VOCs catalytic combustion catalyst and preparation method thereof

Abstract

The invention relates to a VOCs catalytic combustion catalyst and a preparation method thereof, and relates to the technical field of catalysts.The VOCs catalytic combustion catalyst is prepared from, by mass, 0.05-2% of an active component platinum, 0.1-5% of a first auxiliary, 0.1-5% of a second auxiliary, 0.1-5% of a third auxiliary and the balance a carrier, the first auxiliary agent is one or a mixture of more of VIIB group elements; the second auxiliary agent is one or a mixture of more of VIII group elements; and the third auxiliary agent is one or a mixture of more of rare earth elements. The VOCs catalytic combustion catalyst provided by the invention has the characteristics of low noble metal content, good dispersion, low cost, rapid low-temperature ignition, adaptability to large-air-volume and high-airspeed reaction and the like, and effectively solves the problems of high cost, poor active component dispersion and the like of the existing VOCs catalytic combustion noble metal catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a VOCs catalytic combustion catalyst and a preparation method thereof. Background Art

[0002] Volatile organic compounds (VOCs) refer to all organic compounds that can evaporate into the air at normal temperature and pressure. They are very likely to cause atmospheric pollution such as haze and photochemical smog, which can endanger human health. There are more than 350 types of volatile organic compounds (VOCs), of which more than 20 are mutagens or carcinogens, and most are flammable and explosive. At present, common VOCs mainly include some toxic substances such as benzene, toluene, xylene, chlorobenzene, formaldehyde, etc. VOCs mainly come from fine chemicals and petrochemical industries. However, some industries also produce VOCs in industrial production. For example: the pharmaceutical industry, electronic component manufacturing industry, printing industry, etc., will also release benzene-related substances.

[0003] At present, catalytic combustion is considered to be the most promising and effective technology for removing VOCs. Both at home and abroad, extensive and in-depth research is being conducted on the related fields of using catalytic technology to treat VOC substances. Precious metals, especially platinum group elements, have a strong ability to activate molecular oxygen under low temperature conditions. They have high oxidation activity and selectivity for hydrocarbon compounds, low reaction temperature, long life, and high temperature resistance. The active component precious metals are often loaded on γ-Al2O3, TiO2, and CeO2, making the precious metals highly dispersed. Since the research on precious metal catalysts started early, precious metal catalysts are relatively mature so far, and there are many perfect processes. However, due to high costs and low natural reserves, precious metal catalysts are in short supply. Reducing the use of precious metal catalysts while maintaining the level of catalytic activity is a major and ongoing challenge in this field.

[0004] Ao et al. prepared a combined Pt / TiO2 catalyst, whose active components are mainly Pt 0 exists in the form of Pt 0 The catalyst has excellent catalytic activity for toluene oxidation, but the Pt content is high and the catalyst cost is high. 0 Transformed into high-valent Pt, the catalytic activity decreased. Ren et al. prepared Ti by hydrothermal method 3+ Self-doped TiO2, when NaBH4 is added during the hydrothermal process, can be used directly as a reducing agent and can hydrolyze to release H2 to obtain a reducing atmosphere. Its addition can transform part of anatase TiO2 into rutile TiO2 and make the nanoparticles evolve into a layered structure. This Ti that can capture photoexcited electrons 3+Mixed phase nanoparticles with oxygen vacancies can potentially reduce the recombination rate of electron-hole pairs on the TiO2 surface. Patent CN1415410A discloses a catalytic combustion catalyst and its preparation method. The patent uses the precious metal Pt as the active component, which is loaded on the carrier surface by organic acid competitive adsorption. The carrier surface is coated with Al2O3, TiO2, CeO2, and ZrO2 coatings. The prepared catalyst has a high removal rate for common pollutants that do not contain chlorine, but there are problems such as poor structural stability and low dispersion of precious metals. Patent CN1013245B discloses a catalyst for purifying exhaust gas and its production method, wherein the catalyst is composed of a honeycomb carrier with a monolithic structure and a coating coated thereon, and the coating is composed of zirconium oxide loaded with platinum group metals, refractory inorganic oxides and rare earth metal oxides. The preparation method of the catalyst is: first, the inorganic oxide is impregnated with an aqueous solution containing precious metals, and then dried and calcined. Then, the honeycomb ceramic carrier is washed with an aqueous slurry prepared by mixing zirconium oxide loaded with precious metals and other oxides, and finally a monolithic honeycomb ceramic carrier catalyst is obtained after drying and calcination. However, the problem with this preparation method is that a large part of the precious metal active components of the catalyst are covered by other oxides in the coating, thereby affecting the full utilization and effective function of the precious metals, and the precious metal active components cannot be uniformly loaded on the catalyst surface through effective competitive adsorption, thereby reducing the performance of the precious metal active components. Summary of the invention

[0005] In view of the common problems of VOCs catalytic combustion noble metal catalysts such as high cost and poor dispersion of active components, the present invention provides a VOCs catalytic combustion catalyst and a preparation method thereof.

[0006] In a first aspect, the present invention provides a VOCs catalytic combustion catalyst. Based on the total dry mass of the VOCs catalytic combustion catalyst, the VOCs catalytic combustion catalyst comprises the following components by mass fraction:

[0007] The active component is platinum 0.05-2%, the first auxiliary agent 0.1-5%, the second auxiliary agent 0.1-5%, the third auxiliary agent 0.1-5%, and the rest is a carrier;

[0008] The first auxiliary agent is one or a mixture of several elements in Group VIIB;

[0009] The second auxiliary agent is one or a mixture of several elements from Group VIII;

[0010] The third auxiliary agent is one or a mixture of several rare earth elements;

[0011] The carrier is TiO2 with micron tube morphology.

[0012] Furthermore, based on the total dry mass of the VOCs catalytic combustion catalyst, the VOCs catalytic combustion catalyst includes the following components:

[0013] The active component is platinum 0.2-1%, the first auxiliary agent 0.1-3%, the second auxiliary agent 0.1-3%, the third auxiliary agent 0.1-3%, and the rest is carrier.

[0014] Furthermore, the physical and chemical properties of the carrier include: a specific surface area of ​​30 to 150 m 2 / g, particle size 50~200μm.

[0015] Furthermore, the platinum in the active component is derived from one or more of platinum oxide, platinum hydroxide, platinum sulfide, platinum chloride, platinum cyanide, chloroplatinic acid, hexachloroplatinic acid and platinum nitrate;

[0016] The Group VIIB element is derived from one or more of Group VIIB element metal powder, Group VIIB element halide, Group VIIB element oxide, Group VIIB element sulfide, Group VIIB element sulfate, Group VIIB element nitrate, Group VIIB element acetate and Group VIIB element oxalate;

[0017] The Group VIII element is derived from one or more of Group VIII element metal powder, Group VIII element halide, Group VIII element oxide, Group VIII element sulfide, Group VIII element sulfate, Group VIII element nitrate, Group VIII element acetate and Group VIII element oxalate;

[0018] The rare earth metal element is derived from one or more of rare earth metal powder, rare earth metal halide, rare earth metal oxide, rare earth metal sulfide, rare earth metal sulfate, rare earth metal nitrate, rare earth metal acetate and rare earth metal oxalate.

[0019] Furthermore, the first auxiliary agent is Mn; the second auxiliary agent is Fe; and the third auxiliary agent is Ce.

[0020] In a second aspect, the present invention provides a method for preparing the VOCs catalytic combustion catalyst according to any one of the first aspects, the preparation method comprising the following steps:

[0021] preparing a mixed solution containing a first auxiliary agent, a second auxiliary agent, a third auxiliary agent, titanyl sulfate-sulfuric acid hydrate, glycerol, ethanol and ether;

[0022] The mixed solution is subjected to hydrothermal crystallization, washing, drying and calcining to obtain micron-tube TiO2;

[0023] The micronized TiO2 is stirred with a weakly alkaline solution containing NaBH4, and then a platinum solution is added and stirred continuously, and then a precipitant is added, and the pH value is adjusted to 9-10, and stirring is continued, and centrifugation is performed to obtain a semi-finished product;

[0024] The semi-finished product is dried and calcined to obtain the VOCs catalytic combustion catalyst.

[0025] Furthermore, the working condition parameters of the hydrothermal crystallization include: hydrothermal crystallization at 100-150° C. for 20-30 hours.

[0026] Furthermore, the calcination working condition parameters include: calcination at 400-800° C. for 2-6 hours.

[0027] Furthermore, the working condition parameters of the calcination include: calcination at 350-650° C. for 2-10 hours.

[0028] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0029] The embodiment of the present invention provides a VOCs catalytic combustion catalyst and a preparation method thereof. The VOCs catalytic combustion catalyst provided by the present invention has the characteristics of low precious metal content, good dispersion, low cost, rapid low-temperature ignition, and adaptability to large air volume and high space velocity reactions, and effectively solves the problems of high cost and poor dispersion of active components of existing VOCs catalytic combustion precious metal catalysts. Specifically:

[0030] 1. The VOCs catalytic combustion catalyst carrier provided by the present invention has a micron tube morphology and a high specific surface area, which increases the dispersion of precious metals and can reduce the amount of precious metals used. The addition of Group VIIB elements, Group VIII elements, and rare earth elements, on the one hand, makes the catalyst more active and selective. On the other hand, the catalyst exhibits good deep oxidation ability and good low-temperature ignition activity. Since the additive and the carrier will form a relatively more stable titanium-containing spinel structure, the overall stability, strength and abrasion of the catalyst are increased, and the problem of catalyst loss during use is alleviated. In addition, the raw materials for the production of the catalyst are simple and easy to obtain, the preparation process is simple, and the existing production line can be used for efficient, stable and economical production, which can effectively replace the existing traditional platinum-based VOCs catalytic combustion catalyst.

[0031] 2. The Pt-based VOCs catalyst combustion catalyst provided by the present invention uses micron-tube titanium dioxide with a high specific surface area as a carrier, which increases the dispersion of precious metals and can reduce the amount of precious metals used. The addition of Group VIII elements and rare earth elements, on the one hand, controls the existence state of the active center by adjusting the electrical properties of the carrier surface, so that the catalyst has higher activity and selectivity. On the other hand, rare earth and its composite oxides are easy to form surface lattice defects in their structure, so that the surface lattice oxygen has a highly active oxidation center, thereby showing good deep oxidation ability and good low-temperature ignition activity. CeO2 can fix Pt and prevent Pt from aggregating. Since the additive and the carrier will form a relatively more stable titanium-containing spinel structure, the overall stability, strength and wear of the catalyst are increased, and the problem of catalyst loss during use is alleviated. In addition, the raw materials for the production of the catalyst are simple and easy to obtain, the preparation process is simple, and the existing production line can be used for efficient, stable and economical production, which can effectively replace the existing traditional platinum-based VOCs catalytic combustion catalyst.

[0032] 3. The volatile organic compound catalytic combustion catalyst using micron tube TiO2 as a carrier disclosed in the present invention has the following characteristics: a) micron tube TiO2 has a large specific surface area, and a low content of precious metal Pt is highly dispersed on the carrier. b) rare earth and its composite oxides are prone to form surface lattice defects in their structure, which makes the surface lattice oxygen have highly active oxidation centers, so that the catalyst exhibits good deep oxidation ability and good low-temperature ignition activity. c) micron tube TiO2 is used as a carrier to improve the thermal conductivity and stability of the catalyst. d) a large amount of Ov is introduced into the catalyst by an in-situ reduction method to produce an appropriate amount of Ti 3+ and Pt 0 Compared with reduction methods such as the hydrothermal method, the oxidation method of high-temperature calcination under N2 atmosphere, and the high-pressure hydrogenation method using H2 to obtain a reducing atmosphere, the in-situ reduction method consumes less energy, takes less time, and is simple to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 A schematic flow chart of a method for preparing a VOCs catalytic combustion catalyst provided in an embodiment of the present invention.

[0036] Figure 2 This is a transmission electron microscope photograph of the catalyst prepared in Comparative Example 1.

[0037] Figure 3 O1s (a), Ti 2p (b), Pt 4f (c) XPS spectra and fitting results of the catalysts prepared in Comparative Example 1 and Comparative Example 2, respectively. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0040] In a first aspect, the present invention provides a VOCs catalytic combustion catalyst. Based on the total dry mass of the VOCs catalytic combustion catalyst, the VOCs catalytic combustion catalyst comprises the following components by mass fraction:

[0041] The active component is platinum 0.05-2%, the first auxiliary agent 0.1-5%, the second auxiliary agent 0.1-5%, the third auxiliary agent 0.1-5%, and the rest is a carrier;

[0042] The first auxiliary agent is one or a mixture of several elements in Group VIIB;

[0043] The second auxiliary agent is one or a mixture of several elements from Group VIII;

[0044] The third auxiliary agent is one or a mixture of several rare earth elements;

[0045] The carrier is TiO2 with micron tube morphology.

[0046] The embodiment of the present invention provides a VOCs catalytic combustion catalyst. The VOCs catalytic combustion catalyst provided by the present invention has the characteristics of low precious metal content, good dispersion, low cost, rapid ignition at low temperature, and adaptability to large air volume and high space velocity reactions, and effectively solves the problems of high cost and poor dispersion of active components of existing VOCs catalytic combustion precious metal catalysts.

[0047] In some specific embodiments, based on the total dry weight of the VOCs catalytic combustion catalyst, the VOCs catalytic combustion catalyst includes the following components:

[0048] The active component is platinum 0.2-1%, the first auxiliary agent 0.1-3%, the second auxiliary agent 0.1-3%, the third auxiliary agent 0.1-3%, and the rest is carrier.

[0049] In some specific embodiments, the physical and chemical properties of the carrier include: a specific surface area of ​​30 to 150 m 2 / g, particle size 50~200μm.

[0050] In some specific embodiments, the platinum in the active component is derived from one or more of platinum oxide, platinum hydroxide, platinum sulfide, platinum chloride, platinum cyanide, chloroplatinic acid, hexachloroplatinic acid and platinum nitrate;

[0051] The Group VIIB element is derived from one or more of Group VIIB element metal powder, Group VIIB element halide, Group VIIB element oxide, Group VIIB element sulfide, Group VIIB element sulfate, Group VIIB element nitrate, Group VIIB element acetate and Group VIIB element oxalate;

[0052] The Group VIII element is derived from one or more of Group VIII element metal powder, Group VIII element halide, Group VIII element oxide, Group VIII element sulfide, Group VIII element sulfate, Group VIII element nitrate, Group VIII element acetate and Group VIII element oxalate;

[0053] The rare earth metal element is derived from one or more of rare earth metal powder, rare earth metal halide, rare earth metal oxide, rare earth metal sulfide, rare earth metal sulfate, rare earth metal nitrate, rare earth metal acetate and rare earth metal oxalate.

[0054] In some specific embodiments, the first additive is Mn; the second additive is Fe; and the third additive is Ce.

[0055] In the second aspect, based on the same inventive concept, the present invention provides a method for preparing the VOCs catalytic combustion catalyst according to any one of the first aspects, such as Figure 1 As shown, the preparation method comprises the following steps:

[0056] preparing a mixed solution containing a first auxiliary agent, a second auxiliary agent, a third auxiliary agent, titanyl sulfate-sulfuric acid hydrate, glycerol, ethanol and ether;

[0057] The mixed solution is subjected to hydrothermal crystallization, washing, drying and calcining to obtain micron-tube TiO2;

[0058] The micronized TiO2 is stirred with a weakly alkaline solution containing NaBH4, and then a platinum solution is added and stirred continuously, and then a precipitant is added, and the pH value is adjusted to 9-10, and stirring is continued, and centrifugation is performed to obtain a semi-finished product;

[0059] The semi-finished product is dried and calcined to obtain the VOCs catalytic combustion catalyst.

[0060] In some specific embodiments, the working condition parameters of the hydrothermal crystallization include: hydrothermal crystallization at 100-150° C. for 20-30 hours.

[0061] In some specific embodiments, the calcination working condition parameters include: calcination at 400-800° C. for 2-6 hours.

[0062] In some specific embodiments, the working condition parameters of the calcination include: calcination at 350-650° C. for 2-10 hours.

[0063] In some specific embodiments, the required platinum-containing soluble solution is prepared, and the platinum source can use one of platinum oxide, platinum acetate, platinum nitrate and platinum oxalate; the required lanthanum or cerium-containing soluble solution is prepared, and the lanthanum source can use one of lanthanum sulfate, lanthanum chloride and lanthanum nitrate, and the cerium source can use one of cerium chloride, cerium nitrate and cerium sulfate; the required manganese or iron-containing soluble solution is prepared, and the manganese source can use one of manganese sulfate, manganese chloride and manganese nitrate, and the iron source can use one of iron chloride, iron nitrate and iron sulfate.

[0064] In some specific embodiments, in the process of preparing micron tube TiO2 carrier by hydrothermal crystallization method, the hydrothermal crystallization time is preferably 20 to 28 hours, more preferably 22 to 26 hours; the hydrothermal crystallization temperature is preferably 100 to 140°C, more preferably 110 to 130°C; the carrier drying time is preferably 2 to 8 hours, more preferably 4 to 7 hours; the carrier calcination temperature is preferably 400 to 750°C, more preferably 400 to 600°C; the carrier calcination time is preferably 2 to 5 hours, more preferably 3 to 4 hours. In the process of preparing catalyst by coprecipitation method, the semi-finished product calcination temperature is preferably 400 to 600°C, more preferably 500 to 600°C; the calcination time is preferably 4 to 10 hours, more preferably 5 to 8 hours.

[0065] It should be noted that the component raw materials involved in the VOCs catalytic combustion catalyst and the preparation method thereof provided in the embodiments of the present invention, unless otherwise specified or specified, can be directly commercially available products or homemade using existing public preparation methods; at the same time, the steps and parameters involved, unless otherwise specified or specified, can be carried out according to the existing VOCs catalytic combustion catalyst processing technology or directly using existing equipment, and the present invention document will not describe them one by one.

[0066] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0067] Example 1

[0068] This example provides a micron tube TiO2 carrier without additives, and the preparation method thereof comprises the following steps:

[0069] Weigh 21.33g of titanyl sulfate-sulfuric acid hydrate, 63.36g of propylene glycol, 100ml of ethanol, and 49ml of ether, and mix them into a mixed solution. After stirring the mixed solution for 6 hours, hydrothermally crystallize it at 110°C for 24 hours, and wash the obtained product with ethanol three times. Then put it in a 100°C oven and dry it for 8 hours to obtain a precursor; calcine the precursor in a muffle furnace at a calcination temperature of 400°C, a calcination time of 3 hours, and a heating rate of 2°C per minute. When the catalyst naturally cools down to below 100°C, a micron tube TiO2 carrier is obtained.

[0070] Example 2

[0071] This embodiment provides a VOCs catalytic combustion catalyst, and the preparation method thereof includes:

[0072] Weigh 21.33g of titanium sulfate-sulfuric acid hydrate, 63.36g of glycerol, 100ml of ethanol, 49ml of ether, 0.15g of 50% manganese nitrate, and 0.093g of hexahydrated cerium nitrate, and mix them into a mixed solution. After stirring the mixed solution for 6 hours, hydrothermally crystallize it at 110°C for 24 hours, and wash the obtained product with ethanol 3 times. Then put it into a 100°C oven for drying for 8 hours to obtain a precursor; the precursor is calcined in a muffle furnace at a calcination temperature of 400°C, a calcination time of 3 hours, and a heating rate of 2°C per minute. When the catalyst is naturally cooled to below 100°C, a micron tube TiO2 carrier doped with 1% Mn and 0.5% Ce is obtained, which is expressed as TiO2-1%Mn-0.5%Ce.

[0073] Weigh 0.1g NaOH and 0.99g NaBH4, dissolve in 20ml distilled water, add 1g TiO2-1% Mn-0.5% Ce after dissolution, stir vigorously to disperse it to obtain a suspension. Use a syringe pump to control the injection of 0.0138g of 14.56% platinum nitrate aqueous solution into the suspension, and stir the solution vigorously for 3 hours, then gradually add the precipitant sodium hydroxide, adjust the pH to 9.5, continue stirring for 5 hours, and then centrifuge the slurry to obtain a semi-finished product. Dry the semi-finished product at 60°C for 12 hours, and then roast it at 400°C for 5 hours to obtain the catalyst Pt / TiO2-1% Mn-0.5% Ce-R.

[0074] Example 3

[0075] This embodiment provides a VOCs catalytic combustion catalyst, and the preparation method thereof includes:

[0076] Weigh 10.67g of titanyl sulfate-sulfuric acid hydrate, 31.68g of glycerol, 50ml of ethanol, 25ml of ether, 0.087g of ferric nitrate nine hydrate, and 0.038g of 50% manganese nitrate, and mix them into a mixed solution. After the mixed solution is stirred for 6 hours, it is hydrothermally crystallized at 110°C for 24 hours, and the obtained product is washed with ethanol 3 times. Then it is placed in a 100°C oven for drying for 8 hours to obtain a precursor; the precursor is calcined in a muffle furnace at a calcination temperature of 400°C, a calcination time of 3 hours, and a heating rate of 2°C per minute. When the catalyst is naturally cooled to below 100°C, a micron tube TiO2 carrier doped with 1% Fe and 0.5% Mn is obtained, which is expressed as TiO2-1%Fe-0.5%Mn.

[0077] Weigh 0.1g NaOH and 0.99g NaBH4, dissolve in 20ml distilled water, add 1g TiO2-1% Fe-0.5% Mn after dissolution, and stir vigorously to disperse it to obtain a suspension. Use a syringe pump to control the injection of 0.0138g of 14.56% platinum nitrate aqueous solution into the suspension, and stir the solution vigorously for 3 hours, then gradually add the precipitant sodium hydroxide, adjust the pH to 9.5, continue stirring for 5 hours, and then centrifuge the slurry to obtain a semi-finished product. Dry the semi-finished product at 60°C for 12 hours, and then roast it at 400°C for 5 hours to obtain the catalyst Pt / TiO2-1% Fe-0.5% MnR.

[0078] Example 4

[0079] This embodiment provides a VOCs catalytic combustion catalyst, and the preparation method thereof includes:

[0080] Weigh 10.67g of titanium sulfate-sulfuric acid hydrate, 31.68g of glycerol, 50ml of ethanol, 25ml of ether, 0.093g of cerium nitrate hexahydrate, and 0.038g of 50% manganese nitrate, and mix them into a mixed solution. After the mixed solution is stirred for 6 hours, it is hydrothermally crystallized at 110°C for 24 hours, and the obtained product is washed with ethanol 3 times. Then it is placed in a 100°C oven for drying for 8 hours to obtain a precursor; the precursor is calcined in a muffle furnace at a calcination temperature of 400°C, a calcination time of 3 hours, and a heating rate of 2°C per minute. When the catalyst is naturally cooled to below 100°C, a micron tube TiO2 carrier doped with 1% Ce and 0.5% Mn is obtained, which is expressed as TiO2-1% Ce-0.5% Mn.

[0081] Weigh 0.1g NaOH and 0.99g NaBH4, dissolve in 20ml distilled water, add 1g TiO2-1% Ce-0.5% Mn after dissolution, and stir vigorously to disperse it to obtain a suspension. Use a syringe pump to control the injection of 0.0138g of 14.56% platinum nitrate aqueous solution into the suspension, and stir the solution vigorously for 3 hours, then gradually add the precipitant sodium hydroxide, adjust the pH to 9.5, continue stirring for 5 hours, and then centrifuge the slurry to obtain a semi-finished product. Dry the semi-finished product at 60°C for 12 hours, and then roast it at 400°C for 5 hours to obtain the catalyst Pt / TiO2-1% Ce-0.5% Mn-R.

[0082] Example 5

[0083] This embodiment provides a VOCs catalytic combustion catalyst, and the preparation method thereof includes:

[0084] Weigh 7.11g of titanyl sulfate-sulfuric acid hydrate, 21.12g of glycerol, 33ml of ethanol, 16.7ml of ether, 0.062g of lanthanum nitrate hexahydrate, and 0.029g of ferric nitrate nonahydrate, and mix them into a mixed solution. After stirring the mixed solution for 6 hours, hydrothermally crystallize it at 110°C for 24 hours, and wash the obtained product with ethanol 3 times. Then put it in a 100°C oven and dry it for 8 hours to obtain a precursor; the precursor is calcined in a muffle furnace at a calcination temperature of 400°C, a calcination time of 3 hours, and a heating rate of 2°C per minute. When the catalyst is naturally cooled to below 100°C, a micron tube TiO2 carrier doped with 1% La and 0.5% Fe is obtained, which is expressed as TiO2-1%La-0.5%Fe.

[0085] Weigh 0.1g NaOH and 0.99g NaBH4, dissolve in 20ml distilled water, add 1g TiO2-1% La-0.5% Fe after dissolution, and stir vigorously to disperse it to obtain a suspension. Use a syringe pump to control the injection of 0.0138g of 14.56% platinum nitrate aqueous solution into the suspension, and stir the solution vigorously for 3 hours, then gradually add the precipitant sodium hydroxide, adjust the pH to 9.5, continue stirring for 5 hours, and then centrifuge the slurry to obtain a semi-finished product. Dry the semi-finished product at 60°C for 12 hours, and then roast it at 400°C for 5 hours to obtain the catalyst Pt / TiO2-1% La-0.5% Fe-R.

[0086] Comparative Example 1

[0087] Weigh 0.1g NaOH and 0.99g NaBH4, dissolve in 20ml distilled water, add 1g micron tube TiO2 carrier obtained in Example 1 after dissolution, and stir vigorously to disperse it to obtain a suspension. Use a syringe pump to control the injection of 0.0138g of 14.56% platinum nitrate aqueous solution into the suspension, and stir the solution vigorously for 3 hours, then gradually add the precipitant sodium hydroxide, adjust the pH to 9.5, continue stirring for 5 hours, and then centrifuge the slurry to obtain a semi-finished product. Dry the semi-finished product at 60°C for 12 hours, and then roast it at 400°C for 5 hours to obtain the catalyst Pt / TiO2-R.

[0088] Comparative Example 2

[0089] Weigh 1g of the micron tube TiO2 carrier obtained in Example 1 and disperse it in 20ml of distilled water. Use a syringe pump to control the injection of 0.0138g of 14.56% platinum nitrate aqueous solution into the suspension, and stir the solution vigorously for 3 hours, then gradually add the precipitant sodium hydroxide, adjust the pH to 9.5, continue stirring for 5 hours, and then centrifuge the slurry to obtain a semi-finished product. Dry the semi-finished product at 60°C for 12 hours, and then calcine at 400°C for 5 hours to obtain the catalyst Pt / TiO2.

[0090] Comparative Example 3

[0091] Weigh 10.67g of titanium sulfate-sulfuric acid hydrate, 31.68g of glycerol, 50ml of ethanol, 25ml of ether, and 0.047g of cerium nitrate hexahydrate, and mix them into a mixed solution. After stirring the mixed solution for 6 hours, hydrothermally crystallize it at 110°C for 24 hours, and wash the obtained product with ethanol 3 times. Then put it into a 100°C oven for drying for 8 hours to obtain a precursor; the precursor is calcined in a muffle furnace at a calcination temperature of 400°C, a calcination time of 3 hours, and a heating rate of 2°C per minute. When the catalyst is naturally cooled to below 100°C, a micron tube TiO2 carrier doped with 0.5% Ce is obtained, which is expressed as TiO2-0.5%Ce.

[0092] Weigh 0.1g NaOH and 0.99g NaBH4, dissolve in 20ml distilled water, add 1g TiO2-0.5% Ce after dissolution, and stir vigorously to disperse it to obtain a suspension. Use a syringe pump to control the injection of 0.0138g of 14.56% platinum nitrate aqueous solution into the suspension, and stir the solution vigorously for 3 hours, then gradually add the precipitant sodium hydroxide, adjust the pH to 9.5, continue stirring for 5 hours, and then centrifuge the slurry to obtain a semi-finished product. Dry the semi-finished product at 60°C for 12 hours, and then roast it at 400°C for 5 hours to obtain the catalyst Pt / TiO2-0.5% Ce-R.

[0093] Test Example 1

[0094] In this example, the VOCs catalytic combustion catalysts 1-4 obtained in the above examples 2, 3, 4, and 5 and the comparison agents 1-3 in the comparative examples 1, 2, and 3 were respectively subjected to toluene catalytic combustion tests. The process flow adopted is the existing process flow, which is not elaborated in detail in the examples. The control parameters in the process flow are as follows: the toluene concentration is 800ppm, an appropriate amount of nitrogen is introduced, and the toluene volume space velocity is maintained at 10000h -1 The total pressure of the reaction system is atmospheric pressure. The results are shown in Table 1 (T90 and T99 are the reaction temperatures when the toluene conversion rate reaches 90% and 99%, respectively).

[0095] Table 1

[0096]

[0097] It can be seen from Table 1 that after in-situ reduction treatment and doping modification of the carrier, the catalytic activity of the platinum-based catalyst using microtube titanium dioxide as the carrier was greatly improved in the catalytic toluene degradation experiment.

[0098] Test Example 2

[0099] In this example, the toluene degradation performance of the catalyst carrier in Example 4 calcined at different temperatures was tested. The process flow adopted was the existing process flow, which is not elaborated in detail in the example. The control parameters in the process flow are as follows: the toluene concentration is 800ppm, an appropriate amount of nitrogen is introduced, and the toluene volume space velocity is maintained at 10000h -1 , the total pressure of the reaction system is atmospheric pressure; the results are shown in Table 2.

[0100] Table 2

[0101]

[0102]

[0103] It can be seen from Table 2 that a suitable carrier calcination temperature is beneficial to improving the catalytic activity of the platinum-based catalyst using microtube titanium dioxide as a carrier.

[0104] In addition, the transmission electron microscopy photograph of the catalyst prepared in Comparative Example 1 is as follows Figure 2 As shown, the XPS spectra and fitting results of O1s (a), Ti 2p (b), and Pt 4f (c) of the catalysts prepared in Comparative Example 1 and Comparative Example 2 are shown in Figure 3 As shown. Figure 2 and Figure 3 It can be seen that the in-situ reduction treatment did not ads The peak area S(O ads ) increases significantly. In the fitting results of the sample Pt / TiO2-R, the Ti 2p peak is divided into three peaks, namely Ti 4+ 2p 3 / 2 (458.0eV), Ti 3+ 2p 3 / 2 (458.6eV), Ti 4+ 2p 1 / 2 (464.2eV).Pt 0 , Pt 2+ and Pt 4+ The corresponding Pt 4f standard binding energies are 71.1eV, 72.4eV and 74.2eV respectively. 2+ and Pt 4+ , Pt / TiO2-R catalysts also contain Pt 0 , Pt 2+ and Pt 4+ , indicating that Pt 0 Due to the reduction treatment, the binding energy of Pt 4f changes and causes the electron cloud of Pt to shift, which increases the number of electronegative atoms around Pt.

[0105] In summary, the embodiment of the present invention provides a VOCs catalytic combustion catalyst and a preparation method thereof. The platinum-based catalyst using micron tube titanium dioxide as a carrier has excellent reaction activity in the catalytic oxidation reaction of toluene, and compared with the existing traditional platinum-based catalyst, the platinum-based catalyst using micron tube titanium dioxide as a carrier has better dispersibility of active components, lower precious metal dosage, higher activity and better stability. In addition, the raw materials for the production of the platinum-based catalyst using micron tube titanium dioxide as a carrier are simple and easy to obtain, the preparation process is simple, and the existing production line can be used for efficient, stable and economical production, which can effectively replace the existing traditional platinum-based catalyst.

[0106] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0107] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A VOCs catalytic combustion catalyst, characterized in that: Based on the total dry mass of the VOCs catalytic combustion catalyst, the VOCs catalytic combustion catalyst includes the following components in mass fractions: The active component is platinum 0.05-2%, the first auxiliary agent 0.1-5%, the second auxiliary agent 0.1-5%, the third auxiliary agent 0.1-5%, and the rest is a carrier; The first auxiliary agent is one or a mixture of several elements in Group VIIB; The second auxiliary agent is one or a mixture of several elements from Group VIII; The third auxiliary agent is one or a mixture of several rare earth elements; The carrier is TiO2 with micron tube morphology.

2. The VOCs catalytic combustion catalyst according to claim 1, characterized in that: Based on the total dry mass of the VOCs catalytic combustion catalyst, the VOCs catalytic combustion catalyst includes the following components: The active component is platinum 0.2-1%, the first auxiliary agent 0.1-3%, the second auxiliary agent 0.1-3%, the third auxiliary agent 0.1-3%, and the rest is carrier.

3. The VOCs catalytic combustion catalyst according to claim 1, characterized in that: The physical and chemical properties of the carrier include: specific surface area of ​​30 to 150 m 2 / g, particle size 50~200μm.

4. The VOCs catalytic combustion catalyst according to claim 1, characterized in that: The platinum in the active component is derived from one or more of platinum oxide, platinum hydroxide, platinum sulfide, platinum chloride, platinum cyanide, chloroplatinic acid, hexachloroplatinic acid and platinum nitrate; The Group VIIB element is derived from one or more of Group VIIB element metal powder, Group VIIB element halide, Group VIIB element oxide, Group VIIB element sulfide, Group VIIB element sulfate, Group VIIB element nitrate, Group VIIB element acetate and Group VIIB element oxalate; The Group VIII element is derived from one or more of Group VIII element metal powder, Group VIII element halide, Group VIII element oxide, Group VIII element sulfide, Group VIII element sulfate, Group VIII element nitrate, Group VIII element acetate and Group VIII element oxalate; The rare earth metal element is derived from one or more of rare earth metal powder, rare earth metal halide, rare earth metal oxide, rare earth metal sulfide, rare earth metal sulfate, rare earth metal nitrate, rare earth metal acetate and rare earth metal oxalate.

5. The VOCs catalytic combustion catalyst according to claim 1, characterized in that: The first auxiliary agent is Mn; the second auxiliary agent is Fe; and the third auxiliary agent is Ce.

6. A method for preparing a VOCs catalytic combustion catalyst according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: preparing a mixed solution containing a first auxiliary agent, a second auxiliary agent, a third auxiliary agent, titanyl sulfate-sulfuric acid hydrate, glycerol, ethanol and ether; The mixed solution is subjected to hydrothermal crystallization, washing, drying and calcining to obtain micron-tube TiO2; The micronized TiO2 is stirred with a weakly alkaline solution containing NaBH4, and then a platinum solution is added and stirred continuously, and then a precipitant is added, and the pH value is adjusted to 9-10, and stirring is continued, and centrifugation is performed to obtain a semi-finished product; The semi-finished product is dried and calcined to obtain the VOCs catalytic combustion catalyst.

7. The method for preparing a VOCs catalytic combustion catalyst according to claim 6, characterized in that: The working condition parameters of the hydrothermal crystallization include: hydrothermal crystallization at 100-150° C. for 20-30 hours.

8. The method for preparing a VOCs catalytic combustion catalyst according to claim 6, characterized in that: The working condition parameters of the calcination include: calcining at 400-800° C. for 2-6 hours.

9. The method for preparing a VOCs catalytic combustion catalyst according to claim 6, characterized in that: The working condition parameters of the calcination include: calcination at 350-650° C. for 2-10 hours.

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