Preparation and application of boron oxide / zirconium oxide composite catalyst
By preparing the B2O3/ZrO2 composite material, the problems of olefin selectivity control and boron oxide material sintering in the ODHP reaction were solved, and high conversion and stable catalytic performance were achieved.
Patent Information
- Application Number
- CN202510444876.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-10
- Publication Date
- 2025-07-08
AI Technical Summary
In the existing propane oxidative dehydrogenation (ODHP) reaction, selective control of olefins is difficult to achieve, and boron oxide materials are prone to sintering at high temperatures, resulting in activity loss, and existing catalysts do not perform well in carbon deposits.
B2O3/ZrO2 composite material is prepared by acid-base reaction in solution and combined with high-temperature calcination modification method to form a particle stack structure, combining the catalytic characteristics of boron oxide and zirconia, and is used for propane oxidation and dehydrogenation reaction.
High propane conversion and olefin selectivity are achieved, the catalyst maintains good stability at high temperatures, inhibits the excessive oxidation of propylene, and improves the catalytic activity and long-term stability of the reaction.
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Figure CN120268384A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a B2O3 / ZrO2 composite material and its preparation and application. This material can be applied to the thermal catalytic oxidative dehydrogenation of propane to propylene, showing a high propane conversion rate and olefin selectivity, and having good high-temperature stability at the same time. Background Art
[0002] As an important organic olefin chemical second only to ethylene, propylene is widely used in the synthesis of products such as polypropylene, propylene oxide, acrylonitrile, acrylic acid, cumene, and butanol, with a huge market demand. In recent years, natural gas and shale gas rich in propane have been regarded as potential raw materials for propylene production. In this context, propane dehydrogenation (PDH) technology is regarded as an efficient and selective method for producing propylene. However, the PDH process faces many challenges in industrial applications, such as rapid catalyst deactivation caused by carbon deposition and high energy consumption.
[0003] In contrast, propane oxidative dehydrogenation (ODHP) technology has become a very promising alternative method due to its exothermic characteristics and anti-carbon deposition advantages. However, the selective control of olefins in the ODHP reaction system remains a major challenge. Electron-rich allylic carbon atoms are prone to react with oxygen on metal oxide catalysts, resulting in the formation of overoxidation products, thereby reducing the selectivity of the target olefins. Therefore, it is particularly crucial to develop a highly selective catalyst that can limit the deep oxidation pathway.
[0004] In the ODHP reaction, it has been found that a polyatomic system characterized by B-O bonds plays a major role in the highly selective preparation of propylene. Therefore, applying boron oxide materials to the ODHP reaction has important research value. However, due to the melting point of boron oxide being lower than the operating temperature of ODHP (480 - 560 °C), boron oxide materials are prone to sintering under reaction conditions, resulting in the loss of active phases. Therefore, loading boron oxide on a suitable carrier has become the focus of research.
[0005] The purpose of the present invention is to solve the above technical problems. By means of an acid-base reaction in solution combined with high-temperature calcination modification, a B2O3 / ZrO2 composite material with a simple synthesis method and stable structure is prepared. The preparation method of this composite material has not been reported in the existing literature. The obtained metal boron oxide composite material combines the catalytic characteristics of boron oxide and zirconium oxide, and can achieve high propane conversion and ideal olefin selectivity. Summary of the Invention
[0006] The purpose of the present invention is to provide a B2O3 / ZrO2 composite catalyst and its preparation method and application. The preparation method is simple, and the obtained product has a special particle stacking structure and combines the ODHP catalytic characteristics of boron oxide and metal oxide, so it has good catalytic activity for propane oxidative dehydrogenation.
[0007] To achieve the above object, the present invention adopts the following technical solutions: A B2O3 / ZrO2 composite catalyst having a controllable structure of particle stacking.
[0008] The preparation method of the B2O3 / ZrO2 composite catalyst includes the following steps: 1) Add boric acid to deionized water and stir to completely dissolve it to obtain a boric acid solution; 2) Add zirconium hydroxide to the above boric acid solution, and then place the mixed solution in an oil bath and heat and stir until all the solids precipitate; 3) Dry the precipitated solid overnight to obtain a precursor; 4) Calcinate the obtained precursor at high temperature in a nitrogen atmosphere, and wait for it to cool naturally to room temperature to obtain a B2O3 / ZrO2 composite material.
[0009] Further, the concentration of the boric acid solution obtained in step 1) is 0.2 mmol / mL.
[0010] Further, the molar ratio of the amount of zirconium hydroxide added in step 2) to the boric acid used is 3:4.
[0011] Further, the temperature of the heating and stirring in step 2) is 80 °C, and the stirring speed is 500 r / min.
[0012] Further, the drying temperature in step 3) is 60 °C.
[0013] Further, the high-temperature calcination in step 4) is to increase the temperature to 1000 °C at a rate of 10 °C / min and keep it for 2 h.
[0014] Application of the above-obtained B2O3 / ZrO2 composite catalyst in the thermal catalytic propane oxidative dehydrogenation reaction.
[0015] Further, the temperature of the reaction is 520 °C, and the volume ratio of the feed gas is C3H8:O2:He = 6:3:11.
[0016] Compared with the prior art, the advantages of the present invention are as follows: The synthesis method of the present invention is simple, and the prepared material has a novel structure, with abundant oxygen vacancies and boron-oxygen active sites, which can provide more potential reaction sites and diffusion channels. Moreover, it combines the ODHP catalytic characteristics of boron oxide and metal oxides. When used as a catalyst for propane oxidative dehydrogenation reaction, it has good catalytic activity and high-temperature stability, and is also expected to be applied to other fields. Description of the Drawings
[0017] Figure 1Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of the B2O3 / ZrO2 composite material prepared in the example.
[0018] Figure 2 X-ray powder diffraction (XRD) pattern of the B2O3 / ZrO2 composite material prepared in the example.
[0019] Figure 3 Fourier transform infrared spectroscopy (FT-IR) spectrum of the B2O3 / ZrO2 composite material prepared in the example.
[0020] Figure 4 Scanning electron microscopy (SEM) image of the ZrO2 material prepared in Comparative Example 1.
[0021] Figure 5 X-ray powder diffraction (XRD) pattern of the ZrO2 material prepared in Comparative Example 1.
[0022] Figure 6 Fourier transform infrared spectroscopy (FT-IR) spectrum of the ZrO2 material prepared in Comparative Example 1.
[0023] Figure 7 Stability test graph of the B2O3 / ZrO2 composite material prepared in the example.
[0024] Figure 8 Stability test graph of the ZrO2 material prepared in the comparative example.
[0025] Figure 9 Stability test graph of the 10% B2O3 / ZrO2 composite material prepared in Comparative Example 2.
[0026] Figure 10 Stability test graph of the 20% B2O3 / ZrO2 composite material prepared in Comparative Example 3.
[0027] Figure 11 Stability test graph of the B2O3 material prepared in Comparative Example 4. Detailed implementation manners
[0028] To make the content of the present invention easier to understand, the technical solutions of the present invention are further described below in conjunction with specific implementation manners, but the present invention is not limited thereto. Examples
[0029] Add 0.02 mol of boric acid solid to 100 mL of deionized water, stir to completely dissolve it to obtain a boric acid solution; add 0.015 mol of zirconium hydroxide solid to the obtained boric acid solution, and stir in an oil bath at 80 °C and a rotation speed of 500 r / min until all the solid precipitates; then dry the precipitated solid in an oven at 60 °C overnight to obtain a precursor; heat the obtained precursor to 1000 °C at a rate of 10 °C / min under a nitrogen atmosphere, keep it for 2 h, and then naturally cool it to room temperature to obtain a 40% B2O3 / ZrO2 composite material.
[0030] The morphology and structure of the obtained B2O3 / ZrO2 composite material were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the results are shown in Figure 1 . As Figure 1 shown, the obtained material is a stacked structure of uniform particles.
[0031] The crystal structure of the B2O3 / ZrO2 composite material was studied by X-ray powder diffraction (XRD), and the results are as Figure 2 shown. It can be seen from Figure 2 that the obtained B2O3 / ZrO2 exhibits two broad diffraction peaks near 28.2° and 31.5°, which belong to the (-111) and (111) crystal planes of the m-ZrO2 structure respectively.
[0032] The surface functional groups of the B2O3 / ZrO2 composite material were studied by Fourier transform infrared spectroscopy (FT-IR), and the results are as Figure 3 shown. It can be seen from Figure 3 that the absorption peak at 700 - 800 cm -1 corresponds to the stretching vibration of the Zr-O-Zr bridging bond, indicating the presence of a zirconia structure in the sample. There is a lower-frequency absorption peak near 500 - 600 cm -1 , which is related to the vibration of the Zr-O bond, further confirming the presence of zirconia. There is a broad absorption peak near 3200 - 3500 cm -1 , and this peak usually corresponds to the stretching vibration of the B-OH functional group, indicating the presence of hydroxyl groups in the sample. An absorption peak is observed in the range of 1400 - 1500 cm -1 , and this peak is related to the stretching vibration of the boron oxygen triangle (BO3) structure, indicating that the sample contains tricoordinate boron oxygen groups. An absorption peak appears near 1000 - 1100 cm -1 , which usually corresponds to the stretching vibration of the boron oxygen tetrahedron (BO4) structure, indicating that the sample contains tetracoordinate boron oxygen groups and may form a stable structure combined with metal ions. These evidences indicate the successful preparation of the B2O3 / ZrO2 composite material.
[0033] Comparative Example 1 0.015 mol of zirconium hydroxide solid was added to 100 mL of deionized water and stirred until completely dissolved; the solution was placed in an oil bath at 80 °C with a rotation speed of 500 r / min and stirred until all the solids precipitated out; then the precipitated solids were dried overnight in an oven at 60 °C to obtain a precursor; the obtained precursor was heated to 1000 °C at a rate of 10 °C / min under a nitrogen atmosphere, reacted for 2 h, and then naturally cooled to room temperature to obtain ZrO2.
[0034] As Figure 4 shown, the obtained ZrO2 was an irregular block structure.
[0035] The crystal structure of the ZrO2 material was studied by X-ray powder diffraction (XRD), and the results were as Figure 5 shown. It can be seen from Figure 5 that not only the (-111) and (111) crystal planes attributed to m-ZrO2 appeared in the sample, but also the (101) crystal plane of t-ZrO2 was observed near 30.2°.
[0036] The surface functional groups of the ZrO2 material were studied by Fourier transform infrared spectroscopy (FT-IR), and the results were as Figure 6 shown. It can be seen from Figure 6 that an obvious absorption peak appeared between 700 - 800 cm -1 . This peak corresponded to the stretching vibration of the Zr-O-Zr bridging bond, indicating that there was a zirconia structure in the sample and the bridging bond structure between zirconium and oxygen was well retained. An absorption peak appearing near 500 - 600 cm -1 corresponded to the stretching vibration of the Zr-O bond, indicating the existence of the basic structural unit of zirconia in the sample, i.e., the presence of the Zr-O bond. However, the lack of characteristic peaks related to boron oxygen (such as BO3 or BO4) indicated that the sample might be a single zirconia material.
[0037] Comparative Example 2 The amount of boric acid solid was modified to 0.005 mol, and other operations were the same as in the examples to obtain a 10% B2O3 / ZrO2 composite material.
[0038] Comparative Example 3 The amount of boric acid solid was modified to 0.01 mol, and other operations were the same as in the examples to obtain a 20% B2O3 / ZrO2 composite material.
[0039] Comparative Example 4 0.02 mol of boric acid solid was added to 100 mL of deionized water, and stirred to completely dissolve it to obtain a boric acid solution; the obtained boric acid solution was stirred in an oil bath at 80 °C and a rotation speed of 500 r / min until all the solids precipitated out; then the precipitated solids were dried overnight in an oven at 60 °C to obtain a precursor; the obtained precursor was heated to 1000 °C at a rate of 10 °C / min under a nitrogen atmosphere, held for 2 h, and then naturally cooled to room temperature to obtain B2O3.
[0040] Catalytic performance tests were carried out on the catalytic materials prepared in the examples and comparative examples in the propane oxidative dehydrogenation reaction. The experiments were carried out on a heating furnace device with atmospheric pressure reaction and single-stage temperature control, and the materials were loaded into a quartz tube reactor for testing. The specific conditions are as follows: Chromatographic analysis conditions: High-purity N2 was used as the chromatographic carrier gas for both chromatographic columns, the flow pressure of FID was 0.04 MPa, and the flow pressure of TCD was 0.2 MPa; the hydrogen flow pressures of FID1 and FID2 were 0.035 MPa and 0.03 MPa respectively; the air flow pressure was 0.03 MPa. Injector: 150 °C; FID detector: 150 °C; TCD detector: 150 °C; conversion furnace: 330 °C.
[0041] Column furnace temperature rising conditions: The initial temperature was maintained at 70 °C for 14 min and then programmed to rise to 150 °C at a rate of 20 °C / min and held for 5 min to remove the residual components in the chromatographic column.
[0042] Loading: First, 30 mg of quartz wool was laid flat in a quartz tube reactor with an inner diameter of 6 mm, a wall thickness of 2 mm, and a length of 360 mm. Then, 200 mg of catalytic material with a particle size of 20 - 40 mesh was selected and loaded into the quartz tube reactor. Finally, another 30 mg of quartz wool was laid flat on top of the material.
[0043] Catalytic performance evaluation: A raw material gas with a volume ratio of C3H8:O2:He = 6:3:11 was set for the reaction, the reaction gas flow rate was 20 mL / min, and the reaction temperature was 520 °C.
[0044] The conversion rate of the reactants and the selectivity of the products were both calculated using the carbon atom number normalization method. The calculation methods are as follows: Calculation formula for the conversion rate of propane: , Calculation formula for the selectivity of the product: , Calculation formula for the product yield: , Among them, the subscripts "r" and "p" represent reactants and products respectively, "i" represents any species, "C" represents the gas concentration (percentage by volume) of species i, and "n" represents the number of carbon atoms corresponding to species i.
[0045] As Figure 7 , 8 shown, the B2O3 / ZrO2 composite material exhibits good thermal catalytic ODHP reaction performance. Its propane conversion rate is 32.1%, the propylene yield is 21.2%, and the olefin yield is as high as 29.8%. It can maintain catalytic stability for nearly 90 h. This shows that the B2O3 / ZrO2 composite material can effectively inhibit the over-oxidation of propylene, thus ensuring high catalytic selectivity and catalytic activity. In contrast, the thermal catalytic ODHP reaction performance of the ZrO2 material is not good. Its propane conversion rate is 10.0%, the propylene selectivity is 18.8%, and the olefin selectivity is 25.4%.
[0046] Meanwhile, as Figures 9 - 11 shown, at the same reaction temperature, the propane conversion rate of the 10% B2O3 / ZrO2 composite material is 9.3%, the propylene yield is 4.8%, and the olefin yield is 5.5%; the propane conversion rate of the 20% B2O3 / ZrO2 composite material is 10.1%, the propylene yield is 7.4%, and the olefin yield is 8.3%; the propane conversion rate of the B2O3 material is 16.7%, the propylene yield is 12.1%, and the olefin yield is 15.2%. Their thermal catalytic ODHP reaction performances are not good.
[0047] In summary, the B2O3 / ZrO2 composite material prepared in the present invention not only maintains the excellent C-H activation ability of the ZrO2 material but also retains the significant advantages of the boron-based catalyst in inhibiting CO x aspect. Meanwhile, as a carrier, ZrO2 can not only significantly enhance its adsorption of propane but also effectively improve the long-term stability of its ODHP reaction.
[0048] The above are only the preferred embodiments of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope covered by the present invention.
Claims
1. A preparation method of a B2O3 / ZrO2 composite catalyst, characterized in that, It includes the following steps: 1) Add boric acid to deionized water and stir to completely dissolve it to obtain a boric acid solution; 2) Add zirconium hydroxide to the above boric acid solution, and then place the mixed solution in an oil bath and heat and stir until all solids precipitate; 3) Dry the precipitated solid overnight to obtain a precursor; 4) Calcinate the obtained precursor at high temperature under a nitrogen atmosphere and wait for it to cool naturally to room temperature to obtain a B2O3 / ZrO2 composite material.
2. The preparation method of a B2O3 / ZrO2 composite catalyst according to claim 1, characterized in that, The concentration of the boric acid solution obtained in step 1) is 0.2 mmol / mL.
3. The preparation method of a B2O3 / ZrO2 composite catalyst according to claim 1, characterized in that, In step 2), the molar ratio of the addition amount of zirconium hydroxide to the boric acid used is 3:
4.
4. The preparation method of a B2O3 / ZrO2 composite catalyst according to claim 1, characterized in that, In step 2), the temperature of the heating and stirring is 80 °C, and the stirring speed is 500 r / min.
5. The preparation method of a B2O3 / ZrO2 composite catalyst according to claim 1, characterized in that, In step 3), the drying temperature is 60 °C.
6. The preparation method of a B2O3 / ZrO2 composite catalyst according to claim 1, characterized in that, In step 4), the high-temperature calcination is to increase the temperature to 1000 °C at a rate of 10 °C / min and hold for 2 h.
7. A B2O3 / ZrO2 composite catalyst prepared by any of the methods according to claims 1-6.
8. Use of a B2O3 / ZrO2 composite catalyst according to claim 7 in the thermal catalytic propane oxidative dehydrogenation reaction.
9. The application according to claim 8, wherein The temperature of the reaction is 520 °C, and the volume ratio of the feed gases is C3H8:O2:He = 6:3:11.