Application of a SiO2-supported Ru-Pt bimetallic catalyst containing a single atom

Abstract

This invention belongs to the field of industrial catalysis and nanomaterials technology, specifically relating to the application of a Pt-Ru bimetallic catalyst in the catalytic combustion of propane. The invention first deposits Pt metal nanoparticles on a SiO2 support, and then, by controlling the number of ALD cycles, propagates Ru species as a single-atom oxide (Ru1O). x Ru1O was precisely deposited on the surface of Pt metal nanoparticles in a form that allows for precise deposition of a single-atom bimetallic structure, thereby obtaining Ru1O with a highly controllable structure. x / Pt NP / SiO2 catalyst. Compared with the prior art, the special structure of this invention not only maximizes the theoretical bimetallic synergistic effect, but also achieves the optimal electronic state of the bimetal, significantly enhancing the bimetallic synergistic effect. This results in excellent low-temperature activity, excellent reaction stability, and adaptability to reaction conditions in the propane catalytic combustion reaction, solving the serious problem of catalyst activity decline caused by large fluctuations in the reaction atmosphere under actual working conditions.

Description

Technical Field

[0001] This invention belongs to the field of industrial catalysis and nanomaterials technology, specifically relating to the application of a Pt-Ru bimetallic catalyst in the catalytic combustion of propane. Background Technology

[0002] Propane, a typical low-carbon alkane, is widely found in industrial waste gas, natural gas, and vehicle exhaust. It not only harms human health but also causes volatile organic compound (VOC) pollution. Propane catalytic combustion technology is an effective means of eliminating propane pollution, converting it into harmless CO2 and H2O. The core of this technology lies in the development of high-performance catalysts.

[0003] Currently, catalysts used for propane catalytic combustion mainly include noble metal catalysts (such as Pt, Pd, Ru, etc.), transition metal oxide catalysts, and composite metal catalysts. Among them, Pt-based and Ru-based noble metal catalysts have shown high activity in propane catalytic combustion and have attracted much attention. In recent years, utilizing the bimetallic synergistic effect between Ru and Pt to further enhance catalytic performance has become a research hotspot in this field. However, existing research on the application of Ru-Pt bimetallic systems in propane catalytic combustion still has significant limitations: on the one hand, traditional preparation methods (such as impregnation and co-precipitation methods) result in low dispersion of active components and poor structural controllability, making it difficult to fully utilize the bimetallic synergistic effect; on the other hand, the electronic interaction mechanism between Ru and Pt is still unclear, and there is a lack of fine-structure design strategies, limiting the synergistic effect.

[0004] Single-atom catalysts (SACs) boast near 100% theoretical atomic utilization. In bimetallic systems, dispersing one metal in single-atom form promises to maximize synergistic effects. However, unlike traditional SACs which simply require depositing metal atoms onto a bulk support, constructing bimetallic structures containing single atoms presents a greater technical challenge—it demands the precise deposition of a single-atom metal onto the surface of another metal nanoparticle, requiring extremely stringent control over the atomic-level structure. More importantly, the interaction between the single-atom metal and the substrate metal in such structures reaches extreme values, making it difficult to maintain the optimal electronic states of both metals, resulting in exceptionally difficult precise control of catalytic performance.

[0005] Atomic layer deposition (ALD) technology, with its self-limiting layer-by-layer growth, can precisely control the size, composition, and structure of materials at the sub-nanometer scale, providing an ideal platform for constructing well-defined metal catalysts. Previous studies have used ALD technology to prepare SiO2-supported monometallic or conventional bimetallic catalysts. For example, the team led by Lu Junling at the University of Science and Technology of China (Bimetallic monolayer catalyst breaks the activity–selectivity trade-off on metal particle size for efficient chemoselective hydrogenations, Nature Catalysis volume 4, pages 840-849 (2021)) used ALD technology to first deposit an Au core on the SiO2 surface, then coat it with 1-3 Pt shell layers to construct a core-shell bimetallic catalyst. However, the catalytic performance of this core-shell structure is extremely sensitive to the thickness of the Pt shell layer; optimal activity can only be achieved when it is strictly controlled to a single atomic layer. Increased shell thickness hinders contact between the reactants and the Au core, leading to a significant decrease in activity. More importantly, the catalyst's optimized Pt(111) platform site for the hydrogenation reaction is insufficient to meet the requirements of the key step in the propane combustion reaction—CH bond activation.

[0006] Patent CN108993487A discloses a method for preparing Ru-Pt / TiO2 single-atom catalysts using atomic layer deposition (ALD). However, this method primarily utilizes pre-synthesized hexamethyl-methylcyclopentadiene platinum-ruthenium as a precursor, then simultaneously deposits Ru and Pt onto a TiO2 support using ALD, achieving single-atom dispersion of Ru and Pt. However, this method cannot separately modulate the structure and electronic states of Ru and Pt, making it unsuitable for enhancing activity in other reactions. Furthermore, the thermal stability of the single-atom structure poses a significant risk. This technology is only applicable to reactions with a temperature range of 25°C. o C is used.

[0007] Patent CN113996291A discloses a Pt-Ru catalyst supported on a composite oxide support of CuO, TiO2, Al2O3, and SiO2, which exhibits high catalytic activity for dichloromethane and bromomethane. The catalyst can be prepared using methods such as vapor deposition. Although the patent mentions vapor deposition in its specification, the four methods listed in the patent claims and description all employ impregnation. Based on the Pt and Ru precursors used in the examples, it is impossible to synthesize them using ALD, let alone perform precise structural design and construction.

[0008] Patent CN119657119A discloses a platinum-based catalyst, its preparation method, and its application in catalytic methane combustion, achieving a breakthrough reduction in the temperature for complete methane conversion to below 200°C, while maintaining long-term stability. This technology uses rarely used nitrous oxide as the oxidant, whose oxidizing power is significantly stronger than commonly used oxygen, resulting in a significant increase in activity. However, nitrous oxide is a hazardous chemical and cannot be used in actual industrial applications, rendering its high activity useless for practical use. Replacing nitrous oxide with oxygen as the oxidant cannot avoid the competitive adsorption of alkanes and O2 on traditional supported Pt catalysts, making it difficult to overcome the limitations of poor alkane combustion performance in existing literature.

[0009] Therefore, developing Ru-Pt bimetallic catalysts with precise structures and optimized metal electronic states is an effective way to achieve low-temperature and efficient catalytic combustion of propane. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and provide an application of a SiO2-supported Ru-Pt bimetallic catalyst with a single atom containing a precise and controllable structure and excellent catalytic combustion activity in propane catalytic combustion.

[0011] To achieve the above objectives, this invention constructs a bimetallic catalyst with a "metal nanoparticle-metal single atom" composite configuration (i.e., one metal is anchored to the support in the form of nanoparticles, and the other metal is deposited on the surface of the nanoparticles in the form of single atoms). Specifically, this invention utilizes atomic layer deposition (ALD) technology to design a SiO2-supported Ru-Pt bimetallic catalyst with a "Pt nanoparticle-Ru single atom" composite structure, which provides a new approach for developing highly efficient propane combustion catalysts and can achieve the above-mentioned objectives.

[0012] The objective of this invention can be achieved through the following technical solutions: Application of a SiO2-supported Ru-Pt bimetallic catalyst containing a single atom: The Ru-Pt bimetallic catalyst is applied to the catalytic combustion reaction of propane. This catalyst is a Ru1O2 bimetallic structure containing a single atom. x / Pt NP / SiO2, using SiO2 as a carrier, wherein Pt metal nanoparticles (Pt) are loaded on the carrier. NP Ru in the form of a single-atom oxide Ru1O x The form is deposited on the surface of Pt metal nanoparticles.

[0013] Furthermore, Ru has a single-atom structure, and its valence state is +3 to +4, Ru1O x In the equation, 1.5 < x < 2; the valence state of Pt is 0 to +2; and the particle size of Pt metal nanoparticles is 2 to 6 nm.

[0014] Furthermore, when the catalyst catalyzes the combustion of propane, Ru1O x Propane preferentially adsorbs and activates at the site, then undergoes deep oxidation with O2 adsorbed on the Pt particles, producing CO2 and H2O. The ignition temperature is T. 10 Complete combustion of propane can be achieved at temperatures as low as 160°C, and at 245°C, with a reaction rate of 4.02 μmol / g at 200°C. metal / s.

[0015] Furthermore, the catalyst employs ALD technology, and by varying the number of ALD cycles, a Pt-Ru bimetallic catalyst with a well-defined structure is constructed. This method uses SiO2 as a support, supporting Pt metal nanoparticles, and Ru in the form of a single-atom oxide (Ru1O). x The Pt metal nanoparticles are deposited on the surface of Pt metal nanoparticles in the form of a particle size of 2-6 nm. The method includes the following steps: S1. SiO2 support was prepared using the Stöber method; S2. Pt nanoparticles were loaded onto the surface of a SiO2 support using ALD technology to obtain Pt nanoparticles. NP / SiO2; S3. Single-atom Ru was deposited on Pt nanoparticles using ALD technology to obtain a bimetallic Ru1O structure. x / Pt NP / SiO2 catalyst; S4. The deposited sample obtained in step S3 is heat-treated to obtain Ru1O with a single-atom bimetallic structure. x / Pt NP / SiO2 catalyst.

[0016] Furthermore, the process in step S1 is as follows: Tetraethyl silicate (TEOS), NH3·H2O, C2H5OH and H2O are mixed and stirred, and the precipitate is centrifuged, washed with ethanol, dried and then calcined to obtain SiO2 support.

[0017] Furthermore, step S1 involves adding ethyl silicate, NH3·H2O, C2H5OH, and H2O to a reactor at a volume ratio of (15-20):(5-6):(350-380):(25-35). The solution mixture is then vigorously stirred at 25-30°C for 24 hours. The precipitate is centrifuged, washed several times with ethanol, and dried overnight at 70-100°C. Finally, it is calcined in a tube furnace at a flow rate of 10-40 mL / min at 600-800°C for 2-5 hours at 5-10 vol.% O2 / Ar to obtain silica microspheres with an average particle size of 3-5 nm.

[0018] Furthermore, the process in step S2 is as follows: A SiO2 support is placed in an ALD reaction chamber. Platinum acetylacetonate (Pt(acac)2), methylcyclopentadienyltrimethylplatinum (MeCpPtMe3), or (trimethyl)methylcyclopentadienylplatinum (iv) is selected as the Pt precursor. Oxygen is used as the reaction gas, and ALD cycling is performed at 200-300°C. Uniformly dispersed Pt nanoparticles are deposited on the SiO2 support, yielding Pt. NP / SiO2.

[0019] Furthermore, the number of ALD cycles for Pt precursor deposition is 10-20; the particle size of Pt nanoparticles is 2-6 nm.

[0020] Furthermore, the process in step S3 is as follows: Pt NP SiO2 is placed in an ALD reaction chamber, and ruthenium acetylacetonate or dicarbonylbis(pentamethylcyclopentadienyl)ruthenium is selected as the Ru precursor. Oxygen is used as the reaction gas, and ALD cycling is carried out at 200-300℃, so that Ru is deposited in single-atom form on the surface of Pt nanoparticles to form a single-atom structure Ru1O. x The bimetallic structure Ru1O was obtained. x / Pt NP / SiO2 catalyst.

[0021] Furthermore, the Ru precursor is deposited in 1 to 2 cycles to ensure that it covers the surface of the Pt metal particles in the form of isolated single atoms, rather than forming a continuous multilayer shell.

[0022] Furthermore, step S4 involves heat-treating the deposited sample in air at 200–500°C to remove precursor ligands, obtaining a pure metal surface, and further enhancing the interaction between the metal and the support, as well as the bimetallic sites, to obtain Ru1O with a single-atom bimetallic structure. x / Pt NP / SiO2 catalyst.

[0023] The above-mentioned Pt-Ru bimetallic catalyst was applied to the catalytic combustion reaction of propane; the catalyst utilizes its Ru1O... x / Pt NP The hierarchical structure of / SiO2 significantly enhances the bimetallic synergistic effect between Pt and Ru. This synergistic effect is specifically manifested as: Ru1O x Propane is preferentially adsorbed and activated at the site, then undergoes a deep oxidation reaction with O2 adsorbed and activated on Pt nanoparticles to generate CO2 and H2O. The results indicate that Ru1O containing a single-atom bimetallic structure... x / Pt NPThe SiO2 catalyst exhibited excellent low-temperature activity in the catalytic combustion of propane, under reaction atmospheres of 0.2 vol.% C3H8, 2 vol.% O2, and 97.8 vol.% N2, with a space velocity of 30,000 mL·g. -1 ·h -1 At this point, the catalyst ignition temperature (reaction temperature at 10% conversion) is 160℃, complete propane combustion can be achieved at 245℃, and the reaction rate reaches 4.02 μmol / g at 200℃. metal The performance of this catalyst is significantly superior to that of single-metal Pt / SiO2 and Ru / SiO2 catalysts, as well as bimetallic alloy catalysts prepared by the co-impregnation method (PtRu / SiO2). More importantly, the catalyst exhibits excellent reaction stability and adaptability to reaction conditions. Its activity remains unchanged after 100 hours of reaction at 200℃, and the activity only slightly decreases when 3 vol. H2O is introduced into the reaction atmosphere. Furthermore, it maintains excellent activity even when the C3H8:O2 volume ratio changes from 1:5 to 1:20, thus mitigating the significant risk of activity degradation caused by large fluctuations in the reaction atmosphere in practical applications.

[0024] The beneficial effects of this invention are: (1) The core of the catalyst of this invention lies in its unique bimetallic structure containing single atoms. Using silica (SiO2) as a support, a bimetallic synergistic catalyst with a "Pt nanoparticle-Ru single atom" structure was precisely constructed using atomic layer deposition (ALD) technology, namely Ru1O containing a single atom bimetallic structure. x / Pt NP The / SiO2 catalyst maximizes the bimetallic sites and the bimetallic synergistic effect, exhibiting significantly better propane catalytic combustion performance than single metal catalysts and bimetallic catalysts with alloy structures prepared by traditional methods.

[0025] (2) The special structure of the catalyst of the present invention not only realizes the theoretical maximization of the bimetallic synergistic effect, but also realizes the optimal electronic state of Ru and Pt, which strengthens the bimetallic synergistic effect and makes it exhibit excellent low-temperature activity in propane catalytic combustion reaction, which is far superior to that of single metal catalysts and other bimetallic structure catalysts (such as alloy structure bimetallic catalysts prepared by co-impregnation method).

[0026] (3) Maximizing the synergistic effect: Constructing Ru single atoms on Pt metal particles not only maximizes the synergistic catalysis, but also brings the metal close to its optimal electronic state, significantly optimizing the activation of propane CH bonds and the adsorption / activation of oxygen species, thereby greatly improving the catalytic performance.

[0027] (4) Excellent catalytic performance: Ru1O specifically discovered and protected in this invention x / PtNP The / SiO2 structure exhibited significantly higher low-temperature activity than other comparative catalysts in the catalytic combustion of propane, under reaction atmospheres of 0.2 vol.% C3H8, 2 vol.% O2, and 97.8 vol.% N2, with a space velocity of 30,000 mL·g. -1 ·h -1 At that time, the catalyst ignition temperature (reaction temperature at 10% conversion) was 160℃, complete combustion of propane was achieved at 245℃, and the reaction rate reached 4.02 μmol / g at 200℃. metal More importantly, the catalyst exhibits excellent reaction stability and adaptability to reaction conditions. Its activity remains unchanged after 100 hours of reaction at 200℃, and the activity only slightly decreases when 3 vol. H2O is introduced into the reaction atmosphere. When the C3H8:O2 volume ratio changes from 1:5 to 1:20, it can maintain excellent activity. Therefore, it can solve the huge risk of activity decrease caused by large fluctuations in the reaction atmosphere in actual working conditions. Its performance is significantly better than that of single metal Pt / SiO2, Ru / SiO2 catalysts and bimetallic alloy catalysts prepared by traditional methods such as co-impregnation.

[0028] (5) Compared with the technical solution in patent CN119657119A, the present invention uses industrially safe, environmentally friendly and readily available oxygen as an oxidant, and targets the design of Ru1O x / Pt NP The interface utilizes Ru single-atom oxide to promote propane adsorption and activation, while Pt nanoparticles adsorb and activate oxygen, accelerating the deep activation of intermediate products and enabling efficient propane oxidation at low temperatures. More importantly, the catalyst exhibits excellent reaction stability, water resistance, and adaptability to reaction conditions with a C3H8:O2 volume ratio, making it valuable for practical applications in industrial scenarios such as propane purification. Attached Figure Description

[0029] Figure 1 Ru1O prepared in Example 1 x / Pt NP Comparison of propane catalytic combustion activity between SiO2 catalyst and catalysts of Comparative Examples 1-3; Figure 2 Ru1O prepared in Example 1 x / Pt NP Dark-field scanning transmission electron microscopy (TEM) image and particle size distribution of SiO2 catalyst; Figure 3 Ru1O prepared in Example 1 x / Pt NPHigh-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image and energy-dispersive X-ray spectroscopy (EDS) elemental distribution image of the SiO2 catalyst; Figure 4 Ru1O prepared in Example 1 x / Pt NP X-ray photoelectron spectroscopy (XPS) of SiO2 catalyst. Figure 5 Ru1O prepared in Example 1 x / Pt NP Long-term stability test graph of SiO2 catalyst (conversion rate vs time). Figure 6 Ru1O prepared in Example 1 x / Pt NP Comparison of propane catalytic combustion activities of the Ru / SiO2 catalyst prepared in Comparative Example 2 and the Pt / SiO2 catalyst prepared in Comparative Example 3 under dry atmosphere and atmosphere containing 3 vol.% H2O, respectively. Figure 7 Ru1O prepared in Example 1 x / Pt NP Comparison of propane catalytic combustion activities of the Ru / SiO2 catalyst prepared in Comparative Example 2 and the Pt / SiO2 catalyst prepared in Comparative Example 3 under C3H:O2 volume ratios of 1:5 and 1:20, respectively. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0031] Example 1: A Pt-Ru bimetallic catalyst for the catalytic combustion of propane is prepared using the following steps: (1) Preparation of SiO2 support Silica microspheres were prepared using the Stöber method. Specifically, 17.8 mL of tetraethyl orthosilicate (TEOS), 5.4 mL of NH3·H2O, 360 mL of C2H5OH, and 30 mL of H2O were added to a 500 mL beaker. The solution mixture was then vigorously stirred at 25 °C for 24 h. The precipitate was then centrifuged, washed several times with ethanol, and dried overnight at 70 °C. Finally, the precipitate was calcined in a tube furnace at a flow rate of 40 mL / min at 800 °C for 5 h at 10 vol.% O2 / Ar to obtain silica microspheres with an average particle size of 100 ± 10 nm.

[0032] (2) Loading of Pt nanoparticles The SiO2 support obtained in step (1) was placed in an ALD reaction chamber. Platinum tetraamminenitrate (Pt(NH3)4(NO3)2) was selected as the Pt precursor, and oxygen was used as the reaction gas. ALD cycling was performed at 250°C. By controlling the number of ALD cycles to 15, uniformly dispersed Pt nanoparticles were deposited on the SiO2 support, yielding Pt nanoparticles. NP / SiO2 sample. From Figure 2 It can be seen that the size of Pt nanoparticles is 3.4 nm. The particle size distribution diagram shows that the ALD method can significantly improve the uniformity of metal nanoparticle size, making it easy to achieve the goal of accurately constructing highly active structures.

[0033] (3) Deposition of single-atom Ru The Pt obtained in step (2) NP The SiO2 sample was kept in the ALD reaction chamber, and the precursor Ru, ruthenium acetylacetone, was switched to be used. Oxygen was used as the reaction gas, and two ALD cycles were performed at 200-300℃ to deposit Ru in single-atom form on the surface of Pt nanoparticles, forming a single-atom Ru1O structure. x A bimetallic Ru1O structure was prepared. x / Pt NP / SiO2 catalyst.

[0034] (4) Post-processing The sample deposited in step (3) was heat-treated in air at 300°C for 2 hours to remove the precursor ligands, obtain a pure metal surface, and further enhance the interaction between the metal and the support and the bimetallic sites, thus obtaining the final Ru1O with a single-atom bimetallic structure. x / Pt NP / SiO2 catalyst. Figure 3 The obtained Ru1O x / Pt NP High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images and energy-dispersive X-ray spectroscopy (EDS) elemental distribution maps of the SiO2 catalyst, from... Figure 3 It can be seen that the Pt metal particle structure and the Ru single-atom structure on the surface show that the distribution of Pt and Ru metals overlaps, indicating that Ru is selectively deposited on Pt particles. Moreover, Ru has higher dispersibility than Pt, indicating that Ru exists in the form of single atoms. Figure 4 The obtained Ru1O x / Pt NP X-ray photoelectron spectroscopy (XPS) of SiO2 catalyst, by Figure 4 It can be seen that the Ru1O prepared in this embodiment x / PtNP The electronic state of the SiO2 catalyst is basically consistent with that of a single metal, while Pt retains its metallic state (Pt). 0 This ensures that Ru efficiently activates oxygen molecules to generate reactive oxygen species, while Ru exists as a single-atom oxide (Ru 4+ / Ru 3+ The presence of Pt in the form of ⇌ RuO2 avoids the formation of inert RuO2 crystalline phases and maintains the efficient ability to break propane CH bonds. It is precisely due to these electronic structure characteristics of Pt and Ru, and the precise construction of the bimetallic interface structure, that "Ru1O2" exists. x The dual-function synergistic effect of "propane activation-dominant" and "Pt-dominant deep oxidation" is maximized, significantly improving low-temperature activity (ignition at 160℃) and achieving 100 hours without deactivation, breaking through the activity and stability bottleneck of existing catalysts.

[0035] Comparative Example 1: A RuPt / SiO2 catalyst, the specific preparation steps are as follows: (1) Preparation of SiO2 support Silica microspheres were prepared using the Stöber method. Specifically, 17.8 mL of tetraethyl orthosilicate (TEOS), 5.4 mL of NH3·H2O, 360 mL of C2H5OH, and 30 mL of H2O were added to a 500 mL beaker, and the solution mixture was then vigorously stirred at 25 °C for 24 h. The precipitate was then centrifuged, washed several times with ethanol, and dried overnight at 70 °C. Finally, the precipitate was calcined in a tube furnace at a flow rate of 40 mL / min at 800 °C for 5 h at 10 vol.% O2 / Ar to obtain silica microspheres with an average particle size of 100 ± 10 nm.

[0036] (2) Loading of RuPt bimetal The SiO2 support was placed in an ALD reaction chamber. Using Pt(NH3)4(NO3)2 as a precursor and oxygen as the reactant, eight ALD cycles were performed at 250 °C to form RuPt nanoparticles with a size of approximately 3.0 nm on the SiO2, thus obtaining the RuPt / SiO2 catalyst.

[0037] (3) Post-processing The deposited sample was heat-treated in air at 300°C for 2 hours to remove the precursor ligands, obtain a pure metal surface, and thus obtain the final RuPt / SiO2 catalyst (RuPt nanoalloy structure).

[0038] Comparative Example 2: A Ru / SiO2 catalyst, the specific preparation steps are as follows: (1) Preparation of SiO2 support Silica microspheres were prepared using the Stöber method. Specifically, 17.8 mL of tetraethyl orthosilicate (TEOS), 5.4 mL of NH3·H2O, 360 mL of C2H5OH, and 30 mL of H2O were added to a 500 mL beaker, and the solution mixture was then vigorously stirred at 25 °C for 24 h. The precipitate was then centrifuged, washed several times with ethanol, and dried overnight at 70 °C. Finally, the precipitate was calcined in a tube furnace at a flow rate of 40 mL / min at 800 °C for 5 h at 10 vol.% O2 / Ar to obtain silica microspheres with an average particle size of 100 ± 10 nm.

[0039] (2) Load of Ru The SiO2 support was placed in an ALD reaction chamber. Using Ru(acac)3 as a precursor and oxygen as the reactant, 15 ALD cycles were performed at 250 °C to form Ru nanoparticles with a size of approximately 3.0 nm on SiO2, thus obtaining the Ru / SiO2 catalyst.

[0040] (3) Post-processing The deposited sample was heat-treated in air at 300°C for 2 hours to remove the precursor ligands, obtain a pure metal surface, and thus obtain the final Ru / SiO2 catalyst (Ru nanoparticles).

[0041] Comparative Example 3: A Pt / SiO2 catalyst, the specific preparation steps are as follows: (1) Preparation of SiO2 support Silica microspheres were prepared using the Stöber method. Specifically, 17.8 mL of tetraethyl orthosilicate (TEOS), 5.4 mL of NH3·H2O, 360 mL of C2H5OH, and 30 mL of H2O were added to a 500 mL beaker, and the solution mixture was then vigorously stirred at 25 °C for 24 h. The precipitate was then centrifuged, washed several times with ethanol, and dried overnight at 70 °C. Finally, the precipitate was calcined in a tube furnace at 800 °C for 5 h at a flow rate of 40 mL / min under 10 vol.% O2 / Ar to obtain silica microspheres with an average particle size of 100 ± 10 nm.

[0042] (2) Load of Pt The SiO2 support was placed in the ALD reaction chamber. Using Pt(NH3)4(NO3)2 as the precursor and oxygen as the reactant, 15 ALD cycles were performed at 250 °C to form Pt nanoparticles with a size of about 2.5 nm on SiO2, thus obtaining the Ru / SiO2 catalyst (Pt nanoparticles).

[0043] (3) Post-processing The deposited sample was heat-treated in air at 300°C for 2 hours to remove the precursor ligands, obtain a pure metal surface, and thus obtain the final Ru / SiO2 catalyst.

[0044] Propane catalytic combustion performance test: (1) Evaluation of propane catalytic combustion performance of the catalysts obtained in Example 1 and Comparative Examples 1-3: The test was conducted using a fixed-bed reactor. 50 mg of catalyst was placed in a quartz tube and a reaction gas with the composition of 0.2 vol.% C3H8, 2.0 vol.% O2 (generally 1.0-4.0 vol.%) and 97.8 vol.% N2 (generally 98.8-95.8 vol.% as a balance gas) was introduced. The gas flow rate was 25 mL / min and the space velocity was 30,000 mL·g. -1 ·h -1 Once the system stabilizes, start from 30. o Start at C, and gradually increase the temperature until propane is completely converted.

[0045] Test results are as follows Figure 1 As shown, the Ru1O prepared in Example 1 of this invention x / Pt NP / SiO2 catalyst ignition temperature (T) 10 The reaction temperature at a conversion rate of 10% is approximately 160℃, and the complete conversion temperature (T) is... 100 Complete combustion of propane is achieved at only around 245℃, and the reaction rate reaches 4.02 μmol / g at 200℃. metal / s, with significantly better low-temperature activity than other catalysts. Following closely behind is the PtRu / SiO2 catalyst prepared in Comparative Example 1, T 10 Approximately 200℃, T 100 At approximately 345℃, the activity was at a moderate level. In contrast, the Ru / SiO2 prepared in Comparative Example 2 and the Pt / SiO2 prepared in Comparative Example 3 exhibited significantly lower activity as single-metal catalysts: the T0 of Pt / SiO2 was [missing value]. 10 Approximately 200℃, T 100 Approximately 350℃; while the T of Ru / SiO2 10 Up to 250℃, T 100 Temperatures exceeding 380℃ are required for complete conversion; even higher temperatures are needed. These results strongly suggest that Ru1O x / Pt NP In SiO2 catalysts, the unique structure containing bimetallic sites with single atoms plays a key role in enhancing the low-temperature activity of propane catalytic combustion, providing important experimental basis for the design of high-performance low-carbon alkane combustion catalysts.

[0046] (2) Long-term stability test: The Ru1O prepared in Example 1 x / Pt NP Long-term stability tests were conducted on the SiO2 catalyst. The test conditions were: catalyst dosage 50 mg, reaction gas composition: 0.2 vol.% C3H8, 2% O2, equilibrium gas: N2, and total space velocity (HSV): 30,000 mL·g. -1 ·h -1 The reaction temperature is 200°C. o C.

[0047] Test results are as follows Figure 5 As shown, after 100 hours of continuous reaction, the propane conversion rate remained at 75%, indicating that Ru1O x / Pt NP / SiO2 catalysts exhibit excellent reaction stability, meeting the requirements of industrial applications.

[0048] The stability of each comparative example was tested using the same method, and the results are as follows: The table above shows that the activities of the three comparative catalysts, Pt / SiO2, Ru / SiO2, and RuPt / SiO2, all decreased after 100 hours of continuous reaction, indicating that Ru1O x / Pt NP / SiO2 catalysts not only have excellent activity, but also better reaction stability.

[0049] (3) Water resistance test: The Ru1O prepared in Example 1 x / Pt NP The SiO2 catalyst and the catalysts prepared in Comparative Examples 1-3 were subjected to water addition tests. 3 vol% water was added to the reaction atmosphere using a syringe pump. The test conditions were: catalyst dosage 50 mg, reaction gas composition: 0.2 vol.% C3H8, 2 vol.% O2, 3 vol.% H2O, equilibrium gas N2, and total space velocity 30,000 mL·g. -1 ·h -1 .

[0050] Test results are as follows Figure 6 As shown, compared to a dry reaction atmosphere, Ru1O x / Pt NP The reactivity of both the SiO2 catalyst and the comparative catalyst decreased under a water-containing atmosphere, but Ru1O x / Pt NP The / SiO2 catalyst showed the smallest decrease, indicating that its water resistance is superior to that of Pt / SiO2, Ru / SiO2 and RuPt / SiO2 catalysts.

[0051] (4) Reaction adaptability test under different C3H8 / O2 ratios in the reaction atmosphere: The Ru1O prepared in Example 1 x / Pt NP The activity of the SiO2 catalyst and the catalysts prepared in Comparative Examples 1-3 were tested under different C3H8 / O2 molar ratios in reaction atmospheres. The test conditions were: catalyst dosage 50 mg, reaction gas composition: 0.2 vol.% C3H8, O2 content following C3H8:O2 ratios of 1:5, 1:10, and 1:20, equilibrium gas: N2, and total space velocity: 30,000 mL·g⁻¹. -1 ·h -1 .

[0052] Test results are as follows Figure 7 As shown, the activities of Pt / SiO2, Ru / SiO2, and RuPt / SiO2 catalysts changed significantly under three different reaction atmospheres, with only Ru1O showing a change. x / Pt NP The fact that the SiO2 catalyst maintains the same activity indicates that the catalyst has good adaptability to operating conditions.

[0053] As can be seen, the catalyst of this invention exhibits excellent reaction stability and adaptability to reaction conditions, at 200 o The activity remained unchanged after 100 hours of reaction at C. When 3 vol. H2O was introduced into the reaction atmosphere, the activity decreased only slightly, demonstrating excellent water resistance.

Claims

1. The application of a SiO2-supported Ru-Pt bimetallic catalyst containing a single atom, characterized in that, A Ru-Pt bimetallic catalyst was applied to the catalytic combustion reaction of propane. The catalyst was a Ru1O bimetallic structure containing a single atom. x / Pt NP / SiO2, using SiO2 as a support, wherein Pt metal nanoparticles are loaded on the support, and Ru is in the form of a single-atom oxide Ru1O x Formally deposited on the surface of Pt metal nanoparticles, Ru1O x In the equation, 1.5 < x < 2.

2. The application of the SiO2-supported Ru-Pt bimetallic catalyst containing a single atom as described in claim 1, characterized in that, Ru has a single-atom structure, and the valence state of Ru is +3 to +4. (Ru1O) x In the equation, 1.5 < x < 2; the valence state of Pt is 0 to +2; and the particle size of Pt metal nanoparticles is 2 to 6 nm.

3. The application of the SiO2-supported Ru-Pt bimetallic catalyst containing a single atom as described in claim 1, characterized in that, When the catalyst catalyzes the combustion of propane, Ru1O x Propane is preferentially adsorbed and activated at the site, and then undergoes deep oxidation with O2 adsorbed on the Pt particles to produce CO2 and H2O.

4. The application of a SiO2-supported Ru-Pt bimetallic catalyst containing a single atom according to any one of claims 1 to 3, characterized in that, The method for preparing the catalyst includes the following steps: S1. SiO2 support was prepared using the Stöber method; S2. Pt nanoparticles were loaded onto the surface of a SiO2 support using ALD technology to obtain Pt nanoparticles. NP / SiO2; S3. Single-atom Ru was deposited on Pt nanoparticles using ALD technology to obtain a bimetallic Ru1O structure. x / Pt NP / SiO2 catalyst; S4. The deposited sample obtained in step S3 is heat-treated to obtain Ru1O with a single-atom bimetallic structure. x / Pt NP / SiO2 catalyst.

5. The application of the SiO2-supported Ru-Pt bimetallic catalyst containing a single atom as described in claim 4, characterized in that, The preparation process of SiO2 support in step S1 is as follows: Ethyl silicate, NH3·H2O, C2H5OH and H2O are mixed and stirred. The precipitate is centrifuged, washed with ethanol, dried and then calcined to obtain SiO2 support.

6. The application of the SiO2-supported Ru-Pt bimetallic catalyst containing a single atom as described in claim 4, characterized in that, Step S2 Pt NP The specific preparation process of / SiO2 is as follows: SiO2 support is placed in an ALD reaction chamber. Platinum acetylacetonate, methylcyclopentadienyltrimethylplatinum, or (trimethyl)methylcyclopentadienylplatinum is selected as the Pt precursor. Oxygen is used as the reaction gas, and ALD cycling is performed at 200-300℃. Pt nanoparticles are deposited on the SiO2 support to obtain Pt. NP / SiO2.

7. The application of the SiO2-supported Ru-Pt bimetallic catalyst containing a single atom as described in claim 6, characterized in that, The number of ALD cycles for Pt precursor deposition is 10-20; the particle size of Pt nanoparticles is 2-6 nm.

8. The application of the SiO2-supported Ru-Pt bimetallic catalyst containing a single atom according to claim 4, characterized in that, Step S3, which involves depositing single-atom Ru on Pt nanoparticles using ALD technology, is as follows: Pt... NP SiO2 was placed in an ALD reaction chamber, and ruthenium acetylacetonate or dicarbonylbis(pentamethylcyclopentadienyl)ruthenium was selected as the Ru precursor. Oxygen was used as the reaction gas, and ALD cycling was carried out at 200-300 °C, so that Ru was deposited in single-atom form on the surface of Pt nanoparticles to form a single-atom structure Ru1O. x The bimetallic structure Ru1O was obtained. x / Pt NP / SiO2 catalyst.

9. The application of the SiO2-supported Ru-Pt bimetallic catalyst containing a single atom as described in claim 8, characterized in that, The Ru precursor is deposited in 1 to 2 cycles.

10. The application of the SiO2-supported Ru-Pt bimetallic catalyst containing a single atom according to claim 4, characterized in that, The heat treatment process in step S4 specifically involves heat-treating the deposited sample in air at 200-500°C to obtain Ru1O with a bimetallic structure containing a single atom. x / Pt NP / SiO2 catalyst.

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