A manganese-cerium composite oxide catalyst, its preparation method, and its application in the catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone.

Abstract

This invention relates to a manganese-cerium composite oxide catalyst, its preparation method, and its application in the catalytic oxidation of tetrahydrofuran to γ-butyrolactone, belonging to the field of hydrogen energy utilization and chemical hydrogen storage technology. Using a manganese-cerium composite oxide catalyst (manganese-based oxide) as the catalyst, tetrahydrofuran is selectively oxidized to γ-butyrolactone in the presence of an oxidant. It can be used for the resource-based conversion of byproduct tetrahydrofuran in a γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system, achieving closed-loop recycling of materials. Compared with existing technologies, the manganese-based catalytic system of this invention has advantages such as wide availability of raw materials, low cost, mild reaction conditions, and high product selectivity. It can effectively reduce the adverse effects of tetrahydrofuran accumulation on the system's economy during multiple hydrogen storage cycles, and has good prospects for industrial application.

Description

Technical Field

[0001] This invention relates to the fields of hydrogen energy utilization and chemical hydrogen storage technology, and in particular to a manganese-cerium composite oxide catalyst, its preparation method, and its application in the catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone. Background Technology

[0002] The γ-butyrolactone (GBL) / 1,4-butanediol (BDO) cycle system is a promising liquid organic hydrogen storage system that enables efficient hydrogen storage and reversible release. GBL is converted to BDO under hydrogenation conditions, while BDO reversibly regenerates to GBL under dehydrogenation conditions. This system exhibits good reversibility and high hydrogen storage density, attracting widespread attention in the field of hydrogen energy storage and utilization.

[0003] However, in actual operation, a small amount of tetrahydrofuran (THF) byproduct is inevitably generated in both the hydrogenation process of GBL and the dehydrogenation process of BDO. Although the amount of THF generated in a single reaction is low, after multiple cycles, THF will gradually accumulate, causing the composition of the hydrogen storage system to deviate from the design equilibrium, thereby significantly reducing the hydrogen storage efficiency and overall economy of the system.

[0004] Tetrahydrofuran (THF) has a low boiling point (approximately 66 °C), which differs significantly from the boiling points of GBL and BDO, making it relatively easy to separate using methods such as distillation. Removing THF through separation can purify the hydrogen storage system to some extent. However, the separated THF is often present in large quantities, and if it cannot be effectively utilized, additional storage and processing issues will arise. If the separated THF can be further converted into GBL, it is hoped that a closed-loop material cycle for the hydrogen storage system can be achieved, fundamentally improving the system's economics and sustainability.

[0005] However, there are relatively few research reports on the oxidation of tetrahydrofuran to prepare γ-butyrolactone, and the overall performance of existing catalytic systems is limited. For example, some studies have reported the selective oxidation of THF using Au / CeO2 catalysts, with a THF conversion of 47.8% and a GBL yield of only 15.4% (Chem Commun (Camb), 2020, Volume 56, Pages 2638-2641); using H2O2 as an oxidant at 80 °C, the THF conversion was 47.3% and the GBL yield was 41.7% (Catalysts, 2023, Volume 13, Pages 692-709). Furthermore, the ZnFe2O4@γ-Al2O3 catalytic system achieved a THF conversion of 48.1% and a GBL selectivity of 83.9% at 85 °C (Molecules, 2023, Volume 28, Pages 7192-7209); using an iron-based clay catalyst with H2O2 as the oxidant, the THF conversion was 26.9% and the GBL yield was 16.7% at 50–66 °C (Green Chemistry, 2015, Volume 17, Pages 435-441). Comparison of different titanosilicate catalysts showed that TS-1 exhibited the highest catalytic activity, with a conversion of 49 mol%, a γ-butyrolactone selectivity of 91%, and an α-hydroxytetrahydrofuran selectivity of 3.6% (JournaLoM Folecular Catalysis A: 2011, 338, Pages 105-110). In summary, existing catalytic systems for the oxidation of tetrahydrofuran to prepare γ-butyrolactone still suffer from problems such as low conversion or selectivity, high catalyst cost, and demanding process conditions. Overall, the technology lacks maturity and cannot meet the demands of large-scale and industrial applications. Therefore, developing a highly efficient, stable, and economical catalyst and method for the oxidation of tetrahydrofuran to prepare γ-butyrolactone is of significant research importance and application value. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a manganese-cerium composite oxide catalyst, its preparation method, and its application in the catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone. This invention addresses the problem that existing γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage systems inevitably generate and accumulate tetrahydrofuran during circulation, leading to a decrease in system economy and hydrogen storage efficiency. It also addresses the shortcomings of existing tetrahydrofuran oxidation catalytic systems for preparing γ-butyrolactone, such as low conversion rate and selectivity, high catalyst cost, harsh process conditions, and insufficient industrial applicability. This invention provides a highly efficient, stable, and economical manganese-based catalyst and its method for catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone. By constructing a manganese-based catalyst (manganese-cerium composite oxide catalyst) with excellent oxidation activity, the efficient conversion of tetrahydrofuran to γ-butyrolactone is achieved under mild conditions. This converts the byproduct tetrahydrofuran generated in the liquid organic hydrogen storage system back into the hydrogen storage feedstock γ-butyrolactone, achieving a closed-loop material cycle and improving the overall efficiency, economy, and sustainability of the hydrogen storage system.

[0007] The objective of this invention can be achieved through the following technical solutions: The first objective of this invention is to provide a method for preparing a manganese-cerium composite oxide catalyst, the method comprising the following steps: Preparation of solution A: Dissolve manganese source and cerium source in water and stir to obtain solution A; Preparation of manganese-cerium composite oxide precursor: Ammonium bicarbonate aqueous solution was added dropwise to the obtained solution A. After the addition was completed, the resulting suspension was aged, the precipitate was separated, and the precipitate was washed to obtain the washed precipitate. The washed precipitate was dried to obtain the manganese-cerium composite oxide precursor. Preparation of manganese-cerium composite oxide catalyst: The obtained manganese-cerium composite oxide precursor was calcined and cooled to obtain the manganese-cerium composite oxide catalyst.

[0008] Furthermore, in the process of preparing solution A, the manganese source is one of manganese nitrate aqueous solution, manganese acetate, manganese sulfate, and manganese chloride, preferably manganese nitrate aqueous solution.

[0009] Furthermore, the manganese nitrate aqueous solution has a mass fraction of 50 wt%.

[0010] Furthermore, in the process of preparing solution A, the cerium source is a cerium salt.

[0011] Furthermore, the cerium salt is cerium nitrate hexahydrate.

[0012] Furthermore, the molar ratio of cerium to manganese in solution A is 0.00046 to 0.46:1.

[0013] Furthermore, the dropping step includes: adding solution B to solution A at a dropping rate of 8-15 mL / min at room temperature, while continuously stirring during the dropping process until the pH value of the reaction system reaches about 6, thus completing the dropping.

[0014] More preferably, the dropping step includes: adding solution B to solution A at a dropping rate of 10 mL / min at room temperature, while continuously stirring during the dropping process until the pH value of the reaction system reaches about 6, thus completing the dropping.

[0015] Furthermore, in the process of preparing the manganese cerium composite oxide precursor, the aging treatment time is 0.5~2h.

[0016] More preferably, the aging treatment time is 1 hour during the preparation of the manganese cerium composite oxide precursor.

[0017] Furthermore, during the preparation of the manganese-cerium composite oxide precursor, the resulting precipitate is separated by filtration.

[0018] Furthermore, in the process of preparing the manganese-cerium composite oxide precursor, the washing involves washing the precipitate with water 3 to 8 times.

[0019] More preferably, in the process of preparing the manganese cerium composite oxide precursor, the washing involves washing the precipitate five times with water.

[0020] Furthermore, in the process of preparing the manganese-cerium composite oxide precursor, the drying conditions are: drying in a vacuum drying oven at 50~70 ℃ for 8~18 hours.

[0021] More preferably, in the process of preparing the manganese cerium composite oxide precursor, the drying conditions are: drying in a vacuum drying oven at 60 °C for 12 hours.

[0022] Furthermore, in the process of preparing the manganese-cerium composite oxide catalyst, the calcination conditions are: calcination at 500~700℃ for 3~6 hours.

[0023] More preferably, in the process of preparing the manganese-cerium composite oxide catalyst, the calcination conditions are: calcination at 600°C for 4 hours.

[0024] A second objective of this invention is to provide a manganese-cerium composite oxide catalyst, which comprises manganese oxide and cerium oxide.

[0025] Furthermore, the manganese-cerium composite oxide catalyst comprises manganese oxide as the host phase and further comprises cerium oxide.

[0026] Furthermore, in the manganese-cerium composite oxide catalysis, the cerium oxide has a mass fraction of 1-50 wt% as CeO2.

[0027] The third objective of this invention is to provide an application of a manganese-cerium composite oxide catalyst in the catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone, wherein the manganese-cerium composite oxide catalyst is used to catalyze the oxidation of tetrahydrofuran to generate γ-butyrolactone in the presence of an oxidant.

[0028] Furthermore, the tetrahydrofuran is derived from a γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system, and this application is used to suppress the accumulation of tetrahydrofuran during multiple hydrogen storage cycles.

[0029] Furthermore, this application achieves the selective conversion of tetrahydrofuran to γ-butyrolactone without significantly reducing the cycle efficiency of the liquid organic hydrogen storage system.

[0030] Furthermore, the process of catalyzing the oxidation of tetrahydrofuran to γ-butyrolactone using the aforementioned manganese-cerium composite oxide catalyst includes the following conditions: carried out at a temperature of 40-120°C, wherein the oxidant is selected from one or more of molecular oxygen, air, or hydrogen peroxide.

[0031] The fourth objective of this invention is to provide a method for the resource-based conversion of tetrahydrofuran, a byproduct of a liquid organic hydrogen storage cycle system. Under the presence of an oxidant, a manganese-cerium composite oxide catalyst is used to catalyze the oxidation of tetrahydrofuran to γ-butyrolactone. The tetrahydrofuran originates from a γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system. This method is used for the efficient conversion of accumulated THF during multiple hydrogen storage cycles in the γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system.

[0032] This invention relates to a manganese-cerium composite oxide catalyst, its preparation method, and its application in the catalytic oxidation of tetrahydrofuran to γ-butyrolactone, belonging to the field of hydrogen energy utilization and chemical hydrogen storage technology. Using a manganese-cerium composite oxide catalyst (manganese-based oxide) as the catalyst, tetrahydrofuran is selectively oxidized to γ-butyrolactone in the presence of an oxidant. It can be used for the resource-based conversion of byproduct tetrahydrofuran in a γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system, achieving closed-loop recycling of materials. Compared with existing technologies, the manganese-based catalytic system of this invention has advantages such as wide availability of raw materials, low cost, mild reaction conditions, and high product selectivity. It can effectively reduce the adverse economic impact of tetrahydrofuran accumulation during multiple hydrogen storage cycles, and has good prospects for industrial application.

[0033] Compared with the prior art, the present invention has the following beneficial effects: 1) This invention provides a manganese-cerium composite oxide catalyst, its preparation method, and its application in the catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone. It can realize the closed-loop material circulation of liquid organic hydrogen storage system. This invention can efficiently convert tetrahydrofuran, a byproduct generated in the γ-butyrolactone / 1,4-butanediol hydrogen storage system, into γ-butyrolactone, effectively avoiding the accumulation of tetrahydrofuran in multiple cycles, and fundamentally improving the long-term stability and hydrogen storage efficiency of the hydrogen storage system.

[0034] 2) This invention provides a manganese-cerium composite oxide catalyst, its preparation method, and its application in the catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone. The catalyst is low in cost and abundant in resources, and has industrialization potential. It uses a manganese-based catalyst (manganese-cerium composite oxide catalyst) as the core active component. Manganese resources are abundant, inexpensive, and environmentally friendly. Compared with precious metal catalytic systems, it significantly reduces the cost of the catalyst and has good prospects for large-scale application.

[0035] 3) This invention provides a manganese-cerium composite oxide catalyst, its preparation method, and its application in the catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone. It exhibits high conversion rate of tetrahydrofuran and selectivity for γ-butyrolactone. The manganese-based catalyst (manganese-cerium composite oxide catalyst) demonstrates excellent catalytic performance in the tetrahydrofuran oxidation reaction, and can achieve high tetrahydrofuran conversion rate and γ-butyrolactone selectivity under relatively mild reaction conditions, which is significantly better than some of the catalytic systems reported in the prior art.

[0036] 4) This invention provides a manganese-cerium composite oxide catalyst, its preparation method, and its application in the catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone. This is beneficial to improving the overall economic efficiency of liquid organic hydrogen storage systems. By converting tetrahydrofuran, a byproduct that originally needed to be treated or discharged, into high-value hydrogen storage feedstock γ-butyrolactone, not only are the byproduct treatment costs reduced, but the utilization rate of system feedstock is also improved, significantly enhancing the economic competitiveness of liquid organic hydrogen storage systems.

[0037] 5) This invention provides a manganese-cerium composite oxide catalyst, its preparation method, and its application in the catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone. It proposes a manganese-based catalytic oxidation method for preparing γ-butyrolactone from tetrahydrofuran, which can be widely applied as an important supporting technology for liquid organic hydrogen storage systems. It can also be extended to the green oxidation conversion of tetrahydrofuran-related fine chemicals, showing broad application prospects. Attached Figure Description

[0038] Figure 1 The image shows the XRD pattern of the manganese-cerium composite oxide catalyst prepared in the examples.

[0039] Figure 2 The image shows the H2-TPR curve of the manganese-cerium composite oxide catalyst prepared in the examples.

[0040] Figure 3 The image shows the XPS plot of the manganese-cerium composite oxide catalyst prepared in the examples, where A represents Mn 3s, B represents Mn 2p, and C represents O 1s. Detailed Implementation

[0041] The present invention will now be described in detail with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Component models, material names, connection structures, control methods, and other features not explicitly stated in this technical solution are considered to be common technical features disclosed in the prior art.

[0042] In the examples below, unless otherwise specified, the reagents used are commercially available products and the methods employed are those known in the art.

[0043] Example 1 This embodiment provides a method for preparing a manganese-cerium composite oxide catalyst (Ce / Mn2O3-x), wherein the method employs a precipitation method to prepare the manganese-cerium composite oxide catalyst. The phase structure of the synthesized catalyst is shown in [reference needed]. Figure 1 The reduction behavior of the catalyst is shown in Figure 2 This indicates that the introduction of CeO2 has little effect on the reduction of Mn2O3. For example... Figure 3 The image shown is the XPS image of the prepared manganese-cerium composite oxide catalyst. The catalyst surface is Mn2O3, and the addition of Ce did not significantly change the composition and electronic state of Mn2O3.

[0044] The preparation method includes the following steps: First, prepare solution A: Dissolve manganese nitrate aqueous solution (mass fraction of 50 wt%) and cerium nitrate hexahydrate together in 150 mL of deionized water at a predetermined molar ratio, and stir thoroughly to form a homogeneous mixed solution, i.e., solution A.

[0045] Subsequently, solution B was prepared by dissolving ammonium bicarbonate in deionized water to obtain a 1 mol / L ammonium bicarbonate aqueous solution, i.e., solution B.

[0046] At room temperature, solution B was slowly added dropwise to solution A at a rate of 10 mL / min using a peristaltic pump, with continuous stirring during the addition, until the pH of the reaction system reached approximately 6. After the addition was complete, the resulting suspension was aged for 1 hour. After aging, the precipitate was separated by filtration and washed five times with deionized water to remove residual ions. Subsequently, the washed precipitate was dried in a vacuum drying oven at 60 °C for 12 hours to obtain a manganese-cerium composite oxide precursor. The precursor was then calcined in a muffle furnace at 600 °C for 4 hours, and after calcination, it was naturally cooled to room temperature to obtain the manganese-cerium composite oxide catalyst. The obtained sample was denoted as Ce / Mn₂O₃, where x represents the theoretical content of cerium oxide as CeO₂.

[0047] Example 2 This embodiment provides a method for preparing a manganese-cerium composite oxide catalyst (Ce / Mn2O3-0.1). The preparation method is as follows: Ce / Mn2O3-x is prepared according to the method in Example 1, where x = 0.1, and the molar ratio of Ce to Mn precursor in the raw materials is Ce / Mn = 0.00046:1.

[0048] Performance Evaluation: The catalyst was used in an oxidative conversion experiment of tetrahydrofuran, a byproduct of a liquid organic hydrogen storage system (γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system). The operation was carried out in a high-pressure reactor at a pressure of 0.5 MPa. In this example, oxygen was used as the oxidant, 0.5 g of catalyst was loaded, and 10 ml of THF was used. The reaction temperature was 100 °C. o C, reaction time was 2 h. Experimental results showed that the conversion rate of tetrahydrofuran was 44%, and the selectivity of γ-butyrolactone was 78%. The catalyst remained stable after 5 cycles, and no significant decrease in activity was observed.

[0049] Example 3 This embodiment provides a method for preparing a manganese-cerium composite oxide catalyst (Ce / Mn2O3-1). The preparation method is as follows: Ce / Mn2O3-x is prepared according to the method in Example 1, where x = 1. The molar ratio of Ce to Mn precursor in the raw materials is Ce / Mn = 0.0046:1.

[0050] Performance Evaluation: The catalyst was used in an oxidative conversion experiment of tetrahydrofuran, a byproduct of a liquid organic hydrogen storage system (γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system). The operation was carried out in a high-pressure reactor at a pressure of 0.5 MPa. In this example, oxygen was used as the oxidant, 0.5 g of catalyst was loaded, and 10 ml of THF was used. The reaction temperature was 100 °C. oC, reaction time was 2 h. Experimental results showed that the conversion rate of tetrahydrofuran was 54%, and the selectivity of γ-butyrolactone was 80%. The catalyst remained stable after 5 cycles, and no significant decrease in activity was observed.

[0051] Example 4 This embodiment provides a method for preparing a manganese-cerium composite oxide catalyst (Ce / Mn2O3-5). The preparation method is as follows: Ce / Mn2O3-x, where x = 5, is prepared according to the method in Example 1. The molar ratio of Ce to Mn precursor in the raw materials is Ce / Mn = 0.0242:1.

[0052] Performance Evaluation: The catalyst was used in an oxidative conversion experiment of tetrahydrofuran, a byproduct of a liquid organic hydrogen storage system (γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system). The operation was carried out in a high-pressure reactor at a pressure of 0.5 MPa. In this example, oxygen was used as the oxidant, 0.5 g of catalyst was loaded, and 10 ml of THF was used. The reaction temperature was 100 °C. o C, reaction time was 2 h. Experimental results showed that the conversion rate of tetrahydrofuran was 86%, and the selectivity of γ-butyrolactone was 91%. The catalyst remained stable after 5 cycles, and no significant decrease in activity was observed.

[0053] Example 5 This embodiment provides a method for preparing a manganese-cerium composite oxide catalyst (Ce / Mn2O3-10). The preparation method is as follows: Ce / Mn2O3-x, where x = 10, is prepared according to the method in Example 1. The molar ratio of Ce to Mn precursor in the raw materials is Ce / Mn = 0.051:1.

[0054] Performance Evaluation: The catalyst was used in an oxidative conversion experiment of tetrahydrofuran, a byproduct of a liquid organic hydrogen storage system (γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system). The operation was carried out in a high-pressure reactor at a pressure of 0.5 MPa. In this example, oxygen was used as the oxidant, 0.5 g of catalyst was loaded, and 10 ml of THF was used. The reaction temperature was 100 °C. o C, reaction time was 2 h. Experimental results showed that the conversion rate of tetrahydrofuran was 79%, and the selectivity of γ-butyrolactone was 90%. The catalyst remained stable after 5 cycles, and no significant decrease in activity was observed.

[0055] Example 6 This embodiment provides a method for preparing a manganese-cerium composite oxide catalyst (Ce / Mn2O3-30). The preparation method is as follows: Ce / Mn2O3-x, where x = 30, is prepared according to the method in Example 1. The molar ratio of Ce to Mn precursor in the raw materials is Ce / Mn = 0.197:1.

[0056] Performance Evaluation: The catalyst was used in an oxidative conversion experiment of tetrahydrofuran, a byproduct of a liquid organic hydrogen storage system (γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system). The operation was carried out in a high-pressure reactor at a pressure of 0.5 MPa. In this example, oxygen was used as the oxidant, 0.5 g of catalyst was loaded, and 10 ml of THF was used. The reaction temperature was 100 °C. o C, reaction time was 2 h. Experimental results showed that the conversion rate of tetrahydrofuran was 79% and the selectivity of γ-butyrolactone was 88%. The catalyst remained stable after 5 cycles, and no significant decrease in activity was observed.

[0057] Example 7 This embodiment provides a method for preparing a manganese-cerium composite oxide catalyst (Ce / Mn2O3-50). The preparation method is as follows: Ce / Mn2O3-x, where x = 50, is prepared according to the method in Example 1. The molar ratio of Ce to Mn precursor in the raw materials is Ce / Mn = 0.46:1.

[0058] Performance Evaluation: The catalyst was used in an oxidative conversion experiment of tetrahydrofuran, a byproduct of a liquid organic hydrogen storage system (γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system). The operation was carried out in a high-pressure reactor at a pressure of 0.5 MPa. In this example, air was used as the oxidant, 0.5 g of catalyst was loaded, and 10 ml of THF was used. The reaction temperature was 100 °C. o C, reaction time was 2 h. Experimental results showed that the tetrahydrofuran conversion rate was 69% and the γ-butyrolactone selectivity was 79%. In multiple cycles (≥5 cycles), the catalyst maintained good activity and selectivity, demonstrating the synergistic effect of increased Ce content on catalytic performance.

[0059] Comparative Example 1 This comparative example provides a method for preparing a Mn2O3 catalyst. The preparation method involves using a precipitation method to prepare Mn2O3 without adding Ce (specifically, without adding cerium nitrate hexahydrate). Other conditions are the same as in Example 1.

[0060] Performance evaluation: The conversion rate of tetrahydrofuran was 43%, and the selectivity of γ-butyrolactone was 71%.

[0061] The results show that the catalytic performance of Mn2O3 alone is low and cannot achieve the effect of the Mn-Ce composite system.

[0062] Comparative Example 2 This comparative example provides a method for preparing a CeO2 catalyst. The preparation method involves using a precipitation method to prepare the CeO2 catalyst without adding Mn (specifically, without adding an aqueous solution of manganese nitrate (mass fraction of 50 wt%)). Other conditions are the same as in Example 1.

[0063] Performance evaluation: The tetrahydrofuran conversion rate was 5%, and the selectivity for γ-butyrolactone was 44%.

[0064] The catalytic effect of single CeO2 is not as good as that of Mn-Ce composite oxide.

[0065] The above examples and comparative experimental results show that the Mn-Ce composite oxide catalyst has significant advantages in the oxidation of tetrahydrofuran to γ-butyrolactone in a liquid organic hydrogen storage system (γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system). Changing the Ce content can adjust the selectivity and conversion rate of the catalyst; when x is between 5 and 30, the selectivity and conversion rate of the catalyst remain at a high level. The performance of single Mn2O3 or CeO2 catalysts is significantly lower than that of the Mn-Ce composite oxide, demonstrating the synergistic effect of the composite system.

[0066] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments in the catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for producing a manganese-cerium composite oxide catalyst, characterized by, The manganese-cerium composite oxide catalyst is used as a catalyst for the oxidation of tetrahydrofuran to prepare γ-butyrolactone; The preparation method includes the following steps: Preparation of solution A: Dissolve manganese source and cerium source in water and stir to obtain solution A; Preparation of manganese-cerium composite oxide precursor: Ammonium bicarbonate aqueous solution was added dropwise to the obtained solution A. After the addition was completed, the resulting suspension was aged, the precipitate was separated, and the precipitate was washed to obtain the washed precipitate. The washed precipitate was dried to obtain the manganese-cerium composite oxide precursor. Preparation of manganese-cerium composite oxide catalyst: The obtained manganese-cerium composite oxide precursor was calcined and cooled to obtain the manganese-cerium composite oxide catalyst.

2. The method for producing a manganese cerium composite oxide catalyst according to claim 1, characterized by, In the process of preparing solution A, the manganese source is one of manganese nitrate aqueous solution, manganese acetate, manganese sulfate, and manganese chloride; The manganese nitrate aqueous solution has a mass fraction of 50 wt%. In the process of preparing solution A, the cerium source is a cerium salt; The cerium salt is cerium nitrate hexahydrate.

3. The method for producing a manganese cerium composite oxide catalyst according to claim 1, characterized by, The molar ratio of cerium to manganese in solution A is 0.00046 to 0.46:

1.

4. The method for producing a manganese cerium composite oxide catalyst according to claim 1, characterized by, In the process of preparing the manganese cerium composite oxide precursor, the dropping step includes: adding solution B to solution A at a dropping rate of 8~15 mL / min at room temperature, while continuously stirring during the dropping process until the pH value of the reaction system reaches 6, thus completing the dropping; In the process of preparing the manganese-cerium composite oxide precursor, the aging treatment time is 0.5~2 h; In the process of preparing manganese-cerium composite oxide precursor, the precipitate obtained is separated by suction filtration; In the process of preparing the manganese cerium composite oxide precursor, the washing involves washing the precipitate with water 3 to 8 times. In the process of preparing the manganese-cerium composite oxide precursor, the drying conditions are: drying in a vacuum drying oven at 50~70 ℃ for 8~18 hours.

5. The method for producing a manganese cerium composite oxide catalyst according to claim 1, characterized by, In the process of preparing manganese-cerium composite oxide catalyst, the calcination conditions are: calcination at 500~700 ℃ for 3~6 hours.

6. A manganese-cerium composite oxide catalyst prepared by the method described in any one of claims 1-5, characterized in that, The manganese-cerium composite oxide catalyst comprises manganese oxide and cerium oxide.

7. The manganese-cerium composite oxide catalyst according to claim 6, characterized in that, The manganese-cerium composite oxide catalyst uses manganese oxide as the main phase. In the manganese-cerium composite oxide catalysis, the cerium oxide has a mass fraction of 1-50 wt% as CeO2.

8. The application of a manganese-cerium composite oxide catalyst prepared by the method described in any one of claims 1-5 in the catalytic oxidation of tetrahydrofuran to prepare γ-butyrolactone, characterized in that, In the presence of an oxidant, the manganese-cerium composite oxide catalyst is used to catalyze the oxidation of tetrahydrofuran to γ-butyrolactone. The tetrahydrofuran is derived from the γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system.

9. The application according to claim 7, characterized in that, The process of catalyzing the oxidation of tetrahydrofuran to γ-butyrolactone using the aforementioned manganese-cerium composite oxide catalyst includes the following conditions: the process is carried out at a temperature of 40-120°C, and the oxidant is selected from one or more of molecular oxygen, air, or hydrogen peroxide.

10. A method for the resource-based conversion of tetrahydrofuran, a byproduct, in a liquid organic hydrogen storage cycle system, characterized in that, In the presence of an oxidant, the manganese-cerium composite oxide catalyst prepared by the preparation method according to any one of claims 1-5 catalyzes the oxidation of tetrahydrofuran to γ-butyrolactone, wherein the tetrahydrofuran originates from the γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system. The method is used to convert accumulated THF during multiple hydrogen storage cycles in a γ-butyrolactone / 1,4-butanediol liquid organic hydrogen storage cycle system.

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