RuM / CeO2 monatomic alloy catalyst as well as preparation method and application thereof

Abstract

The invention discloses a RuM / CeO2 monatomic alloy catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalysts. The preparation method provided by the invention comprises the following steps: mixing soluble cerium salt, water, ethanol and a precipitator, stirring, filtering, washing and calcining to obtain a CeO2 carrier; and dispersing the CeO2 carrier in ethylene glycol, then adding a Ru-containing solution and an M-containing solution, and carrying out stirring reaction and calcination reduction to obtain the RuM / CeO2 monatomic alloy catalyst. The RuM / CeO2 monatomic alloy catalyst is prepared by adopting ethanol to prepare a CeO2 carrier and combining multiple heavy metal modification, and the obtained catalyst can efficiently catalyze the CO2 methanation process; and a monatomic alloy strategy is adopted, so that the synergistic effect of Ru and M atoms is enhanced, the catalytic activity of the catalyst is improved, and CO2 hydrogenation methanation reaction can be efficiently catalyzed.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and particularly relates to a RuM / CeO 2 single-atom alloy catalyst and its preparation method and application. Background Art

[0002] With the rapid development of industrialization, the massive combustion of global fossil fuels has led to a growing increase in the emissions of CO 2 , intensifying the greenhouse effect and triggering natural disasters such as extreme weather and rising sea levels. CO 2 accounts for more than 75% of the total greenhouse gas emissions (in terms of CO 2 equivalent). Therefore, how to reduce CO 2 emissions has attracted much attention from researchers. Currently, the main ways to reduce CO 2 emissions include: (I) carbon capture and storage (CCS) and (II) CO 2 utilization (CCU). Although CCS technology is feasible in reducing carbon dioxide emissions, it requires CO 2 sequestration near the CO 2 emission source or transporting the captured CO 2 to the storage site, so its application is limited. In comparison, CCU is considered a viable alternative to CCS. Through electrochemical, thermocatalytic, photochemical, biochemical and other methods, CO 2 can be converted into commercially valuable products, such as carbon monoxide, methane, methanol and hydrocarbons. Among them, the CO 2 methanation reaction (CO 2 +4H 2 →CH 4 +2H 2 O, enthalpy change ΔH = -165.0 kJ·mol -1 ) can utilize the large amount of CO 2 in the atmosphere to produce clean energy methane to meet the energy needs of humans. Therefore, the CO 2 methanation reaction is considered an effective way to utilize CO 2 .

[0003] Traditional CO 2 methanation catalysts are mainly single-atom catalysts or composite catalysts, but their catalytic activity, catalytic efficiency and reaction rate are not satisfactory, and they cannot effectively achieve the efficient conversion of CO 2 to methane, which to a certain extent limits the further development of CO 2 methanation.

[0004] Therefore, how to develop a catalyst with high catalytic activity that can efficiently catalyze the 2 methanation of CO is a technical problem that needs to be urgently solved by those skilled in the art. SUMMARY OF THE INVENTION

[0005] To solve the above technical problems, the present invention proposes a RuM / CeO 2 single-atom alloy catalyst and its preparation method and application.

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

[0007] The present invention provides a method for preparing a RuM / CeO 2 single-atom alloy catalyst, comprising the following steps:

[0008] (1) Mix a soluble cerium salt, water, ethanol and a precipitant, and obtain a CeO 2 support through stirring, filtering, washing and calcining;

[0009] (2) Disperse the CeO 2 support in ethylene glycol, then add a Ru-containing solution and an M-containing solution, and obtain the RuM / CeO 2 single-atom alloy catalyst through stirring reaction and calcining reduction; M in the M-containing solution is a transition metal element.

[0010] Technical principle: The present invention prepares a RuM / CeO 2 single-atom alloy catalyst by using ethanol to prepare the CeO 2 support and combining multiple metal modifications. The obtained catalyst can efficiently catalyze the 2 methanation process of CO; by adopting the single-atom alloy strategy, the synergistic effect between Ru and M atoms is enhanced, the catalytic activity of the catalyst is improved, and the 2 hydro-methanation reaction of CO can be efficiently catalyzed.

[0011] Furthermore, in step (1), the mixing of the soluble cerium salt, water, ethanol and the precipitant is specifically: dissolving the soluble cerium salt in ethanol to obtain solution A; dissolving the precipitant in water to obtain solution B; pouring solution B into solution A.

[0012] Furthermore, in step (2), the dosage ratio of the CeO 2 support to ethylene glycol is (0.2-2) g∶(20-100) mL.

[0013] Further, in step (2), the Ru-containing solution is one or more of ruthenium chloride solution, ruthenium acetate solution, and ruthenium acetylacetonate solution; the concentration of Ru ions in the Ru-containing solution is 2-10 mg / mL.

[0014] Further, in step (2), M in the M-containing solution is Co or Ni.

[0015] Further, in step (2), the RuM / CeO 2 The loading amount of Ru in the single-atom alloy catalyst is 0.03-0.2 wt%, and the loading amount of M is 1-10 wt%.

[0016] Further, in step (2), the temperature of the stirring reaction is 120-200 °C, and the time of the stirring reaction is 4-6 h.

[0017] Further, in step (2), the calcination reduction is specifically as follows: heating at a rate of 1-10 °C / min, while heating, introducing H 2 , after heating to 300-600 °C, calcining and reducing for 2-5 h, and then cooling to room temperature at a rate of 1-10 °C / min, and then stopping introducing H 2 ; the flow rate of the H 2 is 20-60 mL / min.

[0018] The present invention provides a RuM / CeO 2 single-atom alloy catalyst prepared by the preparation method described in the above technical solution.

[0019] The present invention also provides the application of the RuM / CeO 2 single-atom alloy catalyst described in the above technical solution in photothermal carbon dioxide methanation.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] The preparation method of the RuM / CeO 2 single-atom alloy catalyst provided by the present invention has simple conditions and small reaction influencing factors. At the same time, since Ru is highly dispersed in the form of single atoms, the usage amount of precious metals is effectively reduced, and the high catalytic activity is maintained, making the catalyst have higher economic value. And the prepared catalyst can generate methane more efficiently and selectively compared with the traditional catalyst, reduce the generation of by-products, and improve the purity of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0023] Figure 1 CeO prepared for Example 1 2 SEM image of the support;

[0024] Figure 2 CeO prepared for Example 1 2 SEM image of the support;

[0025] Figure 3 CeO prepared for Example 1 2 XRD pattern of the support;

[0026] Figure 4 Ni / CeO prepared for Example 4 2 SEM image of the catalyst (10μm);

[0027] Figure 5 Ni / CeO prepared for Example 4 2 SEM image of the catalyst (14μm);

[0028] Figure 6 CeO prepared for Example 1 2 Support and Ni / CeO catalysts prepared in Examples 2 - 5 2 Carbon dioxide conversion rate;

[0029] Figure 7 RuNi / CeO prepared for Example 6 2 Hrtem image of the single - atom alloy catalyst;

[0030] Figure 8 CeO prepared for Example 1 2 Carbon dioxide conversion rate graphs of the support and catalysts prepared in Examples 4, 6 - 7. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0032] To make the above - mentioned objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific implementation manners.

[0033] The embodiments of the present invention provide a preparation method for a RuM / CeO 2 single - atom alloy catalyst, including the following steps:

[0034] (1) Mix a soluble cerium salt, water, ethanol, and a precipitant, followed by stirring, filtration, washing, and calcination to obtain a CeO 2 support;

[0035] (2) Disperse the CeO 2 support in ethylene glycol, then add a Ru-containing solution and an M-containing solution, followed by stirring reaction and calcination reduction to obtain the RuM / CeO 2 single-atom alloy catalyst; M in the M-containing solution is a transition metal element.

[0036] In a preferred embodiment, in step (1), the mixing of the soluble cerium salt, water, ethanol, and the precipitant is specifically as follows: dissolve the soluble cerium salt in ethanol to obtain solution A; dissolve the precipitant in water to obtain solution B; pour solution B into solution A. The present invention uses ethanol to prepare the CeO 2 support, which is beneficial to obtaining a RuM / CeO 2 single-atom alloy catalyst with high catalytic activity.

[0037] In a preferred embodiment, the soluble cerium salt is preferably cerium nitrate; the precipitant is preferably ammonium bicarbonate; the molar ratio of the soluble cerium salt to the precipitant is 20:48.

[0038] In a preferred embodiment, in step (1), the stirring is carried out at room temperature, and the stirring time is 12 h; the filtration method is preferably suction filtration; the detergent used for washing is deionized water and absolute ethanol; after washing, a drying step is further included, the drying temperature is 80 °C, and the drying time is 12 h.

[0039] In a preferred embodiment, in step (1), the calcination temperature is 450 °C, the heat preservation time is 5 h, and the heating rate is 2 °C / min.

[0040] In a preferred embodiment, in step (2), the dosage ratio of the CeO 2 support to ethylene glycol is (0.2 - 2) g:(20 - 100) mL, and more preferably (0.2 - 0.5) g:(20 - 50) mL.

[0041] In a preferred embodiment, in step (2), the method of dispersing the CeO 2 support in ethylene glycol is ultrasonic dispersion; the temperature of the ultrasonic dispersion is 20 - 35 °C, the frequency is 30 - 40 KHz, the power is 520 - 560 W, and the time is 0.2 - 1 h.

[0042] In a preferred embodiment, in step (2), the Ru-containing solution is one or more of ruthenium chloride solution, ruthenium acetate solution, and ruthenium acetylacetonate solution.

[0043] In a preferred embodiment, in step (2), the RuM / CeO 2 The loading amount of Ru in the single-atom alloy catalyst is 0.03 to 0.2 wt%, preferably 0.05 to 0.1 wt%, and further preferably 0.05 wt%.

[0044] In a preferred embodiment, in step (2), M in the M-containing solution is Co or Ni. Further, the M-containing solution is a cobalt nitrate solution or a nickel nitrate solution.

[0045] In a preferred embodiment, in step (2), the RuM / CeO 2 The loading amount of M in the single-atom alloy catalyst is 1 to 10 wt%, preferably 3 to 9 wt%, and further preferably 7 wt%.

[0046] In a preferred embodiment, in step (2), the temperature of the stirring reaction is 120 - 200 °C, and the time of the stirring reaction is 4 - 6 h.

[0047] In a preferred embodiment, in step (2), after the stirring reaction, it further includes filtration separation, washing, and drying steps; the detergent for washing is deionized water and absolute ethanol; the drying temperature is 40 - 90 °C, and the drying time is 6 - 16 h.

[0048] In a preferred embodiment, in step (2), the calcination reduction is specifically: heating at 1 - 10 °C / min, while heating, introducing H 2 , after heating to 300 - 600 °C, calcining and reducing for 2 - 5 h, and then cooling to room temperature at 1 - 10 °C / min, and then stopping introducing H 2 ; the flow rate of the H 2 is 20 - 60 mL / min; the H 2 is introduced in the form of a hydrogen-argon mixture, and the volume ratio of H 2 in the hydrogen-argon mixture is 10%.

[0049] The present invention provides a RuM / CeO 2 single-atom alloy catalyst prepared by the preparation method described in the above technical solution.

[0050] The present invention also provides the application of the RuM / CeO 2 single-atom alloy catalyst described in the above technical solution in photothermal carbon dioxide methanation.

[0051] In the embodiments of the present invention, room temperature refers to "25 ± 2 °C".

[0052] Unless otherwise specified, the raw materials in the embodiments of the present invention are all obtained through commercial channels.

[0053] Example 1

[0054] (1) Weigh 8.69 g (20 mmol) of cerium nitrate and dissolve it in 100 mL of ethanol to obtain solution A;

[0055] (2) Weigh 3.80 g (48 mmol) of ammonium bicarbonate and dissolve it in 100 mL of water to obtain solution B;

[0056] (3) Quickly pour solution B into solution A, stir at room temperature for 12 h, filter by suction and centrifuge to obtain a filtrate and a precipitate. Wash the obtained precipitate with deionized water and absolute ethanol for multiple times, and then place it in an oven at 80 °C for drying for 12 h to obtain a pale yellow powder;

[0057] (4) Take the pale yellow powder obtained in step (3) and place it in a porcelain boat. Put the porcelain boat into a muffle furnace and heat it to 450 °C at a rate of 2 °C / min, and calcine for 5 h to obtain CeO 2 support, denoted as CeO 2 .

[0058] Figure 1 is the SEM image of the CeO 2 support prepared in Example 1, Figure 2 is the SEM image of the CeO 2 support prepared in Example 1, Figure 1 and Figure 2 The difference is the observation position. From Figure 1 and Figure 2 it can be seen that the CeO 2 support presents a flaky structure.

[0059] Figure 3 is the XRD pattern of the CeO 2 support prepared in Example 1. From Figure 3 it can be seen that the composition of the obtained support is completely consistent with the standard peaks of CeO 2 , and it can be determined that the CeO 2 has been successfully synthesized.

[0060] Example 2

[0061] A preparation method of a Ni / CeO 2 catalyst is as follows:

[0062] (1) Take 0.5 g of the CeO 2 support prepared in Example 1 and add it to a round-bottom flask containing 50 mL of ethylene glycol. Under the conditions of 25 °C, 35 KHz and 540 W, ultrasonically vibrate for 0.2 h to uniformly disperse the CeO 2 in ethylene glycol;

[0063] (2) According to the Ni / CeO 2 Add nickel nitrate solution to the round-bottom flask in step (1). Place the round-bottom flask in an oil bath and continuously stir and react at 190 °C for 5 h. After the reaction, cool to room temperature, filter by suction, and centrifuge to obtain a precipitate;

[0064] (3) Wash the precipitate obtained in step (2) by suction with deionized water and anhydrous ethanol successively, and then dry at 80 °C for 12 h to obtain a dried precipitate;

[0065] (4) Place the dried precipitate obtained in step (3) in a tubular furnace, heat at 2 °C / min, and while heating, introduce H 2 , H 2 in the form of a hydrogen-argon mixed gas. The volume ratio of H 2 in the hydrogen-argon mixed gas is 10%, and the flow rate of H 2 is 50 mL / min. After heating to 400 °C, calcine and reduce for 3 h, and then cool to room temperature at 2 °C / min, and then stop introducing H 2 to obtain the Ni / CeO 2 catalyst, denoted as 3Ni / CeO 2 .

[0066] Example 3

[0067] The difference from Example 2 is that in step (2), according to the Ni / CeO 2 The Ni loading in the catalyst is 5 wt%. Add nickel nitrate solution to the round-bottom flask in step (1). The others are the same as in Example 2, denoted as 5Ni / CeO 2 .

[0068] Example 4

[0069] The difference from Example 2 is that in step (2), according to the Ni / CeO 2 The Ni loading in the catalyst is 7 wt%. Add nickel nitrate solution to the round-bottom flask in step (1). The others are the same as in Example 2, denoted as 7Ni / CeO 2 .

[0070] Figure 4 SEM image (10 μm) of the Ni / CeO 2 catalyst prepared in Example 4. From Figure 4 it can be seen that after nickel doping of the CeO 2 support, the morphology has not changed significantly.

[0071] Figure 5 SEM image of the Ni / CeO 2SEM image of the catalyst (4μm). From Figure 5 it can be seen that nickel atoms are evenly dispersed on the CeO 2 support without agglomeration.

[0072] Example 5

[0073] The difference from Example 2 is that in step (2), nickel nitrate solution was added to the round-bottom flask in step (1) according to the Ni loading of 9 wt% in the Ni / CeO 2 catalyst, and the others were the same as Example 2, denoted as 9Ni / CeO 2 .

[0074] Using the CeO 2 support prepared in Example 1 and the Ni / CeO 2 catalysts prepared in Examples 2-5 as catalysts, a PLS-SXE300 xenon lamp light source was used as the light source for the reaction experiment, with a light intensity of 44.60 mW / cm 2 . An ultraviolet carbon dioxide hydrogenation activity experiment was carried out in a fixed-bed reactor using a quartz photoreactor. 0.5 g of the catalyst was pressed into tablets using a tablet press, and 40-60 mesh samples were screened. The catalyst dosage was 100 mg, and the catalyst was evenly spread in the quartz cell. For easy illumination, the middle area was designed as a cuboid structure of 10×10×1.5 mm as the reaction section for filling the catalyst, and both ends were blocked with quartz wool to prevent the sample from falling. The light was focused into a spot with a diameter of about 2 cm through a Fresnel lens, and a quartz glass reactor was placed at the spot. The reaction gas was a mixture of CO 2 / H 2 / N 2 = 10% / 40% / 50% (volume ratio), and the reaction flow rate was 20 mL / min. During the reaction, the reaction products were collected every 8 min for 1.5 h continuously, and the concentration values of CO 2 , CO and CH 4 were detected online by gas chromatography (GC, Shanghai Fan-Wei GC-6600), and were equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD).

[0075] Figure 6 For the CeO 2 support prepared in Example 1 and the Ni / CeO 2 catalysts prepared in Examples 2-5, the carbon dioxide conversion rate. From Figure 6 it can be seen that when the addition amount of nickel nitrate solution is CeO 2When the amount of the carrier is 7% of the mass, the conversion rate of the obtained catalyst for the conversion of carbon dioxide to methane is the highest. Therefore, during the preparation of the catalyst, the addition amount of the nickel nitrate solution is preferably 7%, and the addition amount of the nickel nitrate solution in the subsequent experiments is 7%.

[0076] Example 6

[0077] A RuNi / CeO 2 Preparation method of a single-atom alloy catalyst, the specific steps are as follows:

[0078] (1) Take 0.5 g of the CeO 2 carrier prepared in Example 1, add it to a round-bottom flask containing 50 mL of ethylene glycol, and under the conditions of 25 °C, 35 KHz, and 540 W, ultrasonically vibrate for 0.2 h to make the CeO 2 uniformly dispersed in ethylene glycol;

[0079] (2) According to the Ni loading amount of 7 wt% in the RuNi / CeO 2 single-atom alloy catalyst, add the nickel nitrate solution to the round-bottom flask in step (1), and then according to the Ru loading amount of 0.05 wt% in the RuNi / CeO 2 single-atom alloy catalyst, add the ruthenium acetylacetonate solution. Place the round-bottom flask in an oil bath at 190 °C and continuously stir and react for 5 h. After the reaction is completed, cool to room temperature, filter by suction and centrifuge to obtain a precipitate;

[0080] (3) Filter and wash the precipitate obtained in step (2) successively with deionized water and absolute ethanol, and then dry it at 80 °C for 12 h to obtain a dried precipitate;

[0081] (4) Place the dried precipitate obtained in step (3) in a tubular furnace, heat it up at 2 °C / min, and while heating, introduce H 2 , H 2 is introduced in the form of a hydrogen-argon mixed gas, and the volume ratio of H 2 in the hydrogen-argon mixed gas is 10%, and the flow rate of H 2 is 50 mL / min. After heating to 400 °C, calcine and reduce for 3 h, and then cool to room temperature at 2 °C / min, and then stop introducing H 2 to obtain the RuNi / CeO 2 single-atom alloy catalyst, denoted as 0.05% Ru7% Ni / CeO 2 .

[0082] Figure 7 is the Hrtem image of the RuNi / CeO 2 single-atom alloy catalyst prepared in Example 6. It can be seen from Figure 7 that Example 6 successfully prepared RuNi / CeO 2Single-atom alloy catalyst, containing nickel and ruthenium.

[0083] Example 7

[0084] It is different from Example 6 in that in step (2), ruthenium acetylacetonate solution is added according to the Ru loading of 0.1 wt% in the single-atom alloy catalyst, and the others are the same as Example 6, denoted as 0.1%Ru7%Ni / CeO 2 . 2 .

[0085] Measure the photothermal catalytic activity of the CeO 2 support prepared in Example 1 and the catalysts prepared in Examples 4 and 6-7 (the measurement method is the same as above), and the results are shown in Figure 8 and Table 1.

[0086] Figure 8 is the CeO 2 support prepared in Example 1 and the carbon dioxide conversion rate diagrams of the catalysts prepared in Examples 4 and 6-7.

[0087] Table 1 Photothermal catalytic activities of different catalysts

[0088]

[0089] From Figure 8 and Table 1, it can be seen that when the addition amount of ruthenium acetylacetonate solution is 0.05%, the conversion rate of the obtained catalyst for converting carbon dioxide into methane is the highest.

[0090] In summary, in the preparation process of the RuNi / CeO 2 single-atom alloy catalyst, the addition amount of nickel nitrate solution is 7% and the addition amount of ruthenium acetylacetonate solution is 0.05% is the best, and the carbon dioxide conversion rate is the highest.

[0091] Comparative Example 1

[0092] (1) Weigh 8.69 g (20 mmol) of cerium nitrate and dissolve it in 100 mL of water to obtain solution A;

[0093] (2) Weigh 3.80 g (48 mmol) of ammonium bicarbonate and dissolve it in 100 mL of water to obtain solution B;

[0094] (3) Quickly pour solution B into solution A, stir at room temperature for 12 h, filter by suction and centrifuge to obtain filtrate and precipitate. Wash the obtained precipitate with deionized water and absolute ethanol for several times, and then dry it in an oven at 80 °C for 12 h to obtain a pale yellow powder;

[0095] (4) Place the pale yellow powder obtained in step (3) in a porcelain boat, put the porcelain boat into a muffle furnace, heat it to 450 °C at a rate of 2 °C / min, and calcine for 5 h to obtain CeO 2 support.

[0096] (5) Take 0.5 g of the CeO 2 support obtained in step (4), add it to a round-bottom flask containing 50 mL of ethylene glycol, and under the conditions of 25 °C, 35 KHz, and 540 W, ultrasonically vibrate for 0.2 h to make CeO 2 uniformly dispersed in ethylene glycol;

[0097] (6) According to the Ni loading amount of 7 wt% in the RuNi / CeO 2 catalyst, add nickel nitrate solution to the round-bottom flask in step (1), and then according to the Ru loading amount of 0.05 wt% in the RuNi / CeO 2 catalyst, add ruthenium acetylacetonate solution. Place the round-bottom flask in an oil bath at 190 °C and continuously stir and react for 5 h. After the reaction is completed, cool to room temperature, filter by suction, and centrifuge to obtain a precipitate;

[0098] (7) Wash the precipitate obtained in step (6) successively by suction with deionized water and absolute ethanol, and then dry it at 80 °C for 12 h to obtain a dried precipitate;

[0099] (8) Place the dried precipitate obtained in step (7) in a tubular furnace, heat it at a rate of 2 °C / min, and while heating, introduce H 2 , H 2 is introduced in the form of a hydrogen-argon mixed gas, and the volume ratio of H 2 in the hydrogen-argon mixed gas is 10%, and the flow rate of H 2 is 50 mL / min. After heating to 400 °C, calcine and reduce for 3 h, and then cool to room temperature at a rate of 2 °C / min, and stop introducing H 2 to obtain the RuNi / CeO 2 catalyst.

[0100] Measure the photothermal catalytic activity of the catalysts prepared in Example 4 and Comparative Example 1 (the measurement method is the same as above), and the results are shown in Table 2.

[0101] Table 2 Photothermal catalytic activities of different catalysts

[0102]

[0103]

[0104] As can be seen from Table 2, for the catalyst prepared in Example 4, the carbon dioxide conversion rate is 61%, and the methane production rate is 20.44 mmol / g / h; while for the catalyst prepared in Comparative Example 1, the carbon dioxide conversion rate is only 40.39%, and the methane production rate is 11.36 mmol / g / h. Thus, it can be seen that the CeO 2 support prepared by the method of the present invention has a promoting effect on carbon dioxide methanation compared to the support prepared by the method of Comparative Example 1.

[0105] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for preparing a RuM / CeO2 single-atom alloy catalyst, characterized in that: The following steps are involved: (1) mixing a soluble cerium salt, water, ethanol and a precipitant, stirring, filtering, washing and calcining to obtain a CeO2 carrier; (2) The CeO2 carrier is dispersed in ethylene glycol, and then a Ru-containing solution and a M-containing solution are added, and the RuM / CeO2 single-atom alloy catalyst is obtained through stirring reaction and calcination reduction; M in the M-containing solution is a transition metal element.

2. The method for preparing the RuM / CeO2 single-atom alloy catalyst according to claim 1, characterized in that: In step (1), the mixing of the soluble cerium salt, water, ethanol and the precipitant is specifically as follows: dissolving the soluble cerium salt in ethanol to obtain a solution A; dissolving the precipitant in water to obtain a solution B; and pouring the solution B into the solution A.

3. The method for preparing the RuM / CeO2 single-atom alloy catalyst according to claim 1, characterized in that: In step (2), the usage ratio of the CeO2 carrier and ethylene glycol is (0.2-2) g: (20-100) mL.

4. The method for preparing the RuM / CeO2 single-atom alloy catalyst according to claim 1, characterized in that: In step (2), the Ru-containing solution is one or more of a ruthenium chloride solution, a ruthenium acetate solution and a ruthenium acetylacetonate solution.

5. The method for preparing the RuM / CeO2 single-atom alloy catalyst according to claim 1, characterized in that: In step (2), M in the M-containing solution is Co or Ni.

6. The method for preparing the RuM / CeO2 single-atom alloy catalyst according to claim 1, characterized in that: In step (2), the loading amount of Ru in the RuM / CeO2 single atom alloy catalyst is 0.03-0.2 wt%, and the loading amount of M is 1-10 wt%.

7. The method for preparing the RuM / CeO2 single-atom alloy catalyst according to claim 1, characterized in that: In step (2), the stirring reaction temperature is 120-200° C., and the stirring reaction time is 4-6 hours.

8. The method for preparing the RuM / CeO2 single-atom alloy catalyst according to claim 1, characterized in that: In step (2), the calcination reduction is specifically as follows: heating at 1-10°C / min, introducing H2 while heating, heating to 300-600°C and calcining and reducing for 2-5h, then cooling to room temperature at 1-10°C / min, and stopping introducing H2; the flow rate of H2 is 20-60mL / min.

9. A RuM / CeO2 single atom alloy catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the RuM / CeO2 single-atom alloy catalyst according to claim 9 in photothermal carbon dioxide methanation.

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