Preparation method and application of CeO / CuO composite catalyst with rod-like cerium dioxide embedded in Cu MOF

Abstract

The invention belongs to the technical field of catalysts, and particularly relates to a preparation method and application of a CeO / CuO composite catalyst with rod-like cerium dioxide embedded in Cu MOF. The CeO / CuO composite catalyst can be used for hydrogen evolution and oxygen evolution catalytic reaction in water decomposition. According to the preparation method, N, N-dimethylformamide is used as a solvent in the synthesis process, a copper source is introduced, trimesic acid and polyvinylpyrrolidone K15-19 are used as a morphology regulating agent and a coordination agent, and cerium dioxide nanorods with different contents are added in the synthesis process. The preparation method comprises the following steps: uniformly growing Cu MOF in situ and wrapping the periphery of a cerium dioxide nanorod by properly controlling reaction conditions to form a material which is embedded with rod-like cerium dioxide in the Cu MOF and has octahedral morphology, and carrying out calcination treatment to form the CeO / CuO composite catalyst. The CeO / CuO composite catalyst which is uniform and controllable in morphology, ultrahigh in dispersity and good in two-phase contact is obtained through the preparation method, and the catalytic performance can be effectively improved. Meanwhile, the method has the advantages of simple preparation, controllable process, low cost and the like.

Description

Technical Field

[0001] The present invention provides a CeO2 composite material with rod-shaped cerium dioxide embedded in Cu MOF. 2 The invention discloses a preparation method and application of a CuO / CuO composite catalyst, belonging to the field of catalytic materials with water-decomposing hydrogen performance. Background Art

[0002] Hydrogen energy is a clean and efficient energy carrier. Among the many hydrogen production technologies, the production of hydrogen by water decomposition (including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER)) is considered to be the most promising clean hydrogen production route. However, the reaction kinetics of the water decomposition process are slow, and efficient and stable electrocatalysts are required to reduce the overpotential of the reaction and increase the reaction rate. Therefore, the development of electrocatalysts with high activity, stability and economy is a research hotspot and difficulty in the field of water decomposition.

[0003] Currently, catalysts based on transition metal oxides (such as CuO, NiO, CoO, etc.) have attracted much attention due to their abundant resources, high redox activity and low cost. However, these catalysts often have deficiencies in activity and stability. To further improve the catalytic performance, researchers have tried to combine transition metal oxides with rare earth oxides to optimize the electronic structure and surface chemical properties of the catalyst.

[0004] Cerium dioxide (CeO 2 As a typical rare earth oxide, CeO has been widely used in various catalytic reactions due to its unique redox properties, oxygen storage / release capacity and good surface chemical stability. 2 When combined with CuO, the electrocatalytic performance of the composite material can be significantly improved. 2 In the composite material, the electronic structure and active site distribution of CuO can be regulated to enhance the synergistic catalytic effect of the catalyst on hydrogen evolution and oxygen evolution reactions.

[0005] In addition, in recent years, metal organic framework (MOF) materials have become an important platform for designing new composite catalysts due to their high specific surface area, tunable pore structure and abundant metal centers. Cu MOF is a copper-based MOF material with excellent metal coordination environment and thermal stability, and is an important precursor material for highly active copper-based catalysts. However, single MOF-derived catalysts have deficiencies in conductivity and structural stability. Therefore, CeO 2 Nanorods embedded in Cu MOF-derived materials can form a synergistic CeO 2 / CuO composite materials, thereby achieving efficient water splitting catalytic performance.

[0006] Based on this, the present invention proposes a method of embedding CeO in Cu MOF. 2 Preparation of CeO by Nanorod Method 2 / CuO composite catalyst, and demonstrated its excellent performance in water splitting to produce hydrogen. This catalyst solves the problem of insufficient activity and stability in existing catalysts by optimizing material structure and interface effect, providing new ideas and technical support for the development of efficient water electrolysis catalysts. Summary of the invention

[0007] The present invention provides a CeO2 composite material with rod-shaped cerium dioxide embedded in Cu MOF. 2 Preparation method of / CuO composite catalyst and its application in water decomposition to produce hydrogen. 2 The synergistic effect between the nanorods achieves high activity and excellent stability of the catalyst in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).

[0008] The technical solution of the present invention is: the catalyst of the present invention is composed of Cu MOF and CeO 2 Nanorods are composited and derived into CuO and CeO through calcination process. 2 Nanocomposite structure (CeO 2 / CuO). Among them, CeO 2 The introduction of nanorods can effectively regulate the electronic structure of CuO and provide additional active sites, while improving the conductivity and structural stability of the material. Using N,N-dimethylformamide as a solvent can provide a uniform reaction environment and promote the uniform distribution of metal ions and ligands, which is beneficial to the crystal growth of MOF. When used as a reaction solvent, the high polarity of N,N-dimethylformamide helps to accelerate the dissolution and reaction rate while reducing the occurrence of side reactions. 2 In the composite process of nanorods and Cu MOF, N,N-dimethylformamide can be used as a structural regulator. The carbonyl and amine groups in its molecules can weakly coordinate with metal ions to control the morphology of the material. In the solvothermal reaction, the high boiling point of N,N-dimethylformamide allows the reaction to proceed at high temperatures, promotes the formation of nanorod morphology, and improves the crystallinity of the material. Its polar groups can stabilize the dispersion state of metal salts and organic molecules, prevent the aggregation of particles during the reaction, thereby improving the uniformity of the composite material and the exposure of surface active sites. It can form weakly coordinated complexes with metal ions or organic ligands to avoid excessive reaction of ligands with metals or the formation of unnecessary by-products, thereby improving the purity of the target product.

[0009] A rod-shaped CeO embedded in Cu MOF 2 / CuO composite catalyst, the catalyst is prepared from the following components: N,N-dimethylformamide is used as solvent, and different amounts of cerium dioxide nanorods are added during the synthesis process. By properly controlling the reaction conditions, Cu MOF grows uniformly in situ and wraps around the cerium dioxide nanorods, forming a material with an octahedral morphology in which rod-shaped cerium dioxide is embedded in the Cu MOF, and CeO is formed by calcination. 2 / CuO composite catalyst.

[0010] In the technical solution of the present invention, based on the mass of the carrier of cerium dioxide nanorods, the mass percentage content of the active component Cu MOF is 60% to 99%.

[0011] One of the purposes of the present invention is to provide a CeO2 composite having rod-shaped cerium oxide embedded in a Cu MOF. 2 A method for preparing a CuO / CuO composite catalyst, the method comprising the following steps: First, measure an equal amount of N,N-dimethylformamide solution and set aside.

[0012] Prepare dispersion A by mixing an appropriate amount of cerium dioxide nanorod powder and an appropriate amount of copper nitrate hexahydrate in an equal proportion of N,N-dimethylformamide solution to obtain dispersion A.

[0013] Solution B was prepared by dissolving an appropriate amount of polyvinylpyrrolidone K15-19 and an appropriate amount of trimesic acid in an equal proportion of N,N-dimethylformamide solution to obtain solution B.

[0014] Add solution B into dispersion A and stir thoroughly to obtain CeO 2 / Cu MOF precursor slurry; The reaction system was constructed and CeO 2 / Cu MOF precursor slurry solution is transferred to a hydrothermal reactor, the reactor is sealed, and a hydrothermal reaction is performed at a set temperature and time. After the reaction is completed, N,N-dimethylformamide and ethanol are centrifuged and washed. Drying is performed at a specific temperature to obtain the material having rod-shaped cerium dioxide embedded in the Cu MOF and having an octahedral morphology; The dried material was transferred to a corundum crucible and placed in a muffle furnace. Calcinated at a constant temperature and cooled naturally to room temperature to obtain CeO 2 / CuO composite catalyst.

[0015] In the above method, the mass ratio of the copper source, polyvinyl pyrrolidone K15-19 and trimesic acid is (1-40):(1-10):(1-25). The mass of N,N-dimethylformamide solvent is 10ml-600ml.

[0016] In the above method, cerium dioxide is derived from cerium dioxide nanorod dry powder, with a size of aspect ratio of 10-500 and a diameter of 0.5-100 nm.

[0017] In the above method: during the heating process, the heating temperature is 40-180°C and the heating time is 2-72 hours.

[0018] In the above method: during the calcination process, the calcination temperature is 300-850°C, the heating rate is 5-25°C / min, and the calcination time is 3-15 hours.

[0019] In the technical solution of the present invention, the catalyst can be used to produce hydrogen energy in water decomposition.

[0020] Beneficial effects: The advantages of the present invention are that N,N-dimethylformamide is used as solvent, CeO 2 The nanorods significantly improve the activity of CuO through oxygen defect regulation and electron transfer mechanism. The composite catalyst has a low overpotential in HER and OER, showing excellent bifunctional catalytic performance. CeO 2 The structural support and corrosion resistance provided by the nanorods enable the catalyst to maintain high activity and stability in long-term cycle tests. The method of the present invention is simple and easy to implement, suitable for large-scale preparation, and no expensive raw materials are used in the preparation process, which is cost-effective. In addition to the application in water electrolysis, the composite catalyst of the present invention can also be widely used in other electrocatalytic reactions (such as carbon dioxide reduction and electrocatalytic nitrogen reduction), providing new ideas for the development of multifunctional electrocatalysts. The present invention combines CeO 2 The introduction of Cu MOF-derived materials into nanorods significantly improves the comprehensive performance of the catalyst, providing an innovative solution for the development of water splitting hydrogen production technology. The high efficiency and stability of the catalyst not only help reduce the cost of hydrogen production, but also provide important technical support for the future clean energy industry. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 CeO synthesized in Experimental Example 1 2 Scanning electron micrograph of / CuO composite catalyst.

[0022] Figure 2 CeO synthesized in Experimental Example 1 2 Scanning electron micrograph of / CuO composite catalyst.

[0023] Figure 3 CeO synthesized in Experimental Example 1 2 XPS graph of / CuO composite catalyst.

[0024] Figure 4 CeO synthesized in Experimental Example 1 2 / CuO composite catalyst XRD pattern.

[0025] Figure 5 CeO synthesized in Experimental Example 1 2 / CuO composite catalyst electrochemical OER performance test diagram.

[0026] Figure 6 CeO synthesized in Experimental Example 1 2 / CuO composite catalyst electrochemical HER performance test diagram. Specific implementation methods Example

[0028] 1. Preparation of precursor solution: Take 300 mL of N,N-dimethylformamide solution and set aside.

[0029] Prepare dispersion A, weigh 5.0 g of pre-synthesized dry powdered CeO 2 Nanorods; weigh 5.0 g of copper nitrate hexahydrate; add the above raw materials into 150 mL of N,N-dimethylformamide solution, and stir magnetically for 30 minutes (speed 500 rpm) to obtain a uniformly dispersed dispersion A.

[0030] To prepare solution B, weigh 5.0 g of polyvinyl pyrrolidone K15-19 and 3.0 g of trimesic acid; add the above raw materials into 150 mL of N,N-dimethylformamide and perform ultrasonic treatment for 20 minutes to obtain a transparent solution B.

[0031] Solution B was slowly added dropwise to dispersion A and magnetically stirred for 1 hour (speed 800 rpm) to obtain a uniform CeO 2 / Cu-MOF precursor slurry.

[0032] 2. Reaction system construction: CeO 2 / Cu-MOF precursor slurry was transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor, sealed and placed in an oven for reaction at 100 °C for 10 hours (heating rate 2 °C / min). After the reaction was completed, it was naturally cooled to room temperature (about 2 hours), and the product was centrifuged (speed 5000 rpm, time 10 minutes). The precipitate was washed 3 times with N,N-dimethylformamide and ethanol (20 mL each time, centrifugal speed 5000 rpm, time 5 minutes) to remove unreacted organic matter and solvent. The washed product was placed in a vacuum drying oven and dried at 80 °C for 6 hours to obtain CeO 2 / Cu-MOF composites.

[0033] The dried sample was transferred to a corundum crucible and placed in a muffle furnace. It was heated to 450°C at a heating rate of 5°C / min in an air atmosphere and calcined at a constant temperature for 6.5 hours. It was naturally cooled to room temperature to obtain CeO 2 / CuO composite catalyst.

[0034] Embodiment 2: 1. Precursor Solution Preparation Take 300 mL of N,N-dimethylformamide and set aside.

[0035] Solution 1: Weigh 2.5 g of pre-synthesized dry powdered CeO 2 Nanorods; weigh 5.0 g of copper nitrate hexahydrate; add the above raw materials into 150 mL of N,N-dimethylformamide, and stir magnetically for 30 minutes (speed 500 rpm) to obtain a uniformly dispersed dispersion A.

[0036] Prepare solution 2: weigh 5.0 g of polyvinylpyrrolidone K15-19; weigh 3.0 g of trimesic acid; add the above raw materials into 150 mL of N,N-dimethylformamide, and ultrasonically treat for 20 minutes to obtain a transparent solution B.

[0037] Solution B was slowly added dropwise to dispersion A and magnetically stirred for 1 hour (speed 800 rpm) to obtain a uniform CeO 2 / Cu-MOF precursor slurry.

[0038] 2. Reaction system construction CeO 2 / Cu-MOF precursor slurry was transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor, sealed and placed in an oven for reaction at 100 °C for 10 hours (heating rate 2 °C / min). After the reaction was completed, it was naturally cooled to room temperature (about 2 hours), and the product was centrifuged (speed 5000 rpm, time 10 minutes). The precipitate was washed 3 times with N,N-dimethylformamide and ethanol (20 mL each time, centrifugal speed 5000 rpm, time 5 minutes) to remove unreacted organic matter and solvent. The washed product was placed in a vacuum drying oven and dried at 80 °C for 6 hours to obtain CeO 2 / Cu-MOF composites.

[0039] The dried sample was transferred to a corundum crucible and placed in a muffle furnace. It was heated to 450°C at a heating rate of 5°C / min in an air atmosphere and calcined at a constant temperature for 6.5 hours. It was naturally cooled to room temperature to obtain CeO 2 / CuO composite catalyst.

[0040] Embodiment three: 1. Precursor Solution Preparation Take 300 mL of N,N-dimethylformamide and set aside.

[0041] Solution 1: Weigh 7.5 g of pre-synthesized dry powdered CeO 2 Nanorods; weigh 5.0 g of copper nitrate hexahydrate; add the above raw materials into 150 mL of N,N-dimethylformamide, and stir magnetically for 30 minutes (speed 500 rpm) to obtain a uniformly dispersed dispersion A.

[0042] Prepare solution 2: weigh 5.0 g of polyvinylpyrrolidone K15-19; weigh 3.0 g of trimesic acid; add the above raw materials into 150 mL of N,N-dimethylformamide, and ultrasonically treat for 20 minutes to obtain a transparent solution B.

[0043] Solution B was slowly added dropwise to dispersion A and magnetically stirred for 1 hour (speed 800 rpm) to obtain a uniform CeO 2 / Cu-MOF precursor slurry.

[0044] 2. Reaction system construction CeO 2 / Cu-MOF precursor slurry was transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor, sealed and placed in an oven for reaction at 100 °C for 10 hours (heating rate 2 °C / min). After the reaction was completed, it was naturally cooled to room temperature (about 2 hours), and the product was centrifuged (speed 5000 rpm, time 10 minutes). The precipitate was washed 3 times with N,N-dimethylformamide and ethanol (20 mL each time, centrifugal speed 5000 rpm, time 5 minutes) to remove unreacted organic matter and solvent. The washed product was placed in a vacuum drying oven and dried at 80 °C for 6 hours to obtain CeO 2 / Cu-MOF composites.

[0045] The dried sample was transferred to a corundum crucible and placed in a muffle furnace. The sample was heated to 450°C at a heating rate of 5°C / min in an air atmosphere and calcined at a constant temperature for 6.5 hours. The sample was naturally cooled to room temperature to obtain CeO 2 / CuO composite catalyst.

[0046] Embodiment 4: 1. Precursor Solution Preparation Take 300 mL of N,N-dimethylformamide and set aside.

[0047] Solution 1: Weigh 10.0 g of pre-synthesized dry powdered CeO 2Nanorods; weigh 5.0 g of copper nitrate hexahydrate; add the above raw materials into 150 mL of N,N-dimethylformamide, and stir magnetically for 30 minutes (speed 500 rpm) to obtain a uniformly dispersed dispersion A.

[0048] Prepare solution 2: weigh 5.0 g of polyvinylpyrrolidone K15-19; weigh 3.0 g of trimesic acid; add the above raw materials into 150 mL of N,N-dimethylformamide, and ultrasonically treat for 20 minutes to obtain a transparent solution B.

[0049] Solution B was slowly added dropwise to dispersion A and magnetically stirred for 1 hour (speed 800 rpm) to obtain a uniform CeO 2 / Cu-MOF precursor slurry.

[0050] 2. Reaction system construction CeO 2 / Cu-MOF precursor slurry was transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor, sealed and placed in an oven for reaction at 100 °C for 10 hours (heating rate 2 °C / min). After the reaction was completed, it was naturally cooled to room temperature (about 2 hours), and the product was centrifuged (speed 5000 rpm, time 10 minutes). The precipitate was washed 3 times with N,N-dimethylformamide and ethanol (20 mL each time, centrifugal speed 5000 rpm, time 5 minutes) to remove unreacted organic matter and solvent. The washed product was placed in a vacuum drying oven and dried at 80 °C for 6 hours to obtain CeO 2 / Cu-MOF composites.

[0051] The dried sample was transferred to a corundum crucible and placed in a muffle furnace. The sample was heated to 450°C at a heating rate of 5°C / min in an air atmosphere and calcined at a constant temperature for 6.5 hours. The sample was naturally cooled to room temperature to obtain CeO 2 / CuO composite catalyst.

[0052] Embodiment 5 1. Precursor Solution Preparation Take 300 mL of N,N-dimethylformamide and set aside.

[0053] Solution 1: Weigh 5.0 g of pre-synthesized dry powdered CeO 2 Nanorods; weigh 5.0 g of copper nitrate hexahydrate; add the above raw materials into 150 mL of N,N-dimethylformamide, and stir magnetically for 30 minutes (speed 500 rpm) to obtain a uniformly dispersed dispersion A.

[0054] Prepare solution 2: weigh 7.5 g polyvinylpyrrolidone K15-19; weigh 3.0 g trimesic acid (H 3 BTC, purity>99.5%); the above raw materials were added into 150 mL N,N-dimethylformamide and ultrasonically treated for 20 minutes to obtain a transparent solution B.

[0055] Solution B was slowly added dropwise to dispersion A and magnetically stirred for 1 hour (speed 800 rpm) to obtain a uniform CeO 2 / Cu-MOF precursor slurry.

[0056] 2. Reaction system construction CeO 2 / Cu-MOF precursor slurry was transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor, sealed and placed in an oven for reaction at 100 °C for 10 hours (heating rate 2 °C / min). After the reaction was completed, it was naturally cooled to room temperature (about 2 hours), and the product was centrifuged (speed 5000 rpm, time 10 minutes). The precipitate was washed 3 times with N,N-dimethylformamide and ethanol (20 mL each time, centrifugal speed 5000 rpm, time 5 minutes) to remove unreacted organic matter and solvent. The washed product was placed in a vacuum drying oven and dried at 80 °C for 6 hours to obtain CeO 2 / Cu-MOF composites.

[0057] The dried sample was transferred to a corundum crucible and placed in a muffle furnace. The sample was heated to 450°C at a heating rate of 5°C / min in an air atmosphere and calcined at a constant temperature for 6.5 hours. The sample was naturally cooled to room temperature to obtain CeO 2 / CuO composite catalyst.

[0058] Embodiment six: 1. Precursor Solution Preparation Take 300 mL of N,N-dimethylformamide and set aside.

[0059] Solution 1: Weigh 5.0 g of pre-synthesized dry powdered CeO 2 Nanorods; weigh 5.0 g of copper nitrate hexahydrate; add the above raw materials into 150 mL of N,N-dimethylformamide, and stir magnetically for 30 minutes (speed 500 rpm) to obtain a uniformly dispersed dispersion A.

[0060] Prepare solution 2: weigh 10.0 g polyvinyl pyrrolidone K15-19; weigh 3.0 g trimesic acid (H 3 BTC, purity>99.5%); the above raw materials were added into 150 mL N,N-dimethylformamide and ultrasonically treated for 20 minutes to obtain a transparent solution B.

[0061] Solution B was slowly added dropwise to dispersion A and magnetically stirred for 1 hour (speed 800 rpm) to obtain a uniform CeO 2 / Cu-MOF precursor slurry.

[0062] 2. Reaction system construction CeO 2 / Cu-MOF precursor slurry was transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor, sealed and placed in an oven for reaction at 100 °C for 10 hours (heating rate 2 °C / min). After the reaction was completed, it was naturally cooled to room temperature (about 2 hours), and the product was centrifuged (speed 5000 rpm, time 10 minutes). The precipitate was washed 3 times with N,N-dimethylformamide and ethanol (20 mL each time, centrifugal speed 5000 rpm, time 5 minutes) to remove unreacted organic matter and solvent. The washed product was placed in a vacuum drying oven and dried at 80 °C for 6 hours to obtain CeO 2 / Cu-MOF composites.

[0063] The dried sample was transferred to a corundum crucible and placed in a muffle furnace. The sample was heated to 450°C at a heating rate of 5°C / min in an air atmosphere and calcined at a constant temperature for 6.5 hours. The sample was naturally cooled to room temperature to obtain CeO 2 / CuO composite catalyst.

[0064] Embodiment 7 1. Precursor Solution Preparation Take 300 mL of N,N-dimethylformamide and set aside.

[0065] Solution 1: Weigh 5.0 g of pre-synthesized dry powdered CeO 2 Nanorods; weigh 5.0 g of copper nitrate hexahydrate; add the above raw materials into 150 mL of N,N-dimethylformamide, and stir magnetically for 30 minutes (speed 500 rpm) to obtain a uniformly dispersed dispersion A.

[0066] Prepare solution 2: weigh 5.0 g polyvinyl pyrrolidone K15-19; weigh 4.5 g trimesic acid (H 3 BTC, purity>99.5%); the above raw materials were added into 150 mL N,N-dimethylformamide and ultrasonically treated for 20 minutes to obtain a transparent solution B.

[0067] Solution B was slowly added dropwise to dispersion A and magnetically stirred for 1 hour (speed 800 rpm) to obtain a uniform CeO 2 / Cu-MOF precursor slurry.

[0068] 2. Reaction system construction CeO 2 / Cu-MOF precursor slurry was transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor, sealed and placed in an oven for reaction at 100 °C for 10 hours (heating rate 2 °C / min). After the reaction was completed, it was naturally cooled to room temperature (about 2 hours), and the product was centrifuged (speed 5000 rpm, time 10 minutes). The precipitate was washed 3 times with N,N-dimethylformamide and ethanol (20 mL each time, centrifugal speed 5000 rpm, time 5 minutes) to remove unreacted organic matter and solvent. The washed product was placed in a vacuum drying oven and dried at 80 °C for 6 hours to obtain CeO 2 / Cu-MOF composites.

[0069] The dried sample was transferred to a corundum crucible and placed in a muffle furnace. It was heated to 450°C at a heating rate of 5°C / min in an air atmosphere and calcined at a constant temperature for 6.5 hours. It was naturally cooled to room temperature to obtain CeO 2 / CuO composite catalyst.

[0070] Embodiment eight: 1. Precursor Solution Preparation Take 300 mL of N,N-dimethylformamide and set aside.

[0071] Solution 1: Weigh 5.0 g of pre-synthesized dry powdered CeO 2 Nanorods; weigh 5.0 g of copper nitrate hexahydrate; add the above raw materials into 150 mL of N,N-dimethylformamide, and stir magnetically for 30 minutes (speed 500 rpm) to obtain a uniformly dispersed dispersion A.

[0072] Prepare solution 2: weigh 5.0 g polyvinyl pyrrolidone K15-19; weigh 6.0 g trimesic acid (H 3 BTC, purity>99.5%); the above raw materials were added into 150 mL N,N-dimethylformamide and ultrasonically treated for 20 minutes to obtain a transparent solution B.

[0073] Solution B was slowly added dropwise to dispersion A and magnetically stirred for 1 hour (speed 800 rpm) to obtain a uniform CeO 2 / Cu-MOF precursor slurry.

[0074] 2. Reaction system construction CeO 2 / Cu-MOF precursor slurry was transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor, sealed and placed in an oven for reaction at 100 °C for 10 hours (heating rate 2 °C / min). After the reaction was completed, it was naturally cooled to room temperature (about 2 hours), and the product was centrifuged (speed 5000 rpm, time 10 minutes). The precipitate was washed 3 times with N,N-dimethylformamide and ethanol (20 mL each time, centrifugal speed 5000 rpm, time 5 minutes) to remove unreacted organic matter and solvent. The washed product was placed in a vacuum drying oven and dried at 80 °C for 6 hours to obtain CeO 2 / Cu-MOF composites.

[0075] The dried sample was transferred to a corundum crucible and placed in a muffle furnace. It was heated to 450°C at a heating rate of 5°C / min in an air atmosphere and calcined at a constant temperature for 6.5 hours. It was naturally cooled to room temperature to obtain CeO 2 / CuO composite catalyst.

[0076] Embodiment 9 1. Precursor Solution Preparation Take 300 mL of N,N-dimethylformamide and set aside.

[0077] Solution 1: Weigh 5.0 g of pre-synthesized dry powdered CeO 2 Nanorods; weigh 5.0 g of copper nitrate hexahydrate; add the above raw materials into 150 mL of N,N-dimethylformamide, and stir magnetically for 30 minutes (speed 500 rpm) to obtain a uniformly dispersed dispersion A.

[0078] Prepare solution 2: weigh 5.0 g polyvinyl pyrrolidone K15-19; weigh 3.0 g trimesic acid (H 3 BTC, purity>99.5%); the above raw materials were added into 150 mL N,N-dimethylformamide and ultrasonically treated for 20 minutes to obtain a transparent solution B.

[0079] Solution B was slowly added dropwise to dispersion A and magnetically stirred for 1 hour (speed 800 rpm) to obtain a uniform CeO 2 / Cu-MOF precursor slurry.

[0080] 2. Reaction system construction CeO 2 / Cu-MOF precursor slurries were transferred to 100 mL polytetrafluoroethylene-lined hydrothermal reactors, sealed and placed in an oven for reaction at 120 °C for 12 hours (heating rate 2 °C / min). After the reaction was completed, it was naturally cooled to room temperature (about 2 hours), and the product was centrifuged (speed 5000 rpm, time 10 minutes). The precipitate was washed 3 times with N, N-dimethylformamide and ethanol (20 mL each time, centrifugal speed 5000 rpm, time 5 minutes) to remove unreacted organic matter and solvent. The washed product was placed in a vacuum drying oven and dried at 80 °C for 6 hours to obtain CeO 2 / Cu-MOF composites.

[0081] The dried sample was transferred to a corundum crucible and placed in a muffle furnace. It was heated to 450°C at a heating rate of 5°C / min in an air atmosphere and calcined at a constant temperature for 6.5 hours. It was naturally cooled to room temperature to obtain CeO 2 / CuO composite catalyst.

Claims

1. A CeO2 / CuO composite catalyst with rod-shaped cerium dioxide embedded in a Cu MOF, characterized in that: The catalyst is prepared by the following steps: using N,N-dimethylformamide as a solvent, adding a copper source, trimesic acid and polyvinyl pyrrolidone K15-19 to form a material with rod-shaped cerium dioxide embedded in a Cu MOF and having an octahedral morphology, and forming a CeO2 / CuO composite catalyst through calcination.

2. The CeO2 / CuO composite catalyst according to claim 1, characterized in that: (1) Take 10-600 mL N,N-dimethylformamide and set aside. Prepare dispersion A: Weigh 5-20 g of pre-synthesized dry powdered CeO2 nanorods; weigh 5-20 g of copper source; add the above raw materials to 10-400 mL N,N-dimethylformamide, and stir magnetically for 15-60 minutes (speed 100-8000 rpm) to obtain dispersion A. Prepare solution B: Weigh 5-20 g of polyvinylpyrrolidone K15-19 (PVP, molecular weight 10,000-15,000); weigh 2-25 g of trimesic acid (H3BTC, purity >99.5%). Add the above raw materials to 10-400 mL N,N-dimethylformamide, and ultrasonicate for 10-50 minutes (power 300 W, frequency 40 kHz) to obtain a transparent solution B. Slowly add solution B to dispersion A and stir magnetically for 10-100 minutes (speed 100-8000 rpm) to obtain a uniform CeO2 / Cu-MOF precursor slurry; (2) Transfer the CeO2 / Cu-MOF precursor slurry to a 100-500 mL polytetrafluoroethylene-lined hydrothermal reactor, seal it and place it in an oven to react at 350-600°C for 4-30 hours (heating rate 2-10°C / min). After the reaction is completed, cool it naturally to room temperature (about 2 hours) and centrifuge the product (speed 100-8000 rpm, time 5-20 minutes). Wash the precipitate with N,N-dimethylformamide and ethanol 3-6 times (5-20 mL each time, centrifugal speed 100-8000 rpm, time 5-20 minutes) to remove unreacted organic matter and solvent. The washed product is placed in a vacuum drying oven and dried at 40-180°C for 2-72 hours (vacuum degree ≤ 0.1 MPa) to obtain a CeO2 / Cu-MOF composite material. (3) The dried sample is transferred to a corundum crucible and placed in a muffle furnace. In an air atmosphere, it is heated to 300-850°C at a heating rate of 5-25°C / min and calcined at a constant temperature for 3-15 hours. Naturally cool to room temperature to obtain a CeO2 / CuO composite catalyst.

3. The preparation method according to claim 2, characterized in that: The amount of N,N-dimethylformamide added in step (1) is 10-600 ml.

4. The CeO2 / CuO composite catalyst according to claim 2, characterized in that: The cerium dioxide nanorods are mainly in the form of dry powder, with an addition amount of 5-20 g, a size of an aspect ratio of 10-500, and a diameter of 0.5-100 nm, and no further synthesis is required.

5. The preparation method according to claim 2, characterized in that: The mass ratio of copper source, polyvinyl pyrrolidone K15-19 and trimesic acid is (1-40):(1-10):(1-25).

6. The CeO2 / CuO composite catalyst according to claim 2, characterized in that: The copper sources for preparing CeO2 / CuO composite catalyst are: copper nitrate trihydrate, copper sulfate, including but not limited to the above.

7. The preparation method according to claim 2, wherein the centrifugal detergent is N,N-dimethylformamide and ethanol, the number of times is 3-6 times, the centrifuge speed is 100-8000 rpm, and the time is 5-20 minutes.

8. The preparation method according to claim 2, characterized in that: In step (2), the heating temperature is 40-180° C. and the heating time is 2-72 hours.

9. The preparation method according to claim 2, characterized in that: The calcination temperature in step (3) is 300-850°C, the heating rate is 5-25°C / min, and the calcination time is 3-15 hours.

10. The catalyst according to claim 2 is used in the production of hydrogen energy in water decomposition.

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