Preparation method of photothermal catalyst Ni-RuCeO2 and its application in concentrated photocatalytic carbon dioxide methanation

Abstract

The present invention relates to the technical field of preparation of photothermal catalysts, and specifically to a preparation method of a photothermal catalyst Ni-RuCeO2 and application thereof in polyphotocatalytic carbon dioxide methanation. The preparation method comprises the following steps: S1. adding cerium oxide to deionized water and stirring for 0.5-1h to obtain a first mixed solution; S2. adding a Ni-Ru modifier to the first mixed solution, ultrasonically dispersing for 0.5-1h, and stirring for another 0.5-1h to obtain a second mixed solution; S3. adding sodium hydroxide to the second mixed solution, adjusting the pH to 10-13, adding sodium borohydride in 5 batches under magnetic stirring, and subjecting the mixture to a reduction reaction for 10-12h to obtain a third mixed solution; S4. centrifuging the third mixed solution, washing it to neutrality with a cleaning solution, drying it for 10-12h, grinding it for 0.5-1h to form a fine powder, and passing it through a 100-mesh sieve to obtain the photothermal catalyst Ni-RuCeO2. The present invention can effectively absorb a wide spectrum of sunlight, improve light energy utilization, and thus enhance photothermal conversion efficiency. The photothermal synergistic effect eliminates the necessity of high temperature, and light irradiation increases the generation of oxygen vacancies and electron transfer.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of photothermal catalysts, and specifically to a method for preparing a photothermal catalyst Ni-RuCeO2 and its application in concentrated photocatalytic carbon dioxide methanation. Background Art

[0002] As a widely distributed, nearly unlimited clean energy source, efficient utilization of solar energy is crucial for achieving sustainable development. However, the inherent intermittent and fluctuating nature of solar energy severely restricts its direct application in chemical reactions that require a stable heat source or energy input.

[0003] The carbon dioxide methanation reaction (CO2 + 4H2 → CH4 + 2H2O) converts the greenhouse gas carbon dioxide into high-value-added methane fuel, which is of great significance for achieving carbon recycling and producing renewable clean energy. Current industrial or laboratory carbon dioxide methanation processes rely primarily on external heat sources (such as combustion or electric heating) to maintain the catalyst bed at the required reaction temperature (typically in the range of 300°C to 500°C). This external energy supply not only consumes a large amount of energy and increases operating costs, but if the energy comes from fossil fuels, it may also be accompanied by indirect carbon emissions, undermining the environmental benefits of the technology. Furthermore, attempts to directly drive the reaction using solar energy often face core challenges with existing reactors and catalytic systems: the concentration efficiency is easily affected by the environment, and the instantaneous and violent fluctuations in solar radiation lead to unstable temperature fields within the reactor, which in turn causes large fluctuations in the catalytic reaction rate and methane selectivity, ultimately resulting in low conversion efficiency and unsatisfactory product yields.

[0004] The key to overcoming this bottleneck is developing systems that can efficiently and stably utilize full-spectrum sunlight (especially low-energy-density infrared light) at relatively mild temperatures (e.g., 200°C to 400°C) for photothermal synergistic catalysis. This requires the catalyst to not only possess excellent photothermal conversion capabilities, efficiently converting light energy into heat energy, but also exhibit high activity and selectivity for the CO2 methanation reaction itself at relatively low temperatures. Designing such photothermal catalysts to fully utilize the abundant but fluctuating local sunlight resources to directly convert CO2 into methane fuel, which is easy to store and transport, has significant application value, especially in regions with abundant solar resources but potentially weak traditional energy infrastructure (such as northwest my country). Therefore, there is an urgent need to develop new, high-performance photothermal catalysts that can achieve efficient and stable CO2 methanation conversion under direct sunlight at relatively low temperatures, maximizing the utilization of solar resources while effectively addressing the adverse effects of fluctuating sunlight. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a photothermal catalyst Ni-RuCeO2 and its application in concentrated photocatalytic carbon dioxide methanation.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing a photothermal catalyst Ni-RuCeO2 comprises the following steps:

[0008] S1. In parts by mass, 1-3 parts of cerium oxide were added to 15-30 parts of deionized water and stirred at a speed of 300-350r / min for 0.5-1h to obtain a first mixed solution;

[0009] S2. To the first mixed solution obtained in step S1, 0.08-0.77 parts of Ni-Ru modifier were added, ultrasonically dispersed for 0.5-1h, and then stirred at a speed of 300-350r / min for 0.5-1h to obtain a second mixed solution;

[0010] S3. Sodium hydroxide was added to the second mixed solution obtained in step S2, and the pH was adjusted to 10-13. 0.1-0.95 parts of sodium borohydride were added in 5 batches under magnetic stirring, and the reduction reaction was carried out for 10-12h to obtain a third mixed solution.

[0011] S4. The third mixed solution obtained in step S3 was centrifuged, washed with a cleaning solution until neutral, dried at 60-80 ° C for 10-12h, and then ground for 0.5-1h into a fine powder, and passed through a 100 mesh sieve to obtain a photothermal catalyst Ni-RuCeO2;

[0012] The preparation of Ni-Ru modifier includes the following steps:

[0013] S21. In parts by mass, 0.2-0.5 parts of citric acid were dissolved in 40-50 parts of deionized water and magnetically stirred at a speed of 450-500 r / min until clear, and then 0.5-1 parts of nickel nitrate hexahydrate were added and stirring was continued for 15-20 min to obtain a green transparent solution;

[0014] S22. 0.25-0.5 parts of an oxygen vacancy synergistic modifier was added to the green transparent solution and stirred at 450-500 r / min for 25-30 min at 60 ° C to obtain a yellow-green solution;

[0015] S23. Add 0.05-0.1 parts of carbodiimide to the yellow-green solution and disperse it ultrasonically at a frequency of 40 kHz for 15-20 minutes to obtain a Ni-Ru modifier.

[0016] Preferably, the preparation of the oxygen vacancy synergistic modifier comprises the following steps:

[0017] S221. In parts by mass, 0.03-0.18 parts of ruthenium (III) chloride hydrate and 0.08-0.1 parts of acetylacetone were added to 8-15 parts of deionized water and stirred at a speed of 400-450 r / min for 10-15 min to obtain a preliminary mixed solution;

[0018] S222. To the preliminary mixture was added 0.12-0.15 parts of cetyltrimethylammonium bromide, 0.25-0.3 parts of glucose and 0.25-0.3 parts of urea, and stirred in a water bath at a speed of 350-400r / min for 20-25min to obtain a secondary mixed solution;

[0019] S223. Transfer the mixed solution from the second step to a tetrafluoroethylene reactor and perform a hydrothermal reaction at 80°C for 3-4 hours to obtain an oxygen vacancy synergistic modifier.

[0020] Preferably, the frequency of ultrasonic dispersion in step S2 is 40 kHz.

[0021] Preferably, the rotation speed of the magnetic stirring in step S3 is 400-450 r / min.

[0022] Preferably, the time interval for adding sodium borohydride in batches in step S3 is 30 minutes.

[0023] Preferably, the cleaning liquid in step S4 is a mixture of anhydrous ethanol and deionized water, and the volume ratio between the anhydrous ethanol and the deionized water is 1:3.

[0024] Preferably, the water bath temperature in step S222 is 50°C.

[0025] An application of the photothermal catalyst Ni-RuCeO2 prepared according to the above preparation method in the photocatalytic methanation of carbon dioxide.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention uses oxygen vacancy synergistic modifiers to prepare Ni-Ru modifiers. The two work synergistically, and through reasonable reaction conditions and material ratios, the photothermal catalyst Ni-Ru / CeO2 is successfully synthesized under mild conditions. The synthesis method has a convenient preparation process, and the prepared catalyst can achieve efficient catalytic reaction at 300-400°C, reducing dependence on traditional energy; carbon dioxide and hydrogen are converted into methane and water under normal pressure using concentrated photocatalytic technology. The catalytic process of the entire process consumes almost no non-renewable energy, and can convert greenhouse gases, which is fully in line with the development trend of green chemical industry. In addition, the preparation method and application process of the present invention show significant environmental friendliness, reduce the burden on the environment, and promote the development of the chemical industry in a green and efficient direction.

[0028] 2. The photothermal catalyst Ni-Ru / CeO2 synthesized in the present invention can effectively absorb a wide spectrum of sunlight, improve the utilization rate of light energy, and thus enhance the photothermal conversion efficiency. The photothermal synergistic effect eliminates the necessity of high temperature. Light irradiation increases the generation of oxygen vacancies and electron transfer, promotes the decomposition of reactants, and significantly improves the reaction efficiency. The metal Ni and Ru structures introduced into the material act as electron acceptors, providing a good transmission channel for local electrons near metal defects, promoting the redistribution and migration of free electrons, and further stabilizing the metal defect structure.

[0029] 3. In the preparation process of the photothermal catalyst Ni-Ru / CeO2, the present invention uses magnetic stirring and ultrasound throughout the reaction to evenly combine the oxygen vacancy synergistic modifier and the Ni-Ru modifier to prevent the subsequent photothermal catalyst Ni-Ru / CeO2 from agglomerating excessively. At the same time, the pH of the solution is adjusted by sodium hydroxide, and the metal precursor (such as Ni 2+ and Ru 3+ ) facilitates the formation of hydroxide precipitation, helping to control the formation and distribution of metal particles and the subsequent reduction of sodium borohydride. Adding sodium borohydride in five batches can reduce sodium borohydride decomposition during the reduction reaction. By controlling the sodium borohydride dosage and reaction conditions, the size of the metal particles can be adjusted, thereby optimizing catalyst performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flow chart of the preparation process of the present invention;

[0031] Figure 2 X-ray diffraction patterns of the photothermal catalyst Ni-RuCeO2 prepared in Example 1 and Comparative Example 2 of the present invention;

[0032] Figure 3 This is a scanning electron microscope image of the photothermal catalyst Ni-RuCeO2 prepared in Example 1 of the present invention;

[0033] Figure 4 This is a transmission electron microscope image of the photothermal catalyst Ni-RuCeO2 prepared in Example 1 of the present invention;

[0034] Figure 5 This is a comparison of the ultraviolet-visible light absorption spectra of the photothermal catalyst Ni-RuCeO2 prepared in Example 1 of the present invention and in Comparative Example 2, wherein Ni-RuCeO2 is the photothermal catalyst Ni-RuCeO2 prepared in Example 1, and CeO2 is the photothermal catalyst Ni-RuCeO2 prepared in Comparative Example 2;

[0035] Figure 6 This is a surface temperature change diagram of the photothermal catalyst Ni-RuCeO2 measured by adjusting different light energies in Example 1 of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] See also Figure 1-6 , the present invention provides a technical solution:

[0038] Example 1

[0039] A preparation method of photothermal catalyst Ni-RuCeO2:

[0040] Before preparing the photothermal catalyst Ni-RuCeO2, the oxygen vacancy synergistic modifier and Ni-Ru modifier were prepared:

[0041] The preparation of the oxygen vacancy synergistic modifier comprises the following steps:

[0042] S221. 0.03 g of ruthenium (III) chloride hydrate and 0.08 g of acetylacetone were added to 8 g of deionized water and stirred at 400 rpm for 10 min to obtain a preliminary mixed solution;

[0043] S222. To the preliminary mixture was added 0.12 g of hexadecyltrimethylammonium bromide, 0.25 g of glucose and 0.25 g of urea, and stirred at 350 r / min in a water bath at 50 ° C for 20 min to obtain a secondary mixed solution;

[0044] S223. The mixed solution of the second step was transferred to a tetrafluoroethylene reactor and hydrothermally reacted at 80°C for 3h to obtain an oxygen vacancy synergistic modifier;

[0045] The preparation of Ni-Ru modifier includes the following steps:

[0046] S21. 0.2 g of citric acid was dissolved in 40 g of deionized water and magnetically stirred at 450 rpm until clear. 0.5 g of nickel nitrate hexahydrate was then added and stirred for 15 min to obtain a green, transparent solution.

[0047] S22. 0.25 g of oxygen vacancy synergistic modifier was added to the green transparent solution and stirred at 450 rpm for 25 min at 60 ° C to obtain a yellow-green solution;

[0048] S23. 0.05 g of carbodiimide was added to the yellow-green solution and ultrasonically dispersed at a frequency of 40 kHz for 15-20 min to obtain a Ni-Ru modifier;

[0049] S1. 1-3g of cerium oxide was added to 15-30g of deionized water and stirred at a speed of 300-350r / min for 0.5h to obtain a first mixed solution;

[0050] S2 was added to the first mixed solution obtained in step S1 0.08g Ni-Ru modifier, ultrasonically dispersed at a frequency of 40kHz for 0.5h, and then stirred at a speed of 300r / min for 0.5h to obtain a second mixed solution;

[0051] S3. Sodium hydroxide was added to the second mixed solution obtained in step S2, the pH was adjusted to 10, 0.1 g of sodium borohydride was added in 5 batches under magnetic stirring at 400 r / min, and the reduction reaction was carried out for 10 h to obtain a third mixed solution;

[0052] S4. The third mixed solution obtained in step S3 was centrifuged, washed with a cleaning solution until neutral, dried at 60°C for 10h, and then ground into a fine powder for 0.5h. After passing through a 100-mesh sieve, the photothermal catalyst Ni-RuCeO2 was obtained.

[0053] Example 2

[0054] A preparation method of photothermal catalyst Ni-RuCeO2:

[0055] Before preparing the photothermal catalyst Ni-RuCeO2, the oxygen vacancy synergistic modifier and Ni-Ru modifier were prepared:

[0056] The preparation of the oxygen vacancy synergistic modifier comprises the following steps:

[0057] S221. 0.18 g of ruthenium (III) chloride hydrate and 0.1 g of acetylacetone were added to 15 g of deionized water and stirred at 450 rpm for 15 min to obtain a preliminary mixed solution;

[0058] S222. To the preliminary mixture was added 0.15 g of hexadecyltrimethylammonium bromide, 0.3 g of glucose and 0.3 g of urea, and stirred at 400 r / min in a water bath at 50 ° C for 25 min to obtain a secondary mixed solution;

[0059] S223. The mixed solution of the second step was transferred to a tetrafluoroethylene reactor and hydrothermally reacted at 80°C for 4 hours to obtain an oxygen vacancy synergistic modifier;

[0060] The preparation of Ni-Ru modifier includes the following steps:

[0061] S21. Dissolve 0.5 g of citric acid in 50 g of deionized water and stir magnetically at 500 rpm until clear. Then add 1 g of nickel nitrate hexahydrate and continue stirring for 20 min to obtain a green, transparent solution.

[0062] S22. 0.5 g of oxygen vacancy synergistic modifier was added to the green transparent solution and stirred at 500 rpm for 30 min at 60 ° C to obtain a yellow-green solution;

[0063] S23. 0.1 g of carbodiimide was added to the yellow-green solution and ultrasonically dispersed at a frequency of 40 kHz for 20 min to obtain a Ni-Ru modifier;

[0064] S1. 1-3g of cerium oxide was added to 15-30g of deionized water and stirred at a speed of 300-350r / min for 0.5-1h to obtain a first mixed solution;

[0065] S2 was added to the first mixed solution obtained in step S1 0.77g Ni-Ru modifier, ultrasonically dispersed at a frequency of 40kHz for 1h, and then stirred at a speed of 350r / min for 1h to obtain a second mixed solution;

[0066] S3. Sodium hydroxide was added to the second mixed solution obtained in step S2, the pH was adjusted to 13, 0.95 g of sodium borohydride was added in 5 batches under magnetic stirring at 450 r / min, and the reduction reaction was carried out for 12 h to obtain a third mixed solution;

[0067] S4. The third mixed solution obtained in step S3 was centrifuged, washed with a cleaning solution until neutral, dried at 80°C for 12h, and then ground into fine powder for 1h. After passing through a 100-mesh sieve, the photothermal catalyst Ni-RuCeO2 was obtained.

[0068] Example 3

[0069] A preparation method of photothermal catalyst Ni-RuCeO2:

[0070] Before preparing the photothermal catalyst Ni-RuCeO2, the oxygen vacancy synergistic modifier and Ni-Ru modifier were prepared:

[0071] The preparation of the oxygen vacancy synergistic modifier comprises the following steps:

[0072] S221. 0.06 g of ruthenium (III) chloride hydrate and 0.09 g of acetylacetone were added to 10 g of deionized water and stirred at 420 rpm for 11 min to obtain a preliminary mixed solution;

[0073] S222. To the preliminary mixture was added 0.13 g of hexadecyltrimethylammonium bromide, 0.26 g of glucose and 0.26 g of urea, and stirred at 370 r / min in a water bath at 50 ° C for 22 min to obtain a secondary mixed solution;

[0074] S223. The mixed solution of the second step was transferred to a tetrafluoroethylene reactor and hydrothermally reacted at 80 ° C for 3.5 h to obtain an oxygen vacancy synergistic modifier;

[0075] The preparation of Ni-Ru modifier includes the following steps:

[0076] S21. 0.3 g of citric acid was dissolved in 42 g of deionized water and magnetically stirred at 470 rpm until clear. 0.6 g of nickel nitrate hexahydrate was then added and stirring was continued for 17 min to obtain a green, transparent solution.

[0077] S22. 0.3 g of oxygen vacancy synergistic modifier was added to the green transparent solution and stirred at 470 rpm for 27 min at 60 ° C to obtain a yellow-green solution;

[0078] S23. 0.06 g of carbodiimide was added to the yellow-green solution and ultrasonically dispersed at a frequency of 40 kHz for 16 min to obtain a Ni-Ru modifier;

[0079] S1. 2g of cerium oxide was added to 20g of deionized water and stirred at a speed of 320r / min for 0.6h to obtain a first mixed solution;

[0080] S2 was added to the first mixed solution obtained in step S1 0.25g Ni-Ru modifier, ultrasonically dispersed at a frequency of 40kHz for 0.6h, and then stirred at a speed of 320r / min for 0.6h to obtain a second mixed solution;

[0081] S3. Sodium hydroxide was added to the second mixed solution obtained in step S2, the pH was adjusted to 11, 0.45 g of sodium borohydride was added in 5 batches under magnetic stirring at 420 r / min, and the reduction reaction was carried out for 11 h to obtain a third mixed solution;

[0082] S4. The third mixed solution obtained in step S3 was centrifuged, washed with a cleaning solution until neutral, dried at 70°C for 11 hours, and then ground into a fine powder for 0.6 hours. After passing through a 100-mesh sieve, the photothermal catalyst Ni-RuCeO2 was obtained.

[0083] Example 4

[0084] A preparation method of photothermal catalyst Ni-RuCeO2:

[0085] Before preparing the photothermal catalyst Ni-RuCeO2, the oxygen vacancy synergistic modifier and Ni-Ru modifier were prepared:

[0086] The preparation of the oxygen vacancy synergistic modifier comprises the following steps:

[0087] S221. 0.14 g of ruthenium (III) chloride hydrate and 0.09 g of acetylacetone were added to 14 g of deionized water and stirred at 440 rpm for 14 min to obtain a preliminary mixed solution;

[0088] S222. To the preliminary mixture was added 0.14 g of hexadecyltrimethylammonium bromide, 0.28 g of glucose and 0.28 g of urea, and stirred at 380 r / min in a water bath at 50 ° C for 24 min to obtain a secondary mixed solution;

[0089] S223. The mixed solution of the second step was transferred to a tetrafluoroethylene reactor and hydrothermally reacted at 80 ° C for 3.5 h to obtain an oxygen vacancy synergistic modifier;

[0090] The preparation of Ni-Ru modifier includes the following steps:

[0091] S21. 0.4 g of citric acid was dissolved in 48 g of deionized water and magnetically stirred at 480 rpm until clear. 0.8 g of nickel nitrate hexahydrate was then added and stirring continued for 18 min to obtain a green, transparent solution.

[0092] S22. 0.42 g of oxygen vacancy synergistic modifier was added to the green transparent solution and stirred at 480 rpm for 28 min at 60 ° C to obtain a yellow-green solution;

[0093] S23. 0.08 g of carbodiimide was added to the yellow-green solution and ultrasonically dispersed at a frequency of 40 kHz for 18 min to obtain a Ni-Ru modifier;

[0094] S1. 2.5 g of cerium oxide was added to 25 g of deionized water and stirred at a speed of 340 r / min for 0.8 h to obtain a first mixed solution;

[0095] S2 was added to the first mixed solution obtained in step S1 0.68g Ni-Ru modifier, ultrasonically dispersed at a frequency of 40kHz for 0.8h, and then stirred at a speed of 340r / min for 0.8h to obtain a second mixed solution;

[0096] S3. Sodium hydroxide was added to the second mixed solution obtained in step S2, the pH was adjusted to 12.5, 0.86 g of sodium borohydride was added in 5 batches under magnetic stirring at 440 r / min, and the reduction reaction was carried out for 11.5 h to obtain a third mixed solution;

[0097] S4. The third mixed solution obtained in step S3 was centrifuged, washed with a cleaning solution until neutral, dried at 60-80°C for 11.5h, and then ground into a fine powder for 0.8h. After passing through a 100-mesh sieve, the photothermal catalyst Ni-RuCeO2 was obtained.

[0098] Comparative Example 1

[0099] The only difference between Comparative Example 1 and Example 1 is that no sodium hydroxide is added in Comparative Example 1, and the remaining steps are exactly the same in Comparative Example 1 and Example 1.

[0100] Comparative Example 2

[0101] Comparative Example 2 differs from Example 1 only in that no Ni-Ru modifier is added in Comparative Example 2, and the remaining steps are exactly the same in Comparative Example 2 and Example 1.

[0102] Comparative Example 3

[0103] The only difference between Comparative Example 3 and Example 1 is that all ultrasonic dispersion steps are eliminated in Comparative Example 3, and the remaining steps are exactly the same in Comparative Example 3 and Example 1.

[0104] Comparative Example 4

[0105] Comparative Example 4 differs from Example 1 only in that no oxygen vacancy synergistic modifier is added in Comparative Example 4, and the remaining steps are exactly the same in Comparative Example 4 and Example 1.

[0106] Performance testing:

[0107] In a device capable of continuously capturing and containing hydrogen molecules and carbon dioxide gas, 0.1 g of the photothermal catalyst Ni-RuCeO2 prepared in Example 1 was filled. In a concentrated flow phase test system, the light intensity was 50 kilowatts per square meter. The concentrated light irradiation produced a thermal effect that stably maintained the surface temperature of the catalyst between 300°C and 400°C. At the same time, a gas chromatograph (Shimadzu GC-8A) equipped with a thermal conductivity detector (TCD) and a hydrogen ion flame detector (FID) was used to analyze the reactant gas and the product gas, and the generated products and the conversion rates of hydrogen and carbon dioxide were detected. The volume ratio of hydrogen to carbon dioxide was 4:1, and the flow rate of the reaction gas (H2:CO2) was controlled at 50 mL / min⁻¹. In order to study the catalytic stability of the catalyst, the photothermal catalyst Ni-RuCeO2 of Example 1 was used to carry out a stability test for a total of 10 hours, with sampling every hour. The experimental results are shown in Table 1. The results show that the catalyst can maintain a good catalytic effect and does not lose activity during the cycle test.

[0108] Table 1 Stability performance test results of Ni-Ru / CeO2 prepared in Example 1 for photocatalytic methane production

[0109]

[0110] In a device capable of continuously capturing and containing hydrogen molecules and carbon dioxide gas, 0.1 g of the photothermal catalyst Ni-RuCeO2 prepared in Example 1 was filled. In a concentrated flow phase test system, the light intensity was adjusted to 30 kW / m2, 40 kW / m2, 50 kW / m2, and 60 kW / m2 in sequence. The concentrated light irradiation produced a thermal effect that stably maintained the catalyst surface temperature between 300°C and 400°C. At the same time, a gas chromatograph (Shimadzu GC-8A) equipped with a thermal conductivity detector (TCD) and a hydrogen ion flame detector (FID) was used to analyze the reactant gas and the product gas, and the generated products and the conversion rates of hydrogen and carbon dioxide were detected. The volume ratio of hydrogen to carbon dioxide was 4:1, and the flow rate of the reaction gas (H2:CO2) was controlled at 50 mL / min⁻¹. The specific test results are shown in Table 2 below:

[0111] Table 2 Catalytic effect of photothermal catalyst Ni-RuCeO2 prepared in Example 1 under different light intensities

[0112]

[0113] It can be seen from Table 2 above that as the light intensity increases, the catalytic strength of the photothermal catalyst Ni-RuCeO2 also increases.

[0114] The same test method as that in Table 1 was used, and the test time was 1 hour. The photothermal catalyst Ni-RuCeO2 prepared in Examples 2-4 and Comparative Examples 1-4 was subjected to photocatalytic testing. The test results are shown in Table 3 below:

[0115] Table 3 Comparison of catalytic effects of photothermal catalyst Ni-RuCeO2 obtained in Examples 1-4 and Comparative Examples 1-4

[0116]

[0117] It can be seen from Table 3 above that the photothermal catalyst Ni-RuCeO2 prepared in Comparative Example 2 does not have catalytic performance. In Comparative Example 1, in the absence of the addition of sodium hydroxide, the metal particle size becomes larger due to the lack of hydroxide precipitation, and the catalytic ability is greatly reduced relative to Example 1. It can be seen from the comparison between Comparative Example 3 and Example 1 that in the absence of ultrasonic dispersion, the metal dispersion is uneven and the catalytic performance is also reduced; Comparative Example 4 proves that the catalytic performance is significantly reduced due to the lack of addition of the oxygen vacancy synergistic modifier.

[0118] Attachment Figure 2 The X-ray diffraction patterns of the photothermal catalyst Ni-RuCeO2 prepared in Example 1 and Comparative Example 2 are shown in FIG. Figure 2 It can be seen that the diffraction peaks at 28.6°, 33.1° and 47.5° are the three main strong lines, corresponding to the diffraction peaks of the (111), (220) and (311) crystal planes of the CeO2 standard card (PDF#43-1002), respectively, indicating that the cubic fluorite structured photothermal catalyst Ni-RuCeO2 was successfully synthesized; since the doping amounts of Ni and Ru in the tested samples were relatively low, there was no additional effect on the phase structure, so no other diffraction peaks appeared in the XRD diffraction spectrum; the prepared catalyst material has good crystallinity, and the doping of Ni and Ru does not destroy the basic crystal structure of CeO2, which helps to maintain the stability and activity of the catalyst.

[0119] Attachment Figure 3 This is a scanning electron microscope image of the photothermal catalyst Ni-RuCeO2 prepared in Example 1. Figure 3 It can be observed that the catalyst's appearance mainly presents a uniform nanoparticle morphology, with a particle size distribution between 20-30 nanometers. These nanoparticles have a relatively regular shape, indicating that a relatively uniform crystal structure has been formed during the synthesis process. Figure 4 This is a transmission electron microscope image of the photothermal catalyst Ni-RuCeO2 prepared in Example 1. Figure 4As can be observed in the image, the nanoparticles have a sheet-like stacking structure and are approximately 60-70 nanometers in size. Example 4 has a smaller particle size, indicating a higher specific surface area, which may improve its catalytic performance.

[0120] Attachment Figure 5 This is a comparison of the UV-visible absorption spectra of the photothermal catalyst Ni-RuCeO2 prepared in Example 1 and Comparative Example 2, wherein Ni-RuCeO2 is the photothermal catalyst Ni-RuCeO2 prepared in Example 1, and CeO2 is the photothermal catalyst Ni-RuCeO2 prepared in Comparative Example 2. Figure 5 It can be observed that the UV-visible absorption spectrum in the figure shows that the absorption intensity of Ni-RuCeO2 in the ultraviolet region (200-400nm) is significantly higher than that of CeO2, indicating that the introduction of Ni-Ru enhances the material's ability to absorb ultraviolet light. At the same time, Ni-Ru / CeO2 still exhibits certain absorption in the visible light region (400-800nm), while the absorption of CeO2 is very weak, which shows that the addition of the Ni-Ru modifier gives the catalyst a certain visible light response ability. Overall, the light absorption performance of Ni-Ru / CeO2 in the ultraviolet to visible light region is better than that of pure CeO2, indicating that the synthesized Ni-Ru / CeO2 has excellent photothermal properties.

[0121] Attachment Figure 6 This is a graph showing the surface temperature change of the photothermal catalyst Ni-RuCeO2 in Example 1 by adjusting different light energies. Figure 6 It can be seen that the catalytic reaction system included in the present invention can achieve control of the catalyst surface temperature. When the photothermal catalyst Ni-RuCeO2 of Example 1 is filled into the reaction system, the overall temperature of the reaction system can be stably maintained between 300°C and 400°C regardless of the adjustment of the concentrated light intensity. This also reflects that compared with the traditional heat-driven catalytic reaction process, the photothermal catalyst Ni-Ru / CeO2 in the present invention can more rationally utilize the light efficiency in the photothermal reaction.

[0122] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a photothermal catalyst Ni-RuCeO2, characterized in that: The method comprises the following preparation steps: S1. In parts by mass, 1-3 parts of cerium oxide were added to 15-30 parts of deionized water and stirred at a speed of 300-350r / min for 0.5-1h to obtain a first mixed solution; S2. To the first mixed solution obtained in step S1, 0.08-0.77 parts of Ni-Ru modifier were added, ultrasonically dispersed for 0.5-1h, and then stirred at a speed of 300-350r / min for 0.5-1h to obtain a second mixed solution; S3. Sodium hydroxide was added to the second mixed solution obtained in step S2, and the pH was adjusted to 10-13. 0.1-0.95 parts of sodium borohydride were added in 5 batches under magnetic stirring, and the reduction reaction was carried out for 10-12h to obtain a third mixed solution. S4. The third mixed solution obtained in step S3 was centrifuged, washed with a cleaning solution until neutral, dried at 60-80 ° C for 10-12h, and then ground for 0.5-1h into a fine powder, and passed through a 100 mesh sieve to obtain a photothermal catalyst Ni-RuCeO2; The preparation of the Ni-Ru modifier comprises the following steps: S21. In parts by mass, 0.2-0.5 parts of citric acid were dissolved in 40-50 parts of deionized water and magnetically stirred at a speed of 450-500 r / min until clear, and then 0.5-1 parts of nickel nitrate hexahydrate were added and stirring was continued for 15-20 min to obtain a green transparent solution; S22. 0.25-0.5 parts of an oxygen vacancy synergistic modifier was added to the green transparent solution and stirred at 450-500 r / min for 25-30 min at 60 ° C to obtain a yellow-green solution; S23. 0.05-0.1 parts of carbodiimide were added to the yellow-green solution and ultrasonically dispersed at a frequency of 40 kHz for 15-20 min to obtain a Ni-Ru modifier; The preparation of the oxygen vacancy synergistic modifier comprises the following steps: S221. In parts by mass, 0.03-0.18 parts of ruthenium (III) chloride hydrate and 0.08-0.1 parts of acetylacetone were added to 8-15 parts of deionized water and stirred at a speed of 400-450 r / min for 10-15 min to obtain a preliminary mixed solution; S222. To the preliminary mixture was added 0.12-0.15 parts of cetyltrimethylammonium bromide, 0.25-0.3 parts of glucose and 0.25-0.3 parts of urea, and stirred in a water bath at a speed of 350-400r / min for 20-25min to obtain a secondary mixed solution; S223. Transfer the mixed solution from the second step to a tetrafluoroethylene reactor and perform a hydrothermal reaction at 80°C for 3-4 hours to obtain an oxygen vacancy synergistic modifier.

2. The method for preparing a photothermal catalyst Ni-RuCeO2 according to claim 1, characterized in that: The frequency of ultrasonic dispersion in step S2 is 40 kHz.

3. The method for preparing a photothermal catalyst Ni-RuCeO2 according to claim 1, characterized in that: The rotation speed of the magnetic stirring in step S3 is 400-450 r / min.

4. The method for preparing a photothermal catalyst Ni-RuCeO2 according to claim 1, characterized in that: The time interval for adding sodium borohydride in batches in step S3 is 30 minutes.

5. The method for preparing a photothermal catalyst Ni-RuCeO2 according to claim 1, characterized in that: The cleaning solution in step S4 is a mixture of anhydrous ethanol and deionized water, and the volume ratio between the anhydrous ethanol and the deionized water is 1:

3.

6. The method for preparing a photothermal catalyst Ni-RuCeO2 according to claim 1, characterized in that: The water bath temperature in step S222 is 50°C.

7. Use of the photothermal catalyst Ni-RuCeO2 prepared according to the preparation method according to any one of claims 1 to 6 in concentrated photocatalytic carbon dioxide methanation.

Images