Monodisperse ruthenium-based composite photo-thermal catalytic material and preparation method thereof

Abstract

The invention relates to the technical field of functional materials and synthesis thereof, in particular to a monodisperse ruthenium-based composite photo-thermal catalytic material and a preparation method thereof. Comprising the following steps: mixing and stirring Al (NO3) 39H2O, CO (NH2) 2 and deionized water, then carrying out hydrothermal reaction, cooling, filtering, washing, drying, calcining and grinding to obtain Al2O3 powder; the preparation method comprises the following steps: adding Al2O3 powder into deionized water, then adding a ruthenium nitrosyl nitrate solution, grinding, evaporating to dryness, reducing, and collecting a sample Rux / Al2O3 to obtain the monodisperse ruthenium-based composite photo-thermal catalytic material. The preparation method disclosed by the invention is simple, and the problem that the catalyst is inactivated due to low reforming performance and carbon deposition of a photo-thermal catalytic CH4-CO2 dry method is solved.

Description

Technical Field

[0001] This invention relates to the field of functional materials and their synthesis technology, specifically to a monodisperse ruthenium-based composite photothermal catalytic material and its preparation method. Background Technology

[0002] my country is a major energy consumer, primarily relying on fossil fuels such as coal and crude oil, and faces a significant energy shortage. The combustion of fossil fuels emits large amounts of CO2. Over the past few decades, a strategy of using sunlight to drive CO2 reduction has received widespread attention. However, this strategy needs to address the challenges of low fuel generation rates and low efficiency in converting solar energy into chemical energy.

[0003] In recent years, the photothermal catalytic reduction of CO2 using sunlight has attracted the interest of researchers. This is because this method perfectly combines the advantages of low energy consumption in photocatalysis and high reaction rate in thermocatalysis. Compared with traditional photocatalysis, this method can utilize the full spectrum of solar energy, including ultraviolet, visible, and infrared light, and the fuel yield is also significantly enhanced. Patent CN113117675A discloses a method for preparing a composite catalyst in which Rh nanoparticles and Er nanoparticles are co-supported on Al2O3, at a speed of 0.02 kWm -2 Under normal atmospheric pressure, a CH4 / CO2 mixture with a molar ratio of 1:1 was passed through the light irradiation, and the yields of H2 and CO were 0.29 and 0.85 mmol g, respectively. -1 min -1 Patent CN120515410A discloses a method for preparing a high-valence ruthenium photothermal catalyst at a 20kW m³ / h. -2 The yield of photothermal catalytic CO2 reduction under light irradiation was 16.54 mmol g. -1 min -1 As can be seen from the above work, photothermal catalytic dry reforming of CH4-CO2 (hereinafter referred to as DRM) has great application prospects because its products can be converted into liquid fuels and valuable chemical products through the mature Fischer-Tropsch process.

[0004] Despite the many advantages of the photothermal catalytic DRM strategy, it currently faces challenges such as low intrinsic turnover rate (TOF) of active components and catalyst deactivation due to carbon deposition. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a monodisperse ruthenium-based composite photothermal catalytic material and its preparation method. The preparation method is simple and solves the problems of low performance of photothermal catalytic CH4-CO2 dry reforming and catalyst deactivation caused by carbon deposition.

[0006] To achieve the above objectives, this application provides a method for preparing a monodisperse ruthenium-based composite photothermal catalytic material, comprising the following steps: S1. Mix Al(NO3)3‧9H2O, CO(NH2)2 with deionized water and stir, then carry out hydrothermal reaction, cooling, filtration, washing, drying, calcination and grinding to obtain Al2O3 powder; S2. Add Al2O3 powder to deionized water, then add ruthenium nitrite nitrate solution, grind, evaporate to dryness, reduce, and collect the sample Ru. x / Al2O3 was used to obtain a monodisperse ruthenium-based composite photothermal catalytic material.

[0007] Furthermore, the molar ratio of Al(NO3)3‧9H2O to CO(NH2)2, and the molar ratio of Al(NO3)3‧9H2O to CO(NH2)2 is 1:1.4-1.6.

[0008] Furthermore, the hydrothermal reaction is carried out at a temperature of 190-210℃ for 8-25 hours.

[0009] Furthermore, the drying process involves a drying temperature of 110-130℃ and a drying time of 1-5 hours.

[0010] Furthermore, the calcination is carried out at a temperature of 450-550℃ for 4-5 hours.

[0011] Furthermore, the grinding and evaporation process is carried out at a speed of 80-100 rpm, a time of 30-40 min, and a temperature of 100-190℃.

[0012] Furthermore, the reduction gas is an H2 / Ar mixture, with a volume ratio of H2 to Ar of 5-10:100, a reduction temperature of 650-750℃, and a reduction time of 1-2 hours.

[0013] Furthermore, the Ru x / Al2O3, where 0<x≤0.15.

[0014] This application also provides a method for preparing a monodisperse ruthenium-based composite photothermal catalytic material.

[0015] In summary, this application has the following beneficial effects: The monodisperse ruthenium-based composite photothermal catalytic material prepared in this application, under specific molar ratios and high-temperature growth conditions, achieves a low-Ru-loading, monodisperse Ru... xThe controllable synthesis of Al2O3 (0 < x ≤ 0.15) nanocomposite catalysts provides a material basis for the study of the physical properties of such materials and the fabrication of highly efficient photothermal DRM catalysts. The prepared catalysts exhibit extremely high TOF, solar-to-chemical energy conversion efficiency, and good stability under focused light irradiation. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 For Ru in Examples 1-2 and Comparative Example 1 0.15 / Al2O3、Ru 0.1 XRD patterns of Al2O3 and Ru1 / Al2O3 materials; Figure 2 For Ru in Example 1 0.15 / High-angle annular dark-field image of Al2O3 material by transmission electron microscopy; Figure 3 For Ru in Example 1 0.15 Particle size distribution of Ru nanoparticles in Al2O3 material; Figure 4 For Ru in Example 1 and Comparative Example 2 0.15 / Optical absorption rate diagram of Al2O3 and Al2O3 material in the full spectrum; Figure 5 For Ru in Example 1 0.15 / Graph showing the change in reactant conversion rate of Al2O3 material in thermally catalyzed DRM at high temperature over time; Figure 6 For Ru in Example 1 and Comparative Example 2 0.15 / Graph of the highest surface temperature of Al2O3 and Al2O3 materials during photothermal catalysis of DRM under concentrated light; Figure 7 For example, each gram of Ru in Example 1 0.15 / Rate diagram of photothermal catalysis of DRM by Al2O3 material under concentrated light; Figure 8 For Ru in Example 1 0.15 TOF plots of each component in Al2O3 material during photothermal catalysis of DRM; Figure 9 For Ru in Example 1 0.15 / Solar-to-chemical energy conversion efficiency diagram of Al2O3 material during photothermal catalysis of DRM; Figure 10 This is a high-angle annular dark-field image of the Ru1 / Al2O3 material in Comparative Example 1 obtained by transmission electron microscopy. Figure 11 The particle size distribution of Ru nanoparticles in the Ru1 / Al2O3 material in Comparative Example 1 is shown. Figure 12 The graph shows the rate of DRM catalysis per gram of Ru1 / Al2O3 material under concentrated light in Comparative Example 1. Figure 13 The TOF plots of each component in Comparative Example 1 are shown for the photothermal catalysis of DRM by the Ru1 / Al2O3 material. Figure 14 The graph shows the rate of DRM catalysis per gram of Al2O3 material under concentrated light in Comparative Example 2. Figure 15 The graph shows the solar-to-chemical energy conversion efficiency of Al2O3 material during photothermal catalysis of DRM in Comparative Example 2. Detailed Implementation

[0018] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this invention.

[0019] The raw materials involved in the specific embodiments of this application are analytical grade.

[0020] Example 1 A method for preparing a monodisperse ruthenium-based composite photothermal catalytic material includes the following steps: S1. Mix 15.01g Al(NO3)3‧9H2O, 4.22g CO(NH2)2 and 50ml deionized water and stir (80rpm, 15min). Then place the mixture in an oven and carry out a hydrothermal reaction at 200℃ for 24h. Cool to 25℃, filter the product after the reaction, wash it three times with deionized water, dry it in an oven at 120℃, calcine it in a muffle furnace at 500℃ for 4h, and grind it (80rpm, 20min) to obtain Al2O3 powder. S2. Add 0.5g Al2O3 powder to 3ml deionized water, then add 0.054g 1.5% (w / v) ruthenium nitrite nitrate solution, grind and evaporate to dryness (80rpm, 30min, 180℃), then transfer to a fluidized bed and reduce with a H2 / Ar mixed gas (H2 to Ar volume ratio 5:100) at 700℃ for 1h. Collect the sample Ru. x / Al2O3, to obtain a monodisperse ruthenium-based composite photothermal catalytic material (Ru 0.15 / Al2O3).

[0021] Example 2 A method for preparing a monodisperse ruthenium-based composite photothermal catalytic material includes the following steps: S1. Mix 15.01g Al(NO3)3‧9H2O, 4.22g CO(NH2)2 and 50ml deionized water and stir (80rpm, 15min). Then place the mixture in an oven and carry out a hydrothermal reaction at 200℃ for 24h. Cool to 25℃, filter the product after the reaction, wash it three times with deionized water, dry it in an oven at 120℃, calcine it in a muffle furnace at 500℃ for 4h, and grind it (80rpm, 20min) to obtain Al2O3 powder. S2. Add 0.5g Al2O3 powder to 3ml deionized water, then add 0.036g 1.5% (w / v) ruthenium nitrite nitrate solution, grind and evaporate to dryness (80rpm, 30min, 180℃), then transfer to a fluidized bed and reduce with a H2 / Ar mixed gas (H2 to Ar volume ratio 5:100) at 700℃ for 1h. Collect the sample Ru. x / Al2O3, to obtain a monodisperse ruthenium-based composite photothermal catalytic material (Ru 0.1 / Al2O3).

[0022] Compare with Example 1 A method for preparing a monodisperse ruthenium-based composite photothermal catalytic material includes the following steps: S1. Mix 15.01g Al(NO3)3‧9H2O, 4.22g CO(NH2)2 and 50ml deionized water and stir (80rpm, 15min). Then place the mixture in an oven and carry out a hydrothermal reaction at 200℃ for 24h. Cool to 25℃, filter the product after the reaction, wash it three times with deionized water, dry it in an oven at 120℃, calcine it in a muffle furnace at 500℃ for 4h, and grind it (80rpm, 20min) to obtain Al2O3 powder. S2. Add 0.5g Al2O3 powder to 3ml deionized water, then add 0.363g 1.5% (w / v) ruthenium nitrite nitrate solution, grind and evaporate to dryness (80rpm, 30min, 180℃), then transfer to a fluidized bed and reduce with H2 / Ar mixed gas (H2 to Ar volume ratio 5:100) at 700℃ for 1h. Collect the sample Ru. xA monodisperse ruthenium-based composite photothermal catalytic material (Ru1 / Al2O3) was obtained by using / Al2O3.

[0023] Compare with Example 2 A method for preparing a photothermal catalytic material includes the following steps: S1. Mix 15.01g Al(NO3)3‧9H2O, 4.22g CO(NH2)2 and 50ml deionized water and stir (80rpm, 15min). Then place in an oven and carry out hydrothermal reaction at 200℃ for 24h. Cool to 25℃, filter the product after reaction, wash it 3 times with deionized water, dry it in an oven at 120℃, calcine it in a muffle furnace at 500℃ for 4h, and grind it (80rpm, 20min) to obtain Al2O3 powder.

[0024] Performance testing The material prepared in Example 1 by S1 and S2 was analyzed by X-ray diffraction (e.g., Figure 1 As shown), transmission electron microscope (such as) Figure 2 The obtained material was characterized by its material structure, physical and chemical properties using ICP-OES and UV / Vis / NIR spectrophotometers (as shown), confirming that the material obtained under these conditions is Ru. 0.15 The Al2O3 nanocomposite catalyst was then tested for catalytic activity and stability, specifically including the following steps: 1. Fluidized bed thermocatalytic testing under no light. Take 0.05g Ru 0.15 Al₂O₃ and 0.5g of quartz sand are uniformly mixed and placed in a fluidized bed quartz reactor. A 40 / 40 / 20 vol% CH₄ / CO₂ / Ar mixed gas is introduced; the gas flow rate is adjusted to 30mL / min using a mass flow meter. -1 After the gas stabilizes, it is continuously reacted at 750℃ for 100 hours.

[0025] 2. Photothermal catalytic testing under focused light irradiation Take 0.008g Ru 0.15 Al₂O₃ and 0.004 g SiC were uniformly mixed (mass ratio 2:1) and spread into a 1 cm diameter disc in a self-made stainless steel reactor. A 30 / 30 / 40 vol% CH₄ / CO₂ / Ar mixed gas was introduced; the gas flow rate was adjusted to 90 mL / min using a mass flow meter. -1 After the gas stabilized, photothermal catalytic DRM testing was conducted under the focused light of a 500W xenon lamp.

[0026] Ru prepared in Example 1 0.15The Al₂O₃ nanoparticles are mainly distributed in the range of 0.5-1.0 nm and 1.0-1.5 nm, with an average particle size of 1.0 nm and a dispersion close to 100% (e.g., ...). Figure 3 (As shown). The Ru obtained in Example 1 0.15 Al2O3 exhibits strong optical absorption across the entire spectrum (e.g., Figure 4 As shown). The Ru obtained in Example 1 0.15 The thermal catalytic conversion rates of CH4 and CO2 by Al2O3 in a fluidized bed over time are as follows: Figure 5 As shown; Ru obtained in Example 1 0.15 / Al2O3, the surface temperature of DRM under focused light photothermal catalysis is 630℃ (e.g. Figure 6 As shown), the average H2 and CO production rates per gram of catalyst were obtained over the first 40 minutes (e.g., Figure 7 (As shown) 68.38 mmol g -1 min -1 and 75.06 mmol g -1 min -1 The TOF values ​​for H2 and CO were 4607.3 min. -1 and 5057.7min -1 (like Figure 8 As shown); the obtained solar-to-chemical energy conversion efficiency is 22.2% (e.g. Figure 9 (As shown). The above results indicate that this embodiment is a monodisperse noble metal nanocatalytic material with strong optical absorption across the entire spectrum. At high temperatures, the catalyst obtained in this embodiment did not show a trend of activity decrease during the 100-h thermocatalytic activity test, and can effectively suppress adverse reactions such as carbon deposition. Under focused light irradiation, this embodiment exhibits extremely high TOF and solar-to-chemical energy conversion efficiency.

[0027] The material prepared in Example 2 via S1 and S2 was analyzed by X-ray diffraction (e.g., Figure 1 The obtained material was characterized by analysis of its material structure and chemical composition using ICP-OES (as shown in the image) and determined to be a monodisperse Ru under these conditions. 0.1 / Al2O3 nanocomposite catalyst.

[0028] The material prepared by S1 and S2 in Comparative Example 1 was examined by an X-ray diffractometer (e.g., ...). Figure 1 As shown), ICP-OES and transmission electron microscopy (such as...) Figure 10 The obtained material was analyzed and characterized in terms of its material structure and chemical composition (as shown in the figure), and it was determined that the material obtained under these conditions was a non-monodisperse Ru1 / Al2O3 nanocomposite catalyst.

[0029] 1. Photothermal catalytic testing under focused light irradiation Take 0.008g Ru1 / Al2O3 and 0.004g SiC, mix them evenly (mass ratio 2:1), and place them in a self-made stainless steel reactor to form a disc with a diameter of 1cm. Introduce a 30 / 30 / 40 vol% CH4 / CO2 / Ar mixed gas; adjust the gas flow rate to 90mL / min using a mass flow meter. -1 After the gas stabilized, photothermal catalytic DRM testing was conducted under the focused light of a 500W xenon lamp.

[0030] The Ru nanoparticles of Ru1 / Al2O3 obtained in Comparative Example 1 were mainly distributed in the range of 1.0-1.5 nm and 1.5-2.0 nm, with an average particle size of 1.4 nm and a dispersion of approximately 78% (e.g., ...). Figure 11 (As shown). Compared to the Ru1 / Al2O3 obtained in Example 1, the average H2 and CO generation rates per gram of catalyst obtained under focused light during photothermal catalysis over the first 40 minutes (e.g.) Figure 12 (As shown) 86.55 mmolg -1 min -1 and 96.40 mmol g -1 min -1 The TOF values ​​for H2 and CO were 1098.2 min. -1 and 1223.0min -1 (like Figure 13 (As shown). The above results indicate that this comparative case is a non-monodisperse noble metal nanocatalytic material. Under focused light irradiation, this comparative case achieves a low TOF in photothermal catalysis of DRM.

[0031] The material prepared in S1 of Comparative Example 2 was analyzed by a UV / Vis / NIR spectrophotometer (e.g., Figure 4 (As shown) The obtained material was characterized by physical and chemical properties, followed by catalytic activity testing, specifically including the following steps: 1. Photothermal catalytic testing under focused light irradiation Take 0.008g of Al2O3 and 0.004g of SiC, mix them evenly (mass ratio 2:1), and place them in a self-made stainless steel reactor to form a disc with a diameter of 1cm. Introduce a 30 / 30 / 40 vol% CH4 / CO2 / Ar mixed gas; adjust the gas flow rate to 90mL / min using a mass flow meter. -1 After the gas stabilized, photothermal catalytic DRM testing was conducted under the focused light of a 500W xenon lamp.

[0032] The Al2O3 obtained in Comparative Example 2 showed almost no optical absorption across the entire spectrum (e.g., Figure 4 (As shown). The surface temperature of Al2O3 obtained in Comparative Example 2 during photothermal catalysis of DRM under focused light was 585℃ (as shown). Figure 6As shown in the figure, the average H2 and CO production rates obtained per gram of catalyst in the first 40 minutes were 0.36 mmol g. -1 min -1 and 0.19 mmol g -1 min -1 (like Figure 14 As shown); the resulting solar-to-chemical energy conversion efficiency is 0% (e.g. Figure 15 (As shown). The above results indicate that this comparative example exhibits extremely low or no optical absorption across the full spectrum, a stark contrast to Example 1. This suggests that the high reaction temperature (630°C) during photothermal DRM catalysis in Example 1 is due to the infrared heating effect of focused light and the localized surface plasmon resonance (LSPR) effect on the Ru nanoparticles, which is completely different from traditional photocatalysis or thermocatalysis modes. Under focused light irradiation, this comparative example exhibits extremely low or no catalytic activity, a stark contrast to Example 1, indicating that the Ru nanoparticles are the active center of the catalyst.

[0033] The above description is merely an example and illustration of the concept of this application. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the inventive concept or exceed the scope defined in the claims, they should all fall within the protection scope of this application.

Claims

1. A method for preparing a monodisperse ruthenium-based composite photothermal catalytic material, characterized in that, Includes the following steps: S1. Mix Al(NO3)3‧9H2O, CO(NH2)2 with deionized water and stir, then carry out hydrothermal reaction, cooling, filtration, washing, drying, calcination and grinding to obtain Al2O3 powder; S2. Add Al2O3 powder to deionized water, then add ruthenium nitrite nitrate solution, grind, evaporate to dryness, reduce, and collect the sample Ru. x / Al2O3 was used to obtain a monodisperse ruthenium-based composite photothermal catalytic material.

2. The method for preparing a monodisperse ruthenium-based composite photothermal catalytic material according to claim 1, characterized in that, The molar ratio of Al(NO3)3‧9H2O to CO(NH2)2, and the molar ratio of Al(NO3)3‧9H2O to CO(NH2)2, is 1:1.4-1.

6.

3. The method for preparing a monodisperse ruthenium-based composite photothermal catalytic material according to claim 1, characterized in that, The hydrothermal reaction is carried out at a temperature of 190-210℃ for 8-25 hours.

4. The method for preparing a monodisperse ruthenium-based composite photothermal catalytic material according to claim 1, characterized in that, The drying process is carried out at a temperature of 110-130℃ for 1-5 hours.

5. The method for preparing a monodisperse ruthenium-based composite photothermal catalytic material according to claim 1, characterized in that, The calcination is carried out at a temperature of 450-550℃ for 4-5 hours.

6. The method for preparing a monodisperse ruthenium-based composite photothermal catalytic material according to claim 1, characterized in that, The grinding and evaporation process is carried out at a speed of 80-100 rpm, a time of 30-40 min, and a temperature of 100-190℃.

7. The method for preparing a monodisperse ruthenium-based composite photothermal catalytic material according to claim 1, characterized in that, The reduction process involves using a H2 / Ar mixture as the reducing gas, with a volume ratio of H2 to Ar of 5-10:100, a reduction temperature of 650-750℃, and a reduction time of 1-2 hours.

8. The method for preparing a monodisperse ruthenium-based composite photothermal catalytic material according to claim 1, characterized in that, The Ru x / Al2O3, where 0<x≤0.

15.

9. A monodisperse ruthenium-based composite photothermal catalytic material prepared by a method for preparing a monodisperse ruthenium-based composite photothermal catalytic material as described in any one of claims 1-8.

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