A carrier film, method of manufacture and catalyst composite

Abstract

The application relates to a carrier film, a preparation method and a catalyst composite. The carrier film comprises a first side and a second side, one of the first side and the second side is a smooth film surface, the carrier film is a porous film, a plurality of hole structures are filled in the film, and the carrier film is a Ti3C2Tx material. The carrier film has high absorption in a visible light band and low radiation in an infrared band. Loading a catalyst on the carrier film can promote the photo-thermal effect of the catalyst, improve the catalytic performance, and enable the catalyst to have spectrum selectivity, high catalytic activity and high stability.

Description

TECHNICAL FIELD

[0001] The present application relates to a carrier film, a preparation method and a catalyst composite, and belongs to the field of film materials. BACKGROUND

[0002] Solar energy provides a sustainable, alternative, clean form of energy without additional carbon emissions. Efficiently utilizing solar energy to produce value-added chemicals is a choice that can reduce dependence on fossil fuel resources. Compared with photocatalysis, photothermal catalysis converts photons into heat by utilizing the entire spectrum of sunlight. It has attracted extensive attention due to its high conversion efficiency in the field of catalysis. An important design criterion for photothermal catalysis is to generate the temperature required for the reaction at a low light power input through photothermal effect. Such efficient photothermal conversion can simultaneously reduce energy consumption. Therefore, in order to improve the photothermal efficiency, precise regulation of the optical properties of the catalyst is particularly crucial. First, we need to maximize the absorption rate in the solar waveband. Second, according to the Stefan-Boltzmann law, the blackbody radiation power is proportional to the fourth power of the temperature. Reducing the mid-infrared emissivity of the photothermal catalyst and improving the high absorption of sunlight can significantly improve the reaction temperature, which is particularly applicable to high-temperature emitters. Therefore, the ideal photothermal catalyst should minimize the mid-infrared emissivity of the photothermal catalyst while maximizing the absorption in the solar waveband.

[0003] In the past few years, a large number of studies have focused on designing and manufacturing materials with such broadband selective spectra. And this research covers wastewater treatment, seawater desalination, power generation and photovoltaic fields, and shows great application potential. However, it is still very challenging to integrate these selective spectral materials into catalysts while maintaining their high visible light absorption and low mid-infrared radiation and high catalytic performance. In recent years, some reports show good performance by optimizing the design of photothermal catalysts and further combining with spectrally selective external reactors. However, photothermal catalysts without precise spectral design still rely on external reactors. Therefore, it is necessary to develop a new type of photothermal catalyst carrier material to make the catalyst have high visible light absorption and low mid-infrared radiation, which is necessary for various photothermal catalytic reactions. SUMMARY

[0004] In order to increase the spectral selectivity of the catalyst to improve the photothermal effect and photocatalytic performance of the catalyst, the present application provides a carrier film and a preparation method of the carrier film, which has high absorption in the visible light waveband and low radiation in the infrared waveband. Loading the catalyst on the carrier film can promote the photothermal effect of the catalyst, improve the catalytic performance, and make the catalyst have spectral selectivity, high catalytic activity and high stability.

[0005] The technical scheme adopted by the present application is: a carrier film, comprising a first side and a second side, one of the first side and the second side is a smooth film surface, the carrier film is a porous film, a plurality of pore structures are filled in the film, the carrier film is Ti3C2T x material, one side of which is provided as a smooth surface, when used, light is incident from the smooth film surface, the spectral selectivity of the carrier film is increased, so that it has high absorption in the visible light band and low emission in the infrared band. The smoothness of the smooth surface is adjusted to make the emissivity of the carrier film in the mid-infrared band less than 21%, the pore structures distributed in the film can increase the mass transfer of reactants in the catalytic process of the catalyst and improve the conversion rate; at the same time, the pore structures can increase the carrying capacity of the catalyst, and can carry different nanocluster catalysts, which have universality.

[0006] As a preferred mode, the pore structure in the present application can be a closed pore or an open pore, the open pore can be open to the side of the non-smooth film surface (rough surface), the pore shape can be a spherical pore, a cylindrical pore or an irregular pore shape, the pore structure can increase the mass transfer of reactants on one hand, and can cause diffraction of light during transmission in the film on the other hand, thereby enhancing the spectral selectivity of the film. As a further preferred mode, the pore is a closed pore, the shape is a spherical pore, and the pore diameter is 3-8 μm, which can not only ensure the strength of the film, but also prevent the collapse of the pore, and can ensure the porosity and enhance the mass transfer of the film.

[0007] As a preferred mode, the thickness of the carrier film in the present application is 50 μm-90 μm, and more preferably 70 μm.

[0008] As a preferred mode, the Ti3C2T x material is a single-layer or few-layer material, and more preferably 1-5 layers, in which range the Ti3C2T x material not only is easy to prepare and low in cost, but also has a certain flexibility and is easy to wrap PMMA particles.

[0009] The Ti3C2T x The carrier film has low real and imaginary dielectric constants in the visible light region, providing high solar absorption rate (~88%), and high real and imaginary dielectric constants in the mid-infrared band, making it have low mid-infrared emissivity (~21%).

[0010] On the other hand, the present application provides a preparation method of a carrier film, which is simple in steps, easy to operate, and stable in structure, and comprises the following steps

[0011] A Ti3C2T x and PMMA solution, preferably configured with water as the solvent, so that the Ti3C2T xThe Ti3C2T is configured separately from the PMMA balls, that is, the Ti3C2T is configured x The solution and the PMMA balls are mixed after being configured respectively; or a certain amount of Ti3C2T x is configured in the same aqueous solution; the PMMA is in the form of spherical particles;

[0012] B The Ti3C2T is mixed with the PMMA by stirring x The Ti3C2T is mixed with the PMMA balls sufficiently x The Ti3C2T is mixed with the PMMA by surface functional groups to form PMMA@Ti3C2T x The surface of the PMMA is rich in a large number of (electron-deficient) carbonyl groups, while the T of the Ti3C2T x is an electron-donating group such as a hydroxyl group or a fluorine ion, so that electrostatic adsorption is triggered, and thus the two can be self-assembled.

[0013] C The solvent is removed to obtain a PMMA@Ti3C2T x membrane; the solvent can be removed by evaporation or filtration, and the filtration is preferred; the PMMA@Ti3C2T x membrane is obtained by a hard template method;

[0014] D The PMMA in the PMMA@Ti3C2T x membrane is removed, leaving holes in the membrane, and a porous Ti3C2T x membrane is obtained, that is, a carrier membrane is obtained.

[0015] As a preferred measure, the Ti3C2T x solution is mixed with the PMMA ball solution in a container by stirring, and the PMMA@Ti3C2T x membrane is obtained by removing the solvent by filtration, the PMMA@Ti3C2T x membrane is formed, and the side of the filtration membrane to which the PMMA@Ti3C2T x membrane is attached is a smooth membrane surface. The smooth and flat membrane surface is obtained by the filtration method, which is simple and easy to operate.

[0016] As a preferred measure, the mixing mass ratio of the Ti3C2T x to the PMMA is 1: (4-5),

[0017] As a preferred measure, the Ti3C2T x is obtained by etching a Ti3C2 material; in the present application, the etching is preferably 1-5 layers of structure, and the material of the structure is flexible, can coat the PMMA, and forms a hole structure after the PMMA is removed.

[0018] As a preferred measure, the diameter of the PMMA ball is 3-8 μm, and below this diameter, the Ti3C2T xUnable to wrap in PMMA spheres, higher than the diameter Ti3C2T x Unable to support hole structure, will cause the hole structure to collapse.

[0019] As a preferred measure, the Ti3C2T x The concentration of the aqueous solution is 1-5 mg ml -1 , the concentration of the PMMA aqueous solution is 2-3 mg ml -1 . Above this concentration is not conducive to the removal of solvent by filtration, below this concentration PMMA@Ti3C2T x Film strength is low, easy to crack.

[0020] As a preferred way, the PMMA in the application is removed by annealing process to form a porous Ti3C2T x Film, the annealing temperature is 400~600℃, and PMMA is removed by evaporation during annealing to form a hole.

[0021] In still another aspect, the application provides a catalyst composite, which is loaded on the carrier film or the carrier film obtained by the above preparation method. The catalyst is loaded on the carrier film by impregnation method. Specifically: a preparing a precursor solution of the catalyst, b dropping the precursor solution on the carrier film, c annealing to form a composite of the catalyst and the carrier film.

[0022] The catalyst with ruthenium as active metal, the preparation method of the composite is: a dropping RuCl3·3H2O solution into Ti3C2T x Film carrier, b annealing at 300~400℃ under protective gas atmosphere to obtain the composite of the catalyst.

[0023] The catalyst with palladium and nickel as active metal, the preparation method of the composite is: dropping the precursor solution of palladium and nickel into Ti3C2T x Film carrier, b annealing at 300~400℃ under protective gas atmosphere to obtain the composite of the catalyst.

[0024] The beneficial effects produced by the application include:

[0025] 1. Improve the photo-thermal catalytic performance of the catalyst: the application adopts a new type of photo-thermal catalyst design based on MXene material, which improves the photo-thermal effect of the catalyst, thereby improving the catalytic performance.

[0026] 2. Spectral selectivity and high catalytic activity: the design of the application provides high sunlight absorption rate and low mid-infrared radiation rate, enhances the photo-thermal effect, and the hollow Ti3C2T xThe spheres can increase the mass transfer of the reactants and improve the conversion rate. In addition, the design of the present application can load different nanocluster catalysts for different reactions, which is universal.

[0027] 3. Improved stability of the catalyst: The potential interaction between the photothermal interface of the present application and the supported catalyst hinders the ripening of the catalyst, thereby improving the stability. Specifically, well-dispersed metal nanoparticles sinter and agglomerate at high temperatures, thereby forming large particles and significantly reducing activity. However, metal nanoparticles supported on Ti3C2Tx cannot penetrate the barrier between particles, so they cannot sinter and agglomerate at high temperatures. x The barrier between particles prevents metal nanoparticles from penetrating, so they cannot sinter and agglomerate at high temperatures.

[0028] 4. Solving the problems existing in the prior art: The existing photocatalyst has the problems of poor selectivity and low catalytic activity, while the present application solves these problems through a new catalyst carrier material and design, improves the selectivity and catalytic activity of the catalyst, and has practical application value. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 Photo of the carrier film in Example 1;

[0030] Figure 2 Microstructure diagram of the rough surface of the carrier film in Example 1;

[0031] Figure 3 Spectrum diagram of the carrier film in Example 1;

[0032] Figure 4 Photo of the carrier film in Example 2;

[0033] Figure 5 Microstructure diagram of the rough surface of the carrier film in Example 2;

[0034] Figure 6 Spectrum diagram of the carrier film in Example 2;

[0035] Figure 7 Catalytic efficiency diagram of the catalyst composite in Example 3;

[0036] Figure 8 Catalytic efficiency diagram of the catalyst composite in Example 4 and Example 5. DETAILED DESCRIPTION

[0037] The present application will be further explained in detail below in conjunction with the drawings and specific embodiments, but it should be understood that the scope of protection of the present application is not limited by the specific embodiments.

[0038] The catalyst carrier in the present application is Ti3C2Tx xA membrane, with one side being a smooth, flat surface and the interior or the other side filled with numerous porous structures, exhibits high absorption in the visible light band and low emission in the infrared band when light is incident through the smooth surface. Using this membrane as a catalyst support can enhance the spectral selectivity of the catalyst, improve its photothermal effect, enhance the mass transfer of reactants, and thus increase the conversion rate. The pores within the membrane can be closed or open, and their shapes can be cylindrical, spherical, or irregular, with pore diameters of 3 μm, 6 μm, or 8 μm, and membrane thicknesses of 50 μm, 60 μm, or 80 μm.

[0039] The catalyst support membrane can be prepared by a hard template method, including the following steps:

[0040] A. Polymethyl methacrylate (PMMA) spheres with an average diameter of 5 μm were synthesized by dispersion polymerization.

[0041] B will use Ti3C2T x Thin sheets are coated on the surface of PMMA spheres with polar groups and form self-assembled hybrid spheres in deionized water, Ti3C2T x With a mass ratio of 1:4 or 1:5 to PMMA, configure Ti3C2T x Aqueous PMMA solution was used, followed by hybrid self-assembly. The concentration of the Ti3C2Tx aqueous solution was 1 mg / ml. -1 2 mg ml -1 3 mg ml -1 Or 5mg / ml -1 The PMMA solution concentration was 2 mg / ml. -1 Or 3 mg ml -1 .

[0042] C was filtered through a vacuum filter to obtain the hybrid sphere solution.

[0043] D was subjected to thermal evaporation treatment of the hybrid spheres used to form the film to obtain macroporous Ti3C2T. x (m-Ti3C2T x A membrane is a catalytic substrate with spectral selectivity.

[0044] A metal catalyst is loaded onto a support membrane using an impregnation method, wherein the metal catalyst is used as a solute and a solution of a specified concentration is prepared using ethanol or water as a solvent. A specified amount of the solution is then dropped into a photothermal catalytic substrate as required, followed by annealing in a reducing atmosphere to obtain the catalyst.

[0045] The obtained catalyst composite can achieve high sunlight absorption rate and low mid-infrared radiation rate, thereby improving the catalytic performance. The mass transfer of the reactants is increased by the hollow Ti3C2Tx spheres, thereby improving the conversion rate. The interaction between the photothermal interface and the supported catalyst hinders the ripening of the catalyst, thereby improving the stability. The general structure can easily load different nanocluster catalysts for different reactions.

[0046] Example 1

[0047] The preparation method of the carrier film comprises the following steps

[0048] 1. Prepare 20 mL of 1 mg / mL Ti3C2T x x aqueous solution and 40 mL of 2 mg / mL PMMA sphere aqueous solution, the radius of the PMMA sphere is 5 μm, and the mixture is stirred in a 100 mL flask at a speed of 200 rpm for 24 hours, so that the electrostatic adsorption of the electron-deficient carbonyl group on the surface of the PMMA and the electron-donating hydroxyl group of Ti3C2T x x occurs, and self-assembly is formed to form PMMA@Ti3C2T x .

[0049] 2. The PMMA@Ti3C2T x film is obtained by suction filtration, and the film surface close to the suction filtration film is flat, as shown in Figure 1 . Figure 1 The smooth film surface formed on the side close to the suction filtration film after suction filtration is shown.

[0050] 3. The PMMA@Ti3C2T x film is further annealed at 500°C in 100 sccm of argon gas to remove PMMA and form a hollow Ti3C2T x film. The rough surface of the film (the side opposite to the smooth surface) is observed under SEM, as shown in Figure 2 , a large number of hollow spherical pores with a pore size of about 5 μm, the same as the diameter of the PMMA sphere, are formed in the film, the spherical pores are uniformly distributed, closely arranged and structurally complete, which indicates that the film prepared by the preparation method can not only obtain a large density of pore distribution but also has sufficient supporting force for the pores. x

[0051] The carrier film is prepared by a hard template method, which comprises wrapping Ti3C2T x thin slices on the surface of PMMA spheres through polar groups, and forming self-assembled hybrid spheres in deionized water, and then performing thermal evaporation treatment on the film-forming hybrid spheres to obtain a large-pore Ti3C2T x (m-Ti3C2T x ​This membrane exhibits high absorptivity in the solar radiation band and low emissivity in the mid-infrared band, thus promoting the photothermal effect. This support membrane can be easily loaded with different nanocluster catalysts for various reactions.

[0052] The obtained carrier membrane was subjected to spectral performance testing, such as... Figure 3 As shown, the carrier film has a high absorption rate in the ultraviolet, visible, and near-infrared bands, reaching 88%, with the highest absorption in the visible light band and a mid-infrared emissivity of 21% in the 2.5~18 micrometer range.

[0053] Example 2

[0054] The method for preparing the carrier membrane includes the following steps:

[0055] 1. Prepare 4 mL of 5 mg / mL Ti3C2T x An aqueous solution and 30 mL of 3 mg / mL PMMA spheres (PMMA sphere radius 5 μm) were mixed in a 100 mL flask and stirred at 200 rpm for 24 hours to induce electron-deficient carbonyl groups and Ti3C2T on the PMMA surface. x The hydroxyl groups undergo electrostatic adsorption and self-assembly to form PMMA@Ti3C2T. x .

[0056] 2. PMMA@Ti3C2T was obtained by vacuum filtration. x The membrane surface near the filtration membrane is smooth, such as... Figure 4 As shown, Figure 4 This shows the smooth membrane surface formed on the side near the filtration membrane after vacuum filtration.

[0057] 3. PMMA@Ti3C2T x The membrane was further annealed at 500°C in 100 sccm of argon to remove PMMA and form hollow Ti3C2T. x Membrane. Observe the rough side of the membrane (the side opposite to the smooth side) under SEM, such as... Figure 5 As shown, numerous hollow spherical pores are formed within the membrane, with a pore diameter of approximately 5 μm, the same as the diameter of PMMA spheres. These spherical pores are uniformly distributed, tightly packed, and structurally intact, indicating that the membrane prepared by this method not only achieves a high-density pore distribution but also exhibits high density Ti3C2T... x The membrane provides sufficient support for the pores.

[0058] The carrier membrane was prepared using a hard template method, including the application of Ti3C2T... x Thin films were coated onto the surface of PMMA spheres with polar groups, and self-assembled hybrid spheres were formed in deionized water. The hybrid spheres were then subjected to thermal evaporation to obtain macroporous Ti3C2T. x(m-Ti3C2T x ) membrane. The membrane has high absorption in the solar wavelength range and low emission in the mid-infrared wavelength range, which promotes the photothermal effect. The carrier membrane can easily load different nanocluster catalysts for different reactions.

[0059] The obtained carrier membrane was tested for spectral performance, such as Figure 6 As shown in the figure, the carrier membrane has a high absorption rate in the ultraviolet, visible, and near-infrared wavelength ranges, which can reach 88%, among which the absorption in the visible light wavelength range is the highest, and the mid-infrared emission in the 2.5-18 micrometer range is 21%.

[0060] Example 3

[0061] Preparation method of catalyst complex with ruthenium as active metal: drop RuCl3·3H2O solution into the hollow Ti3C2T x membrane carrier obtained in Example 1, and after the drop is completed, anneal in a mixed gas (10% H2 and 90% Ar) at 350°C for 1 hour to obtain a catalyst complex. According to the catalyst loading amount, which is the mass of the catalyst / mass of the carrier membrane, the loading amount of the catalyst is 0.75%.

[0062] The photothermal catalyst uses hollow Ti3C2T x spheres to increase the mass transfer of reactants and improve the conversion rate. Moreover, the interaction between the photothermal interface and the loaded catalyst hinders the ripening of the catalyst, thereby improving the stability.

[0063] The prepared catalyst complex was subjected to gas phase CO2 hydrogenation experiment in a batch internal gas circulation reactor (CEL-HPR, CEAU-light). In the CO2 hydrogenation test, 4 mg of the catalyst complex was placed on an empty rack. A 300W xenon lamp (pls-sse300d, Beijing Perfectlight) was used to drive the photothermal CO2 hydrogenation.

[0064] The steps are as follows:

[0065] 1. Clean the reactor by bubbling and exhausting the CO2 and H2 (1:4) mixture three times.

[0066] 2. When the injection pressure reaches 4 bar, seal the reactor, turn on the Xe lamp, and start the photothermal catalytic reaction.

[0067] 3. After the reaction is completed, take out 1 ml of gas from the reactor and inject it into a gas chromatograph (GC-2014, Shimadzu) to detect the composition of the gas (the amounts of CO and CH4 are analyzed using a flame ionization detector installed in the same GC).

[0068] The CH4yield in the CO2hydrogenation experiment was tested, and the results, as shown in Figure 7 Table 1, show that the catalyst has excellent spectra and outstanding catalytic performance, and can achieve a CO2to CH4conversion rate of 3.4 mol g h-1under a light power of 2 W cm-2.

[0069] Example 4

[0070] Preparation method of a photo-thermal catalyst with palladium as an active metal:

[0071] A precursor solution of palladium was prepared with water as a solvent, and the solution concentration was 0.001 mol / L.

[0072] The precursor solution of palladium was dropped into a hollow Ti3C2T x x membrane carrier, and after the dropping was completed, the final catalyst was obtained by annealing at 350°C for 1 hour in a mixed gas (10% H2and 90% Ar). The loading of the catalyst was 0.25%.

[0073] The prepared catalyst composite was subjected to a gas phase CO2hydrogenation experiment in a batch internal gas circulation reactor (CEL-HPR, CEAU-light). In the CO2hydrogenation experiment, 4 mg of the catalyst composite was placed on an empty rack. A 300 W xenon lamp (pls-sse300d, Beijing Perfectlight) was used to drive the photo-thermal CO2hydrogenation.

[0074] The steps were as follows:

[0075] 1. The reactor was cleaned by bubbling and exhausting a CO2and H2(1:4) mixture three times.

[0076] 2. When the injection pressure reached 4 bar, the reactor was sealed, the Xe lamp was turned on, and the photo-thermal catalytic reaction was started.

[0077] 3. After the reaction was completed, 1 ml of gas was taken from the reactor and injected into a gas chromatograph (GC-2014, Shimadzu) to detect the composition of the gas (the amounts of CO and CH4were analyzed using a flame ionization detector installed in the same GC).

[0078] The products were CH4and CO, and the yields of CH4and CO were detected, as shown in Figure 8 Table 2, the palladium-based catalyst achieved a CO2hydrogenation conversion rate of 84.6 mmol g h-1under a light power of 2 W cm-2.

[0079] Example 5

[0080] Preparation method of a photo-thermal catalyst with nickel as an active metal:

[0081] A nickel precursor solution was prepared using water as a solvent, with a solution concentration of 0.002 mol / L.

[0082] The nickel precursor solution was dropped into the hollow Ti3C2T core. x After the addition of the catalyst to the membrane carrier was completed, it was annealed at 350°C for 1 hour in a mixed gas (10% H2 and 90% Ar) to obtain the final catalyst with a catalyst loading of 0.25%.

[0083] The testing method is the same as in Example 3, but the product is only CO. The yield of CO is detected, such as... Figure 8 As shown, the nickel-based catalyst at 2 Wcm -2 A CO2 hydrogenation conversion rate of 147.7 mmol g h⁻¹ was achieved at a light power of [missing value].

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A carrier film, characterized by: The carrier film comprises a first side and a second side, is a porous film, has a film thickness of 50-90 μm, is filled with a plurality of pore structures, and is Ti3C2T x The material; the pores are closed pores or non-closed pores, the first side is a smooth film surface, the second side is a rough film surface, and the second side is distributed with pore structures; the pore structures are spherical pores with a pore diameter of 3-8 μm; light is incident from the smooth film surface, the carrier film has high absorption in the visible light band and low emission in the mid-infrared band; and the preparation method of the carrier film comprises the following steps, Configuring Ti3C2T x with PMMA solution; Ti3C2T x mixed with PMMA in solution, after mixing, the mass ratio of Ti3C2T x and PMMA is 1: (4~5), Ti3C2T x self-assembled with PMMA through surface functional groups to form PMMA@Ti3C2T x ; PMMA@Ti3C2T x membrane, PMMA@Ti3C2T x The side of the filtration membrane to which the film is attached forms a smooth film surface; Removing the PMMA yields a porous Ti3C2T x membrane.

2. The carrier film of claim 1, wherein: Configure Ti3C2T respectively x Solution with PMMA solution, then Ti3C2T x The solution and the PMMA ball solution are stirred and mixed in a container.

3. The carrier film of claim 2, wherein: The Ti3C2T x The solution is Ti3C2T x The aqueous solution; the PMMA solution is a PMMA aqueous solution.

4. The carrier film of claim 3, wherein: The Ti3C2T x The concentration of the aqueous solution is 1-5 mg / ml -1 The concentration of the PMMA aqueous solution is 2-3 mg / ml -1 .

5. The carrier film of claim 1, wherein: Removing PMMA by annealing process to form porous Ti3C2T x membrane, annealing temperature is 400-600℃.

6. A catalyst composite, characterized by: The catalyst is supported on the support film of claim 1.

7. The catalyst composite of claim 6, wherein: The catalyst is supported on the support film by an impregnation method.

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