Catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalytic oxidation carbonylation, in particular to a catalyst and a preparation method and application thereof. The invention provides a catalyst. The catalyst comprises nitrogen doped carbon and CoCu bimetallic nanoparticles dispersed in the nitrogen doped carbon. The catalyst has high activity, high selectivity and long service life.

Description

Technical Field

[0001] This invention relates to the field of catalytic oxidative carbonylation technology, and more particularly to a catalyst, its preparation method, and its application. Background Technology

[0002] Dimethyl carbonate (DMC) is an important green chemical. Its molecular structure contains multiple functional groups, including carbonyl, methyl, and methoxy groups, making it suitable as an environmentally friendly carbonylating, methylating, and methoxylating agent. It is widely used in polycarbonate synthesis, lithium battery electrolytes, and fuel additives. With increasing environmental requirements and the development of green chemistry, developing efficient and environmentally friendly DMC synthesis processes has become a research hotspot. Existing DMC synthesis technologies mainly fall into the following categories: Phosgene method: The traditional phosgene method has been gradually phased out due to the use of highly toxic phosgene and severe equipment corrosion; Transesterification method: This method relies on petrochemical raw materials such as ethylene oxide or ethylene carbonate, resulting in high production costs and limited market competitiveness; Oxidative carbonylation method: Using methanol, CO, and O2 as raw materials, this method boasts high atom economy, with water as the only byproduct, making it the most promising green synthesis route. This method can be divided into liquid-phase and gas-phase methods. The liquid-phase method, represented by the CuCl catalyst system from Eni (Italy), achieves a DMC space-time yield of 0.28–0.6 kg / kgcat·h and a methanol selectivity exceeding 95% at 1.5–4.0 MPa and 120–140 °C. However, Cl… - It causes severe corrosion to equipment, and the catalyst is prone to deactivation and difficult to separate. Gas phase method: Pd-based catalysts and methyl nitrite recycling process, represented by Ube Industries, Ltd. of Japan, avoid equipment corrosion, but Pd catalysts are expensive and involve toxic intermediates.

[0003] Therefore, the core problem of existing oxidative carbonylation processes lies in the catalyst. Cu-based catalysts suffer from corrosion and deactivation, while Pd-based catalysts are expensive and lack stability. Thus, highly active, highly selective, and long-life non-precious metal catalysts are crucial for achieving green industrial production of DMC. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a catalyst, its preparation method and application, wherein the catalyst has high activity, high selectivity and long life.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: The present invention provides a catalyst comprising nitrogen-doped carbon and CoCu bimetallic nanoparticles dispersed in the nitrogen-doped carbon.

[0006] Preferably, the molar ratio of Cu to Co in the CoCu bimetallic nanoparticles is (0.01~2):1.

[0007] Preferably, the CoCu bimetallic nanoparticles have a particle size of 10~50 nm.

[0008] Preferably, the nitrogen doping amount in the nitrogen-doped carbon is 0.1~5 wt%; The nitrogen in the nitrogen-doped carbon exists in the forms of pyridine nitrogen, pyrrole nitrogen, and graphitic nitrogen; The carbon in the nitrogen-doped carbon is graphitic carbon.

[0009] Preferably, the mass ratio of the CoCu bimetallic nanoparticles to nitrogen-doped carbon is 1:(4~10).

[0010] The present invention also provides a method for preparing the catalyst described in the above technical solution, comprising the following steps: Soluble cobalt salt, soluble copper salt, nitrogen-containing organic ligand and organic solvent are mixed and subjected to a solvothermal reaction to obtain CoCu-MOF precursor; The catalyst was obtained by pyrolyzing the CoCu-MOF precursor.

[0011] Preferably, the temperature of the solvothermal reaction is 20~200℃ and the time is 4~48h; The pyrolysis is carried out in an inert atmosphere at a temperature of 500-1200°C for a time of 0.5-3 hours.

[0012] The present invention also provides the application of the catalyst described in the above technical solution or the catalyst prepared by the preparation method described in the above technical solution in the catalytic alkyl pure oxidation glycosylation to prepare dialkyl carbonate.

[0013] Preferably, the catalyst prepared by the catalyst described in the above technical solution or the preparation method described in the above technical solution is used as the catalyst, and alkyl alcohol, CO and O2 are used as raw materials to carry out a catalytic reaction to obtain dialkyl carbonate.

[0014] Preferably, the alkyl alcohol is methanol, ethanol, propanol or butanol; The catalytic reaction is carried out at a temperature of 100~140℃ for 1~4 hours. The molar ratio of CO to O2 is (1~4):1; The total pressure of CO and O2 is 1~5 MPa; The mass of the catalyst is 2 to 20% of the mass of the alkyl alcohol.

[0015] This invention provides a catalyst comprising nitrogen-doped carbon and CoCu bimetallic nanoparticles dispersed within the nitrogen-doped carbon. In the catalyst of this invention, Co in the CoCu bimetallic nanoparticles promotes CO activation, while Cu promotes methanol dissociation, synergistically improving reaction efficiency: First stage: Reactant adsorption and activation: Methanol (CH3OH) molecules in the gas phase diffuse to the catalyst surface and adsorb onto Cu. + At the active site, methanol subsequently undergoes dissociative adsorption, breaking the OH bond to generate the key surface intermediate – methoxy group (CH3O). ) and a hydrogen atom (H This step can be represented as: CH3OH+ (Cu) + → CH3O +H Cu + The role of the site: Cu + Its electronic structure is particularly favorable for stabilizing the methoxy intermediate, preparing it for subsequent reactions; at the same time, carbon monoxide molecules adsorb onto the adjacent Co... 0 At the site, and through the d electrons of the metal to the π electrons of CO. The antibonding orbital feeds back electrons, activating CO and weakening its C≡O bond (this step can be represented as: CO + (Co) 0 ) →CO ); Co 0 The role of the site: Cobalt has excellent adsorption and activation capabilities for CO, which is key to the efficient catalytic cycle; Second stage: Surface reaction and DMC formation (the core of the synergistic effect), this stage is the concentrated manifestation of the bimetallic synergistic effect, the reaction takes place at the Cu-Co interface, CO insertion reaction (rate-determining step): Co is... 0 Activated CO migrates from Co sites or inserts directly at the phase boundary into adjacent Cu adsorbed sites. + At the CH3O site, this is the step with the highest energy barrier, the absolute rate step of the entire reaction. This step generates another key intermediate—the surface methoxycarbonyl group (CH3OCO). CH3O (in Cu) + (Above) + CO (from Co) 0 ) → CH3OCO + The formation and desorption of DMC: The surface methoxy carbonyl group (CH3OCO) reacts with another adsorbed methoxy group (CH3O) to form the final product, dimethyl carbonate (DMC). The generated DMC molecules desorb from the catalyst surface and enter the gas phase, thus freeing up active sites for the next round of reaction. CH3OCO + CH3O → (CH3O)2CO (DMC) + Nitrogen-doped carbon supports can enhance metal-support interactions (Cu). + Specializing in the dissociation of methanol, while Co 0 Specializing in CO activation, the close proximity of the two at the nanoscale allows for efficient transfer and reaction of intermediates. This synergistic mechanism constructs a highly efficient, low-energy-barrier "fast channel," guiding reactants to preferentially select the path for DMC formation, preventing particle aggregation and leaching, and improving stability. Firstly, the Co in the catalyst... 0 Nitrogen-doped carbon supports can mildly activate O2, limiting their primary use to "regenerated Cu". + "Active site" and "H generated by removal reaction" "This avoids the direct oxidation of methanol or its reaction intermediates by high concentrations of reactive oxygen species, thus effectively suppressing the deep oxidation pathway that leads to the formation of methyl methacrylate (MF) and dimethoxymethane (DMM). Secondly, the nitrogen-doped carbon support itself has moderate acidity and alkalinity. The introduction of Co can further regulate the surface properties, avoiding excessively strong acidic sites. Excessively strong acidic sites would catalyze the dehydration of methanol to form DMM, while a moderate acid-base environment is conducive to the target carbonylation reaction." Attached Figure Description

[0016] Figure 1 This is a high-resolution transmission electron microscope (HRTEM) image of the catalyst described in Example 1; Figure 2 The infrared spectra of the catalyst described in Example 1 before and after 30 repeated uses are shown below. Figure 3 The XRD patterns of the catalyst described in Example 1 before and after 30 repeated uses are shown. Detailed Implementation

[0017] The present invention provides a catalyst comprising nitrogen-doped carbon and CoCu bimetallic nanoparticles dispersed in the nitrogen-doped carbon.

[0018] In this invention, the molar ratio of Cu to Co in the CoCu bimetallic nanoparticles is preferably (0.01~2):1, more preferably 0.01:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, or 2.0:1. In an embodiment of this invention, the molar ratio of Cu to Co in the CoCu bimetallic nanoparticles is specifically 0.18:1.

[0019] In this invention, the particle size of the CoCu bimetallic nanoparticles is preferably 10~50nm, more preferably 10nm, 20nm, 30nm, 40nm or 50nm.

[0020] In this invention, the nitrogen doping amount in the nitrogen-doped carbon is preferably 0.1% to 5%, more preferably 0.1%, 1%, 2%, 3%, 4%, or 5%. In an embodiment of this invention, the nitrogen doping amount in the nitrogen-doped carbon can be 0.9%.

[0021] In this invention, the nitrogen in the nitrogen-doped carbon is preferably present in the form of pyridine nitrogen, pyrrole nitrogen, and graphitic nitrogen. In this invention, the carbon in the nitrogen-doped carbon is preferably graphitic carbon.

[0022] In this invention, the mass ratio of the CoCu bimetallic nanoparticles to nitrogen-doped carbon is preferably 1:(4~10), more preferably 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10. In an embodiment of this invention, the mass ratio of the CoCu bimetallic nanoparticles to nitrogen-doped carbon can be 1:8.

[0023] The present invention also provides a method for preparing the catalyst described in the above technical solution, comprising the following steps: Soluble cobalt salt, soluble copper salt, nitrogen-containing organic ligand and organic solvent are mixed and subjected to a solvothermal reaction to obtain CoCu-MOF precursor; The catalyst was obtained by pyrolyzing the CoCu-MOF precursor.

[0024] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0025] This invention involves mixing soluble cobalt salt, soluble copper salt, nitrogen-containing organic ligand, and organic solvent, and then performing a solvothermal reaction to obtain a CoCu-MOF precursor.

[0026] In this invention, the soluble cobalt salt preferably includes one or more of cobalt nitrate, cobalt chloride, and cobalt acetate. When the soluble cobalt salt is two or more of the above-mentioned specific selections, this invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio. In an embodiment of this invention, the soluble cobalt salt can be cobalt nitrate.

[0027] In this invention, the soluble copper salt preferably includes one or more of copper nitrate, copper chloride, and copper acetate. When the soluble copper salt is two or more of the above-mentioned specific selections, this invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio. In the embodiments of this invention, the soluble copper salt is specifically copper nitrate.

[0028] In this invention, the nitrogen-containing organic ligand preferably includes one or more of 2-methylimidazole, imidazole, triazole, and aminotriazole. When the nitrogen-containing organic ligand is two or more of the above-mentioned specific selections, this invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio. In the embodiments of this invention, the nitrogen-containing organic ligand is specifically 2-methylimidazole.

[0029] In this invention, the molar ratio of the soluble copper salt to the soluble cobalt salt is preferably (0.01~2):1, more preferably 0.01:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, or 2.0:1. In an embodiment of this invention, the molar ratio of the soluble copper salt to the soluble cobalt salt is specifically 1:1.

[0030] In this invention, the ratio of the total molar amount of metal ions in the soluble cobalt salt and soluble copper salt to the molar amount of nitrogen-containing organic ligands is preferably 1:(2~10), more preferably 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10. In an embodiment of this invention, the ratio of the total molar amount of metal ions in the soluble cobalt salt and soluble copper salt to the molar amount of nitrogen-containing organic ligands is specifically 1:3.

[0031] In this invention, the organic solvent preferably includes one or more of anhydrous methanol, anhydrous ethanol, anhydrous propanol, isopropanol, and N,N-dimethylformamide. When the organic solvent is two or more of the above-mentioned specific selections, this invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and any ratio can be used. In the embodiments of this invention, the organic solvent can be anhydrous methanol.

[0032] In this invention, the preferred ratio of the soluble cobalt salt to the organic solvent is 1 g:(10~50) mL, more preferably 1 g:10 mL, 1 g:20 mL, 1 g:30 mL, 1 g:40 mL, or 1 g:50 mL. In an embodiment of this invention, the specific ratio of the soluble cobalt salt to the organic solvent is 2.9 g:80 mL.

[0033] The present invention does not impose any special limitations on the mixing process; any process known to those skilled in the art can be used.

[0034] In this invention, the temperature of the solvothermal reaction is preferably 20~200℃, more preferably 20℃, 40℃, 60℃, 80℃, 100℃, 120℃, 140℃, 160℃, 180℃, or 200℃; the time is preferably 4~48h, more preferably 4h, 8h, 12h, 16h, 20h, 24h, 28h, 32h, 36h, 40h, 44h, or 48h. In an embodiment of this invention, the temperature of the solvothermal reaction can be room temperature, and the time is 24h. In this invention, the solvothermal reaction is preferably carried out under stirring conditions. This invention does not impose any special limitations on the stirring process; any process well known to those skilled in the art can be used. In this invention, room temperature can be understood as not requiring additional heating and cooling.

[0035] After the solvothermal reaction is completed, the present invention preferably includes solvent removal, wherein the solvent removal method is preferably vacuum removal, and the vacuum removal temperature is preferably 80°C.

[0036] After obtaining the CoCu-MOF precursor, the present invention pyrolyzes the CoCu-MOF precursor to obtain the catalyst.

[0037] In this invention, the pyrolysis temperature is preferably 500~1200℃, more preferably 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, 1100℃, or 1200℃; the time is preferably 0.5~3h, more preferably 0.5h, 1h, 1.5h, 2h, 2.5h, or 3h. In an embodiment of this invention, the pyrolysis temperature can be 900℃, and the time can be 2h. In this invention, the pyrolysis is preferably carried out in an inert atmosphere, which preferably includes a nitrogen atmosphere, an argon atmosphere, or a helium atmosphere. In an embodiment of this invention, the inert atmosphere can be an argon atmosphere.

[0038] The present invention also provides the application of the catalyst described in the above technical solution or the catalyst prepared by the preparation method described in the above technical solution in the catalytic alkyl pure oxidation glycosylation to prepare dialkyl carbonate.

[0039] In this invention, the method of application preferably includes: Using the catalyst described in the above technical solution as the catalyst, and alkyl alcohol, CO, and O2 as raw materials, a catalytic reaction is carried out to obtain dialkyl carbonate.

[0040] In this invention, the alkyl alcohol is preferably methanol, ethanol, propanol or butanol.

[0041] In this invention, the temperature of the catalytic reaction is preferably 100~140℃, more preferably 100℃, 110℃, 120℃, 130℃ or 140℃; the time is preferably 1~4h, more preferably 1h, 2h, 3h or 4h.

[0042] In this invention, the molar ratio of CO to O2 is preferably (1~4):1, more preferably 1:1, 2:1, 3:1 or 4:1. In this invention, the total pressure of CO and O2 is preferably 1~5 MPa, more preferably 1 MPa, 2 MPa, 3 MPa, 4 MPa or 5 MPa.

[0043] In this invention, the mass of the catalyst is preferably 2 to 20% of the mass of the alkyl alcohol, more preferably 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18% or 20%.

[0044] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0045] Example 1 2.9 g of cobalt nitrate and 2.46 g of copper nitrate were added to a 100 mL round-bottom flask, followed by 80 mL of anhydrous methanol. The mixture was then stirred and dissolved at room temperature. After adding 5 g of 2-methylimidazole, the mixture was stirred at room temperature for 24 h. The methanol was removed under reduced pressure at 80 °C, and the mixture was calcined in a tube furnace at 900 °C for 2 h (calcination atmosphere was argon) to obtain a catalyst (comprising nitrogen-doped carbon and CoCu bimetallic nanoparticles dispersed in the nitrogen-doped carbon, wherein the mass ratio of nitrogen-doped carbon to CoCu bimetallic nanoparticles was 8:1, the molar ratio of Cu to Co in the CoCu bimetallic nanoparticles was 0.18:1, and the mass percentage of nitrogen in the nitrogen-doped carbon was 0.9%). Figure 1 Here is a high-resolution transmission electron microscope (HRTEM) image of the catalyst, by... Figure 1It is known that the CoCu bimetallic nanoparticles are uniformly dispersed throughout the catalyst matrix, with an average particle size of 7.13 nm. Furthermore, the CoCu bimetallic nanoparticles are tightly encased in a highly crystalline carbon layer, with a measured interplanar spacing of 0.3424 nm, which matches the characteristic interplanar spacing of graphite (002) crystal planes. This observation directly verifies the formation of the graphitized carbon structure in the catalyst. In addition, the CoCu bimetallic nanoparticles encased in the graphite layer also exhibit high crystallinity, with an interplanar spacing of 0.2026 nm; this value is consistent with the standard interplanar spacing of the CoCu alloy (111) crystal plane. Using the catalyst, multiple dimethyl carbonate synthesis experiments were conducted with methanol, CO, and oxygen as raw materials. The reaction conditions were as follows: a 90 mL high-pressure reactor was used, and the temperature, pressure, and time are shown in Table 1. The catalyst dosage was 5% by mass relative to methanol (5 mL). The experimental results are shown in Table 1. Table 1 Results of the preparation of dimethyl carbonate from methanol catalyzed by the catalyst described in Example 1

[0046] Table 1 shows that as the reaction temperature increases from 100℃ to 120℃, the conversion rate of methanol increases, and the yield of DMC improves. Further increasing the temperature to 140℃ stops the increase in DMC yield. With prolonged reaction time, the conversion rate of methanol increases, and the yield of DMC improves. Further extending the time to 3 hours stops the increase in DMC yield, indicating that the reaction reached equilibrium after 2 hours. As the CO pressure increases, the conversion rate of methanol initially increases and then decreases. Excessively high CO pressure may lead to excessive occupation of active sites, hindering the adsorption and activation of methanol, resulting in a decrease in the yield of DMC. Stability testing of the catalyst: Multiple dimethyl carbonate synthesis experiments were conducted using methanol, CO, and oxygen as raw materials. The reaction conditions were: 5 mL methanol, 2 MPa CO, 1 MPa O2, and 0.2 g CoCu / NC catalyst at 120 °C for 2 h. The test results are shown in Table 2. Stability of the catalysts listed in Table 2

[0047] As shown in Table 2, after repeating the reaction 30 times, the conversion rate of methanol was >18.6% and the yield of DMC was >18%, indicating that the catalyst has good stability. Figure 2 The image shows the infrared spectrum of the catalyst before and after 30 reuses. Figure 3 The XRD patterns of the catalyst before and after 30 repeated uses are shown below. Figures 2-3 It can be seen that the structure of the catalyst remains basically unchanged before and after use, exhibiting good stability and allowing for repeated use.

[0048] Comparative Example 1 2.9 g of cobalt nitrate was added to a 100 mL round-bottom flask, followed by 80 mL of anhydrous methanol. The mixture was then stirred and dissolved at room temperature. 5 g of 2-methylimidazole was added, and the mixture was stirred at room temperature for 24 h. The methanol was removed under reduced pressure at 80 °C, and the mixture was calcined at 900 °C for 2 h in a tube furnace to obtain a catalyst (comprising nitrogen-doped carbon and Co supported on the nitrogen-doped carbon, wherein the mass ratio of Co to nitrogen-doped carbon is 0.2, and the nitrogen content in the nitrogen-doped carbon is 0.5%). Using the catalyst, multiple experiments were conducted to synthesize dialkyl carbonates from alcohols, CO, and oxygen. The reaction conditions were as follows: a 90 mL high-pressure reactor was used; the temperature, pressure, and time are shown in Table 3; the catalyst dosage was 5% by mass relative to the alcohol (5 mL). The experimental results are shown in Table 3. Table 3 Results of methanol preparation of dialkyl carbonate catalyzed by the catalyst described in Comparative Example 1

[0049] As shown in Table 3, with the increase of the carbon chain of alcohols, even with the increase of reaction temperature, the yield of the corresponding dialkyl carbonate gradually decreases, indicating that long-chain alcohols have low reactivity.

[0050] Comparative Example 2 2.48 g of copper nitrate was added to a 100 mL round-bottom flask, 80 mL of anhydrous methanol was added, and the mixture was stirred and dissolved at room temperature. 5 g of 2-methylimidazole was added and the mixture was stirred at room temperature for 24 h. Methanol was removed under reduced pressure at 80 °C and the mixture was calcined at 900 °C for 2 h in a tube furnace to obtain the catalyst. Using the catalyst, multiple dimethyl carbonate synthesis experiments were conducted with methanol, CO, and oxygen as raw materials. The reaction conditions were as follows: a 90 mL high-pressure reactor was used, and the temperature, pressure, and time are shown in Table 4. The catalyst dosage was 5% by mass relative to methanol (5 mL). The experimental results are shown in Table 4. Table 4 Results of the preparation of dimethyl carbonate from methanol catalyzed by the catalyst described in Comparative Example 2

[0051] As shown in Table 4, Cu alone has low catalytic activity as the catalytic active center, and the yield of DMC is less than 2%, indicating that there is a significant synergistic effect between Cu and Co.

[0052] Comparative Example 3 2.9 g of cobalt nitrate and 2.46 g of copper nitrate were added to a 100 mL round-bottom flask, 80 mL of anhydrous methanol was added, and the mixture was stirred and dissolved at room temperature. 2 g of activated carbon support was added and the mixture was stirred at room temperature for 24 h. Methanol was removed under reduced pressure at 80 °C and the mixture was calcined at 900 °C for 2 h in a tube furnace to obtain the catalyst. Using the catalyst, multiple dimethyl carbonate synthesis experiments were conducted with methanol, CO, and oxygen as raw materials. The reaction conditions were as follows: a 90 mL high-pressure reactor was used, and the temperature, pressure, and time are shown in Table 5. The catalyst dosage was 5% by mass relative to methanol (5 mL). The experimental results are shown in Table 5. Table 5 Results of methanol-to-dimethyl carbonate preparation catalyzed by the catalyst described in Comparative Example 3

[0053] As shown in Table 5, the activity of ordinary carbon-supported CuCo catalysts is relatively low, which further confirms the characteristics of the nitrogen-doped carbon support described in this invention in enhancing metal-support interaction, preventing particle agglomeration and leaching, and improving activity stability.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A catalyst, characterized in that, It includes nitrogen-doped carbon and CoCu bimetallic nanoparticles dispersed in the nitrogen-doped carbon.

2. The catalyst according to claim 1, characterized in that, The molar ratio of Cu to Co in the CoCu bimetallic nanoparticles is (0.01~2):

1.

3. The catalyst according to claim 1 or 2, characterized in that, The CoCu bimetallic nanoparticles have a particle size of 10~50 nm.

4. The catalyst according to claim 1, characterized in that, The nitrogen doping amount in the nitrogen-doped carbon is 0.1~5 wt%; The nitrogen in the nitrogen-doped carbon exists in the forms of pyridine nitrogen, pyrrole nitrogen, and graphitic nitrogen; The carbon in the nitrogen-doped carbon is graphitic carbon.

5. The catalyst according to claim 1, characterized in that, The mass ratio of the CoCu bimetallic nanoparticles to nitrogen-doped carbon is 1:(4~10).

6. A method for preparing the catalyst according to any one of claims 1 to 5, characterized in that, Includes the following steps: Soluble cobalt salt, soluble copper salt, nitrogen-containing organic ligand and organic solvent are mixed and subjected to a solvothermal reaction to obtain CoCu-MOF precursor; The catalyst was obtained by pyrolyzing the CoCu-MOF precursor.

7. The preparation method according to claim 6, characterized in that, The temperature of the solvothermal reaction is 20~200℃, and the time is 4~48h; The pyrolysis is carried out in an inert atmosphere at a temperature of 500-1200°C for a time of 0.5-3 hours.

8. The application of the catalyst according to any one of claims 1 to 5 or the catalyst prepared by the preparation method according to claim 6 or 7 in the catalytic alkyl oxidative glycosylation to prepare dialkyl carbonate.

9. The application as described in claim 8, characterized in that, Using the catalyst described in any one of claims 1 to 5 or the catalyst prepared by the preparation method described in claim 6 or 7 as a catalyst, and using alkyl alcohols, CO and O2 as raw materials, a catalytic reaction is carried out to obtain dialkyl carbonate.

10. The application as described in claim 9, characterized in that, The alkyl alcohol is methanol, ethanol, propanol, or butanol; The catalytic reaction is carried out at a temperature of 100~140℃ for 1~4 hours. The molar ratio of CO to O2 is (1~4):1; The total pressure of CO and O2 is 1~5 MPa; The mass of the catalyst is 2 to 20% of the mass of the alkyl alcohol.

Images