Porous photothermal materials with in-situ supported MOFs from biomass and their preparation methods

Abstract

This invention discloses a method for preparing porous photothermal materials with biomass-supported MOFs. The method involves preparing a biomass-supported multi-metal MOF porous photothermal material at room temperature, using natural cotton as a carrier, in-situ growing MOFs on the cotton, subsequently incorporating transition metals to enhance photothermal performance, and finally obtaining the biomass-supported multi-metal MOF porous photothermal material through drying, high-temperature annealing, and cooling to room temperature. The addition of natural cotton and MOF materials results in a photothermal material with high porosity and high stability. This invention uses natural cotton biomass as a carbon source, which is inexpensive; and cotton itself has high porosity, providing abundant pathways for the metal MOF materials, further improving the photothermal conversion capability of the photothermal material. This is a simple, convenient, green, safe, reproducible, and efficient method for preparing porous photothermal materials.

Description

Technical Field

[0001] This invention belongs to the field of porous photothermal materials technology, specifically relating to a method for preparing porous photothermal materials with biomass in situ supported MOFs, and also relating to porous photothermal materials with biomass in situ supported MOFs. Background Technology

[0002] Utilizing solar energy as a heat source to obtain freshwater resources through the liquid-gas phase transition of water molecules is one of the most promising and eco-friendly ways to alleviate the global water shortage problem. Photothermal conversion materials are the most important component in photothermal evaporation systems, and achieving thermal localization while ensuring surface evaporation is the core concept of photothermal evaporation. Therefore, designing high-performance photothermal conversion materials and ensuring water evaporation on the surface of these materials are urgent problems to be solved in solar-driven photothermal evaporation. Carbon possesses abundant conjugated π bonds, which excite electrons from π to π* orbitals under low light energy. It exhibits excellent thermal conversion efficiency, excellent stability, and high light absorption across the entire spectrum. Due to its excellent light absorption properties, high processability, stable chemical properties, and abundant porous structure, carbon materials have achieved remarkable success in solar-driven photothermal surface evaporation. Notably, compared to carbon nanotubes and graphene, biochar is inexpensive and easy to prepare.

[0003] MOFs (metal-organic frameworks) are a class of crystalline porous materials with periodic networks, formed by the self-assembly of metal ions or metal clusters and bridging organic ligands. Carbon-based MOF materials are lightweight, have a large specific surface area, high porosity, excellent light absorption properties, and the ability to store heat. They can enhance the capture of visible light and improve the efficiency of solar energy absorption and utilization. MOFs can provide abundant carbon sources and also enable the doping of metal ions into the carbon channels, further improving the photothermal properties of the materials.

[0004] Current methods for preparing photothermal materials are cumbersome, costly, and suffer from poor stability, limiting their practicality and failing to achieve the goals of being green and simple. Therefore, this study focuses on green and sustainable solar-driven water evaporation technology, applying the in-situ loading of MOFs onto biomass materials for monolithic carbonization as a photothermal material for seawater evaporation. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing porous photothermal materials with in-situ supported MOFs in biomass, which solves the problems of poor photothermal conversion performance and high production cost of existing photothermal materials.

[0006] Another objective of this invention is to provide porous photothermal materials with biomass-supported MOFs in situ.

[0007] The technical solution adopted in this invention is a method for preparing porous photothermal materials with in-situ supported MOFs in biomass, and the specific operation steps are as follows:

[0008] Step 1: Dissolve pyrazole in water, absorb the pyrazole solution with natural cotton, and then place it in an ultrasonic cleaner (JP-040S) for ultrasonication to make the pyrazole evenly distributed in the cotton. The ultrasonication time is set to 20-45 min and the temperature is set to 20-30℃. After ultrasonication, place it in an oven at 60-80℃ for drying for 12-24 h to dry the solvent and obtain product A.

[0009] Step 2: Dissolve zinc chloride in water, add ammonia to provide an alkaline environment, stir evenly, and then completely absorb it with product A. Place it in an ultrasonic cleaner (JP-040S) to make the raw material evenly distributed in the cotton. Set the ultrasonic time to 20-45 min and the temperature to 20-30℃. After ultrasonication, place it in an oven at 60-80℃ for 12-24 h to dry. Dry the solvent to obtain product B.

[0010] Step 3: Mix copper acetate, manganese acetate, cobalt acetate, nickel chloride, and ferric chloride powders in a certain molar ratio and dissolve them in methanol solution. After dissolution, add the solution to product B and place it in an ultrasonic cleaner (JP-040S) to start ultrasonication. Set the ultrasonication time to 20-45 min and the temperature to 20-30℃. After ultrasonication, place it in an oven at 60-80℃ for drying for 12-24 h to dry the solvent and obtain product C.

[0011] Step 4: Place product C into a ceramic boat, place it in a programmable temperature-controlled tube furnace under N2 atmosphere protection, heat it to 900-1000℃ at a heating rate of 5-10℃ / min, hold it at that temperature for 2 hours, and then let it cool naturally to room temperature to obtain a porous photothermal material of biomass in situ supported MOF, namely product D.

[0012] Step 5: The photothermal material prepared in this invention is assembled with different types of polymers / cellulose substrates in a certain amount to form a photothermal evaporator for seawater desalination in actual water bodies.

[0013] The invention is further characterized in that,

[0014] In steps 1, 2, and 3, the ultrasound time is set to 20–45 min and the temperature is set to 20–30 °C.

[0015] In steps 1, 2, and 3, the temperature of the forced-air drying oven should be 60–80°C, and the time should be 12–24 hours.

[0016] In steps 1, 2, and 3, the molar ratio of pyrazole, zinc chloride, copper acetate, manganese acetate, cobalt acetate, nickel chloride, and ferric chloride is 220:75:1:1:1:1:1.

[0017] In step 2, zinc chloride can be replaced by zinc perchlorate hexahydrate or zinc nitrate.

[0018] In step 3, copper acetate, manganese acetate, cobalt acetate, nickel chloride, and ferric chloride can be replaced by any one of chloride, acetate, or sulfate.

[0019] In step 4, the annealing process is carried out in an inert atmosphere, with the temperature set at 900–1000℃ and the holding time at that temperature being 2 hours.

[0020] In step 4, the heating rate is 5–10 °C / min.

[0021] Step 5 involves assembling photothermal materials with different types of polymers / cellulose substrates in a certain amount to form a photothermal evaporator for seawater desalination in actual water bodies.

[0022] The second technical solution adopted in this invention is: a porous photothermal material with biomass in situ supported MOF, which is prepared using the preparation method of porous photothermal material with biomass in situ supported MOF.

[0023] This invention employs a room-temperature synthesis method to synthesize, in situ, porous photothermal materials loaded with pentagonal metal MOFs on natural cotton. Utilizing the porous structure of cotton and MOFs, the capture of visible light is enhanced, improving the absorption and utilization efficiency of solar energy. The sample exhibits characteristics such as low metal loading, low density, ultralight weight, low cost, and high performance. The pores in the porous structure provide abundant pathways for sunlight absorption, resulting in an ideal photothermal absorbing material.

[0024] The beneficial effects of this invention are:

[0025] (1) This invention synthesizes a precursor for biomass-supported MOF porous photothermal material using a simple, mild, and controllable method. It utilizes the lightweight, large specific surface area, high porosity, excellent light absorption properties, and heat storage capacity of cotton and MOF carbon-based materials to obtain a high-porosity biomass-supported MOF photothermal material.

[0026] (2) The porous photothermal material prepared by this invention exhibits excellent photothermal conversion performance under xenon lamp irradiation. When the xenon lamp is adjusted to a solar intensity and irradiated for 12 minutes, the photothermal material reaches a maximum temperature of 93°C, indicating that the sample has excellent photothermal conversion capability.

[0027] (3) The present invention can control the composition of multi-metal MOF by controlling different types of metal salts. This method can also be applied to other metal salts and is an extended synthesis strategy.

[0028] (4) This invention can achieve the in-situ loading of MOF on different biomass materials to prepare photothermal materials by changing the biomass base material, such as sugarcane and other biomass materials with rich fiber channel structure.

[0029] (5) Photothermal materials are assembled with different types of polymers / cellulose substrates in a certain amount to form a photothermal evaporator for seawater desalination in actual water bodies. Attached Figure Description

[0030] Figure 1 This is a flowchart of the preparation method of the biomass in-situ supported MOF porous photothermal material of the present invention;

[0031] Figure 2 This is the XRD diffraction pattern of the precursor (product B) of the biomass in-situ loaded MOF photothermal material in this invention;

[0032] Figure 3 This is a SEM image of the biomass in-situ supported MOF photothermal material of this invention.

[0033] Figure 4 This is an infrared image of the surface of the biomass in-situ supported MOF photothermal material of the present invention after 12 minutes of irradiation under one solar intensity;

[0034] Figure 5 This is a temperature curve image of the biomass in-situ supported MOF photothermal material of the present invention after 12 minutes of irradiation under one solar intensity;

[0035] Figure 6 These are cyclic images of the biomass in-situ loaded MOF photothermal material of this invention being irradiated 10 times under one solar intensity.

[0036] Figure 7 This is the absorption diagram of the porous photothermal material of the present invention in the ultraviolet-visible-near-infrared region. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0038] This invention discloses a method for preparing porous photothermal materials with in-situ supported MOFs in biomass. The method yields a precursor for porous photothermal materials with in-situ supported MOFs in biomass. The synthesis conditions are mild and the synthesis is simple. Through calcination treatment, the porous photothermal material with in-situ supported multi-metal MOFs in biomass is finally obtained.

[0039] Example 1

[0040] The preparation method of the biomass in-situ supported MOF porous photothermal material of the present invention is as follows: Figure 1 As shown, the specific operation steps are as follows:

[0041] Step 1: Dissolve pyrazole in water, absorb the pyrazole solution with natural cotton, and then place it in an ultrasonic cleaner (JP-040S) for ultrasonication to make the pyrazole evenly distributed in the cotton. The ultrasonication time is set to 20 min and the temperature is set to 30℃. After ultrasonication, place it in an oven at 80℃ for 12 h to dry, and dry the solvent to obtain product A.

[0042] Step 2: Dissolve zinc chloride in water, add ammonia to provide an alkaline environment, stir evenly, and then completely absorb it with product A. Place it in an ultrasonic cleaner (JP-040S) to make the raw material evenly distributed in the cotton. Set the ultrasonic time to 20 min and the temperature to 30℃. After ultrasonication, place it in an oven at 80℃ for 12 h to dry. Dry the solvent to obtain product B.

[0043] Step 3: Mix copper acetate, manganese acetate, cobalt acetate, nickel chloride, and ferric chloride powders in a certain molar ratio and dissolve them in methanol solution. After dissolution, add the solution to product B and place it in an ultrasonic cleaner (JP-040S) to start ultrasonication. Set the ultrasonication time to 20 min and the temperature to 30 °C. After ultrasonication, place it in an oven at 80 °C for 12 h to dry. Dry the solvent to obtain product C.

[0044] Step 4: Place product C into a ceramic boat, place it in a programmable temperature-controlled tube furnace under N2 atmosphere protection, heat it to 1000℃ at a heating rate of 5℃ / min, hold it at that temperature for 2 hours, and then let it cool naturally to room temperature to obtain a porous photothermal material of biomass in situ supported MOF, namely product D.

[0045] Step 5: The photothermal material prepared in this invention is assembled with different types of polymers / cellulose substrates in a certain amount to form a photothermal evaporator for seawater desalination in actual water bodies.

[0046] Example 2

[0047] The preparation method of biomass in-situ supported MOF porous photothermal material of the present invention includes the following specific steps:

[0048] Step 1: Dissolve pyrazole in water, absorb the pyrazole solution with natural cotton, and then place it in an ultrasonic cleaner (JP-040S) for ultrasonication to make the pyrazole evenly distributed in the cotton. The ultrasonication time is set to 30 min and the temperature is set to 20℃. After ultrasonication, place it in an oven at 80℃ for 12 h to dry, and dry the solvent to obtain product A.

[0049] Step 2: Dissolve zinc nitrate in water, add ammonia to provide an alkaline environment, stir evenly, and then completely absorb it with product A. Place it in an ultrasonic cleaner (JP-040S) to make the raw material evenly distributed in the cotton. Set the ultrasonic time to 30 min and the temperature to 20℃. After ultrasonication, place it in an oven at 80℃ for 12 h to dry. Dry the solvent to obtain product B.

[0050] Step 3: Mix copper acetate, manganese acetate, cobalt acetate, nickel acetate, and ferric chloride powders in a certain molar ratio and dissolve them in methanol solution. After dissolution, add the solution to product B and place it in an ultrasonic cleaner (JP-040S) to start ultrasonication. Set the ultrasonication time to 30 min and the temperature to 20 °C. After ultrasonication, place it in a 70 °C oven for 15 h of drying to dry the solvent and obtain product C.

[0051] Step 4: Place product C into a ceramic boat, place it in a programmable temperature-controlled tube furnace under N2 atmosphere protection, heat it to 1000℃ at a heating rate of 10℃ / min, hold it at that temperature for 2 hours, and then let it cool naturally to room temperature to obtain a porous photothermal material of biomass in situ supported MOF, namely product D.

[0052] Step 5: The photothermal material prepared in this invention is assembled with different types of polymers / cellulose substrates in a certain amount to form a photothermal evaporator for seawater desalination in actual water bodies.

[0053] Example 3

[0054] The preparation method of biomass in-situ supported MOF porous photothermal material of the present invention includes the following specific steps:

[0055] Step 1: Dissolve pyrazole in water, absorb the pyrazole solution with natural cotton, and then place it in an ultrasonic cleaner (JP-040S) for ultrasonication to make the pyrazole evenly distributed in the cotton. The ultrasonication time is set to 40 min and the temperature is set to 20℃. After ultrasonication, place it in an oven at 80℃ for 12 h to dry, and dry the solvent to obtain product A.

[0056] Step 2: Dissolve perchloric acid hexahydrate in water, add ammonia to provide an alkaline environment, stir evenly, and then completely absorb it with product A. Place it in an ultrasonic cleaner (JP-040S) to make the raw material evenly distributed in the cotton. Set the ultrasonic time to 40 min and the temperature to 20℃. After ultrasonication, place it in an oven at 80℃ for 12 h to dry. Dry the solvent to obtain product B.

[0057] Step 3: Mix copper sulfate, manganese acetate, cobalt acetate, nickel acetate, and ferric sulfate powders in a certain molar ratio and dissolve them in methanol solution. After dissolution, add the solution to product B and place it in an ultrasonic cleaner (JP-040S) to start ultrasonication. Set the ultrasonication time to 40 min and the temperature to 20 °C. After ultrasonication, place it in an oven at 80 °C for 12 h to dry. Dry the solvent to obtain product C.

[0058] Step 4: Place product C into a ceramic boat, place it in a programmable temperature-controlled tube furnace under N2 atmosphere protection, heat it to 900℃ at a heating rate of 8℃ / min, hold it at that temperature for 2 hours, and then let it cool naturally to room temperature to obtain a porous photothermal material of biomass in situ supported MOF, namely product D.

[0059] Step 5: The photothermal material prepared in this invention is assembled with different types of polymers / cellulose substrates in a certain amount to form a photothermal evaporator for seawater desalination in actual water bodies.

[0060] Example 4

[0061] The preparation method of biomass in-situ supported MOF porous photothermal material of the present invention includes the following specific steps:

[0062] Step 1: Dissolve pyrazole in water, absorb the pyrazole solution with natural cotton, and then place it in an ultrasonic cleaner (JP-040S) for ultrasonication to make the pyrazole evenly distributed in the cotton. The ultrasonication time is set to 45 min and the temperature is set to 20℃. After ultrasonication, place it in an oven at 70℃ for 15 h to dry, and dry the solvent to obtain product A.

[0063] Step 2: Dissolve zinc nitrate in water, add ammonia to provide an alkaline environment, stir evenly, and then completely absorb it with product A. Place it in an ultrasonic cleaner (JP-040S) to make the raw material evenly distributed in the cotton. Set the ultrasonic time to 45 min and the temperature to 20℃. After ultrasonication, place it in a 70℃ oven for 15 h of drying to dry the solvent and obtain product B.

[0064] Step 3: Mix copper acetate, manganese acetate, cobalt acetate, nickel chloride, and ferric chloride powders in a certain molar ratio and dissolve them in methanol solution. After dissolution, add the solution to product B and place it in an ultrasonic cleaner (JP-040S) to start ultrasonication. Set the ultrasonication time to 45 min and the temperature to 20 °C. After ultrasonication, place it in an oven at 70 °C for 15 h to dry. Dry the solvent to obtain product C.

[0065] Step 4: Place product C into a ceramic boat, place it in a programmable temperature-controlled tube furnace under N2 atmosphere protection, heat it to 1000℃ at a heating rate of 10℃ / min, hold it at that temperature for 2 hours, and then let it cool naturally to room temperature to obtain a porous photothermal material of biomass in situ supported MOF, namely product D.

[0066] Step 5: The photothermal material prepared in this invention is assembled with different types of polymers / cellulose substrates in a certain amount to form a photothermal evaporator for seawater desalination in actual water bodies.

[0067] Example 5

[0068] The preparation method of biomass in-situ supported MOF porous photothermal material of the present invention includes the following specific steps:

[0069] Step 1: Dissolve pyrazole in water, absorb the pyrazole solution with natural cotton, and then place it in an ultrasonic cleaner (JP-040S) for ultrasonication to make the pyrazole evenly distributed in the cotton. The ultrasonication time is set to 30 min and the temperature is set to 25℃. After ultrasonication, place it in an oven at 60℃ for 18 h to dry, and dry the solvent to obtain product A.

[0070] Step 2: Dissolve zinc chloride in water, add ammonia to provide an alkaline environment, stir evenly, and then completely absorb it with product A. Place it in an ultrasonic cleaner (JP-040S) to make the raw material evenly distributed in the cotton. Set the ultrasonic time to 30 min and the temperature to 25℃. After ultrasonication, place it in a 60℃ oven for 18 h of drying to dry the solvent and obtain product B.

[0071] Step 3: Mix copper sulfate, manganese acetate, cobalt acetate, nickel chloride, and ferric sulfate powders in a certain molar ratio and dissolve them in methanol solution. After dissolution, add the solution to product B and place it in an ultrasonic cleaner (JP-040S) to start ultrasonication. Set the ultrasonication time to 30 min and the temperature to 25 °C. After ultrasonication, place it in an oven at 60 °C for 18 h to dry. Dry the solvent to obtain product C.

[0072] Step 4: Place product C into a ceramic boat, place it in a programmable temperature-controlled tube furnace under N2 atmosphere protection, heat it to 1000℃ at a heating rate of 5℃ / min, hold it at that temperature for 2 hours, and then let it cool naturally to room temperature to obtain a porous photothermal material of biomass in situ supported MOF, namely product D.

[0073] Step 5: The photothermal material prepared in this invention is assembled with different types of polymers / cellulose substrates in a certain amount to form a photothermal evaporator for seawater desalination in actual water bodies.

[0074] like Figure 2 The image shows the XRD diffraction pattern of the biomass in-situ supported MOF photothermal material precursor prepared in this invention. The pattern matches the curve of the standard pyrazole framework, proving that the multi-metal MOF was successfully synthesized in-situ on cotton.

[0075] like Figure 3The image shown is a SEM image of the biomass in-situ loaded MOF porous photothermal material of the present invention. It can be seen from the image that the cotton fibers were not completely destroyed, and MOF particles can be observed loaded on the cotton fibers.

[0076] like Figure 4 The image shown is an infrared image of the surface of the biomass-supported MOF photothermal material of this invention after 1 hour of xenon lamp irradiation at an intensity of one solar irradiance. At the beginning of irradiation, the temperature rapidly increases from 27°C to 80°C within 0–60 seconds. Between 60 and 120 seconds, the temperature increase slightly decreases, rising from 80°C to 90°C. From 120 to 600 seconds, the temperature rise slows and then stabilizes, reaching approximately 93°C. This indicates that the photothermal material possesses excellent photothermal conversion capabilities.

[0077] like Figure 5 The figure shows the temperature rise curve of the biomass in-situ supported MOF porous photothermal material of the present invention under xenon lamp irradiation for 12 minutes with a light intensity of 1 solar intensity. The sample surface temperature rises to 85°C after 60 seconds of irradiation, exhibiting the fastest heating rate. The heating rate slows down between 100 and 200 seconds, reaching approximately 90°C at 200 seconds. After the xenon lamp is turned off, the temperature drops rapidly within 50 seconds, followed by a slow cooling process, reaching room temperature at 800 seconds. This indicates that the photothermal material prepared by the present invention possesses excellent photothermal conversion capabilities.

[0078] like Figure 6 The image shown is a cycle image of the biomass in-situ loaded MOF photothermal material of this invention. Under one solar intensity, the photothermal material underwent 10 light irradiation tests. With increasing time, the photothermal performance of the material tended to stabilize, and the temperature still reached approximately 93°C. This indicates that the photothermal material has good cycle stability.

[0079] like Figure 7 The image shows the absorption curve of the porous photothermal material in the ultraviolet-visible-near-infrared region of this invention. The absorption rate of the material reaches over 80% in the 250–800 nm range, indicating that the sample has strong absorption of ultraviolet and visible light. The absorption rate decreases somewhat in the near-infrared range of 800–2500 nm, but still reaches approximately 75%, indicating that the material has good overall absorbance and a wide light absorption range.

[0080] The synthesis principle of key steps in this invention:

[0081] (I) The present invention synthesizes a precursor of biomass in-situ loaded MOF photothermal material by self-assembly of metal-containing nodes and organic ligands at room temperature. The metal atoms are uniformly distributed inside the MOF material through an ultrasonic process, providing an additional pathway for the absorption of sunlight.

[0082] (ii) Photothermal materials are prepared using a simple method. Multi-metal MOF materials are loaded in situ on biomass materials. The MOF materials are uniformly distributed on cotton by ultrasound. The combination of the two results in materials with higher porosity and enhanced absorption of visible light.

[0083] (III) This invention uses natural cotton biomass material as a carbon source, which is inexpensive; and cotton itself has high porosity, which provides rich pathways for metal MOF materials, further improving the photothermal conversion capability of photothermal materials.

Claims

1. A method for preparing porous photothermal materials with in-situ supported MOFs on biomass, characterized in that, Multi-metal MOF materials were in-situ loaded onto biomass materials to obtain a porous photothermal material precursor with in-situ loaded MOFs on biomass. This precursor was then calcined to obtain the final porous photothermal material with in-situ loaded multi-metal MOFs on biomass. The specific operational steps are as follows: Step 1: Dissolve pyrazole in water, absorb the pyrazole solution with natural cotton, and then put it into an ultrasonic cleaner for ultrasonication to make the pyrazole evenly distributed in the cotton. After ultrasonication, put it into an oven for drying to obtain product A. Step 2: Dissolve zinc chloride in water, add ammonia to provide an alkaline environment, stir evenly and then completely absorb it with product A. Place it in an ultrasonic cleaner to make the raw material evenly distributed in the cotton. After ultrasonic cleaning, place it in an oven to dry and dry the solvent to obtain product B. Step 3: Mix copper acetate, manganese acetate, cobalt acetate, nickel chloride, and ferric chloride powders and dissolve them in methanol solution. After dissolving, add the solution to product B, place the mixture in an ultrasonic cleaner and start ultrasonication. After ultrasonication, place the mixture in an oven to dry and dry the solvent to obtain product C. Step 4: Place product C into a ceramic boat, place it in a programmable temperature-controlled tube furnace under N2 atmosphere protection, heat it to 900-1000℃ at a heating rate of 5-10℃ / min, hold it at that temperature for 2 hours, and then let it cool naturally to room temperature to obtain a porous photothermal material of biomass in-situ supported MOF.

2. The method for preparing porous photothermal materials with in-situ supported MOFs on biomass according to claim 1, characterized in that, In steps 1, 2, and 3, the ultrasonic cleaning time of the ultrasonic cleaner is set to 20-45 minutes, and the ultrasonic temperature is set to 20-30°C.

3. The method for preparing porous photothermal material with in-situ supported MOF in biomass according to claim 1, wherein the molar ratio of pyrazole, zinc chloride, copper acetate, manganese acetate, cobalt acetate, nickel chloride, and ferric chloride is 220:75:1:1:1:1:

1.

4. The method for preparing porous photothermal materials with in-situ supported MOFs on biomass according to claim 1, characterized in that, In step 3, copper acetate, manganese acetate, and cobalt acetate can be replaced by any acetate or sulfate; nickel chloride and ferric chloride can be replaced by any chloride.

5. The method for preparing porous photothermal materials with in-situ supported MOFs on biomass according to claim 1, characterized in that, In step 2, zinc chloride is replaced by zinc perchlorate hexahydrate or zinc nitrate.

6. The method for preparing porous photothermal materials with in-situ supported MOFs on biomass according to claim 1, characterized in that, The oven temperature in steps 1, 2, and 3 is 60℃~80℃, and the drying time is 12~24h.

7. A porous photothermal material with biomass in-situ supported MOF, characterized in that, The porous photothermal material with in-situ supported MOF on biomass was prepared using the method described in any one of claims 1-6.

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