A matrix for a low-temperature denitration catalyst and its preparation method

Abstract

This invention discloses a matrix for a low-temperature denitration catalyst and its preparation method, the method comprising the following steps: S1: mixing Ti3C2T X S1: The MXene colloidal solution is heated and stirred; S2: The solution after step S1 is ultrasonically treated; S3: The solution after step S2 is centrifuged; S4: The lower solid obtained after step S3 is dried to obtain the TiO2 / Ti3C2T matrix of the low-temperature denitration catalyst. X This invention employs a simple ultrasonic method for in-situ synthesis of two-dimensional TiO2 / Ti3C2T. X Nanosheets, TiO2 nanoparticles tightly loaded on Ti3C2T X The formation of heterojunctions on nanosheets increases the specific surface area and active sites, and the presence of Ti elements in multiple valence states is beneficial for catalytic reactions.

Description

Technical Field

[0001] This invention relates to the technical field of low-temperature denitrification, and specifically to a matrix for a low-temperature denitrification catalyst and its preparation method. Background Technology

[0002] NO in sintering flue gas in the metallurgical industry X High-temperature SCR denitrification technology is commonly used for flue gas treatment. The optimal reaction temperature for this technology is 280–320℃. However, after desulfurization and dust removal, the flue gas temperature drops below 100℃. At this temperature, the high-temperature SCR denitrification catalyst cannot meet the denitrification requirements. Therefore, coal gas is often used to heat the flue gas during flue gas treatment, resulting in significant energy consumption. To effectively reduce energy consumption and carbon emissions in the denitrification process, the development of low-temperature denitrification catalysts is particularly important.

[0003] However, since the flue gas after desulfurization and dust removal still contains a small amount of SO2, sulfate deposits easily form at low temperatures, covering the catalyst surface and blocking the pores. SO2 reacts with transition metal active materials to form sulfates, deactivating the catalyst and severely inhibiting the SCR low-temperature denitrification reaction. Poor dispersion of active materials on the catalyst surface during low-temperature denitrification also affects the performance of the SCR catalyst. Currently, commonly used supports for SCR low-temperature denitrification reactions include metal oxides, non-metal oxides, and carbon-based materials. Commonly used metal oxide supports include Al2O3, CeO2, and TiO2. Active components such as V and Ce exhibit good dispersion on TiO2, and TiO2 as a matrix can inhibit the reaction of SO2 in the flue gas with transition metals and ammonia. However, TiO2 as a matrix still suffers from low catalytic activity and small specific surface area.

[0004] Among the existing publicly available technologies, Chinese invention patent CN112456551A discloses a composite material based on in-situ growth of TiO2 heterostructures on two-dimensional MXene, its preparation method, and its application. This method uses Ti3C2T... X Ti2CT X Using titanium as the source, a hydrothermal method was employed in Ti3C2T X Ti2CT X TiO2 is grown in situ on top. Chinese invention patent CN117430115A discloses a Ti3C2T based on intercalation technology. X MXene / CNTs, their in-situ preparation methods, and applications are used to address existing Ti3C2T... X The preparation method of MXene / CNTs requires the dispersion of CNTs and CNTs with Ti3C2T. XThe poor interaction between MXenes results in CNTs growing only on dispersed lamellar layers, failing to grow between layers, or exhibiting low density and non-uniform size of CNTs between layers. Chinese invention patent CN113401937A discloses a method for preparing MXene-TiO2, using PMS as an oxidant. Currently, MXene and TiO2 are commonly used as matrices for low-temperature denitration catalysts, and in-situ grown TiO2 / Ti3C2T... X It is often used in photocatalysis, electronic sensing and other fields. However, current low-temperature denitrification catalysts have shortcomings such as poor dispersion of active components, small specific surface area, and inability to suppress the formation of sulfate deposits in the flue gas SCR low-temperature denitrification reaction, resulting in low efficiency of the low-temperature denitrification reaction. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a matrix for a low-temperature denitration catalyst and its preparation method. This method uses an ultrasonic method to synthesize an in-situ TiO2 / Ti3C2T matrix for a low-temperature denitration catalyst. X The matrix has a two-dimensional sheet-like structure, with TiO2 nanoparticles tightly loaded on Ti3C2T. X The nanosheets have a large specific surface area and active sites, and contain Ti elements in multiple valence states, which is beneficial for electron transfer in catalytic reactions and improves the efficiency of low-temperature denitration reactions.

[0006] To achieve the above objectives, the present invention provides a matrix for a low-temperature denitrification catalyst, wherein the matrix of the low-temperature denitrification catalyst is a two-dimensional TiO2 / Ti3C2T matrix. X Nanosheets, made of Ti3C2T X TiO2 is grown in situ using a Ti source, and TiO2 nanoparticles are loaded onto Ti3C2T. X On nanosheets.

[0007] The present invention also provides a method for preparing the matrix of the above-mentioned low-temperature denitration catalyst, comprising the following steps:

[0008] S1: Ti3C2T X The MXene colloidal solution was heated and stirred.

[0009] S2: The solution after step S1 is subjected to ultrasonic treatment;

[0010] S3: Centrifuge the solution after step S2;

[0011] S4: The lower solid obtained after step S3 is dried to obtain the TiO2 / Ti3C2T matrix of the low-temperature denitration catalyst. X .

[0012] Furthermore, in step S1, Ti3C2T X The concentration of MXene colloidal solution is 0.05–2 mg / mL.

[0013] Furthermore, in step S1, Ti3C2T X The MXene colloidal solution was heated and stirred at a temperature of 30℃ to 60℃ for 10 min to 60 min.

[0014] Furthermore, in step S2, the ultrasonic treatment time is 1 hour to 3 hours.

[0015] Furthermore, in step S3, the centrifugation process involves washing with deionized water and centrifuging at a speed of 8000–11000 r / min for 3–5 min.

[0016] Furthermore, in step S4, the drying temperature is 50℃~80℃.

[0017] Furthermore, in step S4, the drying time is 24h to 28h.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] Firstly, this invention employs a simple and rapid ultrasonic method based on Ti3C2T. X In-situ synthesis of two-dimensional TiO2 / Ti3C2T nanosheets X Nanosheets, in which TiO2 nanoparticles are uniformly dispersed in a Ti3C2T matrix material with a two-dimensional sheet-like structure. X The distribution of active materials in low-temperature denitration catalysts is facilitated on nanosheets.

[0020] Secondly, this invention utilizes two-dimensional TiO2 / Ti3C2T X Nanosheets are used as the matrix for low-temperature denitration catalysts, TiO2 / Ti3C2T X The Ti element in the reaction has multiple valence states, and the free electrons of the metal undergo rapid conversion between different forms of matter during the reaction, which is beneficial to the denitration catalytic reaction.

[0021] Thirdly, the matrix of the low-temperature denitration catalyst of the present invention is two-dimensional TiO2 / Ti3C2T. X Nanosheets, this carrier has a large specific surface area, in-situ grown TiO2 and Ti3C2T X The tightly connected structures form a heterojunction, facilitating electron transfer during the reaction, and Ti3C2T XNanosheets are prepared by etching away the Al layer from Ti3AlC2, exposing a large number of Ti atoms in the TiO2 / Ti3C2T structure. X The presence of multiple valence states and a large number of oxygen vacancies in Ti increases the number of reactive sites, which is beneficial for the low-temperature denitrification reaction. Attached Figure Description

[0022] Figure 1 The TiO2 / Ti3C2T prepared in Example 1 X XRD pattern of the composite material;

[0023] Figure 2 The TiO2 / Ti3C2T prepared in Example 1 X Transmission electron microscope image of the composite material;

[0024] Figure 3 The Ti3C2T prepared in Example 1 X and TiO2 / Ti3C2T X Ti2p XPS spectra of the composite material;

[0025] Figure 4 The TiO2 / Ti3C2T prepared in Example 2 X Transmission electron microscope image of the composite material;

[0026] Figure 5 The TiO2 / Ti3C2T prepared in Example 3 X Transmission electron microscope image of the composite material. Detailed Implementation

[0027] The following examples illustrate the implementation of the present invention in detail, but they do not constitute a limitation on the invention and are merely illustrative. Furthermore, the advantages of the present invention will become clearer and easier to understand by explaining them.

[0028] Example 1:

[0029] The present invention discloses a matrix for a low-temperature denitration catalyst and a method for preparing the same, comprising the following steps:

[0030] S1: Add 50 mL of 0.1 mg / mL Ti3C2T X Pour the MXene colloidal solution into a 100 mL beaker and heat and stir at 50 °C for 30 min;

[0031] S2: Place the solution in the beaker after step S1 into an ultrasonic instrument and sonicate for 2 hours;

[0032] S3: Place the solution in the beaker after step S2 into a centrifuge and centrifuge at 8000 r / min for 3 min.

[0033] S4: The lower solid obtained after centrifugation in step S3 is dried in a 60℃ oven for 24 hours to obtain in-situ grown TiO2 / Ti3C2T X .

[0034] like Figure 1 The image shows the TiO2 / Ti3C2T prepared in Example 1. X The XRD pattern of the composite material shows the presence of characteristic peaks of TiO2 (JCPDS No. 89-4921) in the product, with approximately 5° corresponding to Ti3C2T. X The (0 0 2) crystal plane of MXene;

[0035] like Figure 2 The image shows the TiO2 / Ti3C2T prepared in Example 1. X The transmission electron microscope image of the composite material shows that the sample morphology consists of two-dimensional nanosheets loaded with nanoparticles that are relatively uniformly distributed.

[0036] like Figure 3 The image shows the Ti3C2T prepared in Example 1. X and TiO2 / Ti3C2T X Ti 2p XPS spectrum of the composite material, TiO2 / Ti3C2T X The presence of Ti element in Ti 2+ Ti 3+ Ti 4+ Different states, where Ti 4+ It has the highest content.

[0037] Example 2:

[0038] The present invention discloses a matrix for a low-temperature denitration catalyst and a method for preparing the same, comprising the following steps:

[0039] S1: Add 50 mL of 0.05 mg / mL Ti3C2T X Pour the MXene colloidal solution into a 100 mL beaker and heat and stir at 30 °C for 10 min;

[0040] S2: Place the solution in the beaker after step S1 into an ultrasonic instrument and sonicate for 1 hour;

[0041] S3: Place the solution in the beaker after step S2 into a centrifuge and centrifuge at 8000 r / min for 3 min.

[0042] S4: The lower solid obtained after centrifugation in step S3 is dried in a 50℃ oven for 24 hours to obtain in-situ grown TiO2 / Ti3C2T X .

[0043] like Figure 4 The image shows the TiO2 / Ti3C2T prepared in Example 2. X The transmission electron microscope (TEM) image of the composite material shows that the sample morphology consists of two-dimensional nanosheets loaded with a small number of nanoparticles.

[0044] Example 3:

[0045] The present invention discloses a matrix for a low-temperature denitration catalyst and a method for preparing the same, comprising the following steps:

[0046] S1: Add 50 mL of 2 mg / mL Ti3C2T X Pour the MXene colloidal solution into a 100 mL beaker and heat and stir at 60 °C for 60 min;

[0047] S2: Place the solution in the beaker after step S1 into an ultrasonic instrument and sonicate for 3 hours.

[0048] S3: Place the solution in the beaker after step S2 into a centrifuge and centrifuge at 11000 r / min for 5 min.

[0049] S4: The lower solid obtained after centrifugation in step S3 is dried in an oven at 80℃ for 28 hours to obtain in-situ grown TiO2 / Ti3C2T X .

[0050] like Figure 5 The image shows the TiO2 / Ti3C2T prepared in Example 3. X The transmission electron microscope (TEM) image of the composite material shows that the sample morphology consists of two-dimensional nanosheets loaded with a large number of nanoparticles.

[0051] This invention addresses the shortcomings of current low-temperature denitrification catalysts, such as poor dispersion of active components, small specific surface area, and the inability to suppress sulfate deposit formation in the flue gas SCR low-temperature denitrification reaction. It provides a novel two-dimensional TiO2 / Ti3C2T matrix for the preparation of low-temperature denitrification catalysts. X Nanosheets, this carrier has a large specific surface area, in-situ grown TiO2 and Ti3C2T X The tightly connected structures form a heterojunction, facilitating electron transfer during the reaction, and Ti3C2T X Nanosheets are prepared by etching away the Al layer from Ti3AlC2, exposing a large number of Ti atoms in the TiO2 / Ti3C2T structure. X The presence of multiple valence states and a large number of oxygen vacancies in Ti increases the number of reactive sites, which is beneficial for the low-temperature denitrification reaction.

[0052] The above are merely specific embodiments of the present invention. It should be noted that any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention. Any other aspects not described in detail are prior art.

Claims

1. A method for preparing a low-temperature denitration catalyst matrix, characterized in that: Includes the following steps: S1: heating and stirring the Ti3C2T X MXene colloidal solution, the Ti3C2T X The concentration of the MXene colloidal solution is 0.05-2 mg / mL, the temperature for heating and stirring is 30°C-60°C, and the time is 10 min-60 min. S2: The solution after step S1 is subjected to ultrasonic treatment; S3: Centrifuge the solution after step S2; S4: The lower solid obtained after step S3 is dried to obtain the TiO2 / Ti3C2T matrix of the low-temperature denitration catalyst. X ; The matrix of the low-temperature denitration catalyst is two-dimensional TiO2 / Ti3C2T. X Nanosheets, made of Ti3C2T X TiO2 is grown in situ using a Ti source, and TiO2 nanoparticles are loaded onto Ti3C2T. X On nanosheets.

2. The method for preparing the low-temperature denitration catalyst matrix according to claim 1, characterized in that: In step S2, the ultrasonic treatment time is 1 hour to 3 hours.

3. The method for preparing the low-temperature denitration catalyst matrix according to claim 1, characterized in that: In step S3, the centrifugation process involves washing with deionized water and centrifuging for 3 to 5 minutes at a speed of 8000 to 11000 r / min.

4. The method for preparing the low-temperature denitration catalyst matrix according to claim 1, characterized in that: In step S4, the drying temperature is 50°C to 80°C.

5. The method for preparing the low-temperature denitration catalyst matrix according to claim 1 or 4, characterized in that: In step S4, the drying time is 24h to 28h.

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