A monolithic catalyst with a titanium-containing silicalite coating and a method for its preparation and use

Abstract

The application relates to the technical field of catalyst preparation, and discloses a monolithic catalyst containing a titanium-containing silicon molecular sieve coating as well as a preparation method and application of the monolithic catalyst. The method comprises the following steps: subjecting a regular carrier to acid treatment; mixing an alcohol solution of a titanium source with an aqueous solution containing a micropore template agent and a silicon source, then mixing the obtained gel solution with titanium silicon molecular sieve seeds and a mesopore template agent to obtain a coating slurry; adding the coating slurry into the acid-treated regular carrier, then sequentially performing crystallization, washing, drying and calcination to obtain a carrier containing a coating; and immersing the carrier containing the coating in a mixed solution containing a noble metal precursor and optional structure aids, then sequentially performing drying, calcination and reduction on the immersed catalyst precursor. In the monolithic catalyst containing the titanium-containing silicon molecular sieve coating, the titanium-containing silicon molecular sieve coating and the carrier are combined in a chemical bond mode, and the monolithic catalyst has the advantages of high firmness, strong water resistance and being beneficial to continuous long-period operation.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to an integral catalyst with a titanium-silicon molecular sieve coating, its preparation method, and its application. Background Technology

[0002] In petrochemical production, carbon-based energy molecules often undergo incomplete reactions during directional oxidation, leading to the enrichment of oxygen-containing small molecules in the exhaust gas or circulating carrier gas. This not only poses a risk of combustion and explosion but also generates photochemical phenomena, causing environmental pollution. Currently, the main method for treating oxygen-containing small molecule exhaust gases from petrochemical oxidation processes is catalytic oxidation. Catalytic oxidation can completely oxidize oxygen-containing small molecules into carbon dioxide. Furthermore, to meet the requirements of low pressure drop and high volume operation, catalytic oxidation methods commonly employ monolithic catalysts loaded with precious metals. However, the problems of large amounts of precious metals, high costs, and poor stability still exist.

[0003] Patent application CN102481549B discloses a monolithic catalyst with a Pt-Ru dual active component, a Ce-Cr solid solution and an aqueous tin oxide mixture as coating, and a honeycomb ceramic substrate, used to destroy CO and volatile organic compounds emitted in the process. However, this monolithic catalyst requires loading a large amount of platinum group metals during preparation, and the addition of low specific surface area colloidal silica and titanium oxide binders during the preparation of the monolithic catalyst results in poor dispersion of the noble metals and low effective utilization.

[0004] Patent application CN111036289A discloses a well-structured catalyst with a matrix slurry component of noble metal-modified titanium-silicon molecular sieve. However, the preparation of this catalyst requires the use of nano-titanium sol modified with silane coupling agent, which results in high preparation costs and unclear prospects for industrial application.

[0005] Patent application CN1986035A discloses a method for purifying automobile exhaust gas. The catalyst can purify CO, HC and NOx at a relatively low ignition temperature, but it requires the use of a large amount of precious metals to achieve the expected purification target, and the active components will detach from the carrier after a period of use.

[0006] Patent application CN1488435A discloses a catalytic combustion catalyst and its preparation method. The catalyst has a high conversion efficiency of catalytic combustion of organic waste gas, but it requires the use of a high content of precious metal elements and has disadvantages such as high price, poor anti-poisoning performance and poor general applicability.

[0007] Patent application CN101138728A relates to a catalyst for purifying organic waste gas by a mixture of metal oxides and its preparation method. The method involves loading an active alumina coating modified with a mixture of cerium, lanthanum, and zirconium oxides onto a cordierite support in a single step, along with an active component containing a mixture of various metal oxides. It has the advantages of high catalytic efficiency, simple preparation, low cost, and easy promotion. However, this catalyst is easily deactivated by reducing gas (CO) in industrial waste gas.

[0008] Therefore, the development of catalysts that are highly efficient, inexpensive, environmentally friendly, and durable has become a research hotspot and application trend for catalytic oxidation catalysts both domestically and internationally. Summary of the Invention

[0009] The purpose of this invention is to efficiently remove carbon-based oxygen-containing molecular gases from exhaust gases emitted during petrochemical production processes, and to provide an integral catalyst with a titanium-silicon molecular sieve coating, its preparation method, and its application.

[0010] To achieve the above objectives, the present invention provides a monolithic catalyst with a titanium-silicon molecular sieve coating, the monolithic catalyst comprising:

[0011] The carrier is an acid-treated, structured carrier;

[0012] A coating attached to the carrier, the coating being a titanium-silicon molecular sieve; and

[0013] An active component dispersed in the coating, the active component containing a noble metal and optionally an alloy metal;

[0014] The powder shedding rate of the coating is less than 1%, preferably 0.1-1%, and more preferably 0.1-0.5%.

[0015] Preferably, the particle size of the coating is 50-500 nm.

[0016] Preferably, the mesopore size of the coating is 1-50 nm, and the specific surface area is 300-600 m². 2 / g.

[0017] Preferably, the coating content is 1-10 parts by weight relative to 100 parts by weight of the carrier, and the active component content is 0.1-1 parts by weight.

[0018] Preferably, the regularized carrier is selected from at least one of cordierite honeycomb carrier, mullite honeycomb carrier, diamond honeycomb carrier, corundum honeycomb carrier, zirconium corundum honeycomb carrier, quartz honeycomb carrier, nepheline honeycomb carrier, feldspar honeycomb carrier and alumina honeycomb carrier.

[0019] Preferably, in the active component, the molar ratio of the noble metal to the alloy metal is 1:0.1-0.3.

[0020] Preferably, the precious metal is at least one selected from silver, ruthenium, rhodium, palladium, osmium, iridium, and platinum, and more preferably a combination of platinum and palladium.

[0021] Preferably, the alloy metal is at least one of Fe, La and Ce, and more preferably a combination of La and Ce.

[0022] Preferably, the titanium-silicon molecular sieve is a TS-1 molecular sieve.

[0023] A second aspect of this invention provides a method for preparing a monolithic catalyst with a titanium-silicon molecular sieve coating, the method comprising the following steps:

[0024] (1) Treat the structured carrier with acid;

[0025] (2) Mix the alcohol solution of titanium source with an aqueous solution containing microporous template agent and silicon source, age, remove alcohol, and then mix the resulting gel with titanium silicon molecular sieve seed crystals and mesoporous template agent to obtain coating slurry.

[0026] (3) The coating slurry is added to the acid-treated structured carrier, and then crystallization, washing, drying and calcination are carried out in sequence to obtain a carrier containing the coating.

[0027] (4) The coated carrier is immersed in a mixed solution containing a noble metal precursor and optional structural aids, and then the immersed catalyst precursor is dried, calcined and reduced in sequence.

[0028] Preferably, in step (1), the acid treatment process includes: reflux treatment of the regularized carrier with an acidic solution, followed by washing until neutral and drying.

[0029] Preferably, the concentration of the acidic solution is 1-3 mol / L.

[0030] Preferably, the acid in the acidic solution is at least one of nitric acid, sulfuric acid, and hydrochloric acid.

[0031] Preferably, the reflux treatment conditions include: a temperature of 70-90°C and a time of 12-36 hours.

[0032] Preferably, the regularized carrier is selected from at least one of cordierite honeycomb carrier, mullite honeycomb carrier, diamond honeycomb carrier, corundum honeycomb carrier, zirconium corundum honeycomb carrier, quartz honeycomb carrier, nepheline honeycomb carrier, feldspar honeycomb carrier and alumina honeycomb carrier.

[0033] Preferably, in step (2), the specific process of mixing the alcohol solution of the titanium source with the aqueous solution containing the microporous template agent and the silicon source is as follows: the alcohol solution of the titanium source is added to the aqueous solution containing the microporous template agent and the silicon source at a rate of 0.005-0.015 mL / min, and the mixture is stirred for 2-5 hours.

[0034] Preferably, the titanium source is selected from at least one of tetraalkoxytitanium, tetraalkyl titanate, and titanium tetrachloride.

[0035] Preferably, the microporous template agent is selected from at least one of tetrapropylammonium hydroxide, tetrapropylammonium bromide, and tetraethylammonium hydroxide.

[0036] Preferably, the silicon source is selected from at least one of silicates, silicic acid, silica hydrogels, and tetraethyl orthosilicate.

[0037] Preferably, the titanium-silicon molecular sieve seed crystal is a TS-1 molecular sieve seed crystal.

[0038] Preferably, the mesoporous template agent is selected from at least one of P123 (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer), CTAB (hexadecyltrimethylammonium bromide), and n-butylamine.

[0039] Preferably, in step (3), the crystallization conditions include: a temperature of 150-200℃ and a time of 10-72h.

[0040] Preferably, the roasting conditions include: a temperature of 400-650℃ and a time of 4-10 hours.

[0041] Preferably, in step (4), the pH value of the mixed solution containing the noble metal precursor and the structural aid is 9-12.

[0042] Preferably, the noble metal precursor is selected from at least one of chloroplatinic acid, 2-hydroxyethylamine salt of platinum(IV) hydroxyhydroxide, platinum chloride, platinum nitrate, platinum acetylacetonate, palladium chloride, palladium nitrate, and palladium acetate.

[0043] Preferably, the structural additive is selected from at least one of ferric nitrate, cerium nitrate, lanthanum nitrate, lanthanum sulfate, lanthanum chloride, cerium sulfate, and cerium trioxide.

[0044] Preferably, the roasting conditions include: a temperature of 300-400℃ and a time of 4-10 hours.

[0045] Preferably, during the reduction process, the reducing atmosphere is H2, CO, a combination of H2 and CO, a mixed atmosphere with different hydrogen concentrations, and a mixed atmosphere with different CO concentrations.

[0046] Preferably, the reduction conditions include: a catalyst heating rate of 2-20℃ / min, a reduction temperature of 300-450℃, and a reduction time of 1-10h.

[0047] A third aspect of the present invention provides an integral catalyst with a titanium-silicon molecular sieve coating prepared by the above method.

[0048] The fourth aspect of the present invention provides the application of the above-mentioned monolithic catalyst with titanium-silicon molecular sieve coating in the catalytic oxidation of carbon-based oxygen-containing molecular gases.

[0049] According to the technical solution of this invention, in the preparation process of the catalyst, the titanium-silicon molecular sieve coating is applied after acid treatment of the structured support. The titanium-silicon molecular sieve can react with the exposed hydroxyl groups on the surface of the acid-treated structured support, and a chemical bond is formed between the coating and the structured support. Therefore, the titanium-silicon molecular sieve coating has high firmness and extremely low powder shedding rate. Furthermore, the titanium-silicon molecular sieve coating is formed by crystallization-self-growth, which can promote the dispersion of active noble metals and the exposure of active phase, efficiently construct catalytic active sites on the catalyst surface, and increase the adsorption capacity of carbon-based oxygen-containing molecular gas and oxygen while reducing the content of active noble metal components, promoting oxygen adsorption and activation, thereby improving the catalytic efficiency of the catalyst.

[0050] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0051] (1) The monolithic catalyst with titanium-silicon molecular sieve coating prepared by the present invention has high oxygen adsorption and activation capacity and high catalytic oxidation efficiency.

[0052] (2) The monolithic catalyst with titanium-silicon molecular sieve coating prepared by the present invention has high mechanical strength and is suitable for high space velocity and large volume gas processing conditions.

[0053] (3) In the monolithic catalyst containing titanium-silicon molecular sieve coating of the present invention, the titanium-silicon molecular sieve coating and the support are chemically bonded, which has the advantages of high strength, strong water resistance and is conducive to continuous long-term operation.

[0054] (4) The monolithic catalyst with titanium-silicon molecular sieve coating prepared by the present invention has a low content of active noble metal components, which can greatly reduce operating costs. Attached Figure Description

[0055] Figure 1 This is a SEM image of the monolithic catalyst with a TS-1 molecular sieve coating prepared in Example 1;

[0056] Figure 2 This is a TEM image of the monolithic catalyst with a TS-1 molecular sieve coating prepared in Example 1. Detailed Implementation

[0057] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0058] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0059] In this invention, unless otherwise specified, the gas concentration "%" refers to "volume %"; "space velocity" refers to "volume space velocity"; and "pressure" refers to absolute pressure.

[0060] The monolithic catalyst with a titanium-silicon molecular sieve coating described in this invention comprises:

[0061] The carrier is an acid-treated, structured carrier;

[0062] A coating attached to the carrier, the coating being a titanium-silicon molecular sieve; and

[0063] An active component dispersed in the coating, the active component containing a noble metal and optionally an alloy metal.

[0064] In the monolithic catalyst with a titanium-silicon molecular sieve coating described in this invention, the coating exhibits strong bonding with the structured support. Specifically, the powder shedding rate of the coating is less than 1%, preferably 0.1-1%, and more preferably 0.1-0.5%. In this invention, the powder shedding rate is detected by ultrasonic vibration method, with the detection conditions including: ultrasonic frequency 45kHz, ultrasonic power 130W, and processing time 60min.

[0065] In one specific embodiment, the carrier containing the titanium-silicon molecular sieve coating is prepared according to the following method:

[0066] (1) Treat the structured carrier with acid;

[0067] (2) Mix the alcohol solution of titanium source with an aqueous solution containing microporous template agent and silicon source, age, remove alcohol, and then mix the resulting gel with titanium silicon molecular sieve seed crystals and mesoporous template agent to obtain coating slurry.

[0068] (3) The coating slurry is added to the acid-treated regular carrier, and then crystallization, washing, drying and calcination are carried out in sequence to obtain a carrier containing titanium silicon molecular sieve coating.

[0069] In the above preparation process, a titanium-silicon molecular sieve coating is formed on the structured support through carrier acid treatment and crystallization-self-growth. The titanium-silicon molecular sieve coating and the structured support form chemical bonds, resulting in high strength and extremely low powder shedding rate of the titanium-silicon molecular sieve coating.

[0070] In the monolithic catalyst with titanium-silicon molecular sieve coating described in this invention, the particle size of the coating can be 50-500 nm, preferably 80-480 nm.

[0071] In the monolithic catalyst with a titanium-silicon molecular sieve coating described in this invention, the mesopore size of the coating can be 1-50 nm, preferably 1.7-45 nm; the specific surface area can be 300-600 m². 2 / g, preferably 400-550m 2 / g.

[0072] In the monolithic catalyst with a titanium-silicon molecular sieve coating described in this invention, the content of the coating relative to 100 parts by weight of the support can be 1-10 parts by weight, specifically, for example, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, or 10 parts by weight; the content of the active component can be 0.1-1 part by weight, specifically, for example, 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.4 part by weight, 0.5 part by weight, 0.6 part by weight, 0.7 part by weight, 0.8 part by weight, 0.9 part by weight, or 1 part by weight.

[0073] In this invention, the regularized carrier is preferably selected from at least one of cordierite honeycomb carrier, mullite honeycomb carrier, diamond honeycomb carrier, corundum honeycomb carrier, zirconium corundum honeycomb carrier, quartz honeycomb carrier, nepheline honeycomb carrier, feldspar honeycomb carrier and alumina honeycomb carrier, and most preferably cordierite honeycomb carrier.

[0074] In this invention, the titanium-silicon molecular sieve used to form the titanium-silicon molecular sieve coating can be any conventional mesoporous titanium-silicon molecular sieve. In the most preferred embodiment, the titanium-silicon molecular sieve is a TS-1 molecular sieve.

[0075] In the monolithic catalyst with a titanium-silicon molecular sieve coating described in this invention, the alloy metal is an optional component included in the active component. In a preferred embodiment, the active component contains a noble metal and an alloy metal. In this preferred embodiment, the active component exists in the form of a noble metal element, an alloy, or a noble metal oxide. In the active component, the molar ratio of the noble metal to the alloy metal can be 1:0.1-0.3, preferably 1:0.15-0.2.

[0076] In the monolithic catalyst with a titanium-silicon molecular sieve coating described in this invention, the noble metal in the active component can be selected from at least one of ruthenium, rhodium, palladium, osmium, iridium, and platinum, preferably a combination of platinum and palladium. When the noble metal is a combination of platinum and palladium, the molar ratio of platinum to palladium can be 1:0.5-2, most preferably 1:1.

[0077] In the monolithic catalyst with a titanium-silicon molecular sieve coating described in this invention, the alloy metal in the active component can be at least one of Fe, La, and Ce, preferably a combination of La and Ce. When the alloy metal is a combination of La and Ce, the molar ratio of La to Ce can be 1:0.5-2, and most preferably 1:1.

[0078] The preparation method of the monolithic catalyst with titanium-silicon molecular sieve coating of the present invention includes the following steps:

[0079] (1) Treat the structured carrier with acid;

[0080] (2) Mix the alcohol solution of titanium source with an aqueous solution containing microporous template agent and silicon source, age, remove alcohol, and then mix the resulting gel with titanium silicon molecular sieve seed crystals and mesoporous template agent to obtain coating slurry.

[0081] (3) The coating slurry is added to the acid-treated structured carrier, and then crystallization, washing, drying and calcination are carried out in sequence to obtain a carrier containing the coating.

[0082] (4) The coated carrier is immersed in a mixed solution containing a noble metal precursor and optional structural aids, and then the immersed catalyst precursor is dried, calcined and reduced in sequence.

[0083] In step (1), the acid treatment process may include: refluxing the regularized carrier with an acidic solution, then washing it until neutral and drying it.

[0084] Specifically, the concentration of the acidic solution can be 1-3 mol / L, preferably 1.5-2.5 mol / L, and most preferably 2 mol / L.

[0085] Specifically, the acid in the acidic solution can be an inorganic strong acid, preferably at least one of nitric acid, sulfuric acid, and hydrochloric acid.

[0086] Specifically, the conditions for the reflux treatment may include: a temperature of 70-90°C, preferably 80°C; and a time of 12-36 hours, preferably 24 hours.

[0087] In the method described in this invention, the structured carrier can be selected from at least one of cordierite honeycomb carriers, mullite honeycomb carriers, diamond honeycomb carriers, corundum honeycomb carriers, zirconium corundum honeycomb carriers, quartz honeycomb carriers, nepheline honeycomb carriers, feldspar honeycomb carriers, and alumina honeycomb carriers, preferably cordierite honeycomb carriers. In one specific embodiment, the structured carrier is cordierite honeycomb ceramic.

[0088] In step (2), the specific process of mixing the alcohol solution of the titanium source with the aqueous solution containing the microporous template agent and the silicon source is as follows: the alcohol solution of the titanium source is added to the aqueous solution containing the microporous template agent and the silicon source at a rate of 0.005-0.015 mL / min, and the mixture is stirred for 2-5 hours.

[0089] In this invention, the titanium source can be selected from water-soluble or water-soluble titanium-containing compounds, typically referring to titanium dioxide (TiO2) sources. In specific embodiments, the titanium source includes, but is not limited to, at least one of tetraalkoxytitanium, tetraalkyl titanate, and titanium tetrachloride, with n-butyl titanate being the most preferred.

[0090] In this invention, the alcohol solvent used in the alcohol solution of the titanium source can be at least one of isopropanol, ethanol and n-propanol.

[0091] In this invention, the concentration of the alcohol solution of the titanium source can be 5-15% by weight.

[0092] In this invention, the silicon source can be selected from water-soluble or water-soluble silicon-containing compounds, typically referring to silicon dioxide (SiO2) sources. In specific embodiments, the silicon source includes, but is not limited to, at least one of silicates, silicic acid, silica hydrogels, and tetraethyl orthosilicate, preferably tetraethyl orthosilicate.

[0093] In this invention, the microporous template agent may be selected from at least one of tetrapropylammonium hydroxide, tetrapropylammonium bromide, and tetraethylammonium hydroxide.

[0094] In this invention, the titanium-silicon molecular sieve seed crystal is preferably a TS-1 molecular sieve seed crystal.

[0095] In this invention, the mesoporous template agent may be selected from at least one of P123 (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer), CTAB (cetyltrimethylammonium bromide), and n-butylamine.

[0096] In step (2), the aging process can be carried out at room temperature for 2-5 hours.

[0097] In step (2), the alcohol removal process specifically involves heating the aged mixed solution to 85-95°C at a rate of 1-20°C / min (preferably 5-17°C / min) and removing alcohol at 85-95°C for 10-15 hours.

[0098] In step (2), the process of mixing the gel liquid with the titanium silicon molecular sieve seed crystals and the mesoporous template agent is carried out under stirring. The mixing conditions may include: a temperature of 35-45℃ and a time of 0.5-2 hours.

[0099] In step (3), the process of adding the coating slurry to the acid-treated structured carrier is specifically as follows: the coating slurry is slowly dripped into the acid-treated structured carrier.

[0100] In step (3), the crystallization conditions may include: a temperature of 150-200℃ and a time of 10-72h.

[0101] In step (3), the calcination conditions include: a temperature of 400-650℃, preferably 500-600℃; and a time of 4-10 hours.

[0102] In step (4), the pH value of the mixed solution containing the noble metal precursor and the structural aid is 9-12.

[0103] In this invention, the noble metal in the noble metal precursor is at least one selected from silver, ruthenium, rhodium, palladium, osmium, iridium, and platinum, preferably a combination of platinum and palladium. In a specific embodiment, the noble metal precursor is selected from at least one selected from chloroplatinic acid, 2-hydroxyethylamine salt of platinum(IV) hydroxyacetate, platinum chloride, platinum nitrate, platinum acetylacetonate, palladium chloride, palladium nitrate, and palladium acetate.

[0104] In this invention, the structural aid is added to provide an alloy metal, so that the active component in the prepared monolithic catalyst exists in the form of a noble metal element, an alloy, or a noble metal oxide. In a specific embodiment, the structural aid is selected from at least one of ferric nitrate, cerium nitrate, lanthanum nitrate, lanthanum sulfate, lanthanum chloride, cerium sulfate, and cerium trioxide.

[0105] In step (4), the calcination conditions may include: a temperature of 300-400℃ and a time of 4-10 hours.

[0106] In step (4), during the reduction process, the reducing atmosphere can be H2, CO, a combination of H2 and CO, a mixed atmosphere with different hydrogen concentrations, or a mixed atmosphere with different CO concentrations. In a specific embodiment, the reducing atmosphere is a mixed atmosphere with different H2 concentrations or different CO concentrations. By adjusting the reducing atmosphere, efficient control of oxygen vacancy formation on the catalyst surface can be achieved. Specifically, the reducing atmosphere can be 5% H2 (diluted with N2), 10% H2 (diluted with N2), 15% H2 (diluted with N2), 5% CO (diluted with N2), etc.

[0107] In step (4), the reduction conditions may include: a catalyst heating rate of 2-20℃ / min, a reduction temperature of 300-450℃, and a reduction time of 1-10h.

[0108] In the method described in this invention, the amounts of various reaction raw materials used in steps (1) to (4) are such that, in the monolithic catalyst with titanium-silicon molecular sieve coating prepared, the content of the coating is 1-10 parts by weight, preferably 2-8 parts by weight, relative to 100 parts by weight of the carrier; and the content of the active component is 0.1-1 parts by weight, preferably 0.1-0.5 parts by weight.

[0109] The present invention also provides an integral catalyst with a titanium-silicon molecular sieve coating prepared by the above method.

[0110] The present invention also provides the application of the above-mentioned monolithic catalyst with titanium-silicon molecular sieve coating in the catalytic oxidation of carbon-based oxygen-containing molecular gases.

[0111] The following examples further illustrate the monolithic catalyst with titanium-containing silicon molecular sieve coating, its preparation method, and its application according to the present invention. The examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0112] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0113] Example 1

[0114] This embodiment illustrates a monolithic catalyst with a TS-1 molecular sieve coating, its preparation method, and its application.

[0115] First, take commercially available cordierite honeycomb ceramic with a diameter of 200 cpsi and a diameter of 100×100×50mm, reflux it at 80℃ for 24 hours with 2 mol / L nitric acid, wash it with deionized water until the pH value is 7, and let it air dry for later use.

[0116] Next, 3.6 g of isopropanol and 0.368 g of tetrabutyl titanate were mixed evenly to obtain solution 1. 27.9 g of tetrapropylammonium hydroxide was placed in a beaker, and 22.58 g of tetraethyl orthosilicate and 6.9 g of H2O were added and stirred for 30 minutes to obtain solution 2. Solution 1 was added to solution 2 at a rate of 0.01 ml / min, and stirred for 3 hours to obtain mixed solution 3. Mixed solution 3 was aged at room temperature for 3 hours, then heated to 90°C at a rate of 5-6°C / min, and the alcohol was removed at 90°C for 12 hours to obtain a transparent gel liquid 4. Transparent gel liquid 4 was mixed with 1g of commercially available TS-1 seed crystals and 0.5g of P123 at 40℃ and stirred for 1h to obtain a coating slurry. The coating slurry was then dropped onto acid-treated cordierite honeycomb ceramics and transferred to an autoclave. The ceramics were crystallized at 170℃ for 36h. After washing and drying, the ceramics were calcined at 550℃ in air for 6h to obtain cordierite honeycomb ceramics with a TS-1 molecular sieve coating.

[0117] 0.5 L of a 1 mol / L chloroplatinic acid and palladium chloride mixed solution (platinum-palladium molar ratio 1:1) and 200 mL of a 1 mol / L cerium nitrate and lanthanum nitrate mixed solution (cerium-lanthanum molar ratio 1:1) were stirred at 25 °C and pH = 9 for 3 h to obtain active component solution 5. Cordierite honeycomb ceramic with a TS-1 molecular sieve coating was impregnated in active component solution 5 and allowed to stand for 30 min. The catalyst was then removed, purged with a 2 MPa air knife, and subsequently treated in a 100 °C oven for 12 h, followed by calcination at 250 °C for 6 h. Then, it was reduced at 400 °C for 5 h under a 10% H₂ and 90% N₂ atmosphere to obtain a monolithic catalyst with a TS-1 titanium-silicon molecular sieve coating. The coating particle size was between 80-150 nm, the mesopore channel size distribution was 3-4 nm, and the specific surface area was 550 m². 2 / g, the powder shedding rate of the coating is 0.1%.

[0118] The SEM and TEM images of the monolithic catalyst containing the TS-1 titanium-silicon molecular sieve coating are shown below. Figure 1 and Figure 2 As shown.

[0119] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1 The reaction pressure was 0.1 MPa, and the reaction temperature was 265℃. Gas chromatography was used to detect the CO and VOC concentrations at the reactor outlet. The results showed that CO ≤ 100 ppm, VOCs ≤ 120 ppm, the conversion rate ≥ 99%, and the catalyst stability was 500 h (i.e., the catalyst activity did not significantly decrease after 500 hours of continuous reaction).

[0120] Example 2

[0121] This embodiment illustrates a monolithic catalyst with a TS-1 molecular sieve coating, its preparation method, and its application.

[0122] First, take commercially available cordierite honeycomb ceramic with a diameter of 200 cpsi and a diameter of 100×100×50mm, treat it with 2 mol / L sulfuric acid at 80℃ for 24 hours, wash it with deionized water until the pH value is 7, and let it air dry for later use.

[0123] Next, 3.6g of isopropanol and 0.368g of tetrabutyl titanate were mixed evenly to obtain solution 1. 27.9g of tetrapropylammonium hydroxide was placed in a beaker, and 22.58g of tetraethyl orthosilicate and 6.9g of H2O were added and stirred for 30 minutes to obtain solution 2. Solution 1 was added to solution 2 at a rate of 0.01ml / min, and stirred for 3 hours to obtain mixed solution 3. Mixed solution 3 was aged at room temperature for 3 hours, then heated to 90℃ at a rate of 10-12℃ / min, and the alcohol was removed at 90℃ for 12 hours to obtain a transparent gel liquid 4. Transparent gel liquid 4 was mixed with 2g of commercially available TS-1 seed crystals and 0.5g of CTAB at 40℃ and stirred for 1h to obtain a coating slurry. The coating slurry was then dropped onto acid-treated cordierite honeycomb ceramics and transferred to an autoclave. The ceramics were crystallized at 170℃ for 36h. After washing and drying, the ceramics were calcined at 550℃ in air for 6h to obtain cordierite honeycomb ceramics with a TS-1 molecular sieve coating.

[0124] 0.5 L of a 1 mol / L chloroplatinic acid and palladium chloride mixed solution (platinum-palladium molar ratio 1:1) and 200 mL of a 1 mol / L cerium nitrate and lanthanum nitrate mixed solution (cerium-lanthanum molar ratio 1:1) were stirred at 25 °C and pH = 10 for 3 h to obtain active component solution 5. Cordierite honeycomb ceramic with a TS-1 molecular sieve coating was impregnated in active component solution 5 and allowed to stand for 30 min. The catalyst was then removed, purged with a 2 MPa air knife, and subsequently treated in a 100 °C oven for 12 h, followed by calcination at 350 °C for 6 h. Then, it was reduced at 400 °C for 5 h under a 10% H₂ and 90% N₂ atmosphere to obtain a monolithic catalyst with a TS-1 titanium-silicon molecular sieve coating. The coating particle size was between 150-200 nm, the mesopore channel size distribution was 1.7-45 nm, and the specific surface area was 450 m². 2 / g, the powder shedding rate of the coating is 0.3%.

[0125] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1The reaction pressure was 0.1 MPa, and the reaction temperature was 285℃. Gas chromatography was used to detect the CO and VOC concentrations at the reactor outlet. The results showed that CO ≤ 100 ppm, VOCs ≤ 120 ppm, the conversion rate ≥ 99%, and the catalyst stability was 400 h (i.e., the catalyst activity did not significantly decrease after 400 h of continuous reaction).

[0126] Example 3

[0127] This embodiment illustrates a monolithic catalyst with a TS-1 molecular sieve coating, its preparation method, and its application.

[0128] First, take commercially available cordierite honeycomb ceramic with a diameter of 200 cpsi and a diameter of 100×100×50mm, treat it with 2 mol / L hydrochloric acid at 80℃ for 24 hours, wash it with deionized water until the pH value is 7, and let it air dry for later use.

[0129] Next, 3.6 g of isopropanol and 0.368 g of tetrabutyl titanate were mixed evenly to obtain solution 1. 27.9 g of tetrapropylammonium hydroxide was placed in a beaker, and 22.58 g of tetraethyl orthosilicate and 6.9 g of H2O were added and stirred for 30 minutes to obtain solution 2. Solution 1 was added to solution 2 at a rate of 0.01 ml / min, and stirred for 3 hours to obtain mixed solution 3. Mixed solution 3 was aged at room temperature for 3 hours, then heated to 90℃ at a rate of 15-17℃ / min, and the alcohol was removed at 90℃ for 12 hours to obtain a transparent gel liquid 4. Transparent gel liquid 4 was mixed with 1g of commercially available TS-1 seed crystals and 1g of n-butylamine at 40°C and stirred for 1h to obtain a coating slurry. The coating slurry was then dropped onto acid-treated cordierite honeycomb ceramics and transferred to an autoclave. The ceramics were crystallized at 170°C for 36h. After washing and drying, the ceramics were calcined at 550°C in air for 6h to obtain cordierite honeycomb ceramics with a TS-1 molecular sieve coating.

[0130] 0.5 L of a 1 mol / L chloroplatinic acid and palladium chloride mixed solution (platinum-palladium molar ratio 1:1) and 200 mL of a 1 mol / L cerium nitrate and lanthanum nitrate mixed solution (cerium-lanthanum molar ratio 1:1) were stirred at 25 °C and pH = 11 for 3 h to obtain active component solution 5. Cordierite honeycomb ceramic with a TS-1 molecular sieve coating was impregnated in active component solution 5 and allowed to stand for 30 min. The catalyst was then removed, purged with a 2 MPa air knife, and subsequently treated in a 100 °C oven for 12 h, followed by calcination at 450 °C for 6 h. Then, it was reduced at 400 °C for 5 h under a 10% H₂ and 90% N₂ atmosphere to obtain a monolithic catalyst with a TS-1 titanium-silicon molecular sieve coating. The coating particle size was between 300-450 nm, the mesopore channel size distribution was 1.7-45 nm, and the specific surface area was 350 m² / m³. 2 / g, the powder shedding rate of the coating is 0.5%.

[0131] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1 The reaction pressure was 0.1 MPa, and the reaction temperature was 305℃. Gas chromatography was used to detect the CO and VOC concentrations at the reactor outlet. The results showed that CO ≤ 100 ppm, VOCs ≤ 120 ppm, the conversion rate ≥ 99%, and the catalyst stability was 300 h (i.e., the catalyst activity did not significantly decrease after 300 h of continuous reaction).

[0132] Example 4

[0133] This embodiment illustrates a monolithic catalyst with a TS-1 molecular sieve coating, its preparation method, and its application.

[0134] First, take commercially available cordierite honeycomb ceramic with a diameter of 200 cpsi and a diameter of 100×100×50mm, reflux it at 80℃ for 24 hours with 1 mol / L nitric acid, wash it with deionized water until the pH value is 7, and let it air dry for later use.

[0135] Next, 3.6 g of isopropanol and 0.368 g of tetrabutyl titanate were mixed evenly to obtain solution 1. 27.9 g of tetrapropylammonium hydroxide was placed in a beaker, and 45.16 g of tetraethyl orthosilicate and 6.9 g of H2O were added and stirred for 30 minutes to obtain solution 2. Solution 1 was added to solution 2 at a rate of 0.01 ml / min, and stirred for 3 hours to obtain mixed solution 3. Mixed solution 3 was aged at room temperature for 3 hours, then heated to 90°C at a rate of 5-6°C / min, and the alcohol was removed at 90°C for 12 hours to obtain a transparent gel liquid 4. Transparent gel liquid 4 was mixed with 1g of commercially available TS-1 seed crystals and 0.5g of P123 at 40℃ and stirred for 1h to obtain a coating slurry. The coating slurry was then dropped onto acid-treated cordierite honeycomb ceramics and transferred to an autoclave. The ceramics were crystallized at 170℃ for 36h. After washing and drying, the ceramics were calcined at 550℃ in air for 6h to obtain cordierite honeycomb ceramics with a TS-1 molecular sieve coating.

[0136] 0.5 L of a 1 mol / L chloroplatinic acid and palladium chloride mixed solution (platinum-palladium molar ratio 1:1) and 200 mL of a 1 mol / L cerium nitrate and lanthanum nitrate mixed solution (cerium-lanthanum molar ratio 1:1) were stirred at 25 °C and pH = 9 for 3 h to obtain active component solution 5. Cordierite honeycomb ceramic with a TS-1 molecular sieve coating was impregnated in active component solution 5 and allowed to stand for 30 min. The catalyst was then removed, purged with a 2 MPa air knife, and subsequently treated in a 100 °C oven for 12 h, followed by calcination at 250 °C for 6 h. Then, it was reduced at 400 °C for 5 h under a 10% H₂ and 90% N₂ atmosphere to obtain a monolithic catalyst with a TS-1 titanium-silicon molecular sieve coating. The coating particle size was between 100-350 nm, the mesopore channel size distribution was 3-4 nm, and the specific surface area was 350 m². 2 / g, the powder shedding rate of the coating is 0.5%.

[0137] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1 The reaction pressure was 0.1 MPa, and the reaction temperature was 280℃. Gas chromatography was used to detect the CO and VOC concentrations at the reactor outlet. The results showed that CO ≤ 100 ppm, VOCs ≤ 120 ppm, the conversion rate ≥ 99%, and the catalyst stability was 300 h (i.e., the catalyst activity did not significantly decrease after 300 h of continuous reaction).

[0138] Example 5

[0139] This embodiment illustrates a monolithic catalyst with a TS-1 molecular sieve coating, its preparation method, and its application.

[0140] First, take commercially available cordierite honeycomb ceramic with a diameter of 200 cpsi and a diameter of 100×100×50mm, reflux it at 80℃ for 24 hours with 2 mol / L nitric acid, wash it with deionized water until the pH value is 7, and let it air dry for later use.

[0141] Next, 3.6g of isopropanol and 0.368g of tetrabutyl titanate were mixed evenly to obtain solution 1. 27.9g of tetrapropylammonium hydroxide was placed in a beaker, and 22.58g of tetraethyl orthosilicate and 6.9g of H2O were added and stirred for 30 minutes to obtain solution 2. Solution 1 was added to solution 2 at a rate of 0.1ml / min, and stirred for 3 hours to obtain mixed solution 3. Mixed solution 3 was aged at room temperature for 3 hours, then heated to 90℃ at a rate of 20-30℃ / min, and the alcohol was removed at 90℃ for 12 hours to obtain a transparent gel liquid 4. Transparent gel liquid 4 was mixed with 1g of commercially available TS-1 seed crystals and 0.5g of P123 at 40℃ and stirred for 1h to obtain a coating slurry. The coating slurry was then dropped onto acid-treated cordierite honeycomb ceramics and transferred to an autoclave. The ceramics were crystallized at 170℃ for 36h. After washing and drying, the ceramics were calcined at 550℃ in air for 6h to obtain cordierite honeycomb ceramics with a TS-1 molecular sieve coating.

[0142] 0.5 L of a 1 mol / L chloroplatinic acid and palladium chloride mixed solution (platinum-palladium molar ratio 1:1) and 200 mL of a 1 mol / L cerium nitrate and lanthanum nitrate mixed solution (cerium-lanthanum molar ratio 1:1) were stirred at 25 °C and pH = 9 for 3 h to obtain active component solution 5. Cordierite honeycomb ceramic with a TS-1 molecular sieve coating was impregnated in active component solution 5 and allowed to stand for 30 min. The catalyst was then removed, purged with a 2 MPa air knife, and subsequently treated in a 100 °C oven for 12 h, followed by calcination at 250 °C for 6 h. Then, it was reduced at 400 °C for 5 h under a 10% H₂ and 90% N₂ atmosphere to obtain a monolithic catalyst with a TS-1 titanium-silicon molecular sieve coating. The coating particle size was between 280-350 nm, the mesopore channel size distribution was 10-14 nm, and the specific surface area was 370 m². 2 / g, the powder shedding rate of the coating is 0.6%.

[0143] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1 The reaction pressure was 0.1 MPa, and the reaction temperature was 265℃. Gas chromatography was used to detect the CO and VOC concentrations at the reactor outlet. The results showed that CO ≤ 100 ppm, VOCs ≤ 120 ppm, the conversion rate ≥ 99%, and the catalyst stability was 270 h (i.e., the catalyst activity did not significantly decrease after 270 h of continuous reaction).

[0144] Example 6

[0145] This embodiment illustrates a monolithic catalyst with a TS-1 molecular sieve coating, its preparation method, and its application.

[0146] First, take commercially available cordierite honeycomb ceramic with a diameter of 200 cpsi and a diameter of 100×100×50mm, reflux it at 80℃ for 24 hours with 2 mol / L nitric acid, wash it with deionized water until the pH value is 7, and let it air dry for later use.

[0147] Next, 3.6 g of isopropanol and 0.368 g of tetrabutyl titanate were mixed evenly to obtain solution 1. 27.9 g of tetrapropylammonium hydroxide was placed in a beaker, and 22.58 g of tetraethyl orthosilicate and 6.9 g of H2O were added and stirred for 30 minutes to obtain solution 2. Solution 1 was added to solution 2 at a rate of 0.01 ml / min, and stirred for 3 hours to obtain mixed solution 3. Mixed solution 3 was aged at room temperature for 3 hours, then heated to 90°C at a rate of 5-6°C / min, and the alcohol was removed at 90°C for 12 hours to obtain a transparent gel liquid 4. Transparent gel liquid 4 was mixed with 1g of commercially available TS-1 seed crystals and 1.5g of CTAB at 80℃ and stirred for 1h to obtain a coating slurry. The coating slurry was then dropped onto acid-treated cordierite honeycomb ceramics and transferred to an autoclave. The ceramics were crystallized at 180℃ for 48h. After washing and drying, the ceramics were calcined at 550℃ in air for 6h to obtain cordierite honeycomb ceramics with a TS-1 molecular sieve coating.

[0148] 0.5 L of a 1 mol / L chloroplatinic acid and palladium chloride mixed solution (platinum-palladium molar ratio 1:1) and 200 mL of a 1 mol / L cerium nitrate and lanthanum nitrate mixed solution (cerium-lanthanum molar ratio 1:1) were stirred at 25 °C and pH = 9 for 3 h to obtain active component solution 5. Cordierite honeycomb ceramic with a TS-1 molecular sieve coating was impregnated in active component solution 5 and allowed to stand for 30 min. The catalyst was then removed, purged with a 2 MPa air knife, and subsequently treated in a 100 °C oven for 12 h, followed by calcination at 550 °C for 6 h. Then, it was reduced at 400 °C for 5 h under a 10% H₂ and 90% N₂ atmosphere to obtain a monolithic catalyst with a TS-1 titanium-silicon molecular sieve coating. The coating particle size was between 380-550 nm, the mesopore channel size distribution was 13-14 nm, and the specific surface area was 550 m². 2 / g, the powder shedding rate of the coating is 0.4%.

[0149] The SEM and TEM images of the monolithic catalyst containing the TS-1 titanium-silicon molecular sieve coating are shown below. Figure 1 and Figure 2 As shown.

[0150] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1The reaction pressure was 0.1 MPa, and the reaction temperature was 315℃. Gas chromatography was used to detect the CO and VOC concentrations at the reactor outlet. The results showed that CO ≤ 100 ppm, VOCs ≤ 120 ppm, the conversion rate ≥ 99%, and the catalyst stability was 300 h (i.e., the catalyst activity did not significantly decrease after 300 h of continuous reaction).

[0151] Example 7

[0152] This embodiment illustrates a monolithic catalyst with a TS-1 molecular sieve coating, its preparation method, and its application.

[0153] First, take commercially available cordierite honeycomb ceramic with a diameter of 200 cpsi and a diameter of 100×100×50mm, reflux it at 80℃ for 24 hours with 2 mol / L nitric acid, wash it with deionized water until the pH value is 7, and let it air dry for later use.

[0154] Next, 3.6g of isopropanol and 0.368g of tetrabutyl titanate were mixed evenly to obtain solution 1. 55.8g of tetrapropylammonium hydroxide was placed in a beaker, and 22.58g of tetraethyl orthosilicate and 6.9g of H2O were added and stirred for 30 minutes to obtain solution 2. Solution 1 was added to solution 2 at a rate of 0.05ml / min, and stirred for 3 hours to obtain mixed solution 3. Mixed solution 3 was aged at room temperature for 1 hour, then heated to 50℃ at a rate of 5-6℃ / min, and the alcohol was removed at 50℃ for 12 hours to obtain a transparent gel liquid 4. Transparent gel liquid 4 was mixed with 1g of commercially available TS-1 seed crystals and 0.5g of P123 at 40℃ and stirred for 1h to obtain a coating slurry. The coating slurry was then dropped onto acid-treated cordierite honeycomb ceramics and transferred to an autoclave. The ceramics were crystallized at 170℃ for 36h. After washing and drying, the ceramics were calcined at 550℃ in air for 6h to obtain cordierite honeycomb ceramics with a TS-1 molecular sieve coating.

[0155] 0.5 L of a 1 mol / L chloroplatinic acid and palladium chloride mixed solution (platinum-palladium molar ratio 1:1) and 200 mL of a 1 mol / L cerium nitrate and lanthanum nitrate mixed solution (cerium-lanthanum molar ratio 1:1) were stirred at 25 °C and pH = 9 for 3 h to obtain active component solution 5. Cordierite honeycomb ceramic with a TS-1 molecular sieve coating was impregnated in active component solution 5 and allowed to stand for 30 min. The catalyst was then removed, purged with a 2 MPa air knife, and subsequently treated in a 100 °C oven for 12 h, followed by calcination at 250 °C for 6 h. Then, it was reduced at 400 °C for 5 h under a 10% H₂ and 90% N₂ atmosphere to obtain a monolithic catalyst with a TS-1 titanium-silicon molecular sieve coating. The coating particle size was between 300-400 nm, the mesopore channel size distribution was 10-15 nm, and the specific surface area was 280 m². 2 / g, the powder shedding rate of the coating is 0.3%.

[0156] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1 The reaction pressure was 0.1 MPa, and the reaction temperature was 295℃. Gas chromatography was used to detect the CO and VOC concentrations at the reactor outlet. The results showed that CO ≤ 100 ppm, VOCs ≤ 120 ppm, the conversion rate ≥ 99%, and the catalyst stability was 350 h (i.e., the catalyst activity did not significantly decrease after 350 h of continuous reaction).

[0157] Example 8

[0158] This embodiment illustrates a monolithic catalyst with a TS-1 molecular sieve coating, its preparation method, and its application.

[0159] First, take commercially available cordierite honeycomb ceramic with a diameter of 200 cpsi and a diameter of 100×100×50mm, reflux it at 80℃ for 24 hours with 0.5mol / L nitric acid, wash it with deionized water until the pH value is 7, and let it air dry for later use.

[0160] Next, 3.6 g of isopropanol and 0.368 g of tetrabutyl titanate were mixed evenly to obtain solution 1. 27.9 g of tetrapropylammonium hydroxide was placed in a beaker, and 22.58 g of tetraethyl orthosilicate and 6.9 g of H2O were added and stirred for 30 minutes to obtain solution 2. Solution 1 was added to solution 2 at a rate of 0.01 ml / min, and stirred for 3 hours to obtain mixed solution 3. Mixed solution 3 was aged at room temperature for 3 hours, then heated to 90°C at a rate of 5-6°C / min, and the alcohol was removed at 90°C for 12 hours to obtain a transparent gel liquid 4. Transparent gel liquid 4 was mixed with 1g of commercially available TS-1 seed crystals and 0.5g of P123 at 40℃ and stirred for 1h to obtain a coating slurry. The coating slurry was then dropped onto acid-treated cordierite honeycomb ceramics and transferred to an autoclave. The ceramics were crystallized at 170℃ for 36h. After washing and drying, the ceramics were calcined at 550℃ in air for 6h to obtain cordierite honeycomb ceramics with a TS-1 molecular sieve coating.

[0161] 0.5 L of a 1 mol / L chloroplatinic acid and palladium chloride mixed solution (platinum-palladium molar ratio 1:1) and 200 mL of a 1 mol / L cerium nitrate and lanthanum nitrate mixed solution (cerium-lanthanum molar ratio 1:1) were stirred at 25 °C and pH = 9 for 3 h to obtain active component solution 5. Cordierite honeycomb ceramic with a TS-1 molecular sieve coating was impregnated in active component solution 5 and allowed to stand for 30 min. The catalyst was then removed, purged with a 2 MPa air knife, and subsequently treated in a 100 °C oven for 12 h, followed by calcination at 550 °C for 6 h. Then, it was reduced at 200 °C for 5 h under a 10% H₂ and 90% N₂ atmosphere to obtain a monolithic catalyst with a TS-1 titanium-silicon molecular sieve coating. The coating particle size was between 80-150 nm, the mesopore channel size distribution was 3-4 nm, and the specific surface area was 550 m². 2 / g, the powder shedding rate of the coating is 0.6%.

[0162] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1 The reaction pressure was 0.1 MPa, and the reaction temperature was 285℃. Gas chromatography was used to detect the CO and VOC concentrations at the reactor outlet. The results showed that CO ≤ 100 ppm, VOCs ≤ 120 ppm, the conversion rate ≥ 99%, and the catalyst stability was 160 h (i.e., the catalyst activity did not significantly decrease after 160 h of continuous reaction).

[0163] Example 9

[0164] This embodiment illustrates a monolithic catalyst with a TS-1 molecular sieve coating, its preparation method, and its application.

[0165] First, take commercially available cordierite honeycomb ceramic with a diameter of 200 cpsi and a diameter of 100×100×50mm, reflux it at 80℃ for 24 hours with 2 mol / L nitric acid, wash it with deionized water until the pH value is 7, and let it air dry for later use.

[0166] Next, 3.6 g of isopropanol and 0.368 g of tetrabutyl titanate were mixed evenly to obtain solution 1. 27.9 g of tetrapropylammonium hydroxide was placed in a beaker, and 22.58 g of tetraethyl orthosilicate and 6.9 g of H2O were added and stirred for 30 minutes to obtain solution 2. Solution 1 was added to solution 2 at a rate of 0.01 ml / min, and stirred for 3 hours to obtain mixed solution 3. Mixed solution 3 was aged at room temperature for 3 hours, then heated to 90°C at a rate of 5-6°C / min, and the alcohol was removed at 90°C for 12 hours to obtain a transparent gel liquid 4. Transparent gel liquid 4 was mixed with 1g of commercially available TS-1 seed crystals and 0.5g of P123 at 40℃ and stirred for 1h to obtain a coating slurry. The coating slurry was then dropped onto acid-treated cordierite honeycomb ceramics and transferred to an autoclave. The ceramics were crystallized at 170℃ for 36h. After washing and drying, the ceramics were calcined at 550℃ in air for 6h to obtain cordierite honeycomb ceramics with a TS-1 molecular sieve coating.

[0167] 0.5 L of a 2 mol / L chloroplatinic acid and palladium chloride mixed solution (platinum-palladium molar ratio 1:1) and 200 mL of a 1 mol / L zirconium nitrate and ferric nitrate mixed solution (zirconium-ferric molar ratio 1:1) were stirred at 25 °C and pH = 9 for 3 h to obtain active component solution 5. Cordierite honeycomb ceramic with a TS-1 molecular sieve coating was impregnated in active component solution 5 and allowed to stand for 30 min. The catalyst was then removed, purged with a 2 MPa air knife, and subsequently treated in a 100 °C oven for 12 h, followed by calcination at 250 °C for 6 h. Then, it was reduced at 400 °C for 5 h under a 10% H₂ and 90% N₂ atmosphere to obtain a monolithic catalyst with a TS-1 titanium-silicon molecular sieve coating. The coating particle size was between 80-150 nm, the mesopore channel size distribution was 3-4 nm, and the specific surface area was 550 m². 2 / g, the powder shedding rate of the coating is 0.1%.

[0168] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1 The reaction pressure was 0.1 MPa, and the reaction temperature was 325℃. Gas chromatography was used to detect the CO and VOC concentrations at the reactor outlet. The results showed that CO ≤ 100 ppm, VOCs ≤ 120 ppm, the conversion rate ≥ 99%, and the catalyst stability was 300 h (i.e., the catalyst activity did not significantly decrease after 300 h of continuous reaction).

[0169] Example 10

[0170] This embodiment illustrates a monolithic catalyst with a TS-1 molecular sieve coating, its preparation method, and its application.

[0171] First, take commercially available cordierite honeycomb ceramic with a diameter of 200 cpsi and a diameter of 100×100×50mm, reflux it at 80℃ for 24 hours with 2 mol / L nitric acid, wash it with deionized water until the pH value is 7, and let it air dry for later use.

[0172] Next, 3.6 g of isopropanol and 0.368 g of tetrabutyl titanate were mixed evenly to obtain solution 1. 27.9 g of tetrapropylammonium hydroxide was placed in a beaker, and 22.58 g of tetraethyl orthosilicate and 6.9 g of H2O were added and stirred for 30 minutes to obtain solution 2. Solution 1 was added to solution 2 at a rate of 0.01 ml / min, and stirred for 3 hours to obtain mixed solution 3. Mixed solution 3 was aged at room temperature for 3 hours, then heated to 90°C at a rate of 5-6°C / min, and the alcohol was removed at 90°C for 12 hours to obtain a transparent gel liquid 4. Transparent gel liquid 4 was mixed with 1g of commercially available TS-1 seed crystals and 0.5g of P123 at 40℃ and stirred for 1h to obtain a coating slurry. The coating slurry was then dropped onto acid-treated cordierite honeycomb ceramics and transferred to an autoclave. The ceramics were crystallized at 170℃ for 36h. After washing and drying, the ceramics were calcined at 550℃ in air for 6h to obtain cordierite honeycomb ceramics with a TS-1 molecular sieve coating.

[0173] 0.5 L of a 1 mol / L mixed solution of 2-hydroxyethylamine salt of platinum(IV) hydroxide and palladium acetate (platinum-palladium molar ratio 1:1) and 200 mL of a 1 mol / L mixed solution of cerium nitrate and lanthanum nitrate (cerium-lanthanum molar ratio 1:1) were stirred at 55 °C and pH = 11 for 3 h to obtain active component solution 5. Cordierite honeycomb ceramic with a TS-1 molecular sieve coating was impregnated in active component solution 5 and allowed to stand for 30 min. The catalyst was then removed, purged with a 2 MPa air knife, and subsequently treated in an oven at 100 °C for 12 h, followed by calcination at 450 °C for 6 h. Then, it was reduced at 700 °C for 3 h under a 10% H₂ and 90% N₂ atmosphere to obtain a monolithic catalyst with a TS-1 titanium-silicon molecular sieve coating. The coating particle size was between 80-150 nm, the mesopore size distribution was 3-4 nm, and the specific surface area was 550 m². 2 / g, the powder shedding rate of the coating is 0.1%.

[0174] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1 The reaction pressure was 0.1 MPa, and the reaction temperature was 305℃. Gas chromatography was used to detect the CO and VOC concentrations at the reactor outlet. The results showed that CO ≤ 100 ppm, VOCs ≤ 120 ppm, the conversion rate ≥ 99%, and the catalyst stability was 150 h (i.e., the catalyst activity did not significantly decrease after 150 hours of continuous reaction).

[0175] Comparative Example 1

[0176] The monolithic catalyst with a TS-1 molecular sieve coating prepared according to the method of Example 1 differs in that the cordierite honeycomb ceramic is not acid-treated; instead, the coating slurry is directly added dropwise to the cordierite honeycomb ceramic to prepare a cordierite honeycomb ceramic with a TS-1 molecular sieve coating. This ultimately yields a monolithic catalyst D1 with a TS-1 titanium-silicon molecular sieve coating, wherein the coating particle size is between 80-150 nm, the mesopore channel size distribution is 3-4 nm, and the specific surface area is 550 m². 2 / g, the powder shedding rate of the coating is 4.7%.

[0177] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1 The reaction pressure was 0.1 MPa, and the reaction temperature was 265℃. The CO and VOC concentrations at the reactor outlet were detected using gas chromatography. The results showed that the CO concentration was approximately 1000 ppm, the VOC concentration was approximately 250 ppm, the conversion rate was 97.5%, and the catalyst stability was 50 h.

[0178] Comparative Example 2

[0179] Based on Example 1, the difference lies in that the coating slurry is prepared according to the following process:

[0180] 50g of TS-1 molecular sieve (purchased from Shanghai Zhuoyue Chemical Technology Co., Ltd., Na type, with a micropore size distribution of 0.5-0.65nm) was mixed with 100g of deionized water and wet-milled to obtain a coating slurry. This ultimately yielded a monolithic catalyst D2 with a TS-1 titanium-silicon molecular sieve coating, wherein the coating particle size was between 80-150nm, the mesopore channel size distribution was 3-4nm, and the specific surface area was 500m². 2 / g, the powder shedding rate of the coating is 2.8%.

[0181] The catalyst was packed into a fixed-bed reactor, and the feed gas consisted of 95% CO2, 4% CO, and 1% VOCs, with a reaction space velocity of 5000 h⁻¹. -1 The reaction pressure was 0.1 MPa, and the reaction temperature was 275℃. The CO and VOC concentrations at the reactor outlet were detected using gas chromatography. The results showed that the CO concentration was approximately 800 ppm, the VOC concentration was approximately 200 ppm, the conversion rate was ≥98%, and the catalyst stability was 100 h.

[0182] As can be seen from the above examples and comparative examples, the monolithic catalyst with titanium-containing silicon molecular sieve coating prepared by the present invention exhibits good catalytic effect in the process of catalytic oxidation of carbon-based oxygen-containing molecular gas, and the catalyst has significantly better stability, making it suitable for continuous long-term operation.

[0183] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A monolithic catalyst comprising a coating of a titanium-containing silical molecular sieve, characterized in that, The monolithic catalyst includes: The carrier is an acid-treated, structured carrier; A coating attached to the carrier, the coating being a titanium-silicon molecular sieve coating formed by a crystallization-self-growth process; and An active component dispersed in the coating, the active component containing noble metals and a combination of La and Ce; In the active component, the molar ratio of the noble metal to the combination of La and Ce is 1:0.1-0.3; The precious metal is a combination of platinum and palladium; The powder shedding rate of the coating is 0.1-1%; The particle size of the coating is 50-500 nm, the mesoporous channel size of the coating is 1-50 nm, the specific surface area is 300-600 m 2 / g.

2. The monolithic catalyst with titanium-containing silicalce coating according to claim 1, characterized in that, The content of the coating is 1-10 parts by weight relative to 100 parts by weight of the carrier, and the content of the active component is 0.1-1 parts by weight.

3. The monolithic catalyst with titanium-containing silicalce coating according to claim 1, characterized in that, The regularized carrier is selected from at least one of cordierite honeycomb carrier, mullite honeycomb carrier, diamond honeycomb carrier, corundum honeycomb carrier, zirconium corundum honeycomb carrier, quartz honeycomb carrier, nepheline honeycomb carrier, feldspar honeycomb carrier and alumina honeycomb carrier.

4. The monolithic catalyst with a titanium-containing silicalce coating according to any one of claims 1 to 3, characterized in that The titanium-silicon molecular sieve is TS-1 molecular sieve.

5. A process for the preparation of a monolithic catalyst comprising a titanium-containing silicalite coating according to any one of claims 1 to 4, characterized in that, The method includes the following steps: (1) Treat the structured carrier with acid; (2) Mix the alcohol solution of titanium source with an aqueous solution containing microporous template agent and silicon source, age, remove alcohol, and then mix the resulting gel with titanium silicon molecular sieve seed crystals and mesoporous template agent to obtain coating slurry. (3) The coating slurry is added to the acid-treated structured carrier, and then crystallization, washing, drying and calcination are carried out in sequence to obtain a carrier containing the coating. (4) The coated carrier is immersed in a mixed solution containing a noble metal precursor and a structural aid, and then the immersed catalyst precursor is dried, calcined and reduced in sequence. The structural additives are selected from ferric nitrate, cerium nitrate, lanthanum nitrate, lanthanum sulfate, lanthanum chloride, cerium sulfate, and cerium trioxide.

6. The method of claim 5, wherein, In step (1), the acid treatment process includes: reflux treatment of the regularized carrier with an acidic solution, followed by washing until neutral and drying.

7. The method of claim 6, wherein, In step (1), the concentration of the acidic solution is 1-3 mol / L.

8. The method of claim 6, wherein, In step (1), the acid in the acidic solution is at least one of nitric acid, sulfuric acid and hydrochloric acid.

9. The method of claim 6, wherein, In step (1), the reflux treatment conditions include: a temperature of 70-90°C and a time of 12-36 hours.

10. The method of claim 5, wherein, In step (2), the specific process of mixing the alcohol solution of the titanium source with the aqueous solution containing the microporous template agent and the silicon source is as follows: the alcohol solution of the titanium source is added to the aqueous solution containing the microporous template agent and the silicon source at a rate of 0.005-0.015 mL / min, and the mixture is stirred for 2-5 hours.

11. The method of claim 5, wherein, In step (2), the titanium source is selected from at least one of tetraalkoxytitanium, tetraalkyl titanate and titanium tetrachloride.

12. The method of claim 5, wherein, In step (2), the microporous template agent is selected from at least one of tetrapropylammonium hydroxide, tetrapropylammonium bromide and tetraethylammonium hydroxide.

13. The method of claim 5, wherein, In step (2), the silicon source is selected from at least one of silicates, silicic acid, silica hydrogel and tetraethyl orthosilicate.

14. The method of claim 5, wherein, In step (2), the titanium silicon molecular sieve seed crystal is TS-1 molecular sieve seed crystal.

15. The method of claim 5, wherein, In step (2), the mesoporous template agent is selected from at least one of P123, CTAB and n-butylamine.

16. The method of claim 5, wherein, In step (3), the crystallization conditions include a temperature of 150-200℃ and a time of 10-72h.

17. The method of claim 5, wherein, In step (3), the calcination conditions include a temperature of 400-650℃ and a time of 4-10 hours.

18. The method of any of claims 5-17, wherein, In step (4), the pH of the mixed solution containing the noble metal precursor and the structural aid is 9-12.

19. The method of claim 18, wherein, In step (4), the noble metal precursor is selected from chloroplatinic acid, 2-hydroxyethylamine salt of platinum(IV) hydroxyhydroxide, platinum chloride, platinum nitrate, platinum acetylacetonate, palladium chloride, palladium nitrate and palladium acetate.

20. The method of claim 19, wherein, In step (4), the calcination conditions include a temperature of 300-400℃ and a time of 4-10 hours.

21. The method of claim 19, wherein, In step (4), during the reduction process, the reduction atmosphere is H2, CO, a combination of H2 and CO, a mixed atmosphere with different hydrogen concentrations, and a mixed atmosphere with different CO concentrations.

22. The method of claim 19, wherein, In step (4), the reduction conditions include: the catalyst heating rate is 2-20℃ / min, the reduction temperature is 300-450℃, and the reduction time is 1-10h.

23. The use of the monolithic catalyst with titanium-silicon molecular sieve coating according to any one of claims 1-4 in the catalytic oxidation of carbon-based oxygen-containing molecular gases.

Images