Ru-Au bimetal modified flaky oxygen-vacancy-rich strontium titanate catalyst as well as preparation method and application of Ru-Au bimetal modified flaky oxygen-vacancy-rich strontium titanate catalyst
Ru-Au bimetallic modified sheet-like oxygen-vacancy strontium titanate catalysts were prepared by solvothermal and photodeposition methods, which solved the problems of CO2 adsorption capacity and metal dispersion of DRM catalysts, achieved efficient and stable photothermal synergistic catalytic effect, and reduced energy consumption.
Patent Information
- Application Number
- CN202511298028.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-11
- Publication Date
- 2025-12-23
AI Technical Summary
Existing DRM photothermal catalysts suffer from poor CO2 adsorption capacity, poor metal dispersion, low activity, and difficulty in precise control. Traditional thermocatalytic processes are energy-intensive, and precious metal resources are limited and prone to deactivation.
A sheet-like oxygen-vacancy-enriched strontium titanate support was prepared by a solvothermal method, and Ru-Au bimetal was loaded by photodeposition to form a Ru-Au bimetal-modified sheet-like oxygen-vacancy-enriched strontium titanate catalyst, which improved the metal dispersion and oxygen vacancy concentration, and enhanced the light absorption capacity and photothermal synergistic catalytic effect.
It significantly improves CO2 activation efficiency, exhibits excellent catalytic activity and anti-carbon deposition ability at low temperatures, has good cycle stability, high H2 and CO yields, and reduces energy consumption.
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Figure CN121178162A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photothermal catalyst materials, specifically relating to a Ru-Au bimetallic modified sheet-like oxygen-rich vacancy strontium titanate catalyst, its preparation method, and its application. Background Technology
[0002] The dry reforming of methane (DRM, CH4 + CO2 → 2H2 + 2CO) can convert two greenhouse gases, CH4 and CO2, into high-value-added syngas, achieving both efficient resource utilization and environmental remediation, and has therefore attracted much attention. However, the reaction faces a significant challenge due to the extremely high dissociation energy barriers of the C=O bond (~750 kJ / mol) and the CH bond (~435 kJ / mol), which means that traditional thermocatalytic processes typically need to be carried out at temperatures exceeding 700°C, resulting in high energy consumption.
[0003] Photothermal catalysis offers a new approach to achieving DRM reactions under mild conditions. This technology combines the direct activation of reactant molecules by photogenerated carriers with the localized thermal effect generated by non-radiative relaxation, possessing the advantages of both photocatalysis and thermocatalysis. It can lower the apparent energy barrier of the reaction and increase the surface reaction rate, thus achieving efficient conversion at lower temperatures. In the design of photothermal catalysts, the selection of the support and the active metal is crucial. Perovskite oxide SrTiO3 is considered an ideal DRM catalyst support due to its excellent thermal stability, chemical stability, and tunable electronic structure. However, SrTiO3 prepared by conventional methods has significant limitations: firstly, its intrinsic oxygen vacancy concentration is low, severely limiting its adsorption and activation capacity for CO2; secondly, its specific surface area is small, which is not conducive to the high dispersion of the active metal, hindering the rapid transfer of photogenerated carriers and easily leading to metal sintering and carbon deposition during the reaction process, ultimately causing catalyst deactivation. While transition metals are less expensive, their d-band centers are typically deep, hindering efficient C–H bond breaking and resulting in significantly lower catalytic activity compared to noble metals. Furthermore, they exhibit poor resistance to carbon deposition and sintering, easily leading to rapid deactivation at high temperatures due to carbon buildup covering active sites or metal agglomeration. In contrast, noble metals (such as Ru, Pd, Pt, and Rh) possess unique d-orbital electronic structures that significantly lower the C–H bond dissociation barrier, exhibiting excellent catalytic selectivity and resistance to sintering. They can effectively suppress side reactions such as deep CH4 cracking and CO disproportionation. However, noble metals are expensive and limited in resources. Without achieving high dispersion on the support surface, metal utilization will be low, catalytic economics will be poor, and localized metal concentrations may even exacerbate photogenerated carrier recombination and carbon deposition, limiting their industrial applications.
[0004] In recent years, gold (Au) has shown great potential in photocatalytic and photothermal catalytic systems due to its significant localized surface plasmon resonance (LSPR) effect. Introducing Au into noble metal catalytic systems (such as constructing Ru-Au alloys) can effectively enhance light absorption and photothermal conversion efficiency, thereby promoting photogenerated carrier separation, improving metal dispersion, and modulating the d-band center of the active metal through electronic effects. However, most existing photothermal catalytic DRM studies focus in isolation on single noble metal loading or single modification of oxygen vacancies on the support, failing to systematically combine highly dispersed noble metal alloys with LSPR effects with SrTiO3 supports with high oxygen vacancy concentrations, thus failing to fully leverage the advantages of both in photothermal synergistic catalysis. Furthermore, the structure-activity relationship between metal dispersion, oxygen vacancy concentration, and DRM performance in photoinduced deposition processes remains unclear, lacking in-depth guidance for the rational design of such catalysts.
[0005] Therefore, developing a novel DRM catalyst with both highly dispersed bimetallic active sites and high carrier separation efficiency in oxygen-rich vacancy SrTiO3 to achieve photo-thermal synergistic catalysis is of urgent and important significance for promoting the practical application of this technology. Summary of the Invention
[0006] The purpose of this invention is to solve the problems of poor CO2 adsorption capacity, poor metal dispersion, low activity and difficulty in precise control of existing DRM photothermal catalysts, and to provide a photothermal catalyst with simple preparation method, strong CO2 adsorption and high catalytic activity.
[0007] Specifically, this invention provides a Ru-Au bimetallic modified sheet-like oxygen-enriched strontium titanate catalyst. The catalyst uses sheet-like oxygen-enriched strontium titanate as a support, and Ru and Au metals supported on the surface of the support. The mass fraction of Ru is 1-3 wt% of the support mass, and the mass fraction of Au is 0.25-1.50 wt% of the support mass. The sheet-like oxygen-enriched strontium titanate is a porous material with a specific surface area ≥120 m². 2 ·g -1 The pore size is 5~15 nm, and the pore volume is ≥0.2 cm³. 3 ·g -1 The Ru and Au metals are uniformly distributed on the surface of the sheet-like oxygen-rich vacancy strontium titanate support.
[0008] Furthermore, the Ru-Au bimetallic modified sheet-like oxygen-rich vacancy strontium titanate catalyst has an average size of 80~100 nm.
[0009] This invention also provides a method for preparing a Ru-Au bimetallic modified sheet-like oxygen-rich vacancy strontium titanate catalyst, the method comprising the following steps: Strontium titanate with oxygen-enriched vacancies was prepared in sheet form by a solvothermal method; Ru-Au bimetallic modified sheet form of strontium titanate with oxygen-enriched vacancies was prepared by photodeposition of Ru and Au bimetals.
[0010] Furthermore, the preparation of sheet-like oxygen-rich vacancy strontium titanate using the solvothermal method specifically involves: (1) Dissolve tetrabutyl titanate in ethylene glycol monomethyl ether solution, add concentrated ammonia to form Ti(OH)4 precipitate, wash and centrifuge; (2) Disperse the washed and centrifuged Ti(OH)4 precipitate in ethylene glycol, add Sr(NO3)2 and NaOH in sequence, and stir to disperse to obtain a mixed solution; (3) The mixed solution obtained in step (2) is transferred to a polytetrafluoroethylene-lined reactor and reacted at 160~220℃ for 10~24 h. After washing until the filtrate is neutral, it is dried at 40~80℃ for 6~12 h and then ground to obtain flake-shaped oxygen-rich vacancy strontium titanate.
[0011] Furthermore, the molar ratio of tetrabutyl titanate, strontium nitrate and sodium hydroxide is (1~1.1):1:(4~5).
[0012] Further, the ratio of tetrabutyl titanate to ethylene glycol monomethyl ether is 1g:(8~12) mL; the ratio of tetrabutyl titanate to concentrated ammonia is 1g:(1~1.5) mL; and the ratio of tetrabutyl titanate to ethylene glycol is 1g:(22~26) mL.
[0013] Furthermore, the specific steps for preparing the Ru-Au bimetallic modified sheet-like oxygen-rich vacancy strontium titanate catalyst by supporting Ru and Au bimetals using photodeposition are as follows: (1) Take the flake-shaped oxygen-enriched vacancy strontium titanate and add it to a mixed solution containing RuCl3 and HAuCl4; (2) Stir and disperse in an inert gas atmosphere, then irradiate with a lamp with a wavelength of 310~400 nm and a power of 200~400 W for 1.5~3 h, filter, wash and dry at 50~70℃ for 5~8 h to obtain Ru-Au bimetallic modified sheet-like oxygen-rich vacancy strontium titanate catalyst.
[0014] Further, the Ru mass fraction in RuCl3 is 1-3 wt% of the mass of the plate-like oxygen-enriched vacancy strontium titanate, and the Au mass fraction in HAuCl4 is 0.25-1.50 wt% of the mass of the plate-like oxygen-enriched vacancy strontium titanate; the solvent of the mixed solution containing RuCl3 and HAuCl4 is an ethanol solution with a volume fraction of 20%-30%.
[0015] Furthermore, the inert gas atmosphere is argon or nitrogen.
[0016] This invention also provides an application of a Ru-Au bimetallic modified sheet-like oxygen-vacancy-rich strontium titanate catalyst, which is used in a photothermal catalytic dry reforming reaction of methane.
[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses a solvothermal method to prepare a sheet-like oxygen-rich vacancy strontium titanate (L-STO) support, and uses a photoinduced deposition method to prepare a catalyst uniformly supported on Ru-Au metal nanoparticles. This not only enhances the light absorption capacity of the catalyst and inhibits the recombination of photogenerated carriers, but also the high specific surface area and pore size distribution of L-STO are beneficial to the adsorption and diffusion of reactants.
[0018] (2) The Ru-Au bimetallic modified L-STO of the present invention exhibits a significant photo-thermal synergistic catalytic effect in the photo-driven photothermal catalytic DRM reaction and significantly improves the CO2 activation efficiency.
[0019] (3) The present invention is at 2.0 W·cm -2 Under light intensity, the yield of H2 from the 1.5Ru-0.5Au / L-STO catalyst was 68.5 mmol·g. cat -1 ·h -1 The yield of CO was 118.6 mmol·g. cat -1 ·h -1 The catalyst exhibits excellent catalytic activity and resistance to carbon buildup. Furthermore, stability tests have shown that the catalyst of this invention demonstrates excellent cycle stability. Attached Figure Description
[0020] Figure 1 (a) is a scanning electron microscope (SEM) image of the 1.5Ru-0.5Au / L-STO catalyst prepared in Example 1, and (b) is a high-resolution transmission electron microscope (TEM) image.
[0021] Figure 2 (a) is an annular dark field (ADF) image of the 1.5Ru-0.5Au / L-STO catalyst prepared in Example 1; (b) is a Ru element distribution test image; (c) is an Au element distribution test image; (d) is a Sr element distribution test image; (e) is a Ti element distribution test image; and (f) is an O element distribution test image.
[0022] Figure 3 Electron paramagnetic resonance (EPR) test pattern of the 1.5Ru-0.5Au / L-STO catalyst prepared in Example 1.
[0023] Figure 4Diffuse reflectance (DRS) spectra of catalysts L-STO (Comparative Example 1), 0.5Au / L-STO (Comparative Example 2), 1.5Ru / L-STO (Comparative Example 3), and 0.5Au-1.5Ru / L-STO (Catalyst of the Present Invention).
[0024] Figure 5 Comparative Example 1 catalyst L-STO, Comparative Example 2 catalyst 0.5Au / L-STO, Comparative Example 3 catalyst 1.5Ru / L-STO, and the catalyst of this invention 0.5Au-1.5Ru / L-STO were tested under a light intensity of 2.0 W·cm⁻¹. -2 Test results of photothermal catalysis DRM driven by light.
[0025] Figure 6 Cyclic stability test results of 1.5Ru-0.5Au / L-STO catalyst in photo-driven photothermal catalytic DRM reaction. Detailed Implementation
[0026] The following examples further illustrate specific implementations of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described below are those that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially.
[0027] Example 1 1. Preparation of oxygen-rich vacancy-enriched lamellar strontium titanate (L-STO): 1.7 g of tetrabutyl titanate ((C4H9O)4Ti) was dissolved in 20 mL of ethylene glycol monomethyl ether solution, and then 2 mL of concentrated ammonia solution was slowly added, gradually forming a milky white Ti(OH)4 precipitate. The precipitate was washed with deionized water and centrifuged. Under rapid stirring, the washed Ti(OH)4 was dispersed in 40 mL of ethylene glycol, and 1.1 g of strontium nitrate Sr(NO3)2 and 0.8 g of NaOH were added to the system sequentially, and the mixture was stirred for 30 min. The above mixed solution was transferred to a reaction vessel with a 100 mL polytetrafluoroethylene liner and placed in a 200°C oven for 12 h. After the reaction was completed, the product was repeatedly washed with deionized water until the filtrate was neutral. Finally, the product was dried in a 60°C oven for 12 h, and after grinding, sheet-like SrTiO3 nanosheets were obtained, labeled as L-STO.
[0028] 2. Preparation of metal-modified oxygen-rich vacancy L-STO: Ru-Au / L-STO was prepared by photodeposition. 0.5 g of L-STO, RuCl3 (calculated as mRu : mL-STO, with a Ru content of 1.50 wt%), and HAuCl4 (calculated as mAu : mL-STO, with an Au content of 0.50 wt%) were added to a mixture of 75 mL deionized water and 25 mL ethanol. The mixture was then stirred continuously for 30 min under an argon atmosphere, followed by irradiation with a 250 W lamp (365 nm) for 1.5 h. After the reaction, the mixture was washed several times with deionized water and dried at 60°C for 6 h. The prepared Ru-Au bimetallic modified sheet-like oxygen-vacancy-enriched strontium titanate catalyst was labeled 1.5Ru-0.5Au / L-STO.
[0029] Example 2 1. Preparation of oxygen-rich vacancy-enriched lamellar strontium titanate (L-STO): 1.7 g of tetrabutyl titanate ((C4H9O)4Ti) was dissolved in 20 mL of ethylene glycol monomethyl ether solution, and then 2 mL of concentrated ammonia solution was slowly added, gradually forming a milky white Ti(OH)4 precipitate. The precipitate was washed with deionized water and centrifuged. Under rapid stirring, the washed Ti(OH)4 was dispersed in 40 mL of ethylene glycol, and 1.1 g of strontium nitrate Sr(NO3)2 and 0.8 g of NaOH were added to the system sequentially, and the mixture was stirred for 30 min. The above mixed solution was transferred to a reaction vessel with a 100 mL polytetrafluoroethylene liner and placed in an oven at 160°C for 24 h. After the reaction was completed, the product was repeatedly washed with deionized water until the filtrate was neutral. Finally, the product was dried in an oven at 40°C for 12 h, and after grinding, sheet-like SrTiO3 nanosheets were obtained, labeled as L-STO.
[0030] 2. Preparation of metal-modified oxygen-rich vacancy L-STO: Ru-Au / L-STO was prepared by photodeposition. 0.5 g of L-STO, RuCl3 (calculated as mRu : mL-STO, with a Ru content of 1.0 wt%), and HAuCl4 (calculated as mAu : mL-STO, with an Au content of 0.75 wt%) were added to a mixture of 80 mL deionized water and 20 mL ethanol. The mixture was then stirred continuously for 45 min under a nitrogen atmosphere, followed by irradiation with a 200 W lamp (310 nm) for 3 h. After the reaction was complete, the mixture was washed several times with deionized water and dried at 50°C for 5 h to obtain the Ru-Au bimetallic modified sheet-like oxygen-vacancy-enriched strontium titanate catalyst.
[0031] Example 3 1. Preparation of oxygen-rich vacancy-enriched lamellar strontium titanate (L-STO): 1.87 g of tetrabutyl titanate ((C4H9O)4Ti) was dissolved in 15 mL of ethylene glycol monomethyl ether solution, and then 2 mL of concentrated ammonia solution was slowly added, gradually forming a milky white Ti(OH)4 precipitate. The precipitate was washed with deionized water and centrifuged. Under rapid stirring, the washed Ti(OH)4 was dispersed in 42 mL of ethylene glycol, and 1.1 g of strontium nitrate Sr(NO3)2 and 1.0 g of NaOH were added to the system sequentially, and the mixture was stirred for 30 min. The above mixed solution was transferred to a reaction vessel with a 100 mL polytetrafluoroethylene liner and placed in an oven at 220°C for 10 h. After the reaction was completed, the product was repeatedly washed with deionized water until the filtrate was neutral. Finally, the product was dried in an oven at 80°C for 8 h, and after grinding, sheet-like SrTiO3 nanosheets were obtained, labeled as L-STO.
[0032] 2. Preparation of metal-modified oxygen-rich vacancy L-STO: Ru-Au / L-STO was prepared by photodeposition. 0.5 g of L-STO, RuCl3 (calculated as mRu : mL-STO, with a Ru content of 2.0 wt%), and HAuCl4 (calculated as mAu : mL-STO, with an Au content of 1.0 wt%) were added to a mixture of 70 mL deionized water and 30 mL ethanol. The mixture was then stirred continuously for 40 min under an argon atmosphere, followed by irradiation with a 400 W lamp (400 nm) for 3 h. After the reaction was complete, the mixture was washed several times with deionized water and dried at 70°C for 6 h to obtain the Ru-Au bimetallic modified sheet-like oxygen-vacancy-enriched strontium titanate catalyst.
[0033] Example 4 1. Preparation of oxygen-rich vacancy-enriched lamellar strontium titanate (L-STO): 1.7 g of tetrabutyl titanate ((C4H9O)4Ti) was dissolved in 20 mL of ethylene glycol monomethyl ether solution, and then 2.5 mL of concentrated ammonia solution was slowly added, gradually forming a milky white Ti(OH)4 precipitate. The precipitate was washed with deionized water and centrifuged. Under rapid stirring, the washed Ti(OH)4 was dispersed in 44 mL of ethylene glycol, and 1.1 g of strontium nitrate Sr(NO3)2 and 1.0 g of NaOH were added to the system sequentially, and the mixture was stirred for 30 min. The above mixed solution was transferred to a reaction vessel with a 100 mL polytetrafluoroethylene liner and reacted in a 200°C oven for 20 h. After the reaction was completed, the product was filtered and repeatedly washed with deionized water until the filtrate was neutral. Finally, the product was dried in a 60°C oven for 10 h, and after grinding, sheet-like SrTiO3 nanosheets were obtained, labeled as L-STO.
[0034] 2. Preparation of metal-modified oxygen-rich vacancy L-STO: Ru-Au / L-STO was prepared by photodeposition. 0.5 g of L-STO, RuCl3 (calculated as mRu : mL-STO, with a Ru content of 2.5 wt%), and HAuCl4 (calculated as mAu : mL-STO, with an Au content of 1.25 wt%) were added to a mixture of 80 mL deionized water and 20 mL ethanol. The mixture was then stirred continuously for 45 min under a nitrogen atmosphere, followed by irradiation with a 300 W lamp (365 nm) for 1.8 h. After the reaction was complete, the mixture was filtered, washed repeatedly with deionized water, and dried at 55°C for 7 h to obtain the Ru-Au bimetallic modified sheet-like oxygen-vacancy-enriched strontium titanate catalyst.
[0035] Example 5 1. Preparation of oxygen-rich vacancy-enriched lamellar strontium titanate (L-STO): 1.7 g of tetrabutyl titanate ((C4H9O)4Ti) was dissolved in 20 mL of ethylene glycol monomethyl ether solution, and then 2 mL of concentrated ammonia solution was slowly added, gradually forming a milky white Ti(OH)4 precipitate. The precipitate was washed with deionized water and centrifuged. Under rapid stirring, the washed Ti(OH)4 was dispersed in 40 mL of ethylene glycol, and 1.1 g of strontium nitrate Sr(NO3)2 and 0.8 g of NaOH were added to the system sequentially, and the mixture was stirred for 30 min. The above mixed solution was transferred to a reaction vessel with a 100 mL polytetrafluoroethylene liner and placed in an oven at 180°C for 18 h. After the reaction was completed, the product was filtered and repeatedly washed with deionized water until the filtrate was neutral. Finally, the product was dried in an oven at 70°C for 8 h, and after grinding, sheet-like SrTiO3 nanosheets were obtained, labeled as L-STO.
[0036] 2. Preparation of metal-modified oxygen-rich vacancy L-STO: Ru-Au / L-STO was prepared by photodeposition. 0.5 g of L-STO, RuCl3 (calculated as mRu : mL-STO, with a Ru content of 3.0 wt%), and HAuCl4 (calculated as mAu : mL-STO, with an Au content of 1.5 wt%) were added to a mixture of 80 mL deionized water and 20 mL ethanol. The mixture was then stirred continuously for 30 min under an argon atmosphere, followed by irradiation with a 350 W lamp (365 nm) for 3 h. After the reaction was complete, the mixture was filtered, washed repeatedly with deionized water, and dried at 65°C for 6 h to obtain the Ru-Au bimetallic modified sheet-like oxygen-vacancy-enriched strontium titanate catalyst.
[0037] Example 6 1. Preparation of oxygen-rich vacancy-enriched lamellar strontium titanate (L-STO): 1.7 g of tetrabutyl titanate ((C4H9O)4Ti) was dissolved in 20 mL of ethylene glycol monomethyl ether solution, and then 2 mL of concentrated ammonia solution was slowly added, gradually forming a milky white Ti(OH)4 precipitate. The precipitate was washed with deionized water and centrifuged. Under rapid stirring, the washed Ti(OH)4 was dispersed in 40 mL of ethylene glycol, and 1.1 g of strontium nitrate Sr(NO3)2 and 0.8 g of NaOH were added to the system sequentially, and the mixture was stirred for 45 min. The above mixed solution was transferred to a reaction vessel with a 100 mL polytetrafluoroethylene liner and reacted in a 200°C oven for 16 h. After the reaction was completed, the product was repeatedly washed with deionized water until the filtrate was neutral. Finally, the product was dried in a 60°C oven for 6 h, and after grinding, sheet-like SrTiO3 nanosheets were obtained, labeled as L-STO.
[0038] 2. Preparation of metal-modified oxygen-rich vacancy L-STO: Ru-Au / L-STO was prepared by photodeposition. 0.5 g of L-STO, RuCl3 (calculated as mRu : mL-STO, with a Ru content of 3.0 wt%), and HAuCl4 (calculated as mAu : mL-STO, with an Au content of 0.75 wt%) were added to a mixture of 80 mL deionized water and 20 mL ethanol. The mixture was then stirred continuously for 35 min under a nitrogen atmosphere, followed by irradiation with a 200 W lamp (400 nm) for 2 h. After the reaction was complete, the mixture was filtered, washed repeatedly with deionized water, and dried at 65°C for 6 h to obtain the Ru-Au bimetallic modified sheet-like oxygen-vacancy-enriched strontium titanate catalyst.
[0039] Comparative Example 1 Only oxygen-rich vacancy-filled strontium titanate (L-STO) was prepared, and the preparation steps were the same as step 1 in Example 1.
[0040] Comparative Example 2 The difference from Example 1 is that only HAuCl4 is added (calculated by mass ratio mAu : mL-STO, Au content is 0.5wt%), and RuCl3 is not added.
[0041] Comparative Example 3 The difference from Example 1 is that only RuCl3 is added (calculated by mass ratio mRu : mL-STO, Ru content is 1.50wt%), and HAuCl4 is not added.
[0042] Experimental Example 1: Catalyst Characterization Tests 1. The 1.5Ru-0.5Au / L-STO catalyst prepared in Example 1 was subjected to tests for specific surface area, pore size distribution and pore volume, and was tested by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (TEM).
[0043] The results show that the 1.5Ru-0.5Au / L-STO catalyst has a specific surface area as high as 130.5 m². 2 ·g -1 The pore size of 1.5Ru-0.5Au / L-STO is mainly concentrated in the range of 5~15 nm, indicating that its pore structure is relatively uniform; the pore volume of 1.5Ru-0.5Au / L-STO is 0.30 cm³. 3 ·g -1 This is significantly higher than the 0.02 cm⁻¹ of hydrothermal synthesized cubic strontium titanate. 3 ·g -1 Larger pore volumes facilitate the diffusion of reactants and products.
[0044] Depend on Figure 1 (a) TEM characterization results show that the 1.5 wt%Ru-0.5 wt% Au / L-STO material exhibits a sheet-like morphological structure with an average size of about 100 nm. This structure can increase the specific surface area of the material, thereby enhancing the dispersion of the metal load. Figure 1 (b) High-resolution TEM further showed that Ru nanoparticles were uniformly dispersed on the surface of L-STO support.
[0045] 2. The 1.5Ru-0.5Au / L-STO catalyst prepared in Example 1 was subjected to annular dark field (ADF) imaging and EDX elemental distribution testing.
[0046] Depend on Figure 2 It can be seen that Ru and Au metal clusters are uniformly distributed on the surface of L-STO porous material, providing abundant active sites for the DRM reaction. At the same time, the elemental distribution of Sr, Ti and O is uniform, indicating that Au and Ru metal clusters are precisely deposited on L-STO and highly dispersed, which can effectively synergistically promote the DRM reaction.
[0047] 3. The 1.5Ru-0.5Au / L-STO catalyst prepared in Example 1 was subjected to electron paramagnetic resonance (EPR) testing.
[0048] Figure 3 The EPR spectra of L-STO and 1.5Ru-0.5Au / L-STO are shown. A characteristic signal peak of oxygen vacancies was observed at a g value of 2.003, indicating the presence of oxygen defects in the L-STO support material. This result demonstrates that the solvothermal synthesis method using tetrabutyl titanate as the Ti source can also effectively induce the formation of oxygen vacancies. After introducing Ru-Au composite metal nanoparticles via photoinduced deposition, the EPR signal intensity of oxygen vacancies was significantly enhanced, indicating that the metal modification process further increased the oxygen vacancy concentration. The presence of oxygen vacancies is beneficial for suppressing electron-hole recombination, enhancing the adsorption of CO2 molecules, promoting oxygen migration in the DRM reaction, and thus improving the DRM catalytic activity.
[0049] Experiment Example 2: Light Absorption Performance Test The light absorption capacity of Comparative Example 1 catalyst L-STO, Comparative Example 2 catalyst 0.5Au / L-STO, Comparative Example 3 catalyst 1.5Ru / L-STO and the catalyst of this invention 0.5Au-1.5Ru / L-STO in the wavelength range of 200 nm to 2500 nm was studied by diffuse reflectance spectroscopy (DRS).
[0050] Depend on Figure 4As can be seen, all tested samples exhibited strong light absorption in the 200–400 nm range, which is characteristic of the ultraviolet light absorption of the semiconductor material L-STO. After metal modification, the 0.5Au / L-STO, 1.5Ru / L-STO, and 0.5Au-1.5Ru / L-STO samples showed significantly enhanced light absorption in the visible light region (400–700 nm), with 1.5Ru-0.5Au / L-STO exhibiting the strongest visible light absorption. 0.5Au / L-STO showed a distinct light absorption characteristic signal at 540 nm, which is the characteristic absorption of LSPR in Au nanoparticles. In the infrared region (700–2500 nm), the 1.5Ru-0.5Au / L-STO catalyst still had the highest light absorption, a result of the Ru and Au bimetallic modification. Theoretically, the more Au nanoparticles loaded, the more beneficial it is to enhancing the LSPR effect. In summary, metal modification significantly enhances the light absorption capacity of the catalyst and is expected to increase the catalyst surface temperature through the LSPR and photothermal effects, providing more photogenerated carriers and creating more efficient conditions for the DRM reaction, thus helping to improve reaction performance and reduce energy consumption.
[0051] Experimental Example 3: Test of the photo-driven photothermal catalytic DRM performance of the catalyst The catalysts L-STO (Comparative Example 1), 0.5 Au / L-STO (Comparative Example 2), 1.5 Ru / L-STO (Comparative Example 3), and the catalyst of this invention (0.5 Au-1.5 Ru / L-STO) were subjected to a light intensity of 2.0 W·cm⁻¹. -2 Photothermal catalytic DRM testing was conducted using light-driven methods.
[0052] like Figure 5 As shown, Au metal modification did not exhibit DRM activity; however, when supported with 1.5 wt% Ru metal, the catalytic activity was significantly improved compared to 0.5 wt% Au. Furthermore, the catalyst co-modified with 1.5 wt% Ru and 0.5 wt% Au exhibited the highest activity, with H2 and CO yields reaching 68.5 mmol·g⁻¹. cat -1 ·h -1 and 118.9 mmol·g cat -1 ·h -1 The LSPR effect caused by Au loading works synergistically with the Ru active sites to promote photothermal catalytic DRM.
[0053] Experiment Example 4: Stability Test A fixed-bed reactor was used, at a concentration of 50 mL·min -1 The reaction gas flow rate and 2.0 W·cm -2Under light intensity conditions, three cycles (8 h each) were conducted to evaluate the cyclic stability of the 1.5Ru-0.5Au / L-STO catalyst in the photo-driven photothermal catalytic DRM reaction.
[0054] like Figure 6 As shown, the catalyst exhibits excellent cycling stability: H2 and CO yields are approximately 75 mmol·g, respectively. cat -1 ·h -1 and 140 mmol·g cat -1 ·h -1 The conversion rates of CH4 and CO2 remained at 15% and 10%, respectively.
[0055] In addition, Table 1 summarizes the photo-driven photothermal catalytic DRM performance of various catalysts under different reaction conditions, including catalyst type, reaction temperature (°C), and light intensity (W·cm). -2 ), raw gas composition and mass flow rate (mL·g) cat -1 ·h -1 The yields of H2 and CO (mmol·g) cat -1 ·h -1 Comparative analysis revealed that the 1.5Ru-0.5Au / L-STO catalyst exhibits a higher syngas production rate in the photo-driven photothermal catalytic DRM reaction.
[0056] Table 1. Comparison of catalyst performance for photo-driven photothermal DRM
[0057] [1] Tavasoli A, Gouda A, Zähringer T, et al. Enhanced hybridphotocatalytic dry reforming using a phosphated Ni-CeO2nanorodheterostructure[J]. Nature Communications, 2023, 14(1): 1435. [2] Yang Y, Chai Z, Qin X, et al. Light-induced redox looping of aRhodium / Ce xWO3photocatalyst for highly active and robust dry reforming ofmethane[J]. Angewandte Chemie International Edition, 2022, 61(21):e202200567. [3] Zhou L, Martirez J M P, Finzel J, et al. Light-driven methane dryreforming with single atomic site antenna-reactor plasmonic photocatalysts[J]. Nature Energy, 2020, 5(1): 61-70. [4] Jiang Z K, Li Y Z, Zhang Q, et al. A novel nanocomposite ofmesoporous silica supported Ni nanocrystals modified by ceria clusters withextremely high light-to-fuel efficiency for UV-vis-IR light-drivenCO2reduction[J]. Journal of Materials Chemistry A, 2019, 7(9): 4881-4892. [5] Li Y, Li J, Yu T, et al. Rh / InGaN 1-x O x nanoarchitecture for light-driven methane reforming with carbon dioxide toward syngas[J]. ScienceBulletin, 2024, 69(10): 1400-1409. [6] He CX, Li QX, Ye ZC, et al. Regulating atomically-precise Ptsites for boosting light-driven dry reforming of methane[J]. AngewandteChemie International Edition, 2024, 63(46): e202412308. The above embodiments are merely preferred embodiments of the present invention and are only used to explain the present invention, not to limit the present invention. Any changes, substitutions, modifications, etc., made by those skilled in the art without departing from the spirit and essence of the present invention should be within the protection scope of the present invention.
Claims
1. A Ru-Au bimetallic modified sheet-like oxygen-vacancy-enriched strontium titanate catalyst, characterized in that, The catalyst uses plate-like oxygen-rich vacancy strontium titanate as a support, and Ru and Au metals supported on the surface of the support; the mass fraction of Ru is 1~3 wt% of the support mass, and the mass fraction of Au is 0.25~1.50 wt% of the support mass; the plate-like oxygen-rich vacancy strontium titanate is a porous material with a specific surface area ≥120 m². 2 ·g -1 The pore size is 5~15 nm, and the pore volume is ≥0.2 cm³. 3 ·g -1 The Ru and Au metals are uniformly distributed on the surface of the sheet-like oxygen-rich vacancy strontium titanate support.
2. The Ru-Au bimetallic modified sheet-like oxygen-vacancy-enriched strontium titanate catalyst according to claim 1, characterized in that, The catalyst has an average size of 80~100 nm.
3. A method for preparing the Ru-Au bimetallic modified sheet-like oxygen-vacancy-enriched strontium titanate catalyst according to claim 1 or 2, characterized in that, The method includes the following steps: Strontium titanate with oxygen-enriched vacancies was prepared in sheet form by a solvothermal method; Ru-Au bimetallic modified sheet form of strontium titanate with oxygen-enriched vacancies was prepared by photodeposition of Ru and Au bimetallic components.
4. The preparation method according to claim 3, characterized in that, The preparation of sheet-like oxygen-rich vacancy strontium titanate using the solvothermal method specifically involves: (1) Dissolve tetrabutyl titanate in ethylene glycol monomethyl ether solution, add concentrated ammonia to form Ti(OH)4 precipitate, wash and centrifuge; (2) Disperse the washed and centrifuged Ti(OH)4 precipitate in ethylene glycol, add Sr(NO3)2 and NaOH in sequence, and stir to disperse to obtain a mixed solution; (3) The mixed solution obtained in step (2) is transferred to a polytetrafluoroethylene-lined reactor and reacted at 160~220℃ for 10~24 h. After washing until the filtrate is neutral, it is dried at 40~80℃ for 6~12 h and then ground to obtain flake-shaped oxygen-rich vacancy strontium titanate.
5. The preparation method according to claim 4, characterized in that, The molar ratio of tetrabutyl titanate, strontium nitrate and sodium hydroxide is (1~1.1):1:(4~5).
6. The preparation method according to claim 4, characterized in that, The ratio of tetrabutyl titanate to ethylene glycol monomethyl ether is 1 g: (8~12) mL; the ratio of tetrabutyl titanate to concentrated ammonia is 1 g: (1~1.5) mL; and the ratio of tetrabutyl titanate to ethylene glycol is 1 g: (22~26) mL.
7. The preparation method according to claim 4, characterized in that, The specific steps for preparing Ru-Au bimetallic modified sheet-like oxygen-rich vacancy strontium titanate catalyst by supporting Ru and Au bimetals using photodeposition are as follows: (1) Take the flake-shaped oxygen-enriched vacancy strontium titanate and add it to a mixed solution containing RuCl3 and HAuCl4; (2) Stir and disperse in an inert gas atmosphere, then irradiate with a lamp with a wavelength of 310~400 nm and a power of 200~400 W for 1.5~3 h, filter, wash and dry at 50~70℃ for 5~8 h to obtain Ru-Au bimetallic modified sheet-like oxygen-rich vacancy strontium titanate catalyst.
8. The preparation method according to claim 7, characterized in that, The Ru mass fraction in RuCl3 is 1-3 wt% of the mass of the plate-like oxygen-enriched vacancy strontium titanate, and the Au mass fraction in HAuCl4 is 0.25-1.50 wt% of the mass of the plate-like oxygen-enriched vacancy strontium titanate; the solvent of the mixed solution containing RuCl3 and HAuCl4 is an ethanol solution with a volume fraction of 20%-30%.
9. The preparation method according to claim 7, characterized in that, The inert gas atmosphere is argon or nitrogen.
10. The application of the Ru-Au bimetallic modified sheet-like oxygen-vacancy-enriched strontium titanate catalyst according to claim 1 or 2, characterized in that, The catalyst is used in the photothermal catalytic dry reforming reaction of methane.