High performance ru-based propane combustion catalyst, its preparation method and application

Abstract

This invention discloses a high-performance Ru-based propane combustion catalyst, its preparation method, and its applications, belonging to the field of propane oxidation catalysis technology. The invention involves impregnating a CeO2 support with a ruthenium nitrite solution using a wet impregnation method, followed by calcination to obtain a Ru / CeO2 catalyst; impregnating an Al2O3 support with an ammonium molybdate aqueous solution using a wet impregnation method, followed by calcination to obtain a Mo / Al2O3 catalyst; and then mixing the Ru / CeO2 and Mo / Al2O3 catalysts through grinding to obtain a Ru / CeO2+Mo / Al2O3 propane combustion catalyst. This invention, through impregnation and mechanical grinding, controls the electronic structure and state of Ru, improving the low-temperature activity of the Ru / CeO2 catalyst for propane oxidation. It can solve the problem of alkane oxidation and elimination in industrial flue gas / exhaust gas and vehicle exhaust systems, achieving efficient propane oxidation and reducing hydrocarbon formation, thus possessing broad industrial application prospects.

Description

Technical Field

[0001] This invention belongs to the field of propane oxidation catalysis technology, specifically relating to a high-performance Ru-based propane combustion catalyst, its preparation method, and its application. Background Technology

[0002] Propane (C3H8) plays a vital role in various sectors, including industry, energy, and daily life. As a clean fuel, it is widely used in liquefied petroleum gas (LPG), home heating, industrial cutting, and as a partial alternative to fuel vehicles. However, during its production, storage, transportation, and use, as well as in vehicle exhaust and industrial organic waste gas emissions, the escape or incomplete combustion of C3H8 is unavoidable. C3H8 entering the atmosphere poses serious environmental hazards, such as acting as a precursor in photochemical reactions to form secondary pollutants like photochemical smog, and posing safety risks upon leakage. C3H8 emissions also cause various health problems, primarily affecting the respiratory, eye, skin, and nervous systems. Effective control of C3H8 emissions from both mobile and stationary sources has become a core task in atmospheric environmental governance.

[0003] C3H8 catalytic oxidation is a technology that converts C3H8 into non-toxic and harmless CO2 and H2O using a catalyst. This technology is commonly used to reduce C3H8 emissions and has wide applications in the field of C3H8 emission reduction. However, it also faces some challenges, such as the high cost of precious metal catalysts, which hinders industrial-scale production; a narrow reaction temperature window, making low-temperature catalytic conversion difficult; and the catalyst's susceptibility to sintering and poisoning, leading to deactivation under real-world, harsh operating conditions. Therefore, developing high-performance, low-temperature C3H8 catalytic oxidation catalysts for C3H8 elimination is a key technology.

[0004] Traditional noble metal catalysts exhibit excellent redox capabilities to accelerate reactions, but they suffer from several technical bottlenecks: the highly active sites of noble metal catalysts exhibit competitive adsorption of C3H8 and O2, hindering efficient reaction. A simple design to spatially separate acid sites and redox sites provides crucial additional sites for C3H8 activation, forming a dual-site synergistic elimination that effectively mitigates the competitive adsorption of C3H8 and O2. Chinese patent CN109675556A discloses a high-performance Ru-based propane oxidation catalyst, but it suffers from the technical bottleneck of competitive adsorption of reactant molecules. Our strategy, however, introduces a new acidic site, Mo / Al2O3, into the traditional propane oxidation catalyst Ru / CeO2. A high-performance Ru-based propane combustion catalyst, denoted as Ru / CeO2+Mo / Al2O3, can be obtained through simple mechanical grinding and mixing. This catalyst effectively solves the problem of competitive adsorption in the C3H8 oxidation reaction, enabling efficient catalytic elimination of C3H8 at low temperatures. It also provides a new strategy for reducing noble metal usage and lowering economic costs, meeting the needs of industrial applications and environmental protection. Summary of the Invention

[0005] The first technical problem solved by this invention is to provide a high-performance Ru-based propane combustion catalyst with excellent propane oxidation reaction performance. The second technical problem solved by this invention is to provide a method for preparing a high-performance Ru-based propane combustion catalyst, which is simple and convenient and has practical application prospects. The third technical problem solved by this invention is to provide the application of this catalyst in the propane oxidation reaction.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a high-performance Ru-based propane combustion catalyst involves impregnating a ruthenium nitrite solution onto a CeO2 support using a wet impregnation method, followed by calcination to obtain a Ru / CeO2 catalyst; impregnating an ammonium molybdate aqueous solution onto an Al2O3 support using a wet impregnation method, followed by calcination to obtain a Mo / Al2O3 catalyst; and mixing the Ru / CeO2 catalyst and the Mo / Al2O3 catalyst by grinding to obtain a Ru / CeO2+Mo / Al2O3 propane combustion catalyst.

[0008] Furthermore, the Ru loading is 0.2-2.0 wt.%, and the Mo loading is 1.0-20.0 wt.%.

[0009] Furthermore, the calcination temperature is 400-600℃.

[0010] Furthermore, the calcination time is 2-4 hours.

[0011] Furthermore, the calcination atmosphere is air.

[0012] Furthermore, the mechanical grinding time is 30-60 minutes.

[0013] Furthermore, the Ru-based propane combustion catalyst prepared by the aforementioned method is also described.

[0014] Furthermore, the application of the Ru-based propane combustion catalyst in the propane oxidation reaction.

[0015] Furthermore, the catalytic conditions for the propane oxidation reaction are as follows: catalyst particle size of 40-60 mesh, reaction conditions of 4000 ppm C3H8 and 5% O2, and a tested mass hourly space velocity of 100,000 mL·g. cat -1 ·h -1 .

[0016] Furthermore, the catalytic reaction temperature is 50-450℃.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1) This invention utilizes a ruthenium nitrite nitrate solution, employs a low-temperature drying method via initial wet impregnation, and then calcines it in a muffle furnace at high temperature to obtain a Ru / CeO2 catalyst. Similarly, an ammonium molybdate aqueous solution is used, employs a low-temperature drying method via wet impregnation, and then calcines it in a muffle furnace at high temperature to obtain a Mo / Al2O3 catalyst. Subsequently, Ru / CeO2 and Mo / Al2O3 are simply mechanically ground and mixed to obtain a Ru / CeO2+Mo / Al2O3 catalyst. The preparation method is simple and suitable for large-scale industrial production.

[0019] 2) The highly efficient propane oxidation catalyst developed in this invention has superior catalytic activity, which is of great significance for propane emission reduction and treatment and has great economic benefits.

[0020] 3) The high-efficiency propane oxidation catalyst developed in this invention provides a new strategy for reducing precious metal content and lowering economic costs, and solves the technical problems of propane oxidation catalysts in industrial waste gas treatment and tail gas purification applications. Attached Figure Description

[0021] Figure 1 X-ray diffraction patterns of the 0.5Ru / CeO2, 10Mo / Al2O3 and 0.5Ru / CeO2+10Mo / Al2O3 catalysts prepared for this application;

[0022] Figure 2The results of CO temperature-programmed reduction of the 0.5Ru / CeO2, 10Mo / Al2O3, 0.5Ru / CeO2+10Mo / Al2O3, Mo / Ru / CeO2 and Ru / Mo / CeO2 catalysts prepared for this application are shown in the figure.

[0023] Figure 3 In-situ infrared CO adsorption results of the 0.5Ru / CeO2, 0.5Ru / CeO2+10Mo / Al2O3, Mo / Ru / CeO2 and Ru / Mo / CeO2 catalysts prepared in this application;

[0024] Figure 4 The conversion rates of propane oxidation reaction for the 0.5Ru / CeO2 and 0.5Ru / CeO2+xMo / Al2O3 catalysts prepared in this application are shown in the figure.

[0025] Figure 5 The conversion rate of propane oxidation reaction of 0.5Ru / CeO2+10Mo / Al2O3 catalysts mixed in different mass ratios prepared for this application is shown in the figure.

[0026] Figure 6 The conversion rate of propane oxidation reaction of 0.5Ru / CeO2, 0.5Ru / CeO2+10Mo / Al2O3, Mo / Ru / CeO2 and Ru / Mo / CeO2 prepared in this application is shown in the figure. Detailed Implementation

[0027] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, and it should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0028] Example 1

[0029] Preparation of 0.5Ru / CeO2 catalyst

[0030] Weigh 3g of commercial CeO2 support into a crucible, adjust the Ru mass fraction to 0.5wt.%, weigh 0.1mL of nitrosyl ruthenium nitrate solution, and add the nitrosyl ruthenium nitrate solution dropwise onto the CeO2 support, impregnating it evenly. Place the powder in an oven and dry at 120℃ for 2h, then place it in a muffle furnace for high-temperature calcination at 450℃ for 2h in air atmosphere, with a heating rate of 5℃·min. -1 The resulting sample was denoted as 0.5Ru / CeO2.

[0031] Example 2

[0032] Preparation of 10Mo / Al2O3 catalyst

[0033] Weigh 3g of commercial Al2O3 support into a crucible, adjust the mass fraction of MoO3 to 10 wt.%, weigh 368 mg of ammonium molybdate tetrahydrate and dissolve it in water to prepare an ammonium molybdate aqueous solution. Stir the ammonium molybdate solution and commercial Al2O3 support evenly, place the powder in an oven and dry at 120℃ for 2 hours, then place it in a muffle furnace for high-temperature calcination at 550℃ for 2 hours in air atmosphere, with a heating rate of 5℃·min. -1 The resulting sample was denoted as 10Mo / Al2O3.

[0034] Example 3

[0035] Preparation of 0.5Ru / CeO2+10Mo / Al2O3 catalyst

[0036] Weigh 1g of 0.5Ru / CeO2 catalyst and 1g of 10Mo / Al2O3 catalyst into a mortar, mix the catalysts evenly together using conventional mechanical grinding, grind for 30min, and then dry the powder in an oven at 120℃ for 2h. The resulting sample is recorded as 0.5Ru / CeO2+10Mo / Al2O3.

[0037] Example 4

[0038] Preparation of 5Mo / Al2O3 catalyst

[0039] The difference from Example 2 is that 3g of commercial Al2O3 support was weighed into a crucible, the mass fraction of MoO3 was adjusted to 5wt.%, 184mg of ammonium molybdate tetrahydrate was weighed and dissolved in water to prepare an ammonium molybdate aqueous solution, the ammonium molybdate solution and the commercial Al2O3 support were stirred and impregnated evenly, the powder was placed in an oven and dried at 120℃ for 2h, and then placed in a muffle furnace for high-temperature calcination at 550℃ for 2h in air atmosphere, with a heating rate of 5℃·min. -1 The resulting sample was denoted as 5Mo / Al2O3.

[0040] Preparation of 15Mo / Al2O3 catalyst

[0041] The difference from Example 2 is that 3g of commercial Al2O3 support was weighed into a crucible, the mass fraction of MoO3 was adjusted to 15wt.%, 552mg of ammonium molybdate tetrahydrate was weighed and dissolved in water to prepare an ammonium molybdate aqueous solution, the ammonium molybdate solution and the commercial Al2O3 support were stirred and impregnated evenly, the powder was placed in an oven and dried at 120℃ for 2h, and then placed in a muffle furnace for high-temperature calcination at 550℃ for 2h in air atmosphere, with a heating rate of 5℃·min. -1 The resulting sample was denoted as 15Mo / Al2O3.

[0042] Preparation of 20Mo / Al2O3 catalyst

[0043] The difference from Example 2 is that 3g of commercial Al2O3 support was weighed into a crucible, the mass fraction of MoO3 was adjusted to 20wt.%, 736mg of ammonium molybdate tetrahydrate was weighed and dissolved in water to prepare an ammonium molybdate aqueous solution, the ammonium molybdate solution and the commercial Al2O3 support were stirred and impregnated evenly, the powder was placed in an oven and dried at 120℃ for 2h, and then placed in a muffle furnace for high-temperature calcination at 550℃ for 2h in air atmosphere, with a heating rate of 5℃·min. -1 The resulting sample was denoted as 20Mo / Al2O3.

[0044] Preparation of 0.5Ru / CeO2+5Mo / Al2O3 catalyst

[0045] The difference from Example 3 is that 1g of 0.5Ru / CeO2 catalyst and 1g of 5Mo / Al2O3 catalyst were weighed, and the resulting sample was recorded as 0.5Ru / CeO2+5Mo / Al2O3.

[0046] Preparation of 0.5Ru / CeO2+15Mo / Al2O3 catalyst

[0047] The difference from Example 3 is that 1g of 0.5Ru / CeO2 catalyst and 1g of 15Mo / Al2O3 catalyst were weighed, and the resulting sample was recorded as 0.5Ru / CeO2+15Mo / Al2O3.

[0048] Preparation of 0.5Ru / CeO2+20Mo / Al2O3 catalyst

[0049] The difference from Example 3 is that 1g of 0.5Ru / CeO2 catalyst and 1g of 20Mo / Al2O3 catalyst were weighed, and the resulting sample was recorded as 0.5Ru / CeO2+20Mo / Al2O3.

[0050] Comparative Example 1

[0051] Preparation of Mo / Ru / CeO2 catalyst

[0052] Weigh 3g of commercial CeO2 support into a crucible, adjust the Ru mass fraction to 0.5wt.%, weigh 0.1mL of nitrosylruthenium nitrate solution, and add the nitrosylruthenium nitrate solution dropwise onto the CeO2 support, impregnating it evenly. Place the powder in an oven and dry at 120℃ for 2h, then place it in a muffle furnace for high-temperature calcination at 450℃ for 2h, with a heating rate of 5℃·min. -1The resulting sample was designated Ru / CeO2. 1 g of Ru / CeO2 catalyst was weighed into a crucible, and the mass fraction of MoO3 was adjusted to 8.5 wt.%. 104 mg of ammonium molybdate tetrahydrate was dissolved in water to prepare an ammonium molybdate aqueous solution. The ammonium molybdate solution and Ru / CeO2 catalyst were stirred and thoroughly impregnated. The powder was then dried in an oven at 120°C for 2 hours, followed by high-temperature calcination in a muffle furnace at 550°C for 2 hours, with a heating rate of 5°C / min. -1 The resulting sample is denoted as Mo / Ru / CeO2.

[0053] Comparative Example 2

[0054] Preparation of Ru / Mo / CeO2 catalyst

[0055] Weigh 3g of commercial CeO2 support into a crucible, adjust the mass fraction of MoO3 to 8.5wt.%, weigh 312mg of ammonium molybdate tetrahydrate and dissolve it in water to prepare an ammonium molybdate aqueous solution. Stir the ammonium molybdate solution and commercial CeO2 support evenly, then dry the powder in an oven at 120℃ for 2h, and then calcine it in a muffle furnace at 550℃ for 2h, with a heating rate of 5℃·min. -1 The resulting sample was designated Mo / CeO2. 1 g of Mo / CeO2 catalyst was weighed into a crucible, and the Ru mass fraction was adjusted to 0.5 wt.%. 0.1 mL of ruthenium nitrite nitrate solution was weighed and added dropwise to the Mo / CeO2 catalyst, ensuring uniform impregnation. The powder was then dried in an oven at 120°C for 2 hours, followed by high-temperature calcination in a muffle furnace at 450°C for 2 hours, with a heating rate of 5°C / min. -1 The resulting sample is denoted as Ru / Mo / CeO2.

[0056] Figure 1 The X-ray diffraction patterns of 0.5Ru / CeO2, 10Mo / Al2O3, and 0.5Ru / CeO2+10Mo / Al2O3 catalysts are shown. The results indicate that all 0.5Ru / CeO2 and 0.5Ru / CeO2+10Mo / Al2O3 catalysts exhibit a CeO2 structure, with no obvious RuO2-attributed crystal phase peaks, indicating that Ru species are highly dispersed on the CeO2 surface. The Mo / Al2O3 catalysts all exhibit an Al2O3 structure, with no obvious MoO3-attributed crystal phase peaks, indicating that Mo species are highly dispersed on the Al2O3 surface.

[0057] Figure 2The figures show the CO temperature-programmed reduction results for 0.5Ru / CeO2, 10Mo / Al2O3, 0.5Ru / CeO2+10Mo / Al2O3, Mo / Ru / CeO2, and Ru / Mo / CeO2 catalysts. The results indicate that Ru and Mo form a weak interaction on the 0.5Ru / CeO2+10Mo / Al2O3 catalyst, while Ru and Mo form a strong interaction on the Mo / Ru / CeO2 and Ru / Mo / CeO2 catalysts.

[0058] Figure 3 The in-situ infrared CO adsorption results for 0.5Ru / CeO2, 0.5Ru / CeO2+10Mo / Al2O3, Mo / Ru / CeO2, and Ru / Mo / CeO2 are shown. The results indicate that the interaction between Ru and Mo causes the adsorption peak of CO in the ionic Ru species to shift to higher wavenumbers. The stronger the interaction between Ru and Mo, the higher the wavenumber shift of the adsorption peak of the ionic Ru species.

[0059] Example 4

[0060] Application of Ru / CeO2+Mo / Al2O3 catalyst in C3H8 oxidation reaction

[0061] The prepared catalysts 0.5Ru / CeO2, 0.5Ru / CeO2+xMo / Al2O3, Mo / Ru / CeO2, Ru / Mo / CeO2, and 0.5Ru / CeO2+10Mo / Al2O3 with different mass ratios were applied to the C3H8 oxidation reaction. The 0.5Ru / CeO2+10Mo / Al2O3 catalyst exhibited excellent C3H8 oxidation activity, as shown in the following figures. Figure 4-6 .

[0062] The specific reaction conditions are as follows: The catalytic reaction test was conducted in a fixed-bed continuous flow quartz reactor. The catalyst particle size was 40-60 mesh, and the dosage was 100 mg. The reaction gas composition was: 4000 ppm C3H8, 5% O2, with Ar as the equilibrium gas. The mass hourly space velocity (WHSV) was 100,000 mL·g. -1 ·h -1 The catalytic reaction was carried out at 50-400℃. The product was analyzed by mass spectrometry, and the C3H8 conversion rate was calculated using the following formula:

[0063] C3H8 conversion (%) = {([C3H8] in - [C3H8] out ) / [C3H8] in} × 100%

[0064] Depend on Figure 4The conversion rates of propane oxidation reactions for 0.5Ru / CeO2 and 0.5Ru / CeO2+xMo / Al2O3 show that the conversion rates for 0.5Ru / CeO2+10Mo / Al2O3 and 0.5Ru / CeO2+15Mo / Al2O3 are the best.

[0065] Depend on Figure 5 The conversion rate of propane oxidation reaction of 0.5Ru / CeO2+10Mo / Al2O3 mixed in different mass ratios shows that the optimal mixing ratio of 0.5Ru / CeO2+10Mo / Al2O3 is 1:1.

[0066] Depend on Figure 6 The conversion rates of propane oxidation reactions for 0.5Ru / CeO2, 0.5Ru / CeO2+10Mo / Al2O3, Mo / Ru / CeO2, and Ru / Mo / CeO2 show that 0.5Ru / CeO2+10Mo / Al2O3 has the best conversion rate.

[0067] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high performance Ru-based propane combustion catalyst, characterized by, The ruthenium nitrosyl nitrate solution is impregnated on the CeO2 carrier by the incipient wetness impregnation method, and the Ru / CeO2 catalyst is obtained by calcination; the ammonium molybdate aqueous solution is impregnated on the Al2O3 carrier by the wet impregnation method, and the Mo / Al2O3 catalyst is obtained by calcination; the Ru / CeO2 catalyst and the Mo / Al2O3 catalyst are mixed by grinding to obtain the Ru / CeO2+Mo / Al2O3 propane combustion catalyst.

2. The method for preparing the high-performance Ru-based propane combustion catalyst according to claim 1, characterized in that: The loading of Ru is 0.2-2.0 wt.%, and the loading of Mo is 1.0-20.0 wt.%.

3. The method for preparing the high-performance Ru-based propane combustion catalyst according to claim 1, characterized in that: The calcination temperature is 400-600 ℃.

4. The method for preparing the high-performance Ru-based propane combustion catalyst according to claim 1, characterized in that: The calcination time is 2-4 h.

5. The method for preparing the high-performance Ru-based propane combustion catalyst according to claim 1, characterized in that: The calcination atmosphere is air.

6. The method for preparing the high-performance Ru-based propane combustion catalyst according to claim 1, characterized in that: The mechanical grinding time is 30-60 min.

7. The Ru-based propane combustion catalyst prepared by the method for preparing the high-performance Ru-based propane combustion catalyst according to any one of claims 1-6.

8. The application of the Ru-based propane combustion catalyst according to claim 7 in a propane oxidation reaction.

9. Use of a Ru-based propane combustion catalyst according to claim 8 in a propane oxidation reaction, characterized in that: The catalytic conditions for the propane oxidation reaction were: catalyst particle size of 40-60 mesh, reaction conditions of 4000 ppm C3H8 and 5% O2, and a mass space velocity of 100000 mL-g cat -1 ·h -1 .

10. Use of a Ru-based propane combustion catalyst according to claim 9 in a propane oxidation reaction, characterized in that: The catalytic reaction temperature is 50-450 ℃.

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