A cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO x , preparation method and application

Abstract

The application discloses a preparation method and application of a cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO x and belongs to the technical field of electrocatalytic materials. The method comprises the following steps: selecting graphene oxide GO; calcining the graphene oxide GO at a preset temperature for a preset time to obtain defective reduced graphene oxide rGO; dispersing the prepared rGO in deionized water at a set concentration, adding a cobalt precursor and a ruthenium precursor, stirring for a set time period, stirring at a set rotating speed, then carrying out a hydrothermal reaction at 100 DEG C or below for a preset time, and obtaining the product after the hydrothermal reaction through centrifugation, washing and vacuum drying to obtain the cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO x . The electrocatalyst rGO-CoRuO x prepared by the method has defective rGO loaded with amorphous CoRuO x ultra-small clusters, realizes function division and strong electronic cooperation of bimetallic sites, and significantly improves the activity, selectivity and stability of the electrocatalyst in the co-reduction of CO2 and NO3 ‑ to prepare urea.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic materials technology, specifically, it relates to a cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO x Preparation methods and applications. Background Technology

[0002] Urea is not only the solid nitrogen fertilizer with the highest nitrogen content, but also an important basic raw material in the pharmaceutical and chemical industries. Currently, industrial urea synthesis mainly adopts the Bosch-Meiser process, which requires first synthesizing ammonia under high temperature and pressure conditions via the Haber-Bosch method, and then reacting the ammonia with carbon dioxide under harsh conditions to produce urea. However, the above-mentioned traditional route is extremely energy-intensive. According to statistics, the energy consumption for ammonia synthesis accounts for more than 2% of the global total energy consumption each year, while also accompanied by a large amount of greenhouse gas emissions. Therefore, developing a new, mild, low-energy-consumption, and environmentally friendly urea synthesis route is of great strategic significance.

[0003] In recent years, the electrocatalytic co-reduction of CO2 with nitrogen-containing species to directly achieve C–N coupling has attracted widespread attention. This route avoids the independent ammonia synthesis step in traditional processes, offers mild reaction conditions, and can be coupled with renewable electricity, making it considered the most promising alternative to urea synthesis. Among these methods, nitrate NO3... - Due to its wide availability and high reactivity, it has become an ideal nitrogen source. However, electrocatalysis of CO2 and NO3... - Co-reduction reactions involve multi-electron and multi-proton transfer processes, accompanied by various competing reactions such as CO2 reduction, nitrate reduction, and hydrogen evolution reaction. They generally suffer from prominent problems such as low urea selectivity, low yield, and poor catalyst stability.

[0004] To address the aforementioned issues, researchers have developed various catalyst systems, including single-metal catalysts, bimetallic alloys, and metal compound / carbon composites. However, existing catalysts generally suffer from drawbacks such as unclear functions of bimetallic active sites, weak electronic synergy, easy aggregation of active components, and the support only serving as a conductive support, making it difficult to effectively promote the efficient construction of C–N bonds. Therefore, developing highly efficient electrocatalysts with atomic-level functional partitioning, strong electronic interactions, and ultra-small amorphous cluster structures has become a key scientific and technological problem urgently needing to be solved in this field. Summary of the Invention

[0005] To address the shortcomings and improvement needs of existing technologies, this invention provides a cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO x The invention relates to a preparation method for a cobalt-ruthenium bimetallic oxide electrocatalyst, rGO-CoRuO. x Amorphous CoRuO with defective rGO-loaded xThe ultra-small cluster feature enables functional specialization and strong electronic synergy at bimetallic sites, which can be used to significantly enhance CO2 and NO3 production. - Activity, selectivity and stability of co-reduction urea production.

[0006] To achieve the above objectives, according to one aspect of the present invention, a cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO is provided. x The preparation method includes: S1: Select graphene oxide (GO); S2: Calcine graphene oxide (GO) at a preset temperature for a preset time to obtain defect-type reduced graphene oxide (rGO); S3: The prepared rGO was dispersed in deionized water at a set concentration, and cobalt and ruthenium precursors were added. The mixture was stirred for a set time period and at a set speed. Subsequently, a hydrothermal reaction was carried out at below 100°C for a pre-set time. After the hydrothermal reaction, the product was centrifuged, washed, and vacuum dried to obtain the cobalt-ruthenium bimetallic oxide rGO-CoRuO. x Electrocatalyst.

[0007] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects: This invention introduces defective reduced graphene oxide (rGO) as a support. Its abundant surface defects and high conductivity can significantly improve the dispersion of active components, enhance electron transport capabilities, and provide efficient adsorption sites for the reaction. At the same time, rGO can inhibit the aggregation of active components and improve the overall structural stability of the catalyst.

[0008] This invention utilizes a one-step hydrothermal method to in-situ construct 1-3 nm amorphous CoRuO on the surface of rGO. x The ultra-small clusters have a high density of active sites and no obvious aggregation; the Co, Ru, O and C elements are evenly distributed, realizing strong interaction and efficient interface coupling between the bimetal and the carbon support.

[0009] This invention achieves optimal synergistic catalysis by adjusting the atomic ratio of Co to Ru, with the best catalytic performance observed when Co:Ru = 1:1. At 0.4V (vs. RHE), the urea Faradaic efficiency reached 87.39%, with a yield of 3297.1 μmolh. 1 g 1 It is significantly superior to single-metal catalysts, bimetallic catalysts of different proportions and pure rGO, exhibiting excellent activity and selectivity.

[0010] rGO-CoRuO was prepared by this invention. xIts electrons shift from Co to Ru, and there is a strong interaction between Ru and O, resulting in a clear electron transfer path. This electron transfer path can optimize the electronic structure of active sites and the adsorption energy of intermediates, thereby enhancing CN coupling kinetics. At the same time, the catalyst has a stable structure and its performance does not significantly decline after continuous electrolysis, demonstrating excellent potential for industrial applications. Attached Figure Description

[0011] Figure 1 The image shows a cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO provided according to an embodiment of the present invention. x Flowchart of the preparation method.

[0012] Figure 2 The figures shown are rGO and rGO-CoO involved in the embodiments and comparative examples provided according to the present invention. x rGO-RuO x and rGO-CoRuO x SEM image.

[0013] Figure 3 The image shown is an rGO-CoRuO provided according to an embodiment of the present invention. x STEM images, particle size distribution, XRD patterns, and EDS elemental distribution maps.

[0014] Figure 4 The figures shown are rGO and rGO-CoO involved in the embodiments and comparative examples provided according to the present invention. x rGO-RuO x and rGO-CoRuO x The XRD spectrum.

[0015] Figure 5 The figures shown are rGO-RuO provided and compared according to embodiments of the present invention. x With rGO-CoRuO x XPS (Ru 3p) spectrum.

[0016] Figure 6 The figures shown are rGO-CoO provided in the embodiments of the present invention and in comparative examples. x With rGO-CoRuO x XPS (Co 2p) spectrum.

[0017] Figure 7 The figure shown is a comparison of urea yield and Faraday efficiency at -0.4V for different catalysts provided according to embodiments of the present invention.

[0018] Figure 8 The figure shown illustrates rGO-CoRuO under different rotational speed conditions according to an example of the present invention. x SEM image, Figure 8 Figure a shows the rGO-CoRuO at 200 r / min. x The SEM images are shown in Figure b, which is the rGO-CoRuO2 image at 800 r / min. x SEM image. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0020] In this invention, the terms "first," "second," etc. (if present) in the invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0021] Example 1: This invention discloses a cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO x Preparation methods, such as Figure 1 As shown, it includes: S1: Select graphene oxide (GO). Specifically, graphene oxide (GO) can be used to prepare graphene oxide (rGO), or it can be prepared by itself, including but not limited to preparation using the modified Hummers method. S2: Calcine graphene oxide (GO) at a preset temperature for a preset time to obtain defect-type reduced graphene oxide (rGO), wherein the preset temperature and preset calcination time include, but are not limited to: calcination at 700-900℃ for 0.5-2h; S3: The prepared rGO was dispersed in deionized water at a set concentration, and cobalt and ruthenium precursors were added. The mixture was stirred for a set time period and at a set speed. Subsequently, a hydrothermal reaction was carried out at below 100°C for a pre-set time. After the hydrothermal reaction, the product was centrifuged, washed, and vacuum dried to obtain the cobalt-ruthenium bimetallic oxide rGO-CoRuO. x Electrocatalyst. Specifically, in one optional embodiment, the concentration in S3 is set to 2-5 mg / mL; cobalt precursor and ruthenium precursor are added in S3, the stirring time is set to 30-60 min, and the stirring speed is set to 200-800 r / min; the cobalt precursor in S3 includes cobalt chloride hexahydrate, cobalt nitrate, and cobalt chloride, and the ruthenium precursor includes ruthenium trichloride; the atomic ratio of the cobalt precursor to the ruthenium precursor in S3 is 1:0.5-1:2; the hydrothermal reaction time in S3 at 100°C is set to 24-36 h; the vacuum drying in S3 includes drying in a vacuum drying oven at 30°C-100°C for 6-12 h.

[0022] To better understand the preparation process using the preparation method provided in Example 1 of this invention, some specific preparation examples will be used to illustrate the process below.

[0023] Experiment 1: In one optional embodiment, the preparation of graphene oxide (GO) includes: mixing 1.0 g of natural graphite powder with 23 mL of concentrated sulfuric acid (98 wt%) under ice-water bath and vigorous stirring conditions, controlling the temperature below 5°C, slowly adding 3.0 g of potassium permanganate, heating to 35°C and stirring for 2 hours, slowly adding 46 mL of deionized water, heating to 98°C and maintaining for 30 minutes. After the reaction is complete, adding 140 mL of deionized water for dilution, and adding 10 mL of hydrogen peroxide (30 wt%) dropwise to terminate the reaction, the mixture turns bright yellow; centrifuging and washing (e.g., 8000 rpm, 15 minutes) until the pH of the supernatant is close to neutral, filtering and drying to obtain graphene oxide (GO). The above preparation process is a conventional preparation method, and existing graphene oxide (GO) can also be used. Further, the preparation of reduced graphene oxide (rGO) includes: mixing at 5°C for 1 minute under a high-purity argon atmosphere. - ¹The obtained GO was pyrolyzed at 900°C for 2 hours to obtain reduced graphene oxide (rGO). Finally, the cobalt-ruthenium bimetallic sites were anchored, including: taking 50 mg of the rGO obtained in step 2, dispersing it in 50 mL of deionized water, and in one embodiment, adding 2.5 mg of RuCl3 and 1 mg of CoCl2·6H2O. At this point, the corresponding cobalt-ruthenium atomic ratio is approximately 1:1. Subsequent ratios are approximate and do not represent precise values. The mixture was stirred thoroughly and transferred to a polytetrafluoroethylene-lined high-pressure reactor. The reactor was hydrothermally reacted at 100°C for 24 hours. After the reaction, the product was collected by centrifugation, washed three times with deionized water, and dried in a vacuum drying oven at 60°C for 12 hours to obtain a fluffy black rGO-CoRuO. x Catalyst. The above is merely a specific preparation process based on the preparation method provided in Example 1 of this invention, and is not a limitation of this invention.

[0024] Experiment 2: In another embodiment, after preparing graphene oxide (GO) and reduced graphene oxide (rGO) according to the above method, 50 mg of rGO is dispersed in 50 mL of deionized water, and 1.67 mg of RuCl3 and 1 mg of CoCl2 are added. 6H₂O, at which point the cobalt-ruthenium atomic ratio is approximately 2:1. In one embodiment, the mixture is stirred for 30 minutes (300 rpm) until homogeneous, then transferred to a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 100°C for 24 hours. After the reaction, the mixture is centrifuged, washed three times, and vacuum dried at 60°C for 12 hours to obtain rGO-CoRuO. x catalyst.

[0025] Experiment 3: In another embodiment, the anchoring of the cobalt-ruthenium bimetallic site includes: dispersing 50 mg rGO in 50 mL of deionized water, and adding 2.5 mg RuCl3 and 0.5 mg CoCl2. 6H₂O was added, at which point the atomic ratio of cobalt to ruthenium was approximately 1:2. The mixture was stirred for 30 minutes (300 rpm) until homogeneous, then transferred to a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 100°C for 24 hours. After the reaction, the mixture was centrifuged, washed three times, and vacuum dried at 60°C for 12 hours to obtain rGO-CoRuO₂. x catalyst.

[0026] Experiment 4: In another embodiment, the anchoring of the cobalt-ruthenium bimetallic site includes: dispersing 50 mg rGO in 50 mL of deionized water, and adding 2.5 mg RuCl3 and 1 mg CoCl2. Add 6H₂O (atomic ratio 1:1), stir for 20 min (500 r / min), and after thorough mixing, transfer to a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally react at 100 °C for 24 h. After the reaction, centrifuge, wash three times, and vacuum dry at 60 °C for 12 h to obtain rGO-CoRuO. x catalyst.

[0027] Experiment 5: In one embodiment, the anchoring of the cobalt-ruthenium bimetallic site includes: dispersing 50 mg rGO in 50 mL of deionized water, and adding 2.5 mg RuCl3 and 1 mg CoCl2. 6H2O (atomic ratio 1:1) was stirred for 30 min (300 r / min) until homogeneous. The mixture was then transferred to a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 100℃ for 24 h. After the reaction, the mixture was centrifuged, washed three times, and vacuum dried at 50℃ for 12 h to obtain rGO-CoRuO. x catalyst.

[0028] The above describes the specific preparation of the catalyst rGO-CoRuO. x Those skilled in the art should understand that the above are merely specific implementation methods and are not limitations of the present invention.

[0029] Example 2: This invention discloses a cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO prepared based on the preparation method of Example 1. x The specific preparation process is described in Example 1, and will not be repeated here to avoid redundancy.

[0030] Example 3: This invention discloses a method for co-reduction synthesis of urea, using the cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO in Example 2. x Electrocatalysis of CO2 and NO3 - Urea was synthesized through co-reduction.

[0031] To better illustrate the electrocatalyst rGO-CoRuO prepared in this invention... x The effects will be verified by comparison below, specifically the catalyst rGO-CoRuO2 involved in the comparison with the substances in the comparative example. x All samples used were rGO-CoRuO obtained in Experiment 1. x。

[0032] Comparative Example 1: Pure rGO catalyst The same process as in Experiment 1 of Example 1 was used to prepare the pure rGO catalyst, except that no cobalt or ruthenium precursor was added. The rGO was directly subjected to hydrothermal treatment, washing, and drying to obtain the pure rGO catalyst.

[0033] Electrochemical testing revealed that the urea Faradaic efficiency of pure rGO catalyst was only 3.39%, exhibiting almost no catalytic activity for CN-coupling urea synthesis and poor cycle stability. This is because pure rGO lacks bimetallic active sites, making it unable to synergistically complete CO2 activation and NO3- oxidation. - Co-reduced urea synthesis.

[0034] Comparative Example 2: Single Metal rGO-CoO x catalyst The same process as in Example 1 was used for preparation, except that only a cobalt precursor was added. Specifically, rGO was prepared according to Experiment 1 in Example 1, except that 1 mg of CoCl2·6H2O was added. The process included: taking 50 mg of rGO obtained in step 1, dispersing it in 50 mL of deionized water, adding 1 mg of CoCl2·6H2O, stirring evenly, and then transferring it to a polytetrafluoroethylene-lined high-pressure reactor. The reactor was hydrothermally reacted at 100°C for 24 hours. After the reaction, the product was collected by centrifugation, washed three times with deionized water, and dried in a vacuum drying oven at 60°C for 12 hours to obtain monometallic rGO-CoO. x catalyst..

[0035] Electrochemical testing showed that the catalyst had a urea Faradaic efficiency of 30.01% and a urea yield of only 562.6 μmol / h. 1 g 1 The catalytic performance was significantly lower than that of Example 1. This is because the system lacks Ru active sites, making it unable to efficiently activate NO3. - It also completes the deep reduction of nitrogen intermediates, but the CN coupling efficiency is low.

[0036] Comparative Example 3: Single Metal rGO-RuO x catalyst The same process as in Example 1 was used for preparation, except that only a ruthenium precursor was added. Specifically, rGO was prepared according to Experiment 1 in Example 1, except that 2.5 mg of RuCl3 was added. The process included: taking 50 mg of the rGO obtained in step 1, dispersing it in 50 mL of deionized water, adding 2.5 mg of RuCl3, stirring evenly, and then transferring it to a polytetrafluoroethylene-lined high-pressure reactor. The reactor was hydrothermally reacted at 100°C for 24 hours. After the reaction, the product was collected by centrifugation, washed three times with deionized water, and dried in a vacuum drying oven at 60°C for 12 hours to obtain the single-metal rGO-RuO. x Catalyst, without adding cobalt precursor, yields single-metal rGO-RuO x catalyst.

[0037] Electrochemical testing showed that the catalyst had a urea Faradaic efficiency of 44.34% and a urea yield of only 926.4 μmol / h. 1 g 1 The catalytic performance was significantly lower than that of rGO-CoRuO obtained in Experiment 1 of Example 1. x The reason is that the system lacks Co active sites, which cannot effectively activate CO2 and promote CN bond formation, resulting in poor selectivity for the target product.

[0038] Specifically, all electrochemical tests were performed in an H-type electrolytic cell using a three-electrode system: carbon paper coated with catalyst (1 cm in diameter, 0.2 mg / cm² loading). - ²) is the working electrode, the saturated calomel electrode is the reference electrode, and the platinum sheet is the counter electrode. The electrolyte is a mixed solution of 0.1M KHCO3 and 0.04M KNO3, and CO2 is continuously introduced at a flow rate of 24.5 sccm. All potentials have been converted to the reversible hydrogen electrode (RHE).

[0039] Finally, rGO-CoRuO x Catalyst in Eight consecutive potentiostatic electrolysis tests (1 hour each) were conducted at 0.4V (vs. RHE). The urea Faradaic efficiency and yield of the catalyst showed no significant decline, indicating that the catalyst has a stable structure and its active sites are not easily lost. The cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO prepared in this invention... x It possesses excellent cycle stability.

[0040] Furthermore, by Figure 2 It can be seen that pure rGO exhibits a typical wrinkled, lamellar morphology; single-metal rGO-CoO x rGO-RuO x The surface particles are unevenly distributed and show obvious agglomeration; while the rGO-CoRuO prepared in Example 1 x Maintaining the complete layered structure, specifically the rGO-CoRuO prepared according to Experiment 1. x The surface is loaded with a large number of uniformly dispersed nanoclusters.

[0041] Figure 3 rGO-CoRuO prepared in Example 1 x STEM images, particle size distribution maps, XRD patterns, and EDS elemental distribution maps of the catalyst, specifically the rGO-CoRuO prepared according to Experiment 1. x ,Depend on Figure 3 It can be seen that CoRuO x Ultra-small amorphous clusters of 1-3 nm are uniformly anchored on the rGO surface, with an average particle size of approximately 1.79 nm. EDS elemental distribution maps show uniform distribution of C, Co, Ru, and O elements without elemental segregation. The rGO support provides a highly dispersed loading interface for the bimetallic component, exhibiting high active site density. Figure 3 Figure (a) shows rGO-CoRuO x Transmission electron microscope (TEM) images; Figure 3 Figure (b) shows CoRuO x Statistical analysis of the particle size distribution of nanoparticles; Figure 3 Figure (c) shows rGO and rGO-CoRuO x X-ray diffraction (XRD) pattern; Figure 3 The middle (d) figure is rGO-CoRuO x Energy dispersive X-ray spectroscopy (EDS) elemental distribution diagrams of C, Ru, Co, and O elements.

[0042] Figure 4 for rGO, rGO-CoO x rGO-RuO x and rGO-CoRuO x XRD comparison images, by Figure 4 It can be seen that, compared with pure rGO and single-metal rGO-CoOx and rGO-RuO x In contrast, Example 1 specifically refers to the rGO-CoRuO prepared according to Experiment 1. x The catalyst showed no obvious diffraction peaks of crystalline metal oxides, only the characteristic broad peaks of rGO at 25.9° and 44.1°, proving that CoRuO x It exists in an amorphous state and does not exhibit obvious crystalline phase formation.

[0043] Figure 5 rGO-RuO x With rGO-CoRuO x Ru3 p XPS spectra, by Figure 5 It can be seen that, with the single metal rGO-RuO x In comparison, rGO-CoRuO x Ru3 p The positive shift of the characteristic peak indicates that the Ru site is in an electronic defect state, which is conducive to the adsorption, activation and deep reduction of the intermediate.

[0044] Figure 6 rGO-CoO x With rGO-CoRuO x Co2 p XPS spectrum, rGO-CoRuO x The positive shift of the Co2p characteristic peak indicates that electrons are shifted from Co to Ru, and there is a strong interaction between Ru and O, which optimizes the kinetics of CO2 activation and CN bond construction.

[0045] Figure 7 This is a comparison chart of urea yield and Faradaic efficiency at -0.4V (vs. RHE) for the catalysts of Example 1 and the comparative example. Figure 7 It can be seen that the rGO-CoRuO prepared in Experiments 1, 3 and 2 of Example 1... x The catalyst performance is significantly better than that of pure rGO and rGO-CoO. x rGO-RuO x and physically mixed samples, especially rGO-CoRuO prepared at a cobalt-ruthenium atomic ratio of 1:1. x The urea faradaic efficiency reached 87.39%, and the yield reached 3297.1 μmol / h. 1 g 1 This is due to the functional division of the bimetallic sites, rapid electron and ion transport, and stable amorphous interface structure. At the same time, the defective rGO support effectively improves conductivity and dispersion of active components, further enhancing catalytic performance.

[0046] Figure 8The figure shown illustrates rGO-CoRuO under different rotational speed conditions according to an example of the present invention. x SEM image. Among them... Figure 8 Figure a shows the rGO-CoRuO at 200 r / min. x SEM images, b is the rGO-CoRuO at 800 r / min x The SEM images show that rGO-CoRuO2 can be generated according to the given conditions. x .

[0047] In summary, the modification method of this invention is convenient to operate and easy to scale up for production. The prepared supported cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO x It possesses the following significant advantages: excellent catalytic performance, simple and controllable preparation process, and relatively low raw material cost. This invention provides an electrocatalyst with high activity, high selectivity, and high stability, offering a practical technical route for the electrochemical CN-coupled urea synthesis, and has good prospects for industrial application.

[0048] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO x The preparation method of [the substance] is characterized by, include: S1: Select graphene oxide (GO); S2: Calcine graphene oxide (GO) at a preset temperature for a preset time to obtain defect-type reduced graphene oxide (rGO); S3: The prepared rGO was dispersed in deionized water at a set concentration, and cobalt and ruthenium precursors were added. The mixture was stirred for a set time period and at a set speed. Subsequently, a hydrothermal reaction was carried out at below 100°C for a pre-set time. After the hydrothermal reaction, the product was centrifuged, washed, and vacuum dried to obtain the cobalt-ruthenium bimetallic oxide rGO-CoRuO. x Electrocatalyst.

2. The cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO according to claim 1 x The preparation method of [the substance] is characterized by, The preset temperature and preset time for calcination in S2 include: calcination at 700-900℃ for 0.5-2 hours.

3. The cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO according to claim 1 x The preparation method of [the substance] is characterized by, The concentrations set in S3 include 2-5 mg / mL.

4. The cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO according to claim 1 x The preparation method of [the substance] is characterized by, Add cobalt precursor and ruthenium precursor to S3. The stirring time is set to 30~60min, and the stirring speed is set to 200~800r / min.

5. The cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO according to claim 4 x The preparation method of [the substance] is characterized by, The cobalt precursors in S3 include cobalt chloride hexahydrate, cobalt nitrate, or cobalt chloride, and the ruthenium precursors include ruthenium trichloride.

6. The cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO according to claim 5 x The preparation method of [the substance] is characterized by, In S3, the atomic ratio of cobalt atoms to ruthenium atoms in the cobalt precursor and ruthenium precursor is 1:0.5 to 1:

2.

7. The cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO according to claim 1 x The preparation method of [the substance] is characterized by, In S3, the hydrothermal reaction time at 100℃ is set to 24-36 hours.

8. The cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO according to claim 1 x The preparation method of [the substance] is characterized by, Vacuum drying in S3 includes drying at 30℃-100℃ for 6-12 hours in a vacuum drying oven.

9. A cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO x Its characteristics are, The cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO as described in any of claims 1-8 is used. x It was prepared by the method described above.

10. A method for co-reduction synthesis of urea, characterized in that, The cobalt-ruthenium bimetallic oxide electrocatalyst rGO-CoRuO as described in claim 9 is used. x Electrocatalysis of CO2 and NO3 - Urea was synthesized through co-reduction.

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