A Ni(OH)₂-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst, its preparation method and application

Abstract

The application discloses a kind of Ni (OH) 2 Coated hrGO / Ni-MOF core-shell heterostructure photo-thermal catalyst and its preparation method and application, it is related to catalytic material technical field.The application is realized in situ assembly of functional group on hrGO sheet layer to Ni-MOF by solvothermal method, then in situ induced Ni (OH) 2 Self-assembly shell on Ni-MOF surface by chemical etching, to build hrGO / Ni-MOF@Ni (OH) 2 Core-shell structure.In the structure, the functional group on the surface of hrGO can not only anchor the metal site of MOF, improve the dispersibility and stability of MOF on its surface, but also as efficient electron acceptor and transmission channel effectively inhibit photo-generated carrier recombination, improve photo-generated electron utilization rate;At the same time, its wide spectral response characteristics can significantly enhance the light-thermal conversion capacity.Ni-MOF and in situ generated Ni (OH) 2 Form tight hetero-interface, and hrGO can realize photo-thermal synergistic enhancement effect, further accelerate interface charge separation and transfer efficiency, so as to significantly improve the photo-thermal catalytic performance of methanol aqueous reforming hydrogen production.

Description

Technical Field

[0001] This invention relates to the field of catalytic materials technology, and in particular to a Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst, its preparation method, and its application. Background Technology

[0002] In recent years, hydrogen energy has seen a surge in demand across numerous key sectors, including transportation, industry, and energy storage, thanks to its significant advantage as a zero-carbon fuel. However, the inherent characteristics of hydrogen, such as its low density and flammability / explosiveness, pose significant challenges to its long-distance transportation and storage. This not only leads to a substantial increase in costs but also presents considerable technical difficulties. Therefore, there is an urgent need to develop efficient and safe hydrogen production solutions.

[0003] Among numerous potential solutions, methanol exhibits unique advantages. Methanol is liquid at room temperature and pressure, a characteristic that makes it extremely convenient for transportation. More importantly, methanol has a high hydrogen content of 12.5 wt%, meaning it contains abundant hydrogen. Furthermore, compared to traditional methane reforming methods that require extreme reaction conditions (800–1000°C), methanol liquid-phase reforming for hydrogen production offers milder reaction conditions, enabling hydrogen production at low temperatures and significantly reducing energy consumption. In summary, methanol, with its outstanding performance in terms of convenient transportation, high hydrogen content, and low energy consumption for hydrogen production, becomes a highly ideal hydrogen carrier.

[0004] Photocatalytic hydrogen production technology can utilize abundant solar energy and water to produce hydrogen, effectively avoiding the drawbacks of traditional technologies such as high energy consumption and pollution, making it an ideal approach for developing and acquiring hydrogen energy. However, this technology currently faces a key bottleneck: low photocatalyst activity, hindering efficient solar energy conversion. The root cause of this problem lies in the severe recombination of photoinduced charge carriers, resulting in sluggish migration kinetics and poor light utilization efficiency. Long-term research has revealed that the synergistic effect of light and heat energy can significantly improve the performance of solar-driven hydrogen production processes. Under illumination, photocatalysts can absorb photons and convert them into heat energy, generating a photothermal effect. This increases the temperature during the reaction, accelerates the movement of reactant molecules, and enhances their interaction with the catalyst's active sites. In photocatalytic reactions, the photothermal effect facilitates the separation and migration of photogenerated charge carriers, thereby improving catalytic activity. Furthermore, appropriate heat energy can improve the thermal stability of the catalyst, reduce deactivation, and extend its lifespan. Therefore, developing photothermal catalysts with excellent photothermal conversion and high photocarrier density is both challenging and significant. Summary of the Invention

[0005] The purpose of this invention is to provide a Ni(OH)₂-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst, its preparation method, and its application, to overcome the problems of low photocatalytic activity, high energy consumption in thermal catalytic methanol liquid-phase reforming for hydrogen production, insufficient catalytic activity of single catalysts due to high recombination rates of photogenerated carriers, and poor stability of catalysts during the reaction process due to photocorrosion and thermal deactivation. The photothermal catalyst of this invention possesses a core-shell heterostructure, where photogenerated carriers undergo directional transfer at the heterojunction interface, effectively suppressing electron-hole recombination and extending carrier lifetime, thereby improving the activity and catalytic efficiency of the photothermal catalyst. This photothermal catalyst combines photocatalysis and thermal catalysis; photothermal combined catalysis can utilize light energy to partially replace thermal energy, using both light and heat energy to provide the heat required for the reaction, reducing the required reaction temperature, and thus reducing energy consumption.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] One of the technical solutions of the present invention: a method for preparing a Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst, comprising the following steps:

[0008] hrGO (two-dimensional layered reduced graphene oxide), nickel source, organic ligand and organic solvent are mixed and heated to react, yielding hrGO / Ni-MOF; the hrGO / Ni-MOF is mixed with an alkaline solution and heated and stirred to react, yielding the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst (abbreviated as hrGO / Ni-MOF@Ni(OH)2).

[0009] This invention first achieves in-situ assembly of functional groups on hrGO sheets into Ni-MOF via a solvothermal method. Subsequently, chemical etching induces in-situ self-assembly of Ni(OH)₂ on the Ni-MOF surface to form a shell, thereby constructing an hrGO / Ni-MOF@Ni(OH)₂ core-shell structure. Specifically, after dissolving hrGO, organic ligands, and a nickel source in an organic solvent, during the solvothermal reaction, the functional groups on the hrGO surface anchor nickel ions (Ni... 2+ Organic ligand molecules coordinate with nickel ions in a specific manner, gradually building a multifunctional metal-organic framework to obtain the hrGO / Ni-MOF precursor. When the hrGO / Ni-MOF precursor is mixed with an alkaline solution and heated with stirring, OH... - Attacking some ligand protons on the Ni-MOF surface causes partial ligand dissolution, Ni 2+ - Ligand bond breakage releases free Ni 2+The internal structure of Ni-MOF remains stable, with nickel nodes (Ni) free on the Ni-MOF surface. 2+ In an alkaline environment, it reacts with OH-. - The catalyst combines with hydrolysis to form Ni(OH)₂. In this photothermal catalyst structure, the functional groups on the hrGO surface not only anchor the metal sites of the MOF, improving the dispersibility and stability of the MOF on its surface, but also act as efficient electron acceptors and transport channels to effectively suppress photogenerated carrier recombination and improve the utilization rate of photogenerated electrons. Simultaneously, its broad spectral response characteristics significantly enhance the photothermal conversion capability. A tight heterogeneous interface is formed between the Ni-MOF and the in-situ generated Ni(OH)₂, achieving a synergistic photothermal enhancement effect with hrGO, further accelerating the interface charge separation and transfer efficiency, thereby significantly improving the photothermal catalytic performance of methanol aqueous reforming for hydrogen production. This catalyst possesses advantages such as high structural stability, excellent catalytic efficiency, and adaptability to low-temperature reactions, making it suitable for green, efficient, and sustainable methanol-hydrogen energy systems.

[0010] The Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst obtained by in-situ construction in this invention consists of two parts: an in-situ assembled hrGO / Ni-MOF precursor and a Ni(OH)2 formed by in-situ etching. The Ni(OH)2 acts as a shell coating on the surface of the Ni-MOF in the hrGO / Ni-MOF.

[0011] Furthermore, the organic ligand includes 2,5-dihydroxyterephthalic acid.

[0012] Furthermore, the nickel source includes one or more of nickel acetate, nickel nitrate, and nickel sulfate.

[0013] Furthermore, the organic solvent includes N,N-dimethylformamide (DMF) or ethanol.

[0014] Furthermore, the mass ratio of hrGO, nickel source and organic ligand is 0.004-0.02:1:0.3-0.4.

[0015] Furthermore, the heating reaction is carried out at a temperature of 120–200°C for a duration of 12–36 hours.

[0016] Furthermore, the alkaline solution comprises an aqueous solution of potassium hydroxide.

[0017] Furthermore, the mass ratio of the hrGO / Ni-MOF to the alkali contained in the alkaline solution is 0.01 to 0.02:1.

[0018] Furthermore, the heating and stirring reaction is carried out at a temperature of 90–100°C for a time of 1–3 minutes.

[0019] Furthermore, the stirring speed of the heating and stirring reaction is 300-500 rpm.

[0020] Optionally, the mixing of hrGO, nickel source, organic ligand and organic solvent includes: dispersing hrGO, nickel source and organic ligand in organic solvent, stirring at 300-500 rpm for 30-60 min to obtain a uniformly mixed solution.

[0021] Optionally, after the heating reaction is completed, a post-processing step is also included, which specifically includes cooling, centrifugation and / or filtration, washing, and drying.

[0022] Optionally, mixing the hrGO / Ni-MOF and the potassium hydroxide aqueous solution includes:

[0023] Optionally, after the heating and stirring reaction is completed, a post-processing step is also included, which specifically includes cooling, centrifugation and / or filtration, washing, and drying.

[0024] Optionally, the drying process involves vacuum drying at room temperature for 12–24 hours.

[0025] The second technical solution of the present invention: a Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst prepared according to the above-mentioned preparation method of Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst.

[0026] Furthermore, the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst has a clustered spindle-shaped structure.

[0027] The third technical solution of the present invention: the application of the above-mentioned Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst in photothermal catalysis (i.e. photothermal synergistic catalysis) of methanol liquid-phase low-temperature reforming to produce hydrogen.

[0028] Furthermore, the application includes: mixing the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst with an aqueous methanol solution and an alkali, and reacting the mixture under anaerobic, light-induced, and heated conditions to obtain hydrogen.

[0029] Optionally, the alkali includes one or more of potassium hydroxide and sodium hydroxide.

[0030] Optionally, the molar ratio of methanol to water in the methanol-water solution is 1:1 to 3.

[0031] Optionally, the ratio of the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst to the methanol aqueous solution is (4-6) mg:(10-12) mL.

[0032] Optionally, the mass of the alkali is 5% of the sum of the masses of the methanol and water.

[0033] Optionally, the heating temperature is 90–210°C.

[0034] The present invention discloses the following technical effects:

[0035] (1) The Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst prepared by the present invention has advantages such as adjustable pore structure and surface properties, adjustable active centers, and high structural designability. It can expose more active sites in the methanol liquid-phase reforming hydrogen production reaction to catalyze substrate transport, which is conducive to the rapid separation and transfer of photogenerated charges.

[0036] (2) In the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst prepared by the present invention, the tight heterostructure between Ni(OH)2 and hrGO / Ni-MOF can not only make the catalyst highly stable, but also maximize the collection of solar energy to provide a high surface temperature to accelerate the reaction process.

[0037] (3) The Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst prepared in this invention combines photocatalysis and thermocatalysis. It uses light energy to excite electron transitions on the catalyst surface to drive chemical reactions and uses thermal energy to provide the heat required for the reaction. The two work together to reduce the energy barrier of methanol liquid-phase reforming to produce hydrogen, thereby improving the hydrogen production efficiency. It can also produce a certain amount of hydrogen at low temperatures, meeting the requirements of green, environmentally friendly, energy-saving and sustainable hydrogen production.

[0038] (4) The present invention obtains Ni(OH)2 coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst by a two-step solvent method. The preparation method is simple, low in cost and energy consumption, and easy to implement. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 The XRD patterns are those of hrGO / Ni-MOF, Ni(OH)2-coated hrRGO / Ni-MOF core-shell heterostructure photothermal catalyst, and Ni(OH)2 in Example 1.

[0041] Figure 2The images show SEM images of the hrGO / Ni-MOF and Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts in Example 1, where (a) is hrGO / Ni-MOF and (b) is Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst.

[0042] Figure 3 The images show TEM images of the hrGO / Ni-MOF and Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts in Example 1, where (a) is hrGO / Ni-MOF and (b) is Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst.

[0043] Figure 4 The graph shows a performance comparison of the photothermal catalysts of hrGO / Ni-MOF and Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructures in Example 1, as well as the photothermal / thermal catalytic performance of Ni(OH)2 in methanol liquid-phase low-temperature reforming for hydrogen production. Detailed Implementation

[0044] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0045] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0046] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0047] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0048] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0049] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0050] In specific embodiments of the present invention, room temperature refers to 25±5℃.

[0051] Unless otherwise specified, all raw materials used in the specific embodiments of this invention are commercially available products.

[0052] Example 1

[0053] The preparation steps of a Ni(OH)₂-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst are as follows:

[0054] (1) Preparation of hrGO / Ni-MOF

[0055] 0.02 g hrGO, 0.5 g 2,5-dihydroxyterephthalic acid, and 1.5 g Ni(NO3)2·6H2O were dispersed in 10.5 mL DMF and stirred at 400 rpm for 30 min to ensure thorough mixing. The mixture was then transferred to a 50 mL autoclave lined with polytetrafluoroethylene and heated in a constant temperature drying oven at 150 °C for 24 h. After the reaction was complete, the autoclave was removed and allowed to cool to room temperature. The reaction product was obtained by centrifugation, washed with deionized water until the washings were clear, and then vacuum dried at room temperature for 12 h to obtain hrGO / Ni-MOF.

[0056] (2) In-situ construction of Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure catalyst

[0057] 0.2 g of hrGO / Ni-MOF was added to 50 mL of potassium hydroxide aqueous solution (concentration of 6 mol / L), stirred at 400 rpm for 1 min at 90 °C, then cooled to room temperature, centrifuged to obtain the product, washed with deionized water until the washing liquid was clear, and vacuum dried at room temperature for 12 h to obtain Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst.

[0058] Example 2

[0059] Same as Example 1, except that the amount of hrGO used in step (1) is 0.006g.

[0060] Example 3

[0061] Same as Example 1, except that the amount of hrGO used in step (1) is 0.01g.

[0062] Example 4

[0063] Same as Example 1, except that the amount of hrGO used in step (1) is 0.03g.

[0064] Example 5

[0065] Same as Example 1, except that the stirring time at 400 rpm at 90°C is 2 min.

[0066] Test Example 1

[0067] Characterization test

[0068] X-ray diffraction was used to analyze the crystal structure of hRrGO / Ni-MOF, Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst, and commercially available Ni(OH)2 in Example 1. The obtained XRD patterns are shown below. Figure 1 As shown, the hrGO / Ni-MOF, Ni(OH)2, and Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts all exhibit good crystallinity. Characteristic peaks of hrGO and Ni-MOF can be observed in the XRD diffraction pattern of hrGO / Ni-MOF, indicating that hrGO / Ni-MOF has been successfully prepared. The XRD diffraction patterns of hrGO / Ni-MOF and Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts are basically consistent, indicating that the Ni-MOF framework in the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst has not collapsed, and there are no obvious defects or changes in the structure. Simultaneously, the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst also exhibits characteristic peaks of Ni(OH)2, indicating that the catalyst has been successfully prepared. The XRD patterns of the hrGO / Ni-MOF and Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts in Examples 2-5 are basically consistent with those in Example 1.

[0069] SEM images of the hrGO / Ni-MOF and Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts in Example 1 are shown below. Figure 2As shown, (a) is hrGO / Ni-MOF, and (b) is a Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst. It can be seen that after the in-situ construction of the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst, the main cluster spindle structure did not change. The SEM images of the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts in Examples 2-5 are basically consistent with those in Example 1, and cluster spindle structures were observed in all cases.

[0070] TEM images of the hrGO / Ni-MOF and Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts in Example 1 are shown below. Figure 3 As shown, (a) is hrGO / Ni-MOF, and (b) is a Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst. It can be seen that the structure of the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst is consistent with that of hrGO / Ni-MOF, indicating that the structure of the hrGO / Ni-MOF crystal can remain stable after Ni(OH)2 is coated on the surface of hrGO / Ni-MOF. The TEM images of the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts in Examples 2-5 are basically consistent with those in Example 1.

[0071] Test Example 2

[0072] The hrGO / Ni-MOF and Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts prepared in each embodiment were used for photothermal catalytic (or thermocatalytic) methanol liquid-phase low-temperature reforming hydrogen production tests. The photothermal catalytic (or thermocatalytic) methanol liquid-phase low-temperature reforming hydrogen production tests were conducted in a photothermal reactor, heated by a furnace equipped with a magnetic stirrer and external lighting. The specific test methods are as follows:

[0073] 0.625 g of KOH was added to a methanol-water solution (methanol:water = 1:1 molar ratio), and sonicated until the KOH dissolved, yielding a mixed solution. In this system, the added KOH mass was 5% of the total mass of the methanol-water solution. 5 mg of photothermal catalyst was placed in the lining of the photothermal reactor, and 10 mL of the above mixed solution was added. After assembling the reactor, nitrogen was pressurized to 2 MPa, and the reactor was repeatedly purged three times to ensure complete removal of air. At 210 °C and 2 MPa, the photothermal catalytic reactor was irradiated with a 300 W Xe lamp (CEL-HXF300-T3) for 80 min, while the thermal catalytic reactor was reacted directly for 80 min without irradiation. After the reaction, the gas inside the photothermal reactor was collected using a gas bag and analyzed by GC (GC9790PLUS) to determine the amount of hydrogen produced.

[0074] Figure 4 The graph shows a performance comparison of photothermal and thermocatalytic methanol liquid-phase low-temperature reforming hydrogen production using Ni(OH)₂, hrGO / Ni-MOF, and Ni(OH)₂-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts in Example 1. It can be seen that the photothermal catalytic hydrogen production rate of hrGO / Ni-MOF is also improved compared to the thermocatalytic hydrogen production rate (i.e., H₂ evolution). Under the synergistic effect of photothermal and photocatalysis, the hydrogen production performance of the Ni(OH)₂-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst is significantly improved, reaching 8.12 times its thermocatalytic hydrogen production rate, nearly 3.8 times that of hrGO / Ni-MOF, and 3.87 times that of Ni(OH)₂. This indicates that the synergistic effect of photocatalysis and thermocatalysis exhibits superior performance compared to thermocatalysis alone. By using light energy to excite electron transitions on the catalyst surface to drive the chemical reaction and using thermal energy to provide the heat required for the reaction, the synergistic effect of the two lowers the energy barrier of the methanol liquid-phase reforming hydrogen production reaction, thereby improving the hydrogen production efficiency. The Ni(OH)₂-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst exhibits significantly accelerated directional migration of photogenerated charges and broadened the photoresponse range by forming a pn-type band structure at the heterostructure interface, thus promoting the separation of photogenerated charges. The precise construction of Ni(OH)₂ nanoshells on the surface of hrGO / Ni-MOF provides a high density of basic sites through abundant hydroxyl groups between the Ni(OH)₂ layers, promoting the dissociation of OH and CH bonds in methanol molecules and greatly improving hydrogen production efficiency.

[0075] Using the above method, the heating temperature of the reactor was changed, and the photothermal catalytic performance of the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst in Example 1 was tested at different temperatures. The results are shown in Table 1.

[0076] Table 1

[0077] Temperature / °C <![CDATA[H2evolution(μmol·g cat -1 ·h -1 )]]> 90 359 120 568 150 1279 180 1720 210 261658

[0078] from Figure 1 As can be seen, this photothermal catalyst can also produce a certain amount of hydrogen at low temperatures. At a reaction temperature of 90℃, the photothermal catalyst can achieve a yield of 359 μmol·gcat. -1 ·h -1 The hydrogen production was measured, and the thermocatalytic and photothermal catalytic performance of hrGO / Ni-MOF and Ni(OH)2 in Example 1 at 90°C was tested using the above test method. It was found that hrGO / Ni-MOF and Ni(OH)2 in Example 1 no longer produced hydrogen through photothermal and thermocatalysis (hydrogen production was 0).

[0079] Table 2 shows a comparison of the photothermal catalytic performance of the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalysts in Examples 1-5 at 210℃. It can be seen that the photothermal catalysts prepared in Examples 1-5 can all utilize light energy to generate active species in the catalyst and utilize thermal energy to provide the heat required for the reaction. The two work synergistically to improve the efficiency of methanol liquid-phase reforming to produce hydrogen.

[0080] Table 2

[0081] Example <![CDATA[H2evolution(μmol·g cat -1 ·h -1 )]]> 1 261658 2 158141 3 197716 4 218879 5 166210

[0082] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. The application of a Ni(OH)₂-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst in photothermal catalytic methanol liquid-phase low-temperature reforming for hydrogen production, characterized in that, The preparation steps of the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst include: hrGO, nickel source, organic ligand and organic solvent are mixed and heated to react, yielding hrGO / Ni-MOF; the hrGO / Ni-MOF is mixed with an alkaline solution and heated and stirred to react, yielding the Ni(OH)2-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst. The organic ligand includes 2,5-dihydroxyterephthalic acid; The mass ratio of hrGO, nickel source, and organic ligand is 0.004–0.02:1:0.3–0.

4. The heating reaction is carried out at a temperature of 120–200°C for a duration of 12–36 hours. The heating and stirring reaction is carried out at a temperature of 90–100°C for 1–3 minutes. The hrGO is a two-dimensional layered reduced graphene oxide.

2. The application of the Ni(OH)₂-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst as described in claim 1 in photothermal catalytic methanol liquid-phase low-temperature reforming for hydrogen production, characterized in that, The nickel source includes one or more of nickel acetate, nickel nitrate, and nickel sulfate.

3. The application of the Ni(OH)₂-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst as described in claim 1 in photothermal catalytic methanol liquid-phase low-temperature reforming for hydrogen production, characterized in that, The organic solvent includes N,N-dimethylformamide or ethanol.

4. The application of the Ni(OH)₂-coated hrGO / Ni-MOF core-shell heterostructure photothermal catalyst as described in claim 1 in photothermal catalytic methanol liquid-phase low-temperature reforming for hydrogen production, characterized in that, The alkaline solution includes an aqueous solution of potassium hydroxide; And / or, the mass ratio of the hrGO / Ni-MOF to the alkali contained in the alkaline solution is 0.01 to 0.02:1.

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