A high-entropy perovskite catalyst, a monolithic catalytic device and a preparation method and application thereof

Abstract

The application discloses a high-entropy perovskite catalyst, a monolithic catalytic device and a preparation method and application thereof, and belongs to the technical field of photo-thermal catalysis. The preparation method of the high-entropy perovskite catalyst comprises the following steps: adding organic acid and an organic solvent into an aqueous solution containing lanthanum ions, divalent manganese ions, cadmium ions, iron ions, cobalt ions and copper ions to obtain a mixed metal salt sol; and immersing a molecular sieve substrate in the mixed metal salt sol, and drying and calcining the immersed molecular sieve substrate to obtain the high-entropy perovskite catalyst. In addition, the application further provides application of the high-entropy perovskite catalyst or the high-entropy perovskite catalyst prepared by the above method or the monolithic catalytic device in photocatalytic degradation of VOCs. The preparation method improves the activity and stability of the catalyst in photo-thermal degradation of pollutants.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photo-thermal catalysis, in particular to a high-entropy perovskite catalyst, a monolithic catalytic device and a preparation method and application thereof. BACKGROUND

[0002] Volatile organic compounds (VOCs) are organic compounds with boiling points of 50-260℃ at room temperature, which can participate in the formation of ozone, photochemical smog and other atmospheric environment, and is an important factor to aggravate atmospheric pollution, directly affecting human health and sustainable economic and social development. Photo-thermal catalytic purification technology is expected to utilize solar energy to achieve VOCs governance and purification, and is a low-energy VOCs end treatment technology. Due to low cost and photo-thermal conversion through surface plasmon resonance, perovskite materials are applied to photo-thermal removal of VOCs. However, their narrow light absorption range and wide band gap limit their response to light, thereby affecting their application in photo-thermal degradation of VOCs. Therefore, scholars have combined noble metal oxides and perovskites to improve light absorption and response, but these methods have reduced the stability of photo-thermal catalysts, resulting in reduced photo-thermal catalytic VOCs activity. SUMMARY

[0003] The present application aims to overcome the above technical deficiencies, and provides a high-entropy perovskite catalyst, a preparation method and application thereof, which solves the technical problem of low photo-thermal catalytic VOCs activity of photo-thermal catalysts in the prior art.

[0004] To achieve the above technical purpose, the technical scheme of the present application provides a preparation method of a high-entropy perovskite catalyst, comprising the following steps:

[0005] An organic acid and an organic solvent are added to an aqueous solution containing lanthanide ions, divalent manganese ions, cadmium ions, iron ions, nickel ions and copper ions to obtain a mixed metal salt sol;

[0006] The molecular sieve substrate is immersed in the mixed metal salt sol, and the immersed molecular sieve substrate is dried and calcined to obtain the high-entropy perovskite catalyst.

[0007] In some embodiments, the aqueous solution containing lanthanide ions, divalent manganese ions, cadmium ions, iron ions, nickel ions and copper ions is obtained by dissolving lanthanum nitrate hexahydrate, manganese nitrate tetrahydrate, cadmium nitrate nonahydrate, iron nitrate nonahydrate, nickel nitrate hexahydrate and copper nitrate trihydrate in water.

[0008] In some embodiments, the mass ratio of the lanthanum nitrate hexahydrate, manganese nitrate tetrahydrate, cadmium nitrate nonahydrate, ferric nitrate nonahydrate, nickel nitrate hexahydrate and copper nitrate trihydrate is 1: (1-2): (1-2): (1-2): (1-2): (1-2).

[0009] In some embodiments, the organic acid is one or more of oxalic acid, citric acid and fruit acid.

[0010] In some embodiments, the mass ratio of the organic acid to the lanthanum nitrate hexahydrate is (1-5): 1.

[0011] In some embodiments, the mass ratio of the organic solvent to the lanthanum nitrate hexahydrate is (3-5): 1; and / or, the organic solvent is ethylene glycol.

[0012] In some embodiments, the temperature of the calcination is 500-600°C; and the time of the calcination is preferably 12-40 hours.

[0013] In addition, the present application also proposes a high-entropy perovskite catalyst prepared by the above preparation method.

[0014] Further, the present application also proposes a monolithic catalytic device obtained by packing the above high-entropy perovskite catalyst into a ring-illuminated photo-thermal catalytic reactor.

[0015] In addition, the present application also proposes the application of the above high-entropy perovskite catalyst or the high-entropy perovskite catalyst prepared by the above method or the above monolithic catalytic device in photocatalytic degradation of VOCs.

[0016] Compared with the prior art, the beneficial effects of the present application include: the preparation method of the high-entropy perovskite catalyst proposed by the present application comprises the following steps: adding an organic acid and an organic solvent into an aqueous solution containing lanthanum ions, divalent manganese ions, cadmium ions, iron ions, nickel ions and copper ions to obtain a mixed metal salt sol; and immersing a molecular sieve substrate in the mixed metal salt sol, and drying and calcining the immersed molecular sieve substrate to obtain the high-entropy perovskite catalyst. The synergistic effect of each element in the catalyst improves the light absorption and light response ability of the material, thereby improving the activity and stability of the catalyst in photo-thermal degradation of pollutants. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic structural view of a ring-illuminated photo-thermal catalytic reactor as a whole;

[0018] Figure 2 is a schematic longitudinal sectional structural view of a ring-illuminated photo-thermal catalytic reactor;

[0019] Figure 3is a schematic diagram of the transverse cross-sectional structure of the ring-illuminated photo-thermal catalytic reactor as a whole;

[0020] Figure 4 is a schematic diagram of the structure of the catalytic mesh cylinder in the ring-illuminated photo-thermal catalytic reactor;

[0021] Figure 5 is a schematic diagram of the connection structure of the long-arc xenon lamp and the inner baffling unit in the ring-illuminated photo-thermal catalytic reactor;

[0022] Figure 6 is Figure 3 a schematic diagram of the structure of the local enlargement at A of the ring-illuminated photo-thermal catalytic reactor.

[0023] Figure 7 is an XRD pattern of the high-entropy perovskite catalyst prepared in Example 1.

[0024] Figure 8 is a scanning electron microscope pattern of the high-entropy perovskite catalyst prepared in Example 1.

[0025] Figure 9 is a propylene photo-thermal catalytic activity diagram of the ring-illuminated high-entropy perovskite monolithic catalytic device prepared in Example 1 and Comparative Examples 1-5.

[0026] Figure 10 is a propylene photo-thermal catalytic stability diagram of the ring-illuminated high-entropy perovskite monolithic catalytic device prepared in Example 1 and Comparative Example 1.

[0027] Figure 11 is a surface temperature change diagram of the ring-illuminated high-entropy perovskite monolithic catalytic device prepared in Example 1 and Comparative Example 1.

[0028] Figure 12 is the illumination area of the ring-illuminated high-entropy perovskite monolithic catalytic device prepared in Example 1.

[0029] Figure 13 is a schematic diagram of the device of the flat-illuminated catalytic device.

[0030] In the figure, 1 is a reaction tube body, 11 is an outer shell, 12 is a top plate, 13 is a base, 14 is an air inlet pipe, and 15 is an air outlet pipe;

[0031] 2 is a catalytic assembly, 21 is a catalytic mesh cylinder, 211 is an inner mesh cylinder, 212 is a molecular sieve, 213 is an outer mesh cylinder, 22 is a first air flow channel, and 23 is a second air flow channel;

[0032] 3 is a photo-thermal assembly, 31 is a long-arc xenon lamp;

[0033] 4 is a baffling assembly, 41 is an inner baffling unit, 411 is an inner baffling plate, 42 is an outer baffling unit, and 421 is an outer baffling plate;

[0034] 5 is a long-arc xenon lamp, and 6 is a reactor. DETAILED DESCRIPTION

[0035] In the following description, "some embodiments", "this embodiment" and the like refer to a subset of all possible embodiments, but can also be used interchangeably with "one embodiment", "another embodiment", "at least one embodiment" or "some embodiments" such that "some embodiments", "this embodiment" and like-specific referents can refer to more than one embodiment.

[0036] If the description in the application file appears similar to "first / second", the following description is added: In the following description, the terms "first\second\third" are only used to distinguish similar objects, and do not represent a specific order of the objects. It can be understood that "first\second\third" can be interchanged in a specific order or sequence as allowed, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0037] In this embodiment, the term "and / or" only describes the association relationship of the associated objects, which means that there can be three relationships, for example, object A and / or object B, which means that object A exists alone, object A and object B exist together, and object B exists alone.

[0038] The specific embodiment provides a preparation method of a high-entropy perovskite catalyst, comprising the following steps:

[0039] An organic acid and an organic solvent are added to an aqueous solution containing lanthanum ions, divalent manganese ions, cadmium ions, iron ions, nickel ions and copper ions to obtain a mixed metal salt sol; the aqueous solution containing lanthanum ions, divalent manganese ions, cadmium ions, iron ions, nickel ions and copper ions is obtained by dissolving lanthanum nitrate hexahydrate, manganese nitrate tetrahydrate, cadmium nitrate nonahydrate, iron nitrate nonahydrate, nickel nitrate hexahydrate and copper nitrate trihydrate in water; the mass ratio of the lanthanum nitrate hexahydrate, manganese nitrate tetrahydrate, cadmium nitrate nonahydrate, iron nitrate nonahydrate, nickel nitrate hexahydrate and copper nitrate trihydrate is 1:(1-2):(1-2):(1-2):(1-2):(1-2); the organic acid is one or more of oxalic acid, citric acid and fruit acid; the mass ratio of the organic acid to the lanthanum nitrate hexahydrate is (1-5):1; the mass ratio of the organic solvent to the lanthanum nitrate hexahydrate is (3-5):1; and / or the organic solvent is ethylene glycol;

[0040] The molecular sieve substrate is immersed in the mixed metal salt sol, and the immersed molecular sieve substrate is dried and calcined at 500-600°C for 12-40 hours to obtain the high-entropy perovskite catalyst.

[0041] The embodiment also provides a high-entropy perovskite catalyst prepared by the preparation method.

[0042] The embodiment also provides a monolithic catalytic device, which is obtained by filling the high-entropy perovskite catalyst into a ring-illuminated photo-thermal catalytic reactor.

[0043] In addition, the embodiment also provides an application of the high-entropy perovskite catalyst or the high-entropy perovskite catalyst prepared by the preparation method in photocatalytic degradation of VOCs.

[0044] In addition, the embodiment also provides an application of the high-entropy perovskite catalyst or the high-entropy perovskite catalyst prepared by the preparation method or the monolithic catalytic device in photocatalytic degradation of VOCs.

[0045] The inventive concept of the present application is that: high-entropy material refers to a material composed of at least 5 or more chemical elements in an equal molar ratio or close to an equal molar ratio, and high-entropy perovskite refers to a high-entropy perovskite structure formed by a plurality of cations occupying different positions in a crystal lattice under the concept of high entropy. High-entropy material has four characteristics: high-entropy effect in thermodynamics, lattice distortion effect, delayed diffusion effect in kinetics and cocktail effect. Because of low cost and realization of photo-thermal conversion through surface plasmon resonance, perovskite material is applied to photo-thermal removal of VOCs. The cocktail effect of high-entropy material can adjust the band gap structure of the material, so that the high-entropy perovskite material has a wider light absorption range, stronger light response capability and higher photo-thermal conversion efficiency. Therefore, the high-entropy perovskite material used as a catalyst shows higher activity and stability than traditional materials, and the band gap structure of the perovskite can be reduced to improve its light absorption and light response capability. In the design of existing devices, the light illumination range of the catalyst is small, and the light utilization rate is limited. We consider that the ring design can greatly improve the light illumination area and light utilization rate of the catalyst, thereby improving the ability of the catalytic device to remove VOCs. Therefore, it is expected to construct a perovskite catalyst with high activity and strong light response through a high-entropy strategy, and to design a ring-illuminated high-entropy perovskite monolithic catalytic device, thereby improving the photo-thermal catalytic VOCs purification ability in terms of activity and stability.

[0046] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0047] The structure of the ring-illuminated photo-thermal catalytic reactor used in the following examples is as shown in Figures 1 to 6As shown, the ring-illuminated photo-thermal catalytic reactor relates to the field of air purification technology, and a photo-thermal component 3 capable of generating heat and light is arranged in the middle of the reactor to promote the efficient treatment of volatile organic compounds (VOCs) by the catalytic mesh cylinder 21. A baffle component 4 is arranged in the reaction tube body 1 to prolong the contact time of volatile organic compounds (VOCs) with the catalytic mesh cylinder 21 and improve the purification rate of volatile organic compounds (VOCs).

[0048] Please refer to Figures 1 to 6 The ring-illuminated photo-thermal catalytic reactor includes a reaction tube body 1, a catalytic component 2, a photo-thermal component 3, and a baffle component 4 arranged in sequence from the outside to the inside. The reaction tube body 1 provides a reaction space for the treatment of volatile organic compounds (VOCs), the catalytic component 2 can catalytically decompose volatile organic compounds (VOCs), the photo-thermal component 3 can emit light and heat to the catalytic component 2 to promote the purification rate of the catalytic component 2. The baffle component 4 can drive volatile organic compounds (VOCs) to pass through the catalytic mesh cylinder 21 multiple times, prolonging the contact time of volatile organic compounds (VOCs) with the catalytic mesh cylinder 21 and improving the purification rate of volatile organic compounds (VOCs).

[0049] The reaction tube body 1 is provided with volatile organic compounds (VOCs) moving along its axial direction, and the reaction tube body 1 can enclose volatile organic compounds (VOCs) inside it and drive them to move along its axial direction for purification treatment by other components.

[0050] The catalytic component 2 includes a catalytic mesh cylinder 21 for catalytic decomposition of volatile organic compounds (VOCs), and the catalytic mesh cylinder 21 forms a first air flow channel 22 with the photo-thermal component 3, and a second air flow channel 23 is formed between the catalytic mesh cylinder 21 and the reaction tube body 1. Volatile organic compounds (VOCs) can flow alternately in the first air flow channel 22 and the second air flow channel 23 to realize the guidance and movement of volatile organic compounds (VOCs).

[0051] The photo-thermal component 3 can emit light and heat relative to the catalytic mesh cylinder 21, and the catalytic mesh cylinder 21 is heated by the photo-thermal component 3. Under the dual action of light and heat, the catalytic efficiency of the catalytic mesh cylinder 21 is greatly improved, which can better purify and degrade volatile organic compounds (VOCs) and improve the catalytic efficiency of VOCs.

[0052] The deflection assembly 4 comprises deflection units and outer deflection units. The inner deflection units are arranged in the first airflow channel 22 and can hinder the volatile organic compounds (VOCs) from flowing in the first airflow channel 22 and drive the volatile organic compounds (VOCs) to pass through the catalytic mesh cylinder 21 into the second airflow channel 23. The outer deflection units are arranged in the second airflow channel 23 and can hinder the volatile organic compounds (VOCs) from flowing in the second airflow channel 23 and drive the volatile organic compounds (VOCs) to pass through the catalytic mesh cylinder 21 into the first airflow channel 22. The deflection units and the outer deflection units are arranged alternately and can drive the volatile organic compounds (VOCs) to shuttle back and forth in the two airflow channels and pass through the catalytic mesh cylinder 21 repeatedly, thereby prolonging the contact time of the volatile organic compounds (VOCs) with the catalytic mesh cylinder 21 and improving the purification rate of the volatile organic compounds (VOCs).

[0053] Further, referring to Figures 1 to 5 The outer deflection units comprise at least one outer deflection plate 421 arranged on the catalytic mesh cylinder 21. The inner circular surface of the outer deflection plate 421 is connected with the catalytic sleeve, and the outer circular surface of the outer deflection plate 421 is connected with the inner wall of the reaction tube body 1. The outer deflection plate 421 can block the flow of the second airflow channel 23 and guide the volatile organic compounds (VOCs) to pass through the catalytic mesh cylinder 21 into the first airflow channel 22. The inner deflection units comprise at least one inner deflection plate. The inner circular surface of the inner deflection plate is connected with the light-heat assembly 3, and the outer circular surface of the inner deflection plate is connected with the catalytic sleeve. The inner deflection plate can block the flow of the first airflow channel 22 and guide the volatile organic compounds (VOCs) to pass through the catalytic mesh cylinder 21 into the second airflow channel 23. The outer deflection plate 421 and the inner deflection plate are arranged in axial misalignment and have a spacing in the axial direction. The outer deflection plate 421 and the inner deflection plate can promote the volatile organic compounds (VOCs) to shuttle back and forth in the two airflow channels and pass through the catalytic mesh cylinder 21 repeatedly, thereby prolonging the contact time of the volatile organic compounds (VOCs) with the catalytic mesh cylinder 21 and improving the purification rate of the volatile organic compounds (VOCs).

[0054] As a further implementation, the inner deflection plate and the outer deflection plate 421 each comprise three plates. In the axial direction of the reaction tube body 1, there is only one outer deflection plate 421 between the two inner deflection plates, and the same deflection plates are not adjacent in the axial direction of the reaction tube body 1. The inner deflection plate and the outer deflection plate 421 can form a hairpin-shaped airflow track, so that the volatile organic compounds (VOCs) repeatedly shuttle on the catalytic mesh cylinder 21, thereby prolonging the contact time of the volatile organic compounds (VOCs) with the catalytic mesh cylinder 21 and improving the purification rate of the volatile organic compounds (VOCs).

[0055] Referring to Figure 6The catalytic mesh cylinder 21 comprises an inner mesh cylinder 211, an outer mesh cylinder 213 and a molecular sieve 212 filled in the gap between the inner mesh cylinder 211 and the outer mesh cylinder 213, which can act on volatile organic compounds (VOCs) and promote the decomposition and purification of volatile organic compounds (VOCs) through photo-thermal catalysis.

[0056] The molecular sieve 212 comprises particles with a diameter of 1mm-2mm, the particle material is alumina, and the particle surface is coated with a manganese-cobalt oxide layer for high photo-thermal catalysis. Alumina and manganese-cobalt oxide, as catalysts, have good catalytic effect.

[0057] The pore size of the inner mesh cylinder 211 and the outer mesh cylinder 213 is 30 mesh, which can not only prevent the particles in the molecular sieve 212 from leaking out of the gap of the mesh cylinder, but also ensure that the mesh cylinder has good light transmittance, so that most of the light can be irradiated onto the photo-thermal catalyst on the surface of the molecular sieve 212.

[0058] Please refer to Figure 1 and Figure 2 The reaction tube body 1 comprises an outer shell 11 and a top plate 12 and a base 13 arranged at both ends of the outer shell 11. The outer shell 11, the top plate 12 and the base 13 are provided with a light-reflecting layer on the side facing the inner cavity of the reaction tube body 1. The light-reflecting layer is polished and coated with a chromium plating layer to ensure that most of the light transmitted between the double-layer mesh cylinder and the molecular sieve 212 can be reflected back to the molecular sieve 212 and the mesh cylinder.

[0059] Please refer to Figure 1 and Figure 2 The outer shell 11 is provided with an air inlet pipe 14 near the base 13, which communicates with the second air flow channel 23. The top plate 12 is provided with an air outlet pipe 15 which communicates with the first air flow channel 22. Volatile organic compounds (VOCs) enter from the air inlet pipe 14, pass through the reaction tube body 1, and are output from the air outlet pipe 15.

[0060] Please refer to Figure 2 and Figure 5 The photo-thermal assembly 3 comprises a long-arc xenon lamp 31. The long-arc molecular sieve 212 will be heated and stored heat. The lamp tube of the xenon lamp is arranged in the axial direction of the reaction tube body 1. The long-arc xenon lamp 31 irradiates onto the molecular sieve 212. Under the action of light excitation and heat, VOCs are catalyzed and degraded to generate carbon dioxide and water, which makes up for the shortcomings of photo-catalytic technology and thermal catalytic technology.

[0061] In the implementation process, the long-arc xenon lamp 31 is placed in the center of the catalytic mesh cylinder 21, the power of the long-arc xenon lamp 31 is 500 W, the bottom end of the long-arc xenon lamp 31 is connected with an external xenon lamp trigger, the bottom of the xenon lamp is sealed and fixed by high-temperature-resistant glue, the center of the xenon lamp is about 20 mm away from the catalytic mesh cylinder 21, and under this distance, the long-arc xenon lamp 31 with a power of 500 W can heat the mesh cylinder to 200-300℃ in a short time. After heat storage by the molecular sieve 212, the temperature can be higher under a closed condition, which meets the temperature conditions of most photo-thermal catalysts, and the light intensity can reach more than 10 suns, which also meets the light intensity requirements of most photo-thermal catalysts.

[0062] Through calculation, the effective irradiation area of the ring illumination type is 1.5 times that of the ordinary photo-thermal catalytic device, the light utilization rate is greatly improved, most of the reflected light is avoided, and the energy consumption is greatly saved under the premise of ensuring the catalytic activity.

[0063] Workflow: The air containing volatile organic compounds (VOCs) is input into the reaction tube body 1 through the air inlet pipe 14, and the air passes through the second air flow channel 23, the catalytic mesh cylinder 21, the first air flow channel 22, and the catalytic mesh cylinder 21 again in turn, and then reaches the second air flow channel 23. After three cycles, the purified air passes through the mesh cylinder 7 times, ensuring that the air to be purified passes through a long enough path in the mesh cylinder, and the VOC gas molecules in the air to be purified can be completely absorbed by the molecular sieve 212 and catalyzed and degraded under the action of the photo-thermal catalyst on the surface of the molecular sieve 212.

[0064] The molecular sieve substrate used in the following examples is 4A spherical molecular sieve microspheres (purchased from a reagent platform).

[0065] Example 1:

[0066] This embodiment proposes a high-entropy perovskite catalyst, which is prepared by the following steps:

[0067] First, 0.14 g of lanthanum nitrate hexahydrate, 0.18 g of manganese nitrate tetrahydrate, 0.16 g of cadmium nitrate nonahydrate, 0.25 g of iron nitrate nonahydrate, 0.18 g of nickel nitrate hexahydrate, and 0.15 g of copper nitrate trihydrate are dissolved in 200 mL of water, uniformly mixed, and then 0.03 g of citric acid monohydrate and 0.05 g of ethylene glycol are added and stirred uniformly to obtain a mixed metal salt sol;

[0068] Then, the molecular sieve substrate is immersed in the mixed metal salt sol for 24 hours, and then baked at 80℃ for 24 hours and calcined at 500℃ for 20 hours to obtain a molecular sieve-loaded high-entropy perovskite spherical catalyst.

[0069] The prepared spherical high-entropy perovskite catalyst particles are filled into a ring-illuminating type photo-thermal catalytic reactor, to obtain a ring-illuminating type high-entropy perovskite monolithic catalytic device.

[0070] From Figure 7 The XRD pattern of the high-entropy perovskite catalyst corresponds to the standard card of the common perovskite LaNiO3, indicating that the high-entropy perovskite catalyst is successfully synthesized.

[0071] From Figure 8 It can be seen that the micro-morphology of the prepared high-entropy perovskite catalyst is a flaky and porous structure formed by the close accumulation of some particles.

[0072] Example 2

[0073] The present embodiment proposes a high-entropy perovskite catalyst, which is prepared by the following steps:

[0074] First, 0.14 g of lanthanum nitrate hexahydrate, 0.18 g of manganese nitrate tetrahydrate, 0.16 g of cadmium nitrate nonahydrate, 0.25 g of iron nitrate nonahydrate, 0.18 g of nickel nitrate hexahydrate, and 0.15 g of copper nitrate trihydrate are dissolved in 200 mL of water, uniformly mixed, and then 0.03 g of citric acid monohydrate and 0.05 g of ethylene glycol are added and stirred uniformly to obtain a mixed metal salt sol;

[0075] Then, the molecular sieve substrate is immersed in the mixed metal salt sol, and after immersion for 24 h, it is baked at 80℃ for 36 h and calcined at 600℃ for 30 h to obtain a molecular sieve loaded high-entropy perovskite spherical catalyst.

[0076] The prepared spherical high-entropy perovskite catalyst particles are filled into a ring-illuminating type photo-thermal catalytic reactor, to obtain a ring-illuminating type high-entropy perovskite monolithic catalytic device.

[0077] Example 3

[0078] The present embodiment proposes a high-entropy perovskite catalyst, which is prepared by the following steps:

[0079] First, 0.14 g of lanthanum nitrate hexahydrate, 0.18 g of manganese nitrate tetrahydrate, 0.16 g of cadmium nitrate nonahydrate, 0.25 g of iron nitrate nonahydrate, 0.18 g of nickel nitrate hexahydrate, and 0.15 g of copper nitrate trihydrate are dissolved in 200 mL of water, uniformly mixed, and then 0.03 g of citric acid monohydrate and 0.05 g of ethylene glycol are added and stirred uniformly to obtain a mixed metal salt sol;

[0080] Then, the molecular sieve substrate is immersed in the mixed metal salt sol, and after immersion for 24 h, it is baked at 80℃ for 36 h and calcined at 600℃ for 30 h to obtain a molecular sieve loaded high-entropy perovskite spherical catalyst.

[0081] The prepared spherical high-entropy perovskite catalyst particles are filled into a ring-illuminated photo-thermal catalytic reactor, to obtain a ring-illuminated high-entropy perovskite monolithic catalytic device.

[0082] Comparative Example 1:

[0083] The comparative example proposes a powder high-entropy perovskite catalyst, which is prepared by the following steps:

[0084] First, 0.14 g of lanthanum nitrate hexahydrate, 0.18 g of manganese nitrate tetrahydrate, 0.16 g of cadmium nitrate nonahydrate, 0.25 g of iron nitrate nonahydrate, 0.18 g of nickel nitrate hexahydrate, and 0.15 g of copper nitrate trihydrate are dissolved in 200 mL of water, uniformly mixed, and then 0.03 g of citric acid monohydrate and 0.05 g of ethylene glycol are added and stirred uniformly to obtain a mixed metal salt sol;

[0085] The mixed metal salt sol is baked at 80°C for 24 hours and calcined at 500°C for 20 hours to obtain a high-entropy perovskite powder catalyst.

[0086] Comparative Example 2:

[0087] The comparative example proposes a catalyst, which is prepared by the following steps:

[0088] First, 0.14 g of lanthanum nitrate hexahydrate and 0.18 g of nickel nitrate hexahydrate are dissolved in 200 mL of water, uniformly mixed, and then 0.03 g of citric acid monohydrate and 0.05 g of ethylene glycol are added and stirred uniformly to obtain a mixed metal salt sol;

[0089] Then, the molecular sieve substrate is immersed in the mixed metal salt sol, and after immersion for 24 hours, it is baked at 80°C for 24 hours and calcined at 500°C for 20 hours to obtain a LaNiO3 perovskite spherical catalyst loaded on a molecular sieve;

[0090] The prepared spherical LaNiO3 perovskite catalyst particles are filled into a ring-illuminated photo-thermal catalytic reactor, to obtain a ring-illuminated LaNiO3 perovskite monolithic catalytic device.

[0091] Comparative Example 3:

[0092] The comparative example proposes a catalyst, which is prepared by the following steps:

[0093] First, 0.14 g of lanthanum nitrate hexahydrate, 0.25 g of iron nitrate nonahydrate, 0.16 g of nickel nitrate hexahydrate, and 0.15 g of copper nitrate trihydrate are dissolved in 200 mL of water, uniformly mixed, and then a small amount of 0.03 g of citric acid monohydrate and 0.05 g of ethylene glycol are added and stirred uniformly to obtain a mixed metal salt sol;

[0094] The molecular sieve substrate was then immersed in the mixed metal salt sol for 24 hours, followed by baking at 80°C for 24 hours and calcination at 500°C for 20 hours to obtain La(Fe) molecular sieve supported on the substrate. 0.33 Ni 0.33 Cu 0.33 O3 perovskite spherical catalyst;

[0095] The prepared spherical La(Fe) 0.33 Ni 0.33 Cu 0.33 O3 perovskite catalyst particles are packed into an irradiated photothermal catalytic reactor to obtain irradiated La(Fe) perovskite catalyst particles. 0.33 Ni 0.33 Cu 0.33 O3 perovskite monolithic catalytic device.

[0096] Comparative Example 4:

[0097] This comparative example presents a catalyst prepared by the following steps:

[0098] First, dissolve 0.14g of lanthanum nitrate hexahydrate, 0.16g of manganese nitrate tetrahydrate, 0.16g of cadmium nitrate nonahydrate, 0.25g of ferric nitrate nonahydrate, 0.18g of cobalt nitrate hexahydrate, and 0.15g of copper nitrate trihydrate in 200mL of water. After mixing evenly, add a small amount of 0.03g of citric acid monohydrate and 0.05g of ethylene glycol and stir evenly to obtain a mixed metal salt sol.

[0099] The molecular sieve substrate was then immersed in the mixed metal salt sol for 24 hours, followed by baking at 80°C for 24 hours and calcination at 500°C for 20 hours to obtain La(Mn) molecular sieve-supported substrate. 0.25 Cr 0.25 Fe 0.25 Co 0.25 Cu 0.25 O3 perovskite spherical catalyst;

[0100] The prepared spherical La(Mn) 0.25 Cr 0.25 Fe 0.25 Co 0.25 Cu 0.25 O3 perovskite catalyst particles are packed into an irradiated photothermal catalytic reactor to obtain irradiated La(Mn) perovskite catalyst particles. 0.25 Cr 0.25 Fe 0.25 Co 0.25 Cu 0.25 O3 perovskite monolithic catalytic device.

[0101] Comparative Example 5:

[0102] A comparative example proposes a catalyst prepared by the following steps:

[0103] Firstly, raw materials lanthanum nitrate hexahydrate 0.14 g, manganese nitrate tetrahydrate 0.16 g, cadmium nitrate nonahydrate 0.16 g, nickel nitrate hexahydrate 0.18 g, iron nitrate nonahydrate 0.25 g, cobalt nitrate hexahydrate 0.18 g, copper nitrate trihydrate 0.15 g were dissolved in 200 mL water, and then a small amount of citric acid monohydrate 0.03 g and ethylene glycol 0.05 g were added and stirred uniformly to obtain a mixed metal salt sol;

[0104] Then the molecular sieve substrate was immersed in the mixed metal salt sol, and after 24 h of immersion, it was baked at 80°C for 24 h and calcined at 500°C for 20 h to obtain a molecular sieve loaded La(Mn 0.17 Cr 0.17 Ni 0.17 Fe 0.17 Co 0.17 Cu 0.17 )O3 perovskite spherical catalyst.

[0105] The prepared spherical La(Mn 0.17 Cr 0.17 Ni 0.17 Fe 0.17 Co 0.17 Cu 0.17 )O3 perovskite catalyst particles were filled into a ring-illuminated photo-thermal catalytic reactor to obtain a ring-illuminated La(Mn 0.17 Cr 0.17 Ni 0.17 Fe 0.17 Co 0.17 Cu 0.17 )O3 perovskite monolithic catalytic device.

[0106] The photo-thermal performance test of the ring-illuminated monolithic catalytic device was carried out in a matching setting. The photo-thermal performance test of the high-entropy perovskite powder catalyst was carried out in a self-made quartz reaction device. A power-adjustable xenon lamp (800 w) was used as a simulated sunlight light source to initiate propylene oxidation. The components of the reaction gas were 800 ppm C3H6, 12% O2 and N2 balance, and the total flow rate was set to 100 mL / min. The composition of the tail gas of the catalytic reaction was monitored in real time online by a gas chromatograph (GC-9790) of Taizhou Fulide Company. The instrument setting conditions of the GC were: N2 as the carrier gas, hydrogen flame ionization detector (FID) was used, and the column oven temperature was 70°C. The photo-thermal C3H6 activity comparison of the ring-illuminated monolithic catalytic device and the high-entropy perovskite powder catalyst is as follows Figure 9As shown in the figure, the removal rate of C3H6 of the ring-illuminated high-entropy perovskite monolithic catalytic device prepared in Example 1 reached 99% under 6 solar intensities, showing good photo-thermal catalytic activity, while the photo-thermal activity of the high-entropy powder catalyst of Comparative Example 1 was poor, only 80%, indicating that the method of the application for deviceizing the catalyst can improve the performance of the catalyst.

[0107] The photo-thermal C3H6 activity of the ring-illuminated high-entropy perovskite monolithic catalytic device with different element compositions is as shown in the figure Figure 9 As shown in the figure, the photo-thermal catalytic activity of Comparative Examples 2-5 is also poor, for example, the conversion rate of Comparative Example 2 is only 48%, and the catalyst of the application shows good photo-thermal catalytic activity, indicating that the catalytic performance of the catalyst prepared by the application is the result of the cooperation of each metal element.

[0108] The stability test needs to be tested for 15h under 6 solar intensities, and the components of the reaction gas are 800ppm C3H6, 12% O2 and N2 balance, and the total flow rate is set to 100mL / min. As shown in the figure Figure 10 As shown in the figure, the photo-thermal catalytic C3H6 stability diagram of the ring-illuminated high-entropy perovskite monolithic catalytic device prepared in Example 1, the conversion rate of the catalyst La(Mn 0.2 Cr 0.2 Fe 0.2 Co 0.2 Cu 0.2 )O3 did not decrease within 15 hours, and was maintained above 95%, while the conversion rate of Comparative Example 2 decreased from 48% to 36%. The catalyst of the application shows good photo-thermal catalytic stability.

[0109] The temperature of the surface of the catalyst is obtained by real-time measurement through a thermocouple in contact with the catalyst. As shown in the figure Figure 11 As shown in the figure, the ring-illuminated high-entropy perovskite monolithic catalytic device prepared in Example 1 has strong light absorption and photo-thermal conversion capacity under 6 solar intensities, and the catalyst La(Mn 0.2 Cr 0.2 Fe 0.2 Co 0.2 Cu 0.2 )O3 prepared in Example 1 reached 150℃, and the surface of LaMnO3 prepared in Comparative Example 1 reached 108℃, indicating that the catalyst of the application shows good light absorption and photo-thermal conversion capacity.

[0110] The light-illuminated area of the ring-illuminated high-entropy perovskite monolithic catalytic device is the area of the ring-illuminated outer cylindrical shape, and the light-illuminated area of the flat-illuminated catalytic device is the area of a rectangle with the outer diameter as the width. As shown in the figure Figure 13 The flat-illuminated catalytic device includes a long-arc xenon lamp 5 and a reactor 6; the long-arc xenon lamp 5 irradiates the top of the reactor 6, and the reaction is carried out in the reactor 6; as shown in the figure Figure 12As shown, the light-illuminated area of the annular high-entropy perovskite monolithic catalytic device prepared in Example 1 can reach 314cm 2 , the light-illuminated area of the planar catalytic device can reach 200cm 2 , which shows that the present application can improve the light-illuminated area of the catalyst, improve the performance of the device and increase the utilization of light.

[0111] Other beneficial effects:

[0112] The present application is based on the preparation of high-entropy perovskite La(Mn 0.2 Cr 0.2 Fe 0.2 Ni 0.2 Cu 0.2 )O3 catalyst based on high-entropy strategy, the synergistic effect of multiple elements improves the light absorption and light response ability of the material, thereby improving the activity and stability of the catalyst for photo-thermal degradation of pollutants.

[0113] The method provided by the present application provides a simple and fast preparation method for high-entropy perovskite La(Mn 0.2 Cr 0.2 Fe 0.2 Ni 0.2 Cu 0.2 )O3 catalyst.

[0114] The annular high-entropy perovskite monolithic catalytic device provided by the method of the present application improves the loading capacity and light-illuminated area of the catalyst, thereby improving the ability and effect of photo-thermal degradation of VOCs.

[0115] The product of the present application is applied to photo-thermal degradation of VOCs and has a wide application prospect in the field of low-energy consumption and environmental protection technology, and can be produced on a large scale.

[0116] The specific embodiments of the present application described above do not constitute a limitation on the scope of protection of the present application. Any various other corresponding changes and modifications made in accordance with the technical concept of the present application shall be included in the scope of protection of the claims of the present application.

Claims

1. A method for preparing a high-entropy perovskite catalyst for photocatalytic degradation of VOCs, characterized in that, The method comprises the following steps: adding an organic acid and an organic solvent to an aqueous solution containing lanthanum ions, divalent manganese ions, chromium ions, iron ions, nickel ions and copper ions to obtain a mixed metal salt sol; the aqueous solution containing lanthanum ions, divalent manganese ions, chromium ions, iron ions, nickel ions and copper ions is obtained by dissolving lanthanum nitrate hexahydrate, manganese nitrate tetrahydrate, chromium nitrate nonahydrate, iron nitrate nonahydrate, nickel nitrate hexahydrate and copper nitrate trihydrate in water; immersing a molecular sieve substrate in the mixed metal salt sol, and drying and calcining the immersed molecular sieve substrate to obtain the high-entropy perovskite catalyst; The chemical formula of the oxide in the high-entropy perovskite catalyst is La(Mn 0.2 Cr 0.2 Fe 0.2 Co 0.2 Cu 0.2 )O3; the mass ratio of the lanthanum nitrate hexahydrate, manganese nitrate tetrahydrate, chromium nitrate nonahydrate, iron nitrate nonahydrate, nickel nitrate hexahydrate and copper nitrate trihydrate is 1:(1-2):(1-2):(1-2):(1-2):(1-2); the calcination temperature is 500-600 DEG C; and the calcination time is 12-40 hours.

2. The method for preparing the high-entropy perovskite catalyst according to claim 1, characterized in that, the organic acid is one or more of oxalic acid, citric acid and fruit acid.

3. The method for preparing the high-entropy perovskite catalyst according to claim 1, characterized in that, the mass ratio of the organic acid to the lanthanum nitrate hexahydrate is (1-5):

1.

4. The method for preparing the high-entropy perovskite catalyst according to claim 1, characterized in that, the mass ratio of the organic solvent to the lanthanum nitrate hexahydrate is (3-5):1; and / or, the organic solvent is ethylene glycol.

5. A high-entropy perovskite catalyst for photocatalytic degradation of VOCs, characterized in that, obtained by the preparation method of any one of claims 1-4.

6. A monolithic catalytic device characterized by, obtained by filling the high-entropy perovskite catalyst for photocatalytic degradation of VOCs of claim 5 into a ring-illuminated photo-thermal catalytic reactor.

7. Use of the high-entropy perovskite catalyst for photocatalytic degradation of VOCs of claim 5 or the high-entropy perovskite catalyst for photocatalytic degradation of VOCs obtained by the preparation method of any one of claims 1-4 or the monolithic catalytic device of claim 6 in photocatalytic degradation of VOCs.

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