Titanium-based catalyst and preparation method and application thereof

Abstract

The invention provides a titanium-based catalyst as well as a preparation method and application thereof. The titanium-based catalyst comprises a matrix and an active component, wherein the matrix comprises a heteropoly acid modified Ti oxide; the active component comprises a transition metal oxide; wherein the content of the transition metal oxide is 0.1%-10% by taking the total mass of the matrix as 100%. According to the titanium-based catalyst disclosed by the invention, the PIEI effect can be induced by using heteropolyacid, the PIEI induction effect is beneficial to transition metal such as V-3d orbital occupation of the titanium-based catalyst, the proximity between the transition metal, particularly the d / p band center of V, is improved, and the activation energy of C-Cl bond breakage is remarkably reduced.

Description

Technical Field

[0001] The invention relates to a titanium-based catalyst and a preparation method and application thereof, belonging to the field of catalysts. Background Art

[0002] With the development of large-scale industrialization, the consumption of fossil fuels has increased, leading to the generation of a large number of air pollutants. Multi-pollutant emissions from stationary pollution sources, including waste incinerators and steel sintering flue gases, typically release nitrogen oxides (NOx) and chlorinated volatile organic compounds (CVOCs), which are harmful to the environment and pose serious health risks to humans. Multi-pollutant control (MPC) technology can effectively and simultaneously remove low-concentration chlorobenzene (CB) and high-concentration NOx, thanks to the partially overlapping temperature range of CB oxidation and NOx reduction. This method utilizes a NOx selective catalytic reduction (SCR) device, providing a synergistic approach that is both economical and practical. Vanadium-based nanomaterials have been widely used as reliable SCR catalysts for the co-removal of CVOCs and NOx. However, conventional vanadium-based SCR catalysts encounter several research issues, including suboptimal selectivity for target products such as HCl and N2, and the accumulation of harmful polychlorinated species. Therefore, the design and development of more advanced vanadium-titanium catalysts are crucial to improve the removal efficiency of multiple pollutants.

[0003] Since vanadium compounds are hazardous waste and biotoxic, improving the performance of multi-pollutant control on vanadium-based catalysts with V content below 2% at lower temperatures is a key research focus. One strategy is to enhance the C-Cl bond cleavage of CB during dechlorination while preventing the formation of undesirable byproducts such as N2O or NOx by adding other metal elements. The introduction of noble metals such as ruthenium (Ru) can change the acidity and redox properties of the sample and improve the chlorine yield of the Deacon reaction, but it also increases the application cost of the catalyst. Other strategies are to add non-metallic solid superacids such as phosphates and sulfates to significantly improve The acidity ratio can effectively slow down the formation of polychlorinated species. However, the thermal stability of solid superacids is limited.

[0004] The synergistic catalytic purification of NOx and various non-chlorinated aromatic VOCs has received widespread attention in recent years, including the synergistic removal of NOx with toluene, dichloromethane, and other VOCs. Reference 1 investigated the synergistic catalytic removal performance and mechanism of a bifunctional Cu-VWTi catalyst for NOx and VOCs such as toluene, propylene, dichloromethane, and naphthalene, compared to commercial NH3-SCR catalysts. At temperatures above 350°C, the catalyst achieved a conversion rate of over 99% for various VOCs while maintaining a NOx conversion rate greater than 90%. Furthermore, the catalyst effectively prevented the formation of polycyclic aromatic hydrocarbons. The catalyst's excellent synergistic performance is attributed to the bifunctional active centers constructed at the Cu and V sites. The Cu site promotes VOC oxidation, while the V site promotes NOx reduction, resulting in superior performance over the commercial VWTi catalyst. In addition, for the synergistic removal of NOx and toluene, researchers have also tried catalyst systems such as Mo / Ni-impregnated WVTiOx, MnOx with different morphologies, MnOx / Cu-SAPO-34, and CeO2-TiO2. Using toluene as a model molecule, they have conducted preliminary explorations of the synergistic removal of NOx and aromatic compounds from both performance and mechanistic perspectives. However, these methods are not able to synergistically remove NOx and chlorobenzene.

[0005] Reference 1: Journal of Cleaner Production 459(2024)142567 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] In view of the technical problems existing in the prior art, the present invention first provides a titanium-based catalyst. The titanium-based catalyst of the present invention uses a Ti oxide modified with a heteropolyacid. The use of the heteropolyacid can induce a distal electron interaction (PIEI) effect. This induced distal electron interaction effect helps the transition metal, such as V, of the titanium-based catalyst to occupy the 3d orbitals, thereby increasing the proximity between the d / p band centers of the transition metal, especially V, and significantly reducing the activation energy of C-Cl bond cleavage.

[0008] Furthermore, the present invention also provides a method for preparing a titanium-based catalyst, which is simple and easy to implement, and the raw materials are easy to obtain, and is suitable for mass production.

[0009] Solutions for solving problems

[0010] [1] A titanium-based catalyst comprising a matrix and an active component; wherein:

[0011] The matrix includes a heteropolyacid-modified Ti oxide; and

[0012] The active ingredient includes a transition metal oxide; wherein,

[0013] Based on the total mass of the matrix being 100%, the content of the transition metal oxide is 0.1% to 10%.

[0014] [2] The titanium-based catalyst according to [1] above, wherein the amount of the heteropoly acid in the Ti oxide modified with the heteropoly acid is 0.01-20%, based on the total mass of the Ti oxide being 100%.

[0015] [3] The titanium-based catalyst according to [1] or [2] above, wherein the heteropoly acid comprises one or a combination of two or more of phosphotungstic acid, phosphomolybdic acid, silicotungstic acid and silicomolybdic acid.

[0016] [4] The titanium-based catalyst according to any one of [1] to [3] above, wherein the transition metal oxide comprises one or a combination of two or more of tungsten oxide, vanadium oxide, niobium oxide, copper oxide, nickel oxide, and tin oxide, preferably vanadium oxide.

[0017] [5] A method for preparing a titanium-based catalyst according to any one of [1] to [4] above, wherein the method comprises the step of composite-molding a heteropolyacid-modified Ti oxide and an active ingredient.

[0018] [6] The preparation method according to [5] above, wherein the preparation method of the heteropolyacid-modified Ti oxide comprises the following steps:

[0019] dissolving the heteropoly acid in a solvent to obtain a heteropoly acid solution;

[0020] mixing the heteropoly acid solution with Ti oxide to obtain a first suspension;

[0021] removing the solvent from the first suspension to obtain a first block;

[0022] The first block is dried once, ground, and calcined once to obtain heteropolyacid-modified Ti oxide.

[0023] [7] The preparation method according to [6] above, wherein the mass concentration of the heteropoly acid in the heteropoly acid solution is 0.01 to 1%, and / or

[0024] Removing the solvent from the first suspension by heating in a water bath to obtain a first block; preferably, the water bath heating temperature is 60-100° C.; and / or,

[0025] The primary drying temperature is 80-110°C; the primary drying time is 12-48h; and / or,

[0026] The primary calcination comprises heating to 150-900° C. and calcining for 5-24 hours at a heating rate of 1-20° C. / min.

[0027] [8] The preparation method according to any one of [5] to [7] above, wherein the composite molding comprises the following steps:

[0028] dissolving a precursor of the active ingredient to obtain a precursor solution;

[0029] mixing the heteropolyacid-modified Ti oxide with the precursor solution to obtain a second suspension;

[0030] removing the solvent from the second suspension to obtain a second block;

[0031] The second block is dried twice, ground, and calcined twice to obtain a titanium-based catalyst.

[0032] [9] The preparation method according to any one of [5] to [8] above, wherein the mass concentration of the precursor in the precursor solution is 0.01% to 1%; preferably, the precursor solution further contains a cosolvent, more preferably, the concentration of the cosolvent is 0.01% to 1%; and / or,

[0033] removing the solvent from the second suspension by heating in a water bath to obtain a second block; preferably, the water bath heating temperature is 60-100° C.; and / or,

[0034] The secondary drying temperature is 80-110°C; the secondary drying time is 12-48h; and / or,

[0035] The secondary calcination comprises heating to 150-900° C. and calcining for 5-24 hours at a heating rate of 1-20° C. / min.

[0036]

[10] Use of the titanium-based catalyst according to any one of [1] to [4] above for the synergistic removal of nitrogen oxides and volatile organic compounds containing heteroatoms.

[0037] Effects of the Invention

[0038] The titanium-based catalyst of the present invention uses a heteropolyacid to induce a distal electron interaction (PIEI) effect, which helps the transition metal of the titanium-based catalyst, such as V, to occupy the 3d orbital, improves the proximity between the d / p band centers of the transition metal, especially V, and significantly reduces the activation energy of the C-Cl bond breakage.

[0039] The preparation method of the titanium-based catalyst of the present invention is simple and easy, the raw materials are easy to obtain, and it is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The catalytic performance of the titanium-based catalysts of Examples 1-3 and Comparative Examples 1-2 on chlorobenzene and nitrogen oxides is shown; wherein,

[0041] a is a graph showing the catalytic performance of the titanium-based catalysts of Examples 1-2 and Comparative Examples 1-2 for nitrogen oxides;

[0042] b is a graph showing the catalytic performance of the titanium-based catalysts of Example 1-2 and Comparative Example 1-2 for chlorobenzene;

[0043] c is a schematic diagram of the COx yield of the titanium-based catalysts of Examples 1-2 and Comparative Examples 1-2;

[0044] Qualitative comparison of the titanium-based catalysts of Examples 1-2 and Comparative Examples 1-2 at d = 400°C;

[0045] e is a schematic diagram showing the catalytic performance of the titanium-based catalyst for nitrogen oxides and chlorobenzene and the COx yield of Example 2;

[0046] f is a schematic diagram of the catalytic performance of the titanium-based catalyst of Example 3 for nitrogen oxides and chlorobenzene and the COx yield.

[0047] Figure 2 The X-ray diffraction patterns of the titanium-based catalysts prepared in Examples 1-3 and Comparative Examples 1-2 are shown.

[0048] Figure 3 The nitrogen adsorption-desorption curves of the titanium-based catalysts prepared in Examples 2 and 3 are shown.

[0049] Figure 4 TEM images of the titanium-based catalyst of Example 2 are shown; wherein, a is a high-resolution electron microscope image of TiO2; b is a high-resolution electron microscope image of heteropolyacid; and c is an EDS elemental analysis image of the catalyst.

[0050] Figure 5 The hydrogen temperature-programmed reduction diagram of the titanium-based catalysts prepared in Examples 2 and 3 is shown.

[0051] Figure 6 The temperature-programmed ammonia desorption curves of the titanium-based catalysts prepared in Examples 2 and 3 are shown.

[0052] Figure 7 The durability test graph of the titanium-based catalyst prepared in Example 2 is shown. DETAILED DESCRIPTION

[0053] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior or preferred over other embodiments.

[0054] In addition, numerous specific details are provided in the following detailed description to better illustrate the present invention. Those skilled in the art will appreciate that the present invention can be practiced without certain specific details. In other instances, methods, means, equipment, and steps well known to those skilled in the art are not described in detail in order to highlight the main points of the present invention.

[0055] Unless otherwise stated, the units used in this specification are international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0056] In this specification, the use of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0057] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "embodiments," etc., mean that the specific elements (e.g., features, structures, properties, and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0058] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0059] <First Aspect>

[0060] The first aspect of the present invention provides a titanium-based catalyst comprising a substrate and an active component; wherein,

[0061] The matrix includes a heteropolyacid-modified Ti oxide; and

[0062] The active ingredient includes a transition metal oxide; wherein,

[0063] Based on the total mass of the matrix being 100%, the content of the transition metal oxide is 0.1% to 10%.

[0064] The titanium-based catalyst of the present invention uses a heteropolyacid to induce a distal electron interaction (PIEI) effect, which helps the transition metal of the titanium-based catalyst, such as V, to occupy the 3d orbital, improves the proximity between the d / p band centers of the transition metal, especially V, and significantly reduces the activation energy of the C-Cl bond breakage.

[0065] The average particle size of the Ti oxide can generally be 1 nm to 1000 nm. Specifically, the Ti oxide of the present invention can be TiO2. The crystal form of TiO2 is not particularly limited in the present invention and can be any feasible crystal form such as anatase phase, rutile phase, etc.

[0066] In the present invention, the matrix includes a Ti oxide modified with a heteropolyacid. The inventors of the present invention have discovered that heteropolyacids are a class of solid oxygenated polyacids with strong acidity, and their structure has strong proton conductivity. They can effectively solve the degradation of chlorobenzene, leading to chlorine species poisoning, thereby greatly reducing the degradation temperature of chlorobenzene. The strong acid properties significantly improve the performance of NH3-SCR, ultimately giving the synergistic reaction a common temperature window. Compared with other super-strong solid acid catalysts, heteropolyacids have a more uniform acid site distribution, stronger acidity and higher thermal stability.

[0067] In some specific embodiments, in the Ti oxide modified by the heteropolyacid, based on the total mass of the Ti oxide as 100%, the amount of the heteropolyacid is 0.01-20%, for example, 0.05%, 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 12%, 15%, 18%, etc. When the amount of the heteropolyacid is 0.01-20%, the effect of the heteropolyacid can be more effectively exerted.

[0068] In some specific embodiments, the heteropolyacid comprises phosphotungstic acid (H3PW 12 O 40 ), phosphomolybdic acid (H3PMo 12 O 40 ), silicotungstic acid (H3SiW 12 O 40 ) and silicomolybdic acid (H3SiMo 12 O 40 ) or a combination of two or more.

[0069] In the present invention, when the titanium-based catalyst contains a transition metal oxide, the content of the transition metal oxide is 0.1% to 10%, for example, 0.2%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, etc., based on the total mass of the substrate as 100%. When the content of the transition metal oxide is 0.1% to 10%, its function can be more effectively exerted.

[0070] Specifically, the transition metal oxide may include one or a combination of two or more of tungsten oxide, vanadium oxide, copper oxide, nickel oxide, and tin oxide, preferably vanadium oxide.

[0071] <Second Aspect>

[0072] The second aspect of the present invention provides a method for preparing the titanium-based catalyst according to the first aspect of the present invention, the method comprising the steps of composite-molding the heteropolyacid-modified Ti oxide and the active component.

[0073] The preparation method of the titanium-based catalyst of the present invention is simple and easy, the raw materials are easy to obtain, and it is suitable for mass production.

[0074] In some specific embodiments, the method for preparing the heteropolyacid-modified Ti oxide comprises the following steps:

[0075] dissolving the heteropoly acid in a solvent to obtain a heteropoly acid solution;

[0076] mixing the heteropoly acid solution with Ti oxide to obtain a first suspension;

[0077] removing the solvent from the first suspension to obtain a first block;

[0078] The first block is dried once, ground, and calcined once to obtain heteropolyacid-modified Ti oxide.

[0079] In some specific embodiments, the mass concentration of the heteropoly acid in the heteropoly acid solution is 0.01-1%, for example, 0.02%, 0.05%, 0.08%, 0.1%, 0.2%, 0.5%, 0.8%, etc.

[0080] Furthermore, to facilitate dissolution of the heteropolyacid, the heteropolyacid may be dissolved by heating. Specifically, the heating temperature may be 30°C to 100°C. Furthermore, magnetic stirring may be employed for dissolution. Specifically, the magnetic stirring time may be 1 to 10 hours, and the magnetic stirring speed may be 10 to 150 rpm.

[0081] The heteropolyacid solution is mixed with the Ti oxide to obtain a first suspension. The content of the Ti oxide in the first suspension is not particularly limited in the present invention and can be determined according to the content of the active ingredient. Specifically, for ease of dissolution, the Ti oxide can be first mixed with a solvent to obtain a Ti oxide suspension, and then the heteropolyacid solution is mixed with the Ti oxide suspension to obtain the first suspension. The concentration of the Ti oxide in the suspension is not particularly limited in the present invention and can be set as needed, for example, 0.1-20%. The concentrations of the heteropolyacid and the Ti oxide in the first suspension are not particularly limited in the present invention, as long as the heteropolyacid is fully in contact with the Ti oxide.

[0082] In some specific embodiments, the solvent in the first suspension can be removed by heating in a water bath to obtain a first block. Preferably, the water bath heating temperature is 60-100°C, for example: 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 98°C, etc.

[0083] Furthermore, the first block is dried once, ground, and calcined once to obtain a titanium-based catalyst.

[0084] In some specific embodiments, the primary drying temperature is 80-110°C, for example: 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 98°C, 100°C, 102°C, 105°C, 108°C, etc.; the primary drying time is 12-48h, for example: 15h, 18h, 20h, 22h, 25h, 28h, 30h, 32h, 35h, 38h, 40h, 42h, 45h, etc.

[0085] In some specific embodiments, the primary calcination comprises heating to 150-900° C. and calcining for 5-24 hours at a heating rate of 1-20° C. / min. For example, the heating rate can be 2° C. / min, 4° C. / min, 6° C. / min, 8° C. / min, 10° C. / min, 12° C. / min, 14° C. / min, 16° C. / min, 18° C. / min, etc.; the temperature after heating can be 200° C., 250° C., 300° C., 350° C., 400° C., 450° C., 500° C., 550° C., 600° C., 650° C., 700° C., 750° C., 800° C., 850° C., etc., and the calcination time can be 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, etc.

[0086] In some specific embodiments, the composite molding comprises the following steps:

[0087] dissolving a precursor of the active ingredient to obtain a precursor solution;

[0088] mixing the heteropolyacid-modified Ti oxide with a precursor solution to obtain a second suspension;

[0089] removing the solvent from the second suspension to obtain a second block;

[0090] The second block is dried twice, ground, and calcined twice to obtain a titanium-based catalyst.

[0091] In the present invention, the precursor includes a transition metal precursor. Considering cost issues, the present invention preferably uses a transition metal precursor. More preferably, in order to obtain the desired titanium-based catalyst, two or more transition metal precursors can be used.

[0092] Specifically, the present invention does not particularly limit the transition metal precursor, and generally it can be any feasible transition metal-containing salt in the art. Taking tungsten salts, vanadium salts, niobium salts, nickel salts, copper salts, and tin salts as examples, the transition metal precursor can be (hydrated) ammonium tungstate, (hydrated) ammonium paratungstate, (hydrated) ammonium metatungstate, tungsten hexachloride, tungsten sulfate, tungsten acetate, tungsten nitrate, ammonium vanadate, ammonium metavanadate, vanadium nitrate, vanadium chloride, (hydrated) vanadium oxysulfate, vanadium oxyacetate, vanadium oxalate, (hydrated) ammonium niobate oxalate, niobium nitrate, niobium chloride, ammonium niobium sulfate, niobium acetate, (hydrated) niobium oxalate, nickel nitrate, nickel chloride, nickel sulfate, nickel acetate, nickel oxalate, copper nitrate, copper chloride, copper sulfate, copper acetate, copper oxalate, tin nitrate, tin chloride, tin sulfate, tin acetate, tin oxalate, etc., or a combination of two or more thereof.

[0093] In some specific embodiments, the mass concentration of the precursor in the precursor solution may be 0.01-1%, for example, 0.02%, 0.05%, 0.08%, 0.1%, 0.2%, 0.5%, 0.8%, etc. Preferably, the precursor solution further comprises a co-solvent, and more preferably, the concentration of the co-solvent is 0.01-1%, for example, 0.02%, 0.05%, 0.08%, 0.1%, 0.2%, 0.5%, 0.8%, etc.

[0094] Furthermore, in the present invention, the co-solvent may be an acidic medium, such as acetic acid, oxalic acid and other commonly used acidic media.

[0095] The heteropolyacid-modified Ti oxide is mixed with a precursor solution to produce a second suspension. The content of the precursor in the second suspension is not particularly limited in the present invention and can be determined based on the content of the active ingredient. Generally, the transition metal oxide content is 0.1% to 10% based on the total mass of the substrate as 100%.

[0096] Specifically, for ease of mixing, the heteropolyacid-modified Ti oxide can be first mixed with a solvent to obtain a heteropolyacid-modified Ti oxide suspension, and then the precursor solution is mixed with the heteropolyacid-modified Ti oxide suspension to obtain a second suspension. The present invention does not particularly limit the concentration of the heteropolyacid-modified Ti oxide in the suspension and can be set as needed, for example, 0.1-20%. The present invention does not particularly limit the concentration of the precursor and the heteropolyacid-modified Ti oxide in the second suspension, as long as the precursor and the heteropolyacid-modified Ti oxide are in full contact.

[0097] In some specific embodiments, the solvent in the second suspension can be removed by heating in a water bath to obtain a second block. Preferably, the water bath heating temperature is 60-100°C, for example: 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 98°C, etc.

[0098] Furthermore, the second block is dried twice, ground, and calcined twice to obtain a titanium-based catalyst.

[0099] In some specific embodiments, the secondary drying temperature is 80-110°C, for example: 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 98°C, 100°C, 102°C, 105°C, 108°C, etc.; the secondary drying time is 12-48h, for example: 15h, 18h, 20h, 22h, 25h, 28h, 30h, 32h, 35h, 38h, 40h, 42h, 45h, etc.

[0100] In some specific embodiments, the secondary calcination comprises heating to 150-900° C. and calcining for 5-24 hours at a heating rate of 1-20° C. / min. For example, the heating rate can be 2° C. / min, 4° C. / min, 6° C. / min, 8° C. / min, 10° C. / min, 12° C. / min, 14° C. / min, 16° C. / min, 18° C. / min, etc.; the temperature after heating can be 200° C., 250° C., 300° C., 350° C., 400° C., 450° C., 500° C., 550° C., 600° C., 650° C., 700° C., 750° C., 800° C., 850° C., etc., and the calcination time can be 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, etc.

[0101] The preparation method of the present invention adopts calcination treatment at an appropriate temperature, which can make the catalyst more stable and ensure close charge interaction between active components and between active components and the matrix during the reaction process, so that the reaction gas can more easily participate in the reaction, thereby achieving the purpose of high removal rate and high selectivity of target product.

[0102] <Third Aspect>

[0103] A third aspect of the present invention provides a method for synergistically removing nitrogen oxides and heteroatom-containing volatile organic compounds (VOCs) using the titanium-based catalyst described in the first aspect of the present invention. The heteroatom may be chlorine-containing VOCs, nitrogen-containing VOCs, sulfur-containing VOCs, or the like, preferably chlorine-containing VOCs.

[0104] By using the catalyst of the present invention, the VOCs conversion efficiency can be improved, and the active temperature range of the catalyst can be 150-400°C.

[0105] Example

[0106] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be obtained commercially.

[0107] Example 1

[0108] First, add 100 mL of deionized water to a beaker and heat it to 70°C. After the water temperature is constant, add 0.5 g of phosphotungstic acid (HPW) to the beaker and stir magnetically for 5 h at a speed of 80 r / s until the phosphotungstic acid is completely dissolved to obtain a phosphotungstic acid solution.

[0109] Add 5 g of anatase phase TiO2 ultrafine particles to another beaker, then add 200 ml of deionized water to fully suspend the TiO2 particles, and continue stirring for 0.5 h to form a uniform white suspension.

[0110] The phosphotungstic acid solution obtained in the above step was slowly added to the white suspension to obtain a first suspension. The mixed first suspension was stirred continuously for 2 hours to ensure full contact between the phosphotungstic acid and the TiO2 particles. The mixed first suspension was evaporated to dryness in an 80°C water bath to obtain a first block.

[0111] The first block, obtained after complete evaporation, was placed in a 100°C oven for deep drying for 12 hours. The thoroughly dried first block was reground (<60 mesh) and calcined at 550°C for 5 hours at a heating rate of 10°C / min. This uniformly dispersed the phosphotungstic acid on the surface of the TiO2 support, ultimately yielding a HPW / TiO2 matrix.

[0112] Add 100 mL of deionized water to a beaker and heat to 70°C. After the water temperature is constant, add about 0.12 g of NH4VO3 and 0.18 g of co-solvent oxalic acid to the beaker and stir magnetically for 5 h at a speed of 80 r / s until NH4VO3 is completely dissolved to obtain an NH4VO3 solution.

[0113] Add 5 g of HPW / TiO2 matrix to another beaker, and then add 200 mL of deionized water to fully suspend the HPW / TiO2 matrix. Continue stirring for 0.5 h to form a uniform white suspension.

[0114] The NH₄VO₃ solution obtained in the previous step was slowly added to the white suspension to obtain a second suspension. The mixed second suspension was stirred continuously for 2 hours to ensure full contact between the vanadium and the TiO₂ particles. The mixed second suspension was evaporated to dryness in an 80°C water bath to obtain a second block.

[0115] The second block, obtained after complete evaporation, was placed in a 100°C oven for deep drying for 12 hours. The thoroughly dried block was reground (<60 mesh) and calcined at 550°C for 5 hours at a heating rate of 10°C / min. This allowed the NH₄VO₃ to fully decompose into V₂O₅, which was then evenly dispersed on the surface of the TiO₂ support, resulting in the 1V / HPW / TiO₂ catalyst, designated 1V / HPWTi.

[0116] Example 2

[0117] First, add 100 mL of deionized water to a beaker and heat it to 70°C. After the water temperature is constant, add 0.5 g of phosphotungstic acid (HPW) to the beaker and stir magnetically for 5 h at a speed of 80 r / s until the phosphotungstic acid is completely dissolved to obtain a phosphotungstic acid solution.

[0118] Add 5 g of anatase phase TiO2 ultrafine particles to another beaker, then add 200 mL of deionized water to fully suspend the TiO2 particles, and continue stirring for 0.5 h to form a uniform white suspension.

[0119] The phosphotungstic acid solution obtained in the above step was slowly added to the white suspension to obtain a first suspension. The mixed first suspension was stirred continuously for 2 hours to ensure full contact between the phosphotungstic acid and the TiO2 particles. The mixed first suspension was evaporated to dryness in an 80°C water bath to obtain a first block.

[0120] The first block, obtained after complete evaporation, was placed in a 100°C oven for deep drying for 12 hours. The thoroughly dried first block was reground (<60 mesh) and calcined at 550°C for 5 hours at a heating rate of 10°C / min. This uniformly dispersed the phosphotungstic acid on the surface of the TiO2 support, ultimately yielding the HPW / TiO2 catalyst.

[0121] Add 100 mL of deionized water to a beaker and heat to 70°C. After the water temperature is constant, add about 0.24 g of NH4VO3 and 0.36 g of co-solvent oxalic acid to the beaker and stir magnetically for 5 h at a speed of 80 r / s until NH4VO3 is completely dissolved to obtain an NH4VO3 solution.

[0122] Add 5 g of HPW / TiO2 matrix to another beaker, and then add 200 mL of deionized water to fully suspend the HPW / TiO2 matrix. Continue stirring for 0.5 h to form a uniform white suspension.

[0123] The NH₄VO₃ solution obtained in the previous step was slowly added to the white suspension to obtain a second suspension. The mixed second suspension was stirred continuously for 2 hours to ensure full contact between the vanadium in the solution and the TiO₂ particles. The mixed second suspension was evaporated to dryness in an 80°C water bath to obtain a second block.

[0124] The second block, obtained after complete evaporation, was placed in a 100°C oven for deep drying for 12 hours. The thoroughly dried second block was then reground (<60 mesh) and calcined at 550°C for 5 hours at a heating rate of 10°C / min. This allowed the NH₄VO₃ to fully decompose into V₂O₅, which was then evenly dispersed on the surface of the TiO₂ support, resulting in the 2V / HPW / TiO₂ catalyst, designated 2V / HPWTi.

[0125] Example 3

[0126] First, add 100 mL of deionized water to a beaker and heat it to 70°C. After the water temperature is constant, add 0.5 g of phosphomolybdic acid (HPMo) to the beaker and stir magnetically for 5 h at a speed of 80 r / s until the phosphomolybdic acid is completely dissolved to obtain a phosphomolybdic acid solution.

[0127] Add 5 g of anatase phase TiO2 ultrafine particles to another beaker, then add 200 ml of deionized water to fully suspend the TiO2 particles, and continue stirring for 0.5 h to form a uniform white suspension.

[0128] The phosphomolybdic acid solution obtained in the above step was slowly added to the white suspension to obtain a first suspension. The mixed first suspension was stirred continuously for 2 hours to ensure full contact between the phosphomolybdic acid and the TiO2 particles. The mixed first suspension was evaporated to dryness in an 80°C water bath to obtain a first block.

[0129] The first block, obtained after complete evaporation, was placed in a 100°C oven for deep drying for 12 hours. The thoroughly dried first block was reground (<60 mesh) and calcined at 550°C for 5 hours at a heating rate of 10°C / min. This uniformly dispersed the phosphomolybdic acid on the surface of the TiO2 support, ultimately yielding the HPMo / TiO2 catalyst.

[0130] Add 100 mL of deionized water to a beaker and heat to 70°C. After the water temperature is constant, add about 0.24 g of NH4VO3 and 0.36 g of co-solvent oxalic acid to the beaker and stir magnetically for 5 h at a speed of 80 r / s until NH4VO3 is completely dissolved to obtain an NH4VO3 solution.

[0131] Add 5 g of HPMo / TiO2 matrix to another beaker, and then add 200 mL of deionized water to fully suspend the HPMo / TiO2 matrix. Continue stirring for 0.5 h to form a uniform white suspension.

[0132] The NH₄VO₃ solution obtained in the previous step was slowly added to the white suspension to obtain a second suspension. The mixed second suspension was stirred continuously for 2 hours to ensure full contact between the vanadium and the TiO₂ particles. The mixed second suspension was evaporated to dryness in an 80°C water bath to obtain a second block.

[0133] The second block, obtained after complete evaporation, was placed in a 100°C oven for deep drying for 12 hours. The thoroughly dried block was reground (<60 mesh) and calcined at 550°C for 5 hours at a heating rate of 10°C / min. This allowed the NH₄VO₃ to fully decompose into V₂O₅, which was then evenly dispersed on the surface of the TiO₂ support, resulting in the 2V / HPMo / TiO₂ catalyst, designated as 2V / HPMoTi.

[0134] Comparative Example 1

[0135] Add 100 mL of deionized water to a beaker and heat to 70°C. After the water temperature is constant, add about 0.12 g of NH4VO3 and 0.18 g of co-solvent oxalic acid to the beaker and stir magnetically for 5 h at a speed of 80 r / s until the NH4VO3 is completely dissolved to obtain an NH4VO3 solution.

[0136] Add 5 g of anatase phase TiO2 ultrafine particles to another beaker, then add 200 ml of deionized water to fully suspend the TiO2 particles, and continue stirring for 0.5 h to form a uniform white suspension.

[0137] Slowly add the NH₄VO₃ solution obtained in the previous step to the white suspension to obtain a second suspension. Stir the mixed second suspension for 2 hours to ensure full contact between the vanadium and the TiO₂ particles. Evaporate the mixed suspension to dryness in an 80°C water bath to obtain a block.

[0138] The resulting block, after complete evaporation, was placed in a 100°C oven and deep-dried for 12 hours. The thoroughly dried block was reground (<60 mesh) and calcined at 550°C for 5 hours at a heating rate of 10°C / min. This allowed the NH₄VO₃ to fully decompose into V₂O₅, which was then evenly dispersed on the surface of the TiO₂ support, resulting in a 1V / TiO₂ catalyst, denoted as 1V / Ti.

[0139] Comparative Example 2

[0140] First, add 100 mL of deionized water to a beaker and heat it to 70°C. After the water temperature is constant, add about 0.24 g of NH4VO3 and 0.36 g of co-solvent oxalic acid to the beaker and stir magnetically for 5 h at a speed of 80 r / s until the NH4VO3 is completely dissolved to obtain a yellow transparent solution.

[0141] Add 5 g of anatase phase TiO2 ultrafine particles to another beaker, then add an appropriate amount of deionized water to fully suspend the TiO2 particles, and continue stirring for 0.5 h to form a uniform white suspension.

[0142] Slowly add the yellow transparent solution obtained in the above step to the white suspension and continue stirring the mixed suspension for 2 hours to allow the vanadium in the solution to fully contact the TiO2 particles. Evaporate the mixed light yellow suspension to dryness in an 80°C water bath to obtain a yellow block.

[0143] The yellow block obtained after complete evaporation was placed in a 100°C oven for deep drying for 12 hours. The thoroughly dried block was re-ground (<60 mesh) and calcined at 550°C for 5 hours at a heating rate of 10°C / min. This allowed the metal oxide precursor to fully decompose to form V2O5, which was then evenly dispersed on the surface of the TiO2 support, resulting in a V2O5 / TiO2 catalyst, designated as 2V / Ti.

[0144] Performance Testing

[0145] 1. Catalytic performance test

[0146] The catalysts of Examples 1-3 and Comparative Examples 1-2 were used to treat chlorobenzene and nitrogen oxides (NO x ) catalytic oxidation efficiency, the operation steps are as follows: grind the catalyst and sieve to obtain 40-60 mesh catalyst particles; place the catalyst particles in a quartz tube, introduce chlorobenzene (500ppm), NO (500ppm), NH3 (500ppm) and O2 (vol.10%), use N2 to remove chlorobenzene from the bubbling bottle, and use another N2 as a balance gas, the total gas flow rate is 100mL / min. Among them, the inlet and outlet chlorobenzene (CB) and NO x The content was determined by a portable Fourier infrared gas analyzer GASMET, and the results were as follows Figure 1 shown.

[0147] In the low temperature range (150-250°C), the 1V / HPWTi of Example 1 and the 2V / HPWTi of Example 2 showed better multi-pollutant purification performance. In the simulated flue gas, it also maintained good N2 selectivity in the range of 150-400°C ( Figure 1 a).

[0148] However, for 2V / HPWTi of Example 2, a slight decrease in nitrogen oxide conversion was observed above 225°C, which may be due to excessive oxidation of ammonia by the titanium-based catalyst. In the oxidation of chlorobenzene under multi-pollutant catalytic oxidation conditions, the conversion of chlorobenzene was significantly improved in the range of 150-400°C by modifying TiO2 with phosphotungstic acid ( Figure 1 b).

[0149] Depend on Figure 1 It can be seen from the ab that at 250℃ and 350℃, the turnover frequency (TOF) of the catalytic conversion of nitrogen oxides and chlorobenzene on 1V / HPWTi of Example 1 is 3.37 times and 59.83 times that of 1V / Ti, respectively. In addition, between 225-400℃, the CO x The yield is higher than that of the catalyst of Comparative Example 1-2 ( Figure 1 c), indicating that the selectivity of chlorinated organic byproducts or intermediates is low under multi-pollutant catalytic oxidation conditions.

[0150] The 1V / Ti of Comparative Example 1, the 2V / Ti of Comparative Example 2, the 1V / HPWTi of Example 1 and the 2V / HPWTi of Example 2 were qualitatively compared ( Figure 1 d) shows that the catalyst with heteropolyacid-modified Ti oxide as the matrix has more outstanding multi-pollutant control performance. Figure 1 The NOx and chlorobenzene combustion conversion rates of 2V / HPWTi and CO xThe yield is higher than 2V / HPMoTi.

[0151] 2. X-ray diffraction test

[0152] The X-ray diffraction (XRD) patterns of the titanium-based catalyst samples were obtained using a Bruker D8 / Advance diffractometer. The instrument used a monochromatic Cu Kα light source generator (λ = 0.15418 nm). The current and voltage were 20 mA and 40 kV, respectively. The scanning range (2θ) was 10–90°, and the scanning rate was 5° min -1 .

[0153] Depend on Figure 2 It can be seen that the XRD patterns of the titanium-based catalysts of Examples 1-3 and Comparative Examples 1-2 all show an anatase structure (JCPDS#21-1272) belonging to the TiO2 support, indicating that the heteropolyacid and transition metal oxide are dispersed relatively evenly on the TiO2 support without obvious crystallization.

[0154] 3. Nitrogen adsorption and desorption curve

[0155] The specific surface area and pore structure of the titanium-based catalysts of Examples 2 and 3 were analyzed using a Microtrac BEL Belsorp MAX II physical adsorption instrument. About 200 mg of the titanium-based catalyst sample was used each time. The sample was pretreated at 300°C in a vacuum environment for 3 hours to desorb residual impurities and water vapor on its surface. The nitrogen adsorption capacity of the sample was then measured at -196°C. The Brunauer-Emmett-Teller (BET) formula and the Barrett-Joyner-Halenda (BJH) formula were used to calculate the specific surface area and pore size distribution of the titanium-based catalyst, respectively. The results are shown in FIG. Figure 3 shown.

[0156] Depend on Figure 3 It can be seen that compared with the 2V / HPWTi catalyst of Example 2 and the 2V / HPMoTi catalyst of Example 3, the 2V / HPWTi catalyst has a larger specific surface area and a larger reaction contact area.

[0157] 4. Transmission electron microscopy (TEM) scanning electron microscopy (EDS) energy spectrum test

[0158] The morphology of the titanium-based catalyst of Example 2 was observed by FEI Tecnai G2 F30 high-resolution transmission electron microscope (HRTEM) at an accelerating voltage of 300 kV. Energy dispersive spectroscopy (EDS) was used to observe the distribution of various elements on the titanium-based catalyst. The titanium-based catalyst sample was pre-treated by ultrasonic dispersion in anhydrous ethanol. Figure 4 shown.

[0159] like Figure 4 As shown, the STEM-EDS image of the 2V / HPWTi catalyst of Example 3 shows that the V element, the W element and the P element are evenly distributed in the titanium-based catalyst without obvious aggregation.

[0160] 5. Programmed temperature reduction test

[0161] The test was performed using a Micromeritics AutoChem II 2920 chemisorption analyzer equipped with a thermal conductivity detector (TCD) using hydrogen temperature programmed reduction (H2-TPR). In each experiment, 50 mg of titanium-based catalyst sample was placed in a U-shaped tube and an Ar gas flow (50 mL min -1 ) and pre-treated the sample at 300 °C for 1 hour. After the sample cooled to 50 °C, the gas flow was switched to 5% H2 / Ar (50 mL min -1 ), after the baseline remains unchanged, the -1 The heating rate was increased to 950℃, and the changes of H2 signal were recorded in real time. The results are as follows Figure 5 As shown. Figure 5 It can be seen that the titanium-based catalyst obtained by using heteropolyacid-modified Ti oxide as the matrix has better low-temperature reducibility.

[0162] 6. Temperature-programmed ammonia desorption test

[0163] Ammonia temperature-programmed desorption (NH3-TPD) was used to analyze the strength and number of acidic sites on the surface of the titanium-based catalyst. The test was performed using a Gasmet DX-4000 FTIR gas analyzer. 100 mg of 2V / HPWTi from Example 2 and 2V / HPMoTi from Example 3 were used. First, a N2 gas flow (100 mL min -1 ) and pre-treated the sample at 300 ° C for 1 hour, and then after the sample cooled to 30 ° C, the gas flow was switched to 500 ppm NH3 / N2 (100 mL·min -1 ) and continued to flow for 1 hour to allow NH3 to be saturated and adsorbed, then the gas flow was switched back to N2 to purge the sample for 1 hour. After the baseline remained unchanged, the sample was heated at 10 °C·min -1 The heating rate was increased to 750℃, and the changes of NH3 signal were recorded in real time. The results are as follows Figure 6 shown.

[0164] Depend on Figure 6 It can be seen that compared with 2V / HPWTi of Example 2 and 2V / HPMoTi of Example 3, the NH3-TPD results show that after doping with phosphotungstic acid, the intensity of the weak acid site (<200°C) decreases more, while the intensity of the medium and strong acid site (>200°C) increases.

[0165] 7. Durability test

[0166] The experiment was conducted using the 2V / HPWTi catalyst of Example 2. First, cylinder gases containing N2 (99.99%), O2 (99.99%), NO (1%), NH3 (1%), chlorobenzene (CB) (0.1%), and SO2 (0.1%, if needed) were flowed through a mass flow meter and fed into a mixing bottle to be mixed with simulated flue gas of a certain concentration. The total flow rate of the flue gas was 100 mL min. -1 Before each test, 100 mg of titanium-based catalyst (40-60 mesh) was placed in the center of the quartz reaction tube. The mass space velocity of the titanium-based catalyst was 60,000 cm 3 ·g -1 ·h -1 .

[0167] During the reaction, the simulated flue gas passed through the titanium-based catalyst bed, and the heating temperature of the tubular furnace was continuously measured and controlled by a thermocouple and a temperature controller. The concentrations of NO, NO2, N2O, NH3, CB, CO, CO2 and O2 at the inlet and outlet of the catalytic reactor were measured and recorded online in real time using a GASMET DX-4000 infrared gas analyzer. If necessary, a Hiden mass spectrometer was used to detect the signal intensity of Cl2 (m / z=70) at the outlet of the gas analyzer. Chlorobenzene (500ppm), NO (500ppm), NH3 (500ppm) and O2 (vol.10%) were introduced, and N2 was used to remove the chlorobenzene from the bubbling bottle. Another N2 was used as a balance gas, and the total gas flow rate was 100mL / min. The temperature was kept constant at 325°C, and the results were as follows. Figure 7 shown.

[0168] Depend on Figure 7 It can be seen that the 2V / HPWTi catalyst has excellent stability. In addition, the coexistence of SO2 and H2O has little effect on the catalytic oxidation, and only produces a reversible inhibitory effect on the oxidation of benzene oxide.

[0169] It should be noted that, although the technical solutions of the present invention are described with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0170] While various embodiments of the present invention have been described above, the above descriptions are intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A titanium-based catalyst, characterized in that It comprises a matrix and an active ingredient; wherein, The matrix includes a heteropolyacid-modified Ti oxide; and The active ingredient includes a transition metal oxide; wherein, Based on the total mass of the substrate being 100%, the content of the transition metal oxide is 0.1% to 10%.

2. The titanium-based catalyst according to claim 1, characterized in that In the Ti oxide modified by the heteropoly acid, based on the total mass of the Ti oxide being 100%, the amount of the heteropoly acid used is 0.01-20%.

3. The titanium-based catalyst according to claim 1 or 2, characterized in that The heteropoly acid includes one or a combination of two or more of phosphotungstic acid, phosphomolybdic acid, silicotungstic acid and silicomolybdic acid.

4. The titanium-based catalyst according to any one of claims 1 to 3, characterized in that The transition metal oxide includes one or a combination of two or more of tungsten oxide, vanadium oxide, niobium oxide, copper oxide, nickel oxide, and tin oxide, preferably vanadium oxide.

5. A method for preparing a titanium-based catalyst according to any one of claims 1 to 4, characterized in that: The preparation method comprises the steps of composite-molding the Ti oxide modified by heteropoly acid and the active component.

6. The preparation method according to claim 5, characterized in that: The preparation method of the heteropolyacid-modified Ti oxide comprises the following steps: dissolving a heteropoly acid in a solvent to obtain a heteropoly acid solution; Mixing the heteropoly acid solution with Ti oxide to obtain a first suspension; removing the solvent in the first suspension to obtain a first block; The first block is dried once, ground, and calcined once to obtain a heteropolyacid-modified Ti oxide.

7. The preparation method according to 6 above, characterized in that The mass concentration of the heteropoly acid in the heteropoly acid solution is 0.01-1%, and / or, Removing the solvent in the first suspension by water bath heating to obtain a first block; preferably, the water bath heating temperature is 60-100° C.; and / or, The primary drying temperature is 80-110°C; the primary drying time is 12-48h; and / or, The primary calcination includes heating to 150-900° C. and calcining for 5-24 hours at a heating rate of 1-20° C. / min.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The composite molding comprises the following steps: dissolving a precursor of an active ingredient to obtain a precursor solution; Mixing the heteropolyacid-modified Ti oxide with the precursor solution to obtain a second suspension; removing the solvent in the second suspension to obtain a second block; The second block is dried twice, ground, and calcined twice to obtain a titanium-based catalyst.

9. The preparation method according to claim 8, characterized in that: The mass concentration of the precursor in the precursor solution is 0.01% to 1%; preferably, the precursor solution further comprises a co-solvent, and more preferably, the concentration of the co-solvent is 0.01% to 1%; and / or, Removing the solvent in the second suspension by water bath heating to obtain a second block; preferably, the water bath heating temperature is 60-100° C.; and / or, The secondary drying temperature is 80-110°C; the secondary drying time is 12-48h; and / or, The secondary calcination includes heating to 150-900° C. and calcining for 5-24 hours at a heating rate of 1-20° C. / min.

10. Use of the titanium-based catalyst according to any one of claims 1 to 4 for the synergistic removal of nitrogen oxides and volatile organic compounds containing heteroatoms.

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