High specific surface area nano-cu catalyst, its preparation method and application

Abstract

This invention provides a high specific surface area nano-Cu catalyst, its preparation method, and its application, relating to the field of catalyst preparation technology. The high specific surface area nano-Cu catalyst of this invention includes the promoter MO. x The catalyst comprises 1 wt.%–10 wt.% active component Cu, 40 wt.%–80 wt.% active component, and the balance being SiO2 support. It is obtained from a mixed salt solution containing copper salt and auxiliary metal salt, and silica sol, through co-precipitation, aging, filtration, washing, calcination, and reduction. The reduction is carried out in a polyol-H2 system at a temperature of 160 °C–240 °C for 6–24 h. This invention constructs a SiO2 / Cu-MO catalyst. x A reverse-phase catalyst structure was developed, and a nano-Cu catalyst with high specific surface area, high activity, high selectivity, and excellent stability was successfully prepared using a polyol-H2 system for reduction treatment. This catalyst achieved high-yield hydrogenolysis of glycerol to 1,2-propanediol under mild conditions and possesses the advantages of high catalytic activity and high stability, showing promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, and in particular to a high specific surface area nano-Cu catalyst, its preparation method, and its application. Background Technology

[0002] 1,2-Propanediol is an important chemical raw material widely used in the food, pharmaceutical, and cosmetic industries. It can also be used as a monomer for the synthesis of unsaturated polyesters and is a fundamental raw material for the preparation of epoxy resins, polyurethanes, plasticizers, and surfactants. The selective hydrogenolysis of glycerol from biomass sources to produce 1,2-propanediol not only exhibits excellent biocompatibility but also holds significant importance for the high-value utilization of glycerol, a byproduct of biodiesel production. Therefore, research on the technology of selective hydrogenolysis of glycerol to produce 1,2-propanediol has attracted widespread attention, with the development of an efficient and stable catalytic hydrogenation system being crucial for the industrialization of this process.

[0003] Currently, glycerol hydrogenolysis catalysts mainly fall into two categories: one is noble metal catalysts such as Ru, Rh, Pd, and Au, and the other is non-noble metal catalysts such as Cu and Ni. Although noble metal catalysts have high activity, their high cost makes large-scale industrial application difficult. In contrast, non-noble metal catalysts, especially Cu-based catalysts, have become a research focus due to their lower cost and good catalytic performance.

[0004] For example, Chinese patent CN201110286769 discloses an Ag-modified Ni / Al2O3 catalyst for glycerol hydrogenolysis, but the selectivity for 1,2-propanediol is low, only about 90%. US patent US5214219 discloses a glycerol selective hydrogenation process using a supported Cu-Zn bimetallic catalyst. Although it achieves good propylene glycol yields under conditions of temperatures above 220°C and hydrogen pressures above 10 MPa, the reaction conditions are harsh and energy consumption is high. Chinese patents CN200610105255 and CN201110292276 disclose the application of an additive-modified CuO-SiO2 catalyst in the glycerol hydrogenolysis to propylene glycol production. Although the initial catalytic performance is excellent, the catalyst is prone to Cu particle sintering, loss of active components, and structural reconstruction during long-term use, leading to a rapid decline in reaction performance and poor stability, making it unsuitable for continuous industrial production.

[0005] In summary, existing Cu-based catalysts still suffer from problems such as insufficient catalytic activity and selectivity for target products, poor stability, harsh reaction conditions, and demanding equipment requirements. Developing nano-Cu catalysts with high specific surface area, high activity, high selectivity, and long-term stability remains crucial for advancing the industrialization of selective hydrogenolysis of glycerol to 1,2-propanediol. Summary of the Invention

[0006] In view of this, the present invention provides a high specific surface area nano-Cu catalyst, its preparation method, and its application. The present invention constructs a SiO2 / Cu-MO catalyst. x A reverse-phase catalyst structure was developed, and a polyol-H2 system was used for reduction treatment. This successfully solved the technical problems existing in the prior art, and a nano-Cu catalyst with high specific surface area, high activity, high selectivity, and excellent stability was successfully prepared. This catalyst achieved high-yield hydrogenolysis of glycerol to 1,2-propanediol under mild conditions and possesses the advantages of high catalyst activity and high stability, showing promising application prospects.

[0007] The first aspect of this invention is to provide a high specific surface area nano-Cu catalyst, wherein the catalyst is obtained by co-precipitation, aging, filtration, washing, calcination and reduction of a mixed salt solution containing copper salt and auxiliary metal salt and silica sol as raw materials; The high specific surface area nano-Cu catalyst comprises the following components: Additive MO x 1 wt.%-10 wt.%, active component Cu 40 wt.%-80 wt.%, balance SiO2 support.

[0008] Preferably, the MO x It is at least one of MgO, CaO, BaO, ZrO2, ZnO, Al2O3 and Cr2O3.

[0009] A second aspect of this invention provides a method for preparing the high specific surface area nano-Cu catalyst, specifically comprising the following steps: The pH of a mixed salt solution containing copper salt and auxiliary metal salt was adjusted to alkaline, and then silica sol was added. The solution was then aged, filtered, washed, calcined, and reduced to obtain a high specific surface area nano-Cu catalyst.

[0010] Preferably, the pH of the mixed salt solution is adjusted by adding an alkaline solution dropwise under vigorous stirring, wherein the alkaline solution is at least one selected from sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, ammonia, and urea.

[0011] Preferably, the copper salt is at least one of copper nitrate, sulfate, acetate, and halide.

[0012] Preferably, the auxiliary metal salt is at least one selected from Mg(NO3)2·6H2O, Ca(NO3)2·4H2O, Ba(NO3)2, ZrOCl2·8H2O, Zn(NO3)2·6H2O, Al(NO3)3·9H2O, and Cr(NO3)3·9H2O.

[0013] Preferably, the concentration of metal ions in the mixed salt solution is 1 mol / L, and the pH of the mixed salt solution after adjustment is 10.

[0014] Preferably, the concentration of the silica sol is 30 wt%.

[0015] Preferably, the aging temperature is 80°C and the aging time is 4 hours.

[0016] Preferably, the calcination temperature is 500 °C, the calcination time is 4 h, and the calcination is carried out in an air atmosphere.

[0017] Preferably, the reduction is carried out in a polyol-H2 system, the reduction temperature is 160 ℃-240 ℃, and the reduction time is 6-24 h; the polyol is at least one selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, glycerol, 1,4-butanediol, and 1,5-pentanediol; and the amount of polyol introduced is 0.1-5 mol / h / g catalyst.

[0018] A third aspect of this invention is to provide the application of a high specific surface area nano-Cu catalyst in the selective hydrogenolysis of glycerol to prepare 1,2-propanediol.

[0019] Preferably, the selective hydrogenolysis of glycerol to prepare 1,2-propanediol is carried out at a reaction temperature of 160-240°C, a hydrogen reaction pressure of 1-8 MPa, and a glycerol mass hourly space velocity of 0.3-1.5 h⁻¹. -1 The molar ratio of hydrogen to glycerol is (10-30):1.

[0020] Preferably, the selective hydrogenolysis of glycerol to prepare 1,2-propanediol is carried out in a high-pressure fixed-bed continuous reactor.

[0021] This invention constructs SiO2 / Cu-MO x The reversed-phase catalyst structure allows for a dual synergistic effect between the promoter and the support, significantly suppressing the migration rate of Cu atoms during the reaction process and effectively preventing the sintering and agglomeration of Cu particles. Simultaneously, the basic nature of the promoter enhances the catalyst's tolerance to active hydrogen ions generated in the glycerol selective hydrogenation system, further reducing the catalyst's sintering rate and thus significantly improving its long-term stability.

[0022] This invention employs a polyol-H2 system to reduce the catalyst precursor, significantly increasing the catalyst's specific surface area. The high specific surface area creates a stable porous structure, providing more active sites for the selective hydrogenation of glycerol, greatly enhancing the adsorption / desorption of glycerol on the catalyst surface and the reaction rate, thereby significantly improving catalytic activity and target product selectivity.

[0023] This invention achieves highly efficient catalysis under mild conditions, which not only significantly reduces energy consumption and equipment requirements, but also improves the safety and economy of the production process.

[0024] The preparation process of this invention is simple, low-cost, and easily industrialized. The catalyst precursor is prepared by a simple acid-base neutralization precipitation method, and the activation and reduction processes can be completed directly in the reaction system without complex equipment and operations, making it suitable for large-scale industrial production. Compared with catalysts that require precious metals, this invention uses the non-precious metal Cu as the active component, significantly reducing raw material costs and resulting in significant economic benefits.

[0025] Compared with the prior art, the beneficial technical effects of the present invention are as follows: This invention, through structural design and process innovation, successfully prepared a nano-Cu catalyst with high specific surface area, high activity, high selectivity, and excellent stability. It achieved high-yield 1,2-propanediol production via glycerol hydrogenolysis under mild conditions and maintained long-term stable operation. This invention solves the problems of low catalyst activity, poor stability, and harsh reaction conditions in existing technologies, providing a practical technical solution for the industrial application of selective hydrogenolysis of glycerol to produce 1,2-propanediol. It has significant application value and broad market prospects. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] Unless otherwise specified, all experiments were repeated three times, and the results are expressed as averages.

[0028] Example 1 A high specific surface area nano-Cu catalyst, with the following composition by mass percentage: Cu 60%, MgO 5%, support SiO2 35%; The preparation method of the high specific surface area nano-Cu catalyst is as follows: Weigh 228.07 g Cu(NO3)2·3H2O and 31.81 g Mg(NO3)2·6H2O and add them to 1068 mL of deionized water to obtain a 1 mol / L mixed salt solution. Under vigorous stirring, add 2 mol / L sodium hydroxide solution dropwise to the mixed salt solution until the pH value of the solution reaches 10. Then add 116.67 g of 30 wt% silica sol. After completion, age the solution at 80 ℃ for 4 h, filter and wash until the pH of the filtrate is 7 to obtain a solid precipitate. Dry the precipitate at 110 ℃ for 12 h and calcine it at 500 ℃ for 4 h in air to obtain catalyst precursor A. 20 g of catalyst precursor A was crushed and ground into 20-40 mesh particles, loaded into a fixed-bed reactor, and 100 mL / min of hydrogen and 60 mol / h of ethylene glycol were introduced. The mixture was then reduced at 200 °C for 15 h to obtain catalyst A1.

[0029] Example 2 A high specific surface area nano-Cu catalyst, with the following composition by mass percentage: Cu 40%, CaO 1%, support SiO2 59%; The preparation method of the high specific surface area nano-Cu catalyst is as follows: Weigh 157.15 g CuSO4·5H2O and 4.21 g Ca(NO3)2·4H2O and add them to 647 mL of deionized water to obtain a 1 mol / L mixed salt solution. Under vigorous stirring, add 2 mol / L potassium hydroxide solution dropwise to the mixed salt solution until the pH value of the solution reaches 10. Then add 196.67 g 30 wt% silica sol. After completion, age at 80 ℃ for 4 h, filter and wash until the pH of the filtrate is 7 to obtain a solid precipitate. Dry the precipitate at 110 ℃ for 12 h and calcine it at 500 ℃ for 4 h in air to obtain catalyst precursor B. 20 g of catalyst precursor B was crushed and ground into 20-40 mesh particles, loaded into a fixed-bed reactor, and 100 mL / min of hydrogen and 60 mol / h of 1,2-propanediol were introduced. The reactor was then reduced at 200 °C for 15 h to obtain catalyst B1.

[0030] Example 3 A high specific surface area nano-Cu catalyst, with the following composition by mass percentage: Cu 80%, BaO 10%, support SiO2 10%; The preparation method of the high specific surface area nano-Cu catalyst is as follows: 251.33 g of Cu(OAc)₂·H₂O and 17.04 g of Ba(NO₃)₂ were weighed and added to 1324 mL of deionized water to obtain a 1 mol / L mixed salt solution. Under vigorous stirring, a 2 mol / L sodium carbonate solution was added dropwise to the mixed salt solution until the pH value of the solution reached 10. Then, 33.33 g of 30 wt% silica sol was added dropwise. After completion, the solution was aged at 80 °C for 4 h, filtered, and washed until the pH of the filtrate was 7 to obtain a solid precipitate. The precipitate was dried at 110 °C for 12 h and then calcined at 500 °C for 4 h in air to obtain catalyst precursor C. 20 g of catalyst precursor C was crushed and ground into 20-40 mesh particles, loaded into a fixed-bed reactor, and 100 mL / min of hydrogen and 60 mol / h of 1,3-propanediol were introduced. The reactor was then reduced at 200 °C for 15 h to obtain catalyst C1.

[0031] Example 4 A high specific surface area nano-Cu catalyst, with the following composition by mass percentage: Cu 60%, ZrO2 5%, support SiO2 35%; The preparation method of the high specific surface area nano-Cu catalyst is as follows: 160.98 g of CuCl2·H2O and 13.08 g of ZrOCl2·8H2O were weighed and added to 985 mL of deionized water to obtain a 1 mol / L mixed salt solution. Under vigorous stirring, a 2 mol / L sodium bicarbonate solution was added dropwise to the mixed salt solution until the pH reached 10. Then, 116.67 g of 30 wt% silica sol was added dropwise. After this process, the solution was aged at 80 ℃ for 4 h, filtered, and washed until the pH of the filtrate reached 7, yielding a solid precipitate. This precipitate was dried at 110 ℃ for 12 h and then calcined at 500 ℃ for 4 h in air to obtain catalyst precursor D. 20 g of catalyst precursor D was pulverized and ground into 20-40 mesh particles, loaded into a fixed-bed reactor, and subjected to reduction treatment at 200 °C for 15 h with 100 mL / min hydrogen and 2 mol / h glycerol to obtain catalyst D1.

[0032] Example 5 A high specific surface area nano-Cu catalyst, with the following composition by mass percentage: Cu 60%, ZnO 5%, support SiO2 35%; The preparation method of the high specific surface area nano-Cu catalyst is as follows: Weigh 228.07 g Cu(NO3)2·3H2O and 18.27 g Zn(NO3)2·6H2O and add them to 1006 mL of deionized water to obtain a 1 mol / L mixed salt solution. Under vigorous stirring, add 2 mol / L concentrated ammonia solution dropwise to the mixed salt solution until the pH value of the solution reaches 10. Then add 116.67 g of 30 wt% silica sol. After completion, age at 80 ℃ for 4 h, filter and wash until the pH of the filtrate is 7 to obtain a solid precipitate. Dry the precipitate at 110 ℃ for 12 h and calcine it at 500 ℃ for 4 h in air to obtain catalyst precursor E. 20 g of catalyst precursor E was pulverized and ground into 20-40 mesh particles, loaded into a fixed-bed reactor, and 100 mL / min of hydrogen and 100 mol / h of 1,4-butanediol were introduced. The reactor was then reduced at 200 °C for 15 h to obtain catalyst E1.

[0033] Example 6 A high specific surface area nano-Cu catalyst, with the following composition by mass percentage: Cu 60%, Al2O3 5%, support SiO2 35%; The preparation method of the high specific surface area nano-Cu catalyst is as follows: Weigh 228.07 g Cu(NO3)2·3H2O and 36.79 g Al(NO3)3·9H2O and add them to 1042 mL of deionized water to obtain a 1 mol / L mixed salt solution. Under vigorous stirring, add 2 mol / L urea solution dropwise to the mixed salt solution until the pH value of the solution reaches 10. Then add 116.67 g 30 wt% silica sol. After completion, age at 80℃ for 4 h, filter and wash until the pH of the filtrate is 7 to obtain a solid precipitate. Dry the precipitate at 110℃ for 12 h and calcine it at 500℃ for 4 h in air atmosphere to obtain catalyst precursor F. 20 g of catalyst precursor F was crushed and ground into 20-40 mesh particles, loaded into a fixed-bed reactor, and 100 mL / min of hydrogen and 60 mol / h of 1,5-pentanediol were introduced. The reactor was then reduced at 240 °C for 6 h to obtain catalyst F1.

[0034] Example 7 A high specific surface area nano-Cu catalyst, with the following composition by mass percentage: Cu 60%, Cr2O3 5%, support SiO2 35%; The preparation method of the high specific surface area nano-Cu catalyst is as follows: Weigh 228.07 g Cu(NO3)2·3H2O and 22.37 g Cr(NO3)3·9H2O and add them to 1010 mL of deionized water to obtain a 1 mol / L mixed salt solution. Under vigorous stirring, add 2 mol / L sodium hydroxide solution dropwise to the mixed salt solution until the pH value of the solution reaches 10. Then add 116.67 g of 30 wt% silica sol. After completion, age the solution at 80 ℃ for 4 h, filter and wash until the pH of the filtrate is 7 to obtain a solid precipitate. Dry the precipitate at 110 ℃ for 12 h and calcine it at 500 ℃ for 4 h in air to obtain catalyst precursor G. 20 g of catalyst precursor G was crushed and ground into 20-40 mesh particles, loaded into a fixed-bed reactor, and 100 mL / min of hydrogen and 60 mol / h of ethylene glycol were introduced. The mixture was then reduced at 160 °C for 24 h to obtain catalyst G1.

[0035] Comparative Examples 1-7 20 g of catalyst precursor AG was crushed and ground into 20-40 mesh particles, loaded into a fixed bed reactor, and reduced by 100 mL / min of 20% H2-N2 mixed gas. The reduction temperature and reduction time were the same as in Examples 1-7, respectively, to obtain the reduced high specific surface area nano-Cu catalyst A0-G0.

[0036] The specific surface area of ​​the catalysts obtained in Examples 1-7 and Comparative Examples 1-7 before and after treatment in a high-temperature, high-pressure polyol-H2 system was determined. The specific surface area of ​​a catalyst is often closely related to its catalytic performance, adsorption performance, storage capacity, surface activity, and stability. The N2 adsorption-desorption isotherms of the samples were obtained using a TriStarII 3020 adsorption analyzer from McMurray Technology, USA, at 77 K under liquid nitrogen conditions. Before measurement, the samples were desorbed at 300 °C for 4 h in a helium atmosphere. The sample amount used was approximately 150 mg, and experimental data were selected with relative pressures (P / P0) in the range of 0.05-0.99. The lower limit of the specific surface area detectable by the instrument using nitrogen was 0.01 m². 2 / g, with pore diameters ranging from 3.5 to 5000 Å. The specific surface area of ​​the material was calculated using the BET (Brunauer-Emmett-Teller) model method.

[0037] Table 1. Specific surface area of ​​the catalysts obtained in Examples 1-7 and Comparative Examples 1-7

[0038] As shown in Table 1, the catalysts treated with the polyol-H2 system (A1-G1) exhibited significantly improved specific surface areas compared to the catalysts treated with the traditional H2-N2 mixed gas (A0-G0). Specifically, the specific surface area of ​​catalyst A increased from 155 m² / g. 2 / g increased to 264 m 2 / g, an increase of 70.3%; catalyst B increased from 265 m 2 / g increased to 434 m 2 / g, an increase of 63.8%; catalyst C increased from 321 m 2 / g increased to 578 m 2 / g, an increase of 80.1%. Particularly noteworthy is the most significant increase in specific surface area for catalysts F and G, from 134 m² / g to 100 m² / g. 2 / g and 112 m 2 / g increased to 287 m 2 / g and 254 m 2 / g, with increases of 114.2% and 126.8%, respectively. These data fully demonstrate that the reduction treatment of the polyol-H2 system can effectively construct a more developed porous structure, providing more active sites for catalytic reactions.

[0039] The catalysts obtained in Examples 1-7 and Comparative Examples 1-7 were evaluated for their catalytic performance using the following method: After the temperature of the reduced catalyst AG bed stabilized at the reaction temperature of 180 °C, feeding began. The feed concentration was 40% glycerol-methanol solution, the hydrogen reaction pressure was 3.0 MPa, and the glycerol mass hourly space velocity was 1.0 h⁻¹. -1 The molar ratio of hydrogen to glycerol was 20 / 1. The evaluation results are shown in Table 2.

[0040] Example 8 After the temperature of the reduced catalyst A1 bed stabilized at the reaction temperature of 180 °C, feeding began. The feedstock concentration was a 40% glycerol-methanol solution, the hydrogen reaction pressure was 3.0 MPa, and the glycerol mass hourly space velocity (WHSV) was 1.0 h⁻¹. -1 The molar ratio of hydrogen to glycerol was 20 / 1. Samples were taken every 4 hours for a total reaction time of 500 hours. The evaluation results are shown in Table 3.

[0041] Comparative Example 8 After the temperature of the reduced catalyst A0 bed stabilized at the reaction temperature of 180 °C, feeding began. The feedstock concentration was a 40% glycerol-methanol solution, the hydrogen reaction pressure was 3.0 MPa, and the glycerol mass hourly space velocity (WHSV) was 1.0 h⁻¹. -1 The molar ratio of hydrogen to glycerol was 20 / 1. Samples were taken every 4 hours for a total reaction time of 500 hours. The evaluation results are shown in Table 3.

[0042] Example 9 After the temperature of the reduced catalyst A1 bed dropped to the reaction temperature of 160 °C, feeding began. The feed concentration was 40% glycerol-methanol solution, the hydrogen reaction pressure was 8.0 MPa, and the glycerol mass hourly space velocity was 0.3 h⁻¹. -1 The molar ratio of hydrogen to glycerol was 30 / 1. The evaluation results are shown in Table 2.

[0043] Example 10 After the temperature of the reduced catalyst A1 bed stabilized at the reaction temperature of 240 °C, feeding began. The feed concentration was 40% glycerol-methanol solution, the hydrogen reaction pressure was 1.0 MPa, and the glycerol mass hourly space velocity was 1.5 h⁻¹. -1 The molar ratio of hydrogen to glycerol was 10 / 1. The evaluation results are shown in Table 2.

[0044] Table 2 Evaluation results of the influence of different reaction conditions on catalytic performance

[0045] Table 2's catalytic performance evaluation results further validate the promoting effect of high specific surface area on catalytic activity. Under the same reaction conditions, catalysts reduced by the polyol-H2 system generally exhibited superior catalytic performance. Taking catalyst A as an example, A1 achieved a glycerol conversion rate as high as 99.82% and a 1,2-propanediol selectivity of 98.27%, while A0's conversion rate was only 63.55% and its selectivity was 96.83%. Catalysts B1, C1, D1, E1, F1, and G1 all maintained glycerol conversion rates above 90%, significantly higher than their corresponding B0-G0 catalysts. Furthermore, different promoters had varying effects on catalytic performance. In addition, the results of Examples 9 and 10 showed that catalyst A1 maintained excellent performance under different reaction conditions, achieving a conversion rate of 98.23% and a selectivity of 99.55% under mild conditions (160℃, 8.0 MPa), and achieving 100% glycerol conversion under more demanding conditions (240℃, 1.0 MPa), fully demonstrating the catalyst's wide applicability.

[0046] Table 3 Performance evaluation results of different catalysts

[0047] In Comparative Example 8, catalyst A0, using a conventional reduction method, showed a gradual decrease in glycerol conversion from an initial 70.43% to 61.17% during a 500-hour continuous reaction, a drop of 13.2%. The 1,2-propanediol selectivity also decreased slightly from 97.21% to 96.88%, indicating a gradual decline in catalyst activity. In contrast, catalyst A1 in Example 8 remained highly stable throughout the entire 500-hour reaction period. The glycerol conversion consistently remained between 98.54% and 98.77%, with a fluctuation of only 0.23 percentage points, and the 1,2-propanediol selectivity remained stable between 98.76% and 98.89%, showing almost no significant decline. This comparison clearly demonstrates that the high specific surface area nano-Cu catalyst constructed through a polyol-H2 system possesses excellent anti-sintering and anti-deactivation properties, maintaining stable catalytic activity and selectivity during long-term continuous reactions, and has excellent prospects for industrial application.

[0048] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A high specific surface area nano-Cu catalyst, characterized in that, The catalyst is obtained by co-precipitation, aging, filtration, washing, calcination and reduction of a mixed salt solution containing copper salt and auxiliary metal salt and silica sol. The high specific surface area nano-Cu catalyst comprises the following components: Additive MO x 1 wt.%-10 wt.%, active component Cu 40 wt.%-80 wt.%, balance SiO2 support; The reduction is carried out in a polyol-H2 system at a temperature of 160 ℃-240 ℃ for 6-24 h.

2. The high specific surface area nano-Cu catalyst according to claim 1, characterized in that, The MO x It is at least one of MgO, CaO, BaO, ZrO2, ZnO, Al2O3 and Cr2O3.

3. The method for preparing the high specific surface area nano-Cu catalyst according to claim 1 or 2, characterized in that, Includes the following steps: The pH of a mixed salt solution containing copper salt and auxiliary metal salt was adjusted to alkaline, then silica sol was added, followed by aging, filtration, washing, calcination, and reduction to obtain a high specific surface area nano-Cu catalyst.

4. The preparation method according to claim 3, characterized in that, The pH of the mixed salt solution is adjusted by adding an alkaline solution dropwise under vigorous stirring. The alkaline solution is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, ammonia, and urea. The copper salt is at least one of copper nitrate, sulfate, acetate, and halide. The auxiliary metal salt is at least one of Mg(NO3)2·6H2O, Ca(NO3)2·4H2O, Ba(NO3)2, ZrOCl2·8H2O, Zn(NO3)2·6H2O, Al(NO3)3·9H2O, and Cr(NO3)3·9H2O.

5. The preparation method according to claim 3, characterized in that, The pH of the adjusted mixed salt solution is 10.

6. The preparation method according to claim 3, characterized in that, The roasting temperature is 500°C, the roasting time is 4 hours, and the roasting is carried out in an air atmosphere.

7. The preparation method according to claim 3, characterized in that, The reduction is carried out in a polyol-H2 system at a temperature of 160 ℃-240 ℃ for 6-24 h. The polyol is at least one selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, glycerol, 1,4-butanediol, and 1,5-pentanediol. The amount of polyol introduced is 0.1-5 mol / h / g catalyst.

8. The application of a high specific surface area nano-Cu catalyst in the selective hydrogenolysis of glycerol to prepare 1,2-propanediol, characterized in that, The high specific surface area nano-Cu catalyst is the high specific surface area nano-Cu catalyst according to claim 1 or 2, or the high specific surface area nano-Cu catalyst prepared by the preparation method according to any one of claims 3-8.

9. The application according to claim 8, characterized in that, The selective hydrogenolysis of glycerol to prepare 1,2-propanediol is carried out at a reaction temperature of 160-240 °C, a hydrogen reaction pressure of 1-8 MPa, and a glycerol mass hourly space velocity of 0.3-1.5 h⁻¹. -1 The molar ratio of hydrogen to glycerol is (10-30):1.

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