle size distribution range and average particle size measured by SEM are 60 - 100 nm and 81.1 nm respectively, and the surface Ti after 10 times of deionized water circulation washing at 100 °C 3+ The content loss rate is 0.88%.

[0178] The TEM - EELS test results show that the elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and no fluorine and Ti 3+ are found inside the particles.

[0179] The formaldehyde concentration test shows that the removal rate is 79.8% after 90 min.

[0180] Example 11

[0181] Replace the nano - titanium oxide in Example 3 with tetragonal ZrO2 with a particle size in the range of 20 - 45 nm and an average particle size of 34.6 nm, and the other conditions remain the same. The sample analysis and formaldehyde degradation test methods are also the same as in Example 1.

[0182] The test results of ultraviolet - visible diffuse reflectance absorption spectroscopy show that the absorbance at a wavelength of 760 nm is 0.43, the absorbance at 800 nm is 0.44, and the absorbance at 850 nm is 0.45.

[0183] Combined with the literature information, XPS is used to analyze the element composition and valence state of the product. The product is composed of Zr, O, and F elements. The analysis of the position and line - type symmetry of the Zr3d peak shows that zirconium elements exist in Zr 3+ and Zr 4+ two valence states. After fitting, the peaks of Zr 3+ and Zr 4+ are obtained. The ratio of Zr 3+ / Zr total is 48.9%, and the ratio of Zr 3+ / Zr total before the reaction is 6.8%. The XPS spectrum of the O 1s electron energy level is an asymmetric Gaussian line type, indicating that it is composed of multiple oxygen bonding states superimposed; after fitting O1s, the peaks corresponding to adsorbed oxygen (O a ), oxygen vacancy (O V ), and lattice oxygen (O L ) are obtained. The value of O V / O 总 is 40.2%, and the ratio of O v / O 总The value is 8.2%. The fluorine element content is 0.72%. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.88%. The particle size distribution range and average particle size measured by SEM are 20 - 45 nm and 33.8 nm respectively.

[0184] The TEM-EELS test results show that Zr 3+ and fluorine elements are mainly distributed within about 3 nm from the surface of ZrO2 particles, and no fluorine is found inside the particles.

[0185] The formaldehyde concentration test shows that the removal rate is 82.4% after 90 min.

[0186] Example 12

[0187] Replace the nano-titanium oxide in Example 3 with hexagonal wurtzite ZnO with a particle size in the range of 25 - 65 nm and an average particle size of 32.5 nm, and keep the other conditions the same. The sample analysis and formaldehyde degradation test methods are also the same as those in Example 1.

[0188] The test results of ultraviolet-visible diffuse reflectance absorption spectrum show that the absorbance at a wavelength of 760 nm is 0.52, the absorbance at 800 nm is 0.54, and the absorbance at 850 nm is 0.56.

[0189] Combined with the literature information, XPS is used to analyze the element composition and valence state of the product. The product is composed of Zn, O, and F elements. The analysis of the position and linear symmetry of the Zn2p peak shows that the zinc element is a single component of Zn 2+ . The XPS spectrum of the O 1s electron energy level is an asymmetric Gaussian line shape, indicating that it is composed of a superposition of multiple oxygen bonding states; after fitting O1s, peaks corresponding to adsorbed oxygen (O a ), oxygen vacancies (O V ), and lattice oxygen (O L ) are obtained. The O V / O 总 value is 18.2%. Before the reaction of ZnO, the O v / O 总 value is 4.2%. The fluorine element content is 0.68%. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.79%. The particle size distribution range and average particle size measured by SEM are 25 - 65 nm and 32.8 nm respectively.

[0190] The TEM-EELS test results show that the fluorine element is mainly distributed within about 3 nm from the surface of ZnO particles, and no fluorine is found inside the particles.

[0191] The formaldehyde concentration test shows that the removal rate is 79.6% after 90 min.

[0192] Example 13

[0193] Replace the titanium oxide nanoparticles in Example 3 with monoclinic BiVO4 having a particle size in the range of 20 - 70 nm and an average particle size of 31.2 nm, and keep the other conditions the same. The sample analysis and formaldehyde degradation test methods are also the same as those in Example 1.

[0194] The test results of ultraviolet - visible diffuse reflectance absorption spectroscopy show that the absorbance at a wavelength of 760 nm is 0.51, the absorbance at 800 nm is 0.52, and the absorbance at 850 nm is 0.54.

[0195] XPS is used to analyze the element composition and valence state of the product. The product is composed of Bi, V, O, and F elements. The doublet position of Bi 4f indicates that the chemical state of bismuth element is Bi 3+ . According to the peak shape, combined with the literature, peak fitting is performed on O1s, V 2p, and F1s. After O1s fitting, peaks corresponding to adsorbed oxygen (O a ), oxygen vacancy (O V ), and lattice oxygen (O L ) are obtained. O 总 = O a + O v + O L . O V / O 总 = 28.3%. Before the reaction of BiVO4, O v / O 总 = 5.1%. After fitting, peaks of V 4+ and V 5+ are obtained. The value of V 4+ / V 5+ is 30.3%, which is higher than the value of V 4+ / V 5+ (2.4%) before the reaction of BiVO4. For BiVO4, the existence of oxygen vacancies and V 4+ can improve the light absorption ability to a certain extent. The fluorine element is 0.80%. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.81%. The particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 31.5 nm respectively.

[0196] The TEM - EELS test results show that fluorine elements and V 4+ are mainly distributed within about 3 nm from the surface of BiVO4 particles, and the presence of fluorine and V 4+ is not found inside the particles.

[0197] The formaldehyde concentration test shows that the removal rate is 83.5% after 90 min.

[0198] Example 14

[0199] Replace the nano-titanium oxide in Example 3 with monoclinic WO3 having a particle size in the range of 20 - 80 nm and an average particle size of 51.2 nm, and keep the other conditions the same. The sample analysis and formaldehyde degradation test methods are also the same as those in Example 1.

[0200] The test results of ultraviolet-visible diffuse reflectance absorption spectroscopy show that the absorbance at a wavelength of 760 nm is 0.42, the absorbance at 800 nm is 0.44, and the absorbance at 850 nm is 0.46.

[0201] Analyze the XPS peaks of nitrogen and tungsten elements in the product. According to the peak shapes, after fitting, peaks corresponding to adsorbed oxygen (O a ), oxygen vacancies (O V ), and lattice oxygen (O L ) are obtained. O 总 =O a +O v +O L , O V / O 总 =25.8%, the O v / O L of WO3 before reaction = 5.6%; after fitting, peaks of W 5+ and W 6+ are obtained. The contents of W 5+ before and after the reaction are 4.1% and 49.6% respectively; the fluorine element is 0.69%. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.79%. The particle size distribution range and average particle size measured by SEM method are 20 - 80 nm and 50.5 nm respectively.

[0202] The TEM-EELS test results show that W 5+ and fluorine elements are mainly distributed within about 3 nm from the surface of tungsten oxide particles, and the presence of fluorine and Ti 3+ is not found inside the particles.

[0203] The formaldehyde concentration test shows that the removal rate is 76.5% after 90 min.

[0204] Example 15

[0205] Replace the nano-titanium oxide in Example 3 with rutile-structured SnO2 having a particle size in the range of 20 - 50 nm and an average particle size of 31.2 nm, and keep the other conditions the same. The sample analysis and formaldehyde degradation test methods are also the same as those in Example 1.

[0206] The test results of ultraviolet-visible diffuse reflectance absorption spectroscopy show that the absorbance at a wavelength of 760 nm is 0.47, the absorbance at 800 nm is 0.49, and the absorbance at 850 nm is 0.51.

[0207] The elemental composition and valence state of the product were analyzed by XPS. The product is composed of Sn, O, and F elements. The positions of the doublets of Sn 3d (487.5, 495.6 eV) indicate that the chemical state of tin element is Sn 4+ . According to the spectral peak shape, the peaks of O 1s and F 1s were fitted by combining with the literature. After fitting O 1s, the peaks corresponding to adsorbed oxygen (O a ), oxygen vacancy (O V ), and lattice oxygen (O L ) were obtained. O 总 =O a +O v +O L , O V / O 总 =23.6%, and before the reaction of SnO2, O v / O 总 =3.1%; the fluorine element is 0.91%, and it is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.74%. The particle size distribution range and average particle size measured by SEM are 20 - 50 nm and 31.5 nm, respectively.

[0208] The TEM - EELS test results show that the fluorine element is mainly distributed within about 3 nm from the surface of SnO2 particles, and no fluorine is found inside the particles.

[0209] The formaldehyde concentration test shows that the removal rate is 84.3% after 90 min.

[0210] Example 16

[0211] The aeration condition in Example 3 was cancelled, and the other conditions were the same. The sample analysis and formaldehyde degradation test methods were also the same as those in Example 1.

[0212] The test results of ultraviolet - visible diffuse reflectance absorption spectroscopy show that the absorbance at a wavelength of 760 nm is 0.30, the absorbance at 800 nm is 0.32, and the absorbance at 850 nm is 0.34.

[0213] The XPS peaks of oxygen and titanium elements in the product were analyzed. According to the spectral peak shape, the peaks corresponding to lattice oxygen (O L ), oxygen vacancy (O V ), and adsorbed oxygen (O a ) were obtained after fitting. It was calculated that O V / O 总 =13.2%; the peaks of Ti 4+ and Ti 3+ were obtained after fitting, (Ti 3+ / Ti total ) was 26.4%, and Ti 4+ (Ti 4+ / Titotal ) The content is 73.6%, and the surface Ti 3+ The ratio of the content to the surface Ti 4+ The ratio of the content is 0.359; the fluorine element is 0.69%, and it is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300°C is 0.76%, the surface hydroxyl content measured by infrared spectroscopy is 0.25 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 38.7 nm respectively, and the surface Ti 3+ The content loss rate after 10 times of deionized water circulation washing at 100°C is 0.75%.

[0214] The TEM - EELS test results show that the elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of fluorine and Ti 3+ is not found inside the particles.

[0215] The formaldehyde concentration test shows that the removal rate is 71.8% after 90 min.

[0216] Example 17

[0217] The product dried in Example 3 was calcined at 250°C for 1 hour, and the other conditions were the same. The sample analysis and formaldehyde degradation test methods were also the same as in Example 1.

[0218] The ultraviolet - visible diffuse reflectance absorption spectrum test results show that the absorbance at a wavelength of 760 nm is 0.27, the absorbance at 800 nm is 0.28, and the absorbance at 850 nm is 0.31.

[0219] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancies (O V ), and adsorbed oxygen (O a ) are obtained. It is calculated that O V / O 总 = 10.3%; after fitting, the peaks of Ti 4+ and Ti 3+ are obtained. The value of (Ti 3+ / Ti total ) is 22.4%, the content of Ti 4+ (Ti 4+ / Ti total ) is 77.6%, and the surface Ti 3+ The ratio of the content to the surface Ti 4+The ratio is 0.289; fluorine element is 0.16%, and it is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.22%, the surface hydroxyl content measured by infrared spectroscopy is 0.16 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 39.4 nm respectively, and the surface Ti after 10 times of deionized water circulation washing at 100 °C 3+ The content loss rate is 0.88%.

[0220] The TEM-EELS test results show that the elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and no fluorine and Ti 3+ are found inside the particles.

[0221] The formaldehyde concentration test shows that the removal rate is 69.2% after 90 min.

[0222] Example 18

[0223] The first raw material mixture in Example 3 was irradiated simultaneously with ordinary ultraviolet light at 248 nm (power 2 W) and vacuum ultraviolet light at 193 nm, and the other conditions were the same. The light source and irradiation method of the 193 nm vacuum ultraviolet light were the same as those in Example 3. The 248 nm ultraviolet light used the CL7750 light source of OptoSystems Inc., which acted on the first raw material mixture from the side of the reactor through quartz glass. The light generation medium of the CL7750 was KrF, and the output ultraviolet light was adjusted in spot size and shape through a beam expander to match the side of the reaction vessel. The output spot power was tested and adjusted with a beam analyzer (PM10X laser power meter of Coherent Inc., USA), and the spot power acting on the solution was adjusted to 2 W. Then the irradiation doses of 248 nm and 193 nm were both 2 W / g.

[0224] The test results of ultraviolet-visible diffuse reflectance absorption spectroscopy show that the absorbance at a wavelength of 760 nm is 0.59, the absorbance at 800 nm is 0.62, and the absorbance at 850 nm is 0.64.

[0225] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancies (O V ), and adsorbed oxygen (O a ) were obtained. It was calculated that O V / O 总 = 27.4%; after fitting, the peaks of Ti 4+ and Ti 3+ were obtained, (Ti 3+ / Ti total ) was 45.6%, Ti4+ (Ti 4+ / Ti total ) content is 54.4%, and the ratio of surface Ti 3+ content to surface Ti 4+ content is 0.838; fluorine element is 0.75% and it is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 1.13%, the surface hydroxyl content measured by infrared spectroscopy is 0.23 mmol / g, the particle size distribution range and average particle size measured by SEM method are 20 - 70 nm and 39.8 nm respectively, and the surface Ti 3+ content loss rate after 10 times of deionized water circulation washing at 100 °C is 0.71%.

[0226] The TEM - EELS test results show that elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of fluorine and Ti 3+ is not found inside the particles.

[0227] The formaldehyde concentration test shows that the removal rate is 84.4% after 90 min.

[0228] Example 19

[0229] The first raw material mixture in Example 3 is irradiated simultaneously with ordinary ultraviolet light at 248 nm (total power is 40 W) and vacuum ultraviolet light at 193 nm, and the other conditions are the same; the light source and irradiation method of the 193 nm vacuum ultraviolet light are the same as those in Example 3, and the other conditions are also the same as those in Example 3. The 248 nm ultraviolet light uses two CL7750 light sources from OptoSystems, which act on the first raw material mixture through quartz glass from two sides of the reactor respectively. The photo - generating medium of the CL7750 is KrF, and the output ultraviolet light is adjusted in spot size and shape by a beam expander to match the side of the reaction vessel. The output spot power is tested and adjusted with a beam analyzer (PM10X laser power meter from Coherent, USA), and the spot power acting on each solution is adjusted to 20 W, with a total power of 40 W. Then the irradiation doses of 248 nm and 193 nm are 40 W / g and 2 W / g respectively.

[0230] The test results of ultraviolet - visible diffuse reflectance absorption spectrum show that the absorbance at a wavelength of 760 nm is 0.51, the absorbance at 800 nm is 0.53, and the absorbance at 850 nm is 0.54.

[0231] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shape, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancy (O V ), and adsorbed oxygen (O a) peaks, and the calculated O V / O 总 = 22.1%; After fitting, the peaks of Ti 4+ and Ti 3+ were obtained. (Ti 3+ / Ti total ) was 43.2%, and the content of Ti 4+ (Ti 4+ / Ti total ) was 56.8%. The ratio of the surface Ti 3+ content to the surface Ti 4+ content was 0.761; The fluorine element was 0.58% and was substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C was 0.97%. The surface hydroxyl content measured by infrared spectroscopy was 0.19 mmol / g. The particle size distribution range and average particle size measured by SEM were 20 - 70 nm and 40.4 nm respectively. After washing 10 times with deionized water circulation at 100 °C, the surface Ti 3+ content loss rate was 0.64%.

[0232] The TEM - EELS test results showed that the elements fluorine and Ti 3+ were mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of fluorine and Ti 3+ was not found inside the particles.

[0233] The formaldehyde concentration test showed that the removal rate was 81.6% after 90 min.

[0234] Example 20

[0235] The ordinary ultraviolet light power of 248 nm of the two CL7750 light sources in Example 23 was adjusted to 35 W, so that the total power was 70 W, and the other conditions were the same. Then the irradiation doses of 248 nm and 193 nm were 70 W / g and 2 W / g respectively.

[0236] The ultraviolet - visible diffuse reflectance absorption spectrum test results showed that the absorbance at a wavelength of 760 nm was 0.46, the absorbance at 800 nm was 0.47, and the absorbance at 850 nm was 0.49.

[0237] Analyze the XPS peaks of the oxygen and titanium elements of the product. According to the peak shapes, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancies (O V ), and adsorbed oxygen (O a ) were obtained. The calculated O V / O 总 = 19.4%; After fitting, the peaks of Ti 4+ and Ti 3+ were obtained. (Ti 3+ / Titotal ) is 39.7%, Ti 4+ (Ti 4+ / Ti total ) content is 60.3%, surface Ti 3+ content and surface Ti 4+ content ratio is 0.658; fluorine element is 0.52% and is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.75%, the surface hydroxyl content measured by infrared spectroscopy is 0.16 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 40.7 nm respectively, and the surface Ti 3+ content loss rate after washing 10 times with deionized water circulation at 100 °C is 0.60%.

[0238] The TEM - EELS test results show that elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of fluorine and Ti 3+ is not found inside the particles.

[0239] The formaldehyde concentration test shows that the removal rate is 77.5% after 90 min.

[0240] Comparative Example 1

[0241] Take the first raw material mixture in Example 3, stop stirring and aeration; after natural sedimentation, remove the supernatant, filter to obtain wet titanium oxide, use the ArF excimer light source system in Example 3, place it 2 cm above the catalyst, adjust the light source spot so that its output power is 2 W, irradiate the catalyst, then the irradiation dose is 2 W / g, and the irradiation time is 24 hours. During this period, continuously turn the catalyst to make it evenly illuminated. Finally, wash the sample several times with distilled water and dry it at 60 °C for 6 hours to obtain the product.

[0242] The ultraviolet - visible diffuse reflectance absorption spectrum test results show that the absorbance at a wavelength of 760 nm is 0.07, the absorbance at 800 nm is 0.08, and the absorbance at 850 nm is 0.09.

[0243] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancy (O V ) and adsorbed oxygen (O a ) are obtained. Calculate O V / O 总 = 6.1%; after fitting, the peaks of Ti 4+ and Ti 3+ are obtained, (Ti 3 + / Ti total) is 7.8%, Ti 4+ (Ti 4+ / Ti total ) content is 92.2%, surface Ti 3+ content and surface Ti 4+ content ratio is 0.085; fluorine element is 0.04%. The mass loss percentage measured by thermogravimetric analysis at 300°C is 0.07%, the surface hydroxyl content measured by infrared spectroscopy is 0.07 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 39.3 nm respectively, and the surface Ti 3+ content loss rate after washing 10 times with deionized water circulation at 100°C is 0.12%.

[0244] The TEM - EELS test results show that elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of fluorine and Ti 3+ is not found inside the particles.

[0245] The formaldehyde concentration test shows that the removal rate is 4.1% after 90 min.

[0246] Comparative Example 2

[0247] The wetted titanium oxide in Comparative Example 1 was dried at 60°C, and then irradiated with ultraviolet light under the same irradiation conditions as in Comparative Example 1. Finally, the sample was washed several times with distilled water and dried to obtain the product.

[0248] The ultraviolet - visible diffuse reflectance absorption spectrum test results show that the absorbance at a wavelength of 760 nm is 0.05, the absorbance at 800 nm is 0.06, and the absorbance at 850 nm is 0.08.

[0249] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, peaks corresponding to lattice oxygen (O L ), oxygen vacancy (O V ) and adsorbed oxygen (O a ) are obtained. Calculate O V / O 总 = 3.2%; after fitting, peaks of Ti 4+ and Ti 3+ are obtained, (Ti 3 + / Ti total ) is 3.5%, Ti 4+ (Ti 4+ / Ti total ) content is 96.5%, surface Ti 3+ content and surface Ti 4+The ratio is 0.036; fluorine element is 0.02%, and it is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.05%, the surface hydroxyl content measured by infrared spectroscopy is 0.05 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 39.8 nm respectively, and the surface Ti after 10 times of deionized water circulation washing at 100 °C 3+ The content loss rate is 0.16%.

[0250] The TEM-EELS test results show that the elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and no fluorine and Ti 3+ are found inside the particles.

[0251] The formaldehyde concentration test shows that the removal rate is 3.5% after 90 min.

[0252] Comparative Example 3

[0253] Take the wet titanium oxide in Example 3 and irradiate it under vacuum ultraviolet light with the same irradiation conditions as in Comparative Example 1. During this period, continuously spray distilled water onto the catalyst and turn the catalyst to keep it always wet and evenly illuminated. Finally, wash the sample several times with distilled water and dry it at 60 °C for 6 hours to obtain the product.

[0254] The ultraviolet-visible diffuse reflectance absorption spectrum test results show that the absorbance at a wavelength of 760 nm is 0.18, the absorbance at 800 nm is 0.17, and the absorbance at 850 nm is 0.15.

[0255] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancy (O V ), and adsorbed oxygen (O a ) are obtained. Calculate O V / O 总 = 8.7%; after fitting, the peaks of Ti 4+ and Ti 3+ are obtained, (Ti 3 + / Ti total ) is 8.9%, the content of Ti 4+ (Ti 4+ / Ti total ) is 91.1%, the surface Ti 3+ content and the surface Ti 4+The ratio is 0.098; fluorine element is 0.09%, and it is used to replace oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.21%, the surface hydroxyl content measured by infrared spectroscopy is 0.11 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 39.4 nm respectively, and the surface Ti after 10 times of deionized water circulation washing at 100 °C 3+ The content loss rate is 0.19%.

[0256] The TEM - EELS test results show that the elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and no fluorine and Ti 3+ are found inside the particles.

[0257] The formaldehyde concentration test shows that the removal rate is 4.2% after 90 min.

[0258] Comparative Example 4

[0259] Adopt the light source system of PL - ZW222L from Beijing Primax Company. The light source can output ultraviolet light of 222 nm with a power of about 2 W. This light source system is equipped with a reaction flask with a capacity of 500 ml. The cylindrical light source is placed in the center of the volumetric flask, and the reaction temperature is controlled by a water bath method. Pour 0.4 L of pure water into the reaction flask, continuously stir at 200 rpm, and at the same time introduce nitrogen gas into the bottom of the container at a gas flow rate of 50 ml / min; then add 1.0 g of the titanium dioxide with the particle size in Example 1 into the reaction flask, continuously stir and ventilate until the titanium oxide is evenly mixed with water to obtain the first raw material mixture. Then turn on the light source, with an irradiation dose of 2 W / g, the particles are randomly dispersed in water, the average coverage depth of the liquid is 3.5 mm, and irradiate and react for 24 hours to obtain the first product mixture. The treatment method of the first product mixture is the same as that in Example 1 to obtain the product, and the product analysis and formaldehyde degradation test method are also the same as those in Example 1.

[0260] The test results of ultraviolet - visible diffuse reflectance absorption spectrum show that the absorbance at a wavelength of 760 nm is 0.12, the absorbance at 800 nm is 0.14, and the absorbance at 850 nm is 0.15.

[0261] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shape, after fitting, the peaks corresponding to lattice oxygen (O L ), oxygen vacancy (O V ), and adsorbed oxygen (O a ) are obtained. Calculate O V / O 总 = 2.3%; after fitting, the peaks of Ti 4+ and Ti 3+ are obtained, (Ti 3+ / Ti total ) is 9.8%, Ti 4+ (Ti 4+ / Ti total ) content is 90.2%, surface Ti 3+ content and surface Ti 4+ content ratio is 0.109; fluorine element is 0.18%, and it is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300 °C is 0.29%, the surface hydroxyl content measured by infrared spectroscopy is 0.14 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 40.3 nm respectively, and the surface Ti 3+ content loss rate after 10 times of deionized water circulation washing at 100 °C is 0.21%.

[0262] TEM - EELS test results show that elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and the presence of fluorine and Ti 3+ is not found inside the particles.

[0263] Formaldehyde concentration test shows that the removal rate is 4.5% after 90 min.

[0264] Comparative Example 5

[0265] Replace the ArF excimer laser light source in Example 3 with a 4W ordinary light source. The light source only contains 254 nm ultraviolet light (photoelectric conversion efficiency is 50%). The light source is cylindrical and waterproof, and is vertically inserted into the center of the reaction vessel and completely immersed in water. Then its irradiation dose is 2W / g, the particles are randomly dispersed in water, and the average covering depth of the liquid is 20 mm. Other conditions are the same as in Example 3.

[0266] Ultraviolet - visible diffuse reflectance absorption spectrum test results show that the absorbance at a wavelength of 760 nm is 0.1, the absorbance at 800 nm is 0.12, and the absorbance at 850 nm is 0.14.

[0267] Analyze the XPS peaks of oxygen and titanium elements in the product. According to the peak shapes, after fitting, peaks corresponding to lattice oxygen (O L ), oxygen vacancy (O V ), and adsorbed oxygen (O a ) are obtained. Calculate O V / O 总 = 2.5%; after fitting, peaks of Ti 4+ and Ti 3+ are obtained, (Ti 3 + / Ti total ) is 9.2%, Ti 4+ (Ti4+ / Ti total ) content is 90.2%, and the surface Ti 3+ content ratio to the surface Ti 4+ content is 0.102; fluorine element is 0.11%, and it is substitutional oxygen doping. The mass loss percentage measured by thermogravimetric analysis at 300°C is 0.24%, the surface hydroxyl content measured by infrared spectroscopy is 0.12 mmol / g, the particle size distribution range and average particle size measured by SEM are 20 - 70 nm and 40.1 nm respectively, and the surface Ti 3+ content loss rate after 10 times of deionized water circulation washing at 100°C is 0.23%.

[0268] The TEM - EELS test results show that the elements fluorine and Ti 3+ are mainly distributed within about 3 nm from the surface of titanium oxide particles, and no fluorine and Ti 3+ are found inside the particles.

[0269] The formaldehyde concentration test shows that the removal rate is 4.2% after 90 min.

Claims

1. A photocatalytic material comprising titanium dioxide, wherein the ratio of the surface Ti content measured by XPS method to the surface Ti content is 1:19 - 19:1 (preferably 1:4 - 4:1), and in its ultraviolet-visible diffuse reflection spectrum, the absorbance at a wavelength of 760 nm is 0.20 - 2.0 (preferably 0.30 - 1.8), the absorbance at a wavelength of 800 nm is 0.25 - 1.8 (preferably 0.35 - 1.6), and the absorbance at a wavelength of 850 nm is 0.25 - 1.7 (preferably 0.35 - 1.5). 3+ content and surface Ti 4+ content ratio is 1:19 - 19:1 (preferably 1:4 - 4:1), and in its ultraviolet-visible diffuse reflection spectrum, the absorbance of light at a wavelength of 760 nm is 0.20 - 2.0 (preferably 0.30 - 1.8), the absorbance of light at a wavelength of 800 nm is 0.25 - 1.8 (preferably 0.35 - 1.6), and the absorbance of light at a wavelength of 850 nm is 0.25 - 1.7 (preferably 0.35 - 1.5).

2. The photocatalytic material according to claim 1, wherein the particle size distribution range measured by SEM method is 5 - 150 nm (preferably 10 - 110 nm) or the average particle size is 20 - 85 nm (preferably 30 - 70 nm).

3. The photocatalytic material according to claim 1, wherein the surface Ti measured by XPS method 3+ content is 5%-95% (preferably 20%-80%), and the surface Ti measured by XPS method 4+ content is 5%-95% (preferably 20%-80%), and / or, after the O1s peak of its XPS measurement is fitted, the content of the oxygen vacancy O V peak is 10%-80% (preferably 15%-60%), and / or, the mass loss percentage measured by its thermogravimetric analysis at 300 °C is 0.2-7 wt% (preferably 0.5-5 wt%), and / or, the surface hydroxyl content measured by its infrared spectroscopy is 0.03-3 mmol / g (preferably 0.05-1.5 mmol / g), and / or, the surface Ti 3+ content loss rate after being washed 10 times with deionized water at 100 °C is less than 2% (preferably less than 1%).

4. The photocatalytic material according to claim 1, further comprising at least one doping element, such as at least one doping element selected from the elements of Group VIIA of the periodic table (preferably F) and at least one doping element selected from the elements of Group VA of the periodic table (preferably at least one of N and P), preferably at least one doping element selected from N and F, and / or, based on the total weight of the photocatalytic material, the content of the doping element (calculated as the element) is 0.01 - 15 wt% (preferably 0.01 - 10 wt% or 0.1 - 5 wt%).

5. The photocatalytic material according to claim 4, wherein the doping is surface doping, and / or, the F doping is substitutional oxygen doping or a mixture of interstitial doping and substitutional oxygen doping (preferably substitutional oxygen doping), and / or, the N doping includes lattice doping and interstitial doping, wherein the proportion of the lattice doping in the total doping is 80 - 20% (preferably 70 - 30%), the proportion of the interstitial doping in the total doping is 20 - 80% (preferably 30 - 70%), and the sum of the two is 100%.

6. A method for manufacturing a photocatalytic material, comprising the following steps: 1) Providing a photocatalytic material precursor covered with a liquid, 2) Irradiating the photocatalytic material precursor with rays having a wavelength of less than 200 nm (preferably 100 - 200 nm or 120 - 200 nm) (preferably vacuum ultraviolet light) to obtain the photocatalytic material.

7. The manufacturing method according to claim 6, wherein the operating conditions of the irradiation include: The operating temperature is -50 - 95 °C (preferably 10 - 70 °C), the operating pressure is 0 - 1 MPaG (preferably 0 - 0.1 MPaG), the lower limit of the duration is 0.1 h (preferably 1 h, 2 h or 3 h), and the upper limit of the duration is 120 h (preferably 60 h, 36 h, 20 h, 15 h or 10 h).

8. The manufacturing method according to claim 6, wherein the photocatalytic material precursor is selected from at least one of sulfide - type photocatalytic materials and their precursors, metal oxide - type photocatalytic materials and their precursors, carbon nitride - based photocatalytic materials and their precursors, metal oxysalts and their precursors, and composites of these photocatalytic materials and their precursors, particularly preferably selected from at least one of TiO2, ZrO2, ZnO, BiVO4, WO3, SnO2, and composites of these photocatalytic materials and their precursors, more preferably selected from at least one of titanium dioxide and its precursors, and / or, based on the total weight of the photocatalytic material precursor, the photocatalytic material precursor contains more than 80 wt% (preferably 80 - 99.9 wt% or 85 - 99.5 wt%) of titanium dioxide.

9. The manufacturing method according to claim 6, wherein the photocatalytic material precursor is in the form of solid particles, and the particle size distribution of the solid particles measured by SEM ranges from 5 to 150 nm (preferably 10 to 110 nm) or the average particle size is 20 to 85 nm (preferably 30 to 70 nm).

10. The manufacturing method according to claim 6, wherein the covering depth of the liquid is 0.0001 to 200 mm (preferably 0.01 to 120 mm or 0.5 to 80 mm).

11. The manufacturing method according to claim 6, wherein the irradiation is carried out in an inert gas atmosphere, preferably under the conditions of inert gas flow or nitrogen gas flow aeration, and / or the liquid is replaced with an inert gas.

12. The manufacturing method according to claim 6, wherein the irradiation dose of the irradiation is 0.01 to 50 W / g (preferably 0.1 to 20 W / g), and the irradiation power of the ray is 0.1 to 200 W (preferably 1 to 50 W).

13. The manufacturing method according to claim 6, wherein the mass ratio of the liquid to the photocatalytic material precursor is 1 to 10,000:1 (preferably 2 to 5,000:1, more preferably 5 to 1,000:1).

14. The manufacturing method according to claim 6, wherein the liquid further comprises at least one doping element, such as at least one doping element selected from Group VIIA elements (preferably F) and Group VA elements (preferably at least one of N and P) of the periodic table of elements, preferably at least one doping element selected from N and F, and based on the total weight of the photocatalytic material precursor, the dosage of the doping element (calculated as an element) is 0.01 to 1,000 wt% (preferably 0.1 to 200 wt%).

15. The manufacturing method according to claim 6 further comprises the step of irradiating the photocatalytic material precursor with ultraviolet light having a wavelength of 200 to 400 nm.

16. The manufacturing method according to claim 15, wherein the ratio of the ultraviolet light to the ray is 1:1 to 30:1 (preferably 3:1 to 20:1).

17. The manufacturing method according to claim 6, without subjecting the photocatalytic material to heat treatment at a temperature above 300 °C (preferably above 200 °C).

18. A photocatalytic article (such as photocatalytic particles, a photocatalytic plate or a photocatalytic film) comprising the photocatalytic material according to claim 1 or the photocatalytic material manufactured by the manufacturing method according to claim 6.

19. A conversion method (such as a method for treating a gas containing VOCs), comprising the step of irradiating a raw material to be converted (such as a gas containing VOCs) with light in the presence of the photocatalytic material according to claim 1, the photocatalytic material manufactured by the manufacturing method according to claim 6 or the photocatalytic article according to claim 18.