Multifunctional auxiliary modified composite catalyst, preparation method and application thereof

Abstract

The application provides a multifunctional additive modified composite catalyst, a preparation method and application thereof. The catalyst is M1-MgAlM2M3 catalyst, which comprises a first metal additive M1, Mg, Al, a second metal additive M2 and a semiconductor additive M3. The catalyst comprises 0.1wt%-10wt% of M1, 5wt%-40wt% of Mg element, 5wt%-40wt% of Al element, 0-20wt% of M2 and 0-50wt% of M3 in percentage of the mass of the catalyst. The preparation method is simple, mild, controllable, low in cost, high in preparation efficiency and capable of realizing large-scale production. When applied to a photo-thermal catalytic methane dry reforming reaction, the catalyst has excellent comprehensive catalytic performance, high efficiency in activating CO2 and CH4 under photo-thermal conditions, and good stability and is not easy to deactivate for 120h to generate synthesis gas.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, and in particular relates to a multifunctional additive-modified composite catalyst, its preparation method and its application. Background Technology

[0002] Photothermal catalytic dry reforming of methane (DRM) is a process that uses photothermal catalysis to convert methane (CH4) and carbon dioxide (CO2) into syngas (CO and H2). In recent years, research in this field has been significantly advanced due to strong concerns about greenhouse gas emission reduction and sustainable energy development. The DRM reaction not only effectively utilizes two major greenhouse gases but also produces syngas, an important chemical feedstock for the production of liquid fuels and various chemicals, demonstrating significant industrial application prospects.

[0003] In photothermal catalytic DRM research, catalyst development is a core issue. Currently, the main catalytic systems include noble metal catalysts, non-noble metal catalysts, and bifunctional catalysts.

[0004] Noble metal catalysts such as platinum (Pt), palladium (Pd), rhodium (Rh), and ruthenium (Ru) are widely used in this field due to their excellent catalytic performance. These noble metals are typically supported on high specific surface areas, such as alumina (Al₂O₃) and titanium dioxide (TiO₂), to improve their dispersibility and stability. However, the high cost of noble metals limits their large-scale industrial application; therefore, developing efficient and economical alternative catalysts has become a research focus.

[0005] In the field of non-precious metal catalysts, transition metals such as nickel (Ni) and cobalt (Co) have become research hotspots due to their low cost and good catalytic performance. Nickel-based catalysts, in particular, have been widely studied and applied due to their relatively low cost and good reactivity. However, nickel-based catalysts face two main problems in practical applications: first, carbon deposition, where methane decomposition at high temperatures leads to carbon buildup on the catalyst surface, covering active sites and causing catalyst deactivation; and second, sintering, where catalyst metal particles tend to aggregate and grow under high-temperature operation, resulting in reduced activity. Therefore, improving the resistance to carbon deposition and sintering of nickel-based catalysts while maintaining catalytic activity is an important current research direction.

[0006] To overcome these problems, research on catalysts modified with multifunctional additives has emerged. These catalysts combine the advantages of photocatalysis and thermocatalysis, participating in the reaction through photogenerated carriers (i.e., photogenerated electrons and holes). This not only allows the reaction to proceed at lower temperatures but also reduces carbon deposition. For example, using titanium dioxide (TiO2) as a photocatalyst support, TiO2 can generate electron-hole pairs under illumination. These photogenerated carriers can participate in the catalytic reaction, promoting the conversion of CH4 and CO2. This photothermal synergy not only improves reaction efficiency but also lowers the reaction temperature and reduces energy consumption. Studies have also shown that the stability of catalysts can be improved to some extent by controlling their composition, structure, and preparation process. For example, introducing alkali metals or rare earth metals into nickel-based catalysts can effectively inhibit carbon deposition; employing highly dispersed loading techniques can reduce particle aggregation and improve resistance to sintering.

[0007] Despite the great potential shown by photothermal catalysis DRM, it still faces many challenges in practical applications. First, there is the issue of catalyst stability. Second, carbon deposition and sintering are the main causes of catalyst deactivation. Therefore, developing catalysts with high resistance to carbon deposition and sintering is the current research focus. Summary of the Invention

[0008] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a multifunctional additive-modified composite catalyst, its preparation method and its application, to solve the problems existing in the photothermal methane dry reforming catalyst in the prior art.

[0009] To achieve the above and other related objectives, the present invention provides a multifunctional additive-modified composite catalyst, wherein the catalyst is an M1-MgAlM2M3 catalyst, comprising a first metal additive M1, Mg element, Al element, a second metal additive M2, and a semiconductor additive M3;

[0010] The catalyst comprises, by mass percentage, 0.1 wt% to 10 wt% of a first metal promoter M1, 5 wt% to 40 wt% of Mg, 5 wt% to 40 wt% of Al, 0 to 20 wt% of a second metal promoter M2, and 0 to 50 wt% of a semiconductor promoter M3.

[0011] Preferably, the first metal additive M1 is selected from one or a combination of Cu, Au, Ag, Ni, and Ru.

[0012] Preferably, the second metal additive M2 is selected from one or a combination of Ca, Sr, and Ba.

[0013] Preferably, the semiconductor additive M3 is selected from one or a combination of CeO2, TiO2, ZnO, Bi2O3, In2O3, and g-C3N4.

[0014] This invention also provides a method for preparing the above-mentioned multifunctional additive-modified composite catalyst, wherein the catalyst is prepared by co-precipitation and ultraviolet-assisted deposition, specifically including the following steps:

[0015] S1. Provide Mg salt, Al salt, and salt of the second metal auxiliary M2. Dissolve the Mg salt, Al salt, and salt of the second metal auxiliary M2 in deionized water or ethanol according to the mass percentage of the catalyst to obtain a mixed metal salt solution.

[0016] S2. Disperse semiconductor additive M3 in deionized water or ethanol to obtain mother liquor;

[0017] S3. The mixed metal salt solution and the alkaline solution are simultaneously added dropwise to the mother liquor to cause co-precipitation and obtain a co-precipitation solution;

[0018] S4. After aging, centrifuging, washing and drying the coprecipitation solution, the MgAlM2M3 precursor is obtained.

[0019] S5. Dissolve the salt of the first metal additive M1 in deionized water to obtain a first metal salt solution;

[0020] S6. According to the mass percentage of the catalyst, the first metal salt solution is added to the MgAlM2M3 precursor, and ultraviolet light is used to irradiate it to cause a precipitation reaction, so as to obtain M1-MgAlM2M3 precursor.

[0021] S7. After aging, rotary evaporation, calcination and reduction treatment of the M1-MgAlM2M3 precursor, the M1-MgAlM2M3 catalyst is obtained.

[0022] Preferably, the Mg salt in step S1 is selected from one or a combination of Mg chloride, nitrate, sulfate, carbonate, and acetate.

[0023] Preferably, the Al salt in step S1 is selected from one or a combination of Al chloride, nitrate, sulfate, carbonate, and acetate.

[0024] Preferably, in step S1, the salt of the second metal auxiliary M2 is selected from one or a combination of chloride, nitrate, sulfate, carbonate, and acetate of element M2.

[0025] Preferably, the total molar concentration of the metal in the mixed metal salt solution obtained in step S1 is 1 mol / L to 5 mol / L.

[0026] Preferably, in the mother liquor of step S2, the mass concentration of the semiconductor additive M3 is 5 g / L to 40 g / L.

[0027] Preferably, the alkaline solution in step S3 is a NaOH solution or a KOH solution with a molar concentration of 6 mol / L.

[0028] Preferably, the temperature of coprecipitation in step S3 is 30℃~80℃, and the pH of the solution is maintained at 6~10 during the coprecipitation process.

[0029] Preferably, the aging temperature in step S4 is 30℃~80℃, and the aging time is 12h~48h.

[0030] Preferably, the drying temperature in step S4 is 80℃~120℃, and the drying time is 12h~48h.

[0031] Preferably, in step S5, the salt of the first metal auxiliary M1 is selected from one or a combination of the chloride, nitrate, sulfate, carbonate, and acetate of M1, and the first metal auxiliary M1 is selected from one or a combination of Cu, Au, Ag, Ni, and Ru.

[0032] Preferably, in step S5, the molar concentration of the first metal auxiliary agent M1 in the first metal salt solution is 2 mol / L to 5 mol / L.

[0033] Preferably, the temperature of the ultraviolet light irradiation in step S6 is 30°C to 80°C.

[0034] Preferably, the wavelength of the ultraviolet light irradiation in step S6 is 300nm to 420nm.

[0035] Preferably, the precipitation reaction time caused by ultraviolet light irradiation in step S6 is 4h to 24h.

[0036] Preferably, the aging temperature in step S7 is 30℃~80℃, and the aging time is 8h~48h.

[0037] Preferably, the rotary evaporation step in step S7 specifically involves performing vacuum rotary evaporation at 50°C to 100°C, with a rotation speed of 50 r / min to 120 r / min.

[0038] Preferably, the calcination step in step S7 specifically involves calcining in a static or flowing atmosphere at 200°C to 600°C for 0.5 to 10 hours.

[0039] Preferably, the reduction in step S7 is a high-temperature reduction, the reduction temperature is 200℃~600℃, the reduction time is 4h~16h, and the reduction atmosphere is one of pure H2 gas, H2 / Ar mixture, and H2 / CO2 mixture.

[0040] The present invention also provides an application of a multifunctional additive-modified composite catalyst, wherein the catalyst is used in a photothermal catalytic dry reforming reaction of methane, and the catalyst is the aforementioned multifunctional additive-modified composite catalyst.

[0041] Preferably, the feed gas used in the methane dry reforming reaction is CH4 and CO2, with a volume ratio of 1:1 to 3:1.

[0042] Preferably, the space velocity of the raw material gas is 10000–97000 ml / g. cat -1 ·h -1 .

[0043] Preferably, the surface temperature of the methane dry reforming reaction is 300–800°C, and the pressure of the methane dry reforming reaction is 0.1 MPa.

[0044] As described above, the multifunctional additive-modified composite catalyst, its preparation method, and its application of the present invention have the following beneficial effects:

[0045] The multifunctional modified composite catalyst M1-MgAlM2M3 of this invention comprises, by mass percentage: 0.1wt%–10wt% of a first metal promoter M1, 5wt%–40wt% of Mg, 5wt%–40wt% of Al, 0–20wt% of a second metal promoter M2, and 0–40wt% of a semiconductor promoter M3. This catalyst is prepared using a co-precipitation method and an ultraviolet-assisted deposition method. The preparation method is simple, the operating conditions are mild, and the reaction is highly controllable, which can reduce preparation costs, improve preparation efficiency, and facilitate large-scale production. The first metal promoter, which exhibits a localized surface plasmon resonance (LSPR) effect, is introduced through ultraviolet-assisted deposition. Agent M1 enables the catalyst to absorb light energy and convert it into heat energy within a specific wavelength range, significantly improving the photothermal catalytic activity of the catalyst surface and achieving efficient conversion of light energy to heat energy. Combined with the composite structure of the second metal promoter M2 and the semiconductor promoter M3, the catalyst effectively improves the reaction efficiency and stability in the photothermal methane dry reforming reaction. The introduction of the second metal promoter M2 enables efficient CO2 adsorption and activation, while the introduction of the semiconductor promoter M3 improves the efficiency of photothermal conversion, further promoting the reaction. Furthermore, the magnesium-aluminum structure design not only improves the catalyst's resistance to sintering and carbon deposition but also enhances the stability of the catalyst structure, thereby improving the catalyst's recyclability.

[0046] The multifunctional modified composite catalyst of this invention exhibits excellent comprehensive catalytic performance when applied to solar-driven photothermal catalytic dry reforming of methane. The optimized catalyst composition and structure improve its selectivity and specificity for CO2 and CH4, achieving high purity and high yield of the product while reducing energy consumption and cost in subsequent product purification processes. Under photothermal conditions, it has the ability to efficiently activate CO2 and CH4, with a CH4 conversion rate of up to 38.8%, and can stably generate syngas with an H2 / CO ratio of approximately 1:1 for 120 hours. The catalyst has good stability and is not easily deactivated, enabling large-scale production. Attached Figure Description

[0047] Figure 1 The diagram shows the catalytic performance of the catalyst Ni-MgAlCaCeO2 in Example 6 of this invention in the solar-driven photothermal dry reforming reaction of methane. Detailed Implementation

[0048] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0049] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.

[0050] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0051] This invention provides a highly efficient, stable, and sustainable multifunctional additive-modified composite catalyst to promote the development of photothermal methane dry reforming technology, realize the resource utilization of CO2 and the chemical conversion of methane, and contribute to addressing challenges in the energy and environmental fields. The catalyst is an M1-MgAlM2M3 catalyst, comprising a first metal additive M1, Mg, Al, a second metal additive M2, and a semiconductor additive M3. Specifically, by mass percentage, the catalyst comprises 0.1wt%–10wt% of the first metal additive M1, 5wt%–40wt% of Mg, 5wt%–40wt% of Al, 0–20wt% of the second metal additive M2, and 0–50wt% of the semiconductor additive M3.

[0052] Specifically, based on the mass percentage of the M1-MgAlM2M3 catalyst, the mass percentage of the first metal promoter M1 can include any value within the range of 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2.5wt%, 3wt%, 5wt%, 7wt%, 10wt%, etc.; the mass percentage of Mg can include any value within the range of 5wt%, 13wt%, 15wt%, 22wt%, 25wt%, 30wt%, 32wt%, 35wt%, 40wt%, etc.; and the mass percentage of Al can include any value within the range of 5wt%, 13wt%, 15wt%, 22wt%, 25wt%, 30wt%, 32wt%, 35wt%, 30wt%, 35wt%, 40wt%, etc. The mass percentage of the second metal additive M2 can be any value within the range of 2wt%, 35wt%, 40wt%, etc., and the mass percentage of the semiconductor additive M3 can be any value within the range of 0wt%, 1wt%, 5wt%, 10wt%, 15wt%, 20wt%, etc., and the mass percentage of the semiconductor additive M3 can be any value within the range of 0wt%, 1wt%, 5wt%, 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, etc.; when the mass percentage of the second metal additive M2 is 0, it means that the catalyst does not contain the second metal additive M2; when the mass percentage of the semiconductor additive M3 is 0, it means that the catalyst does not contain the semiconductor additive M3.

[0053] Specifically, the first metal promoter M1 is a metal with localized surface plasmon resonance (LSPR) effect. The LSPR effect enables the catalyst to absorb light energy within a specific wavelength range and convert it into heat energy, thereby enhancing the photothermal catalytic activity of the catalyst surface. The second metal promoter enables efficient adsorption and activation of CO2. The semiconductor promoter can improve the efficiency of photothermal conversion and further promote the reaction. The magnesium-aluminum structure can improve its anti-toxicity and anti-carbon deposition properties, while stabilizing the catalyst structural components, further improving the stability and recyclability of the catalyst.

[0054] Preferably, in the catalyst, the first metal promoter M1 accounts for 2wt% to 4wt% by mass (e.g., 2wt%, 2.2wt%, 2.5wt%, 2.8wt%, 3wt%, 3.2wt%, 3.4wt%, 3.6wt%, 3.8wt%, 4wt%, etc.); the second metal promoter M2 accounts for 5wt% to 10wt% by mass (e.g., 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, etc.); and the semiconductor promoter M3 accounts for 8wt% to 15wt% by mass (e.g., 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, etc.).

[0055] As an example, the first metal additive M1 is selected from one or a combination of Cu, Au, Ag, Ni, and Ru.

[0056] Specifically, the first metal additive M1 is a metal with local surface plasmon resonance (LSPR) effect. When incident light irradiates the surface of the metal particles, the free electrons in the metal will interact with photons to generate a local electromagnetic field enhancement effect. This effect can significantly improve the light absorption capacity and photothermal catalytic activity of the catalyst.

[0057] Preferably, the first metal additive M1 is Ni or Ru. As an example, the second metal additive M2 is selected from one or a combination of Ca, Sr, and Ba. As an example, the semiconductor additive M3 is selected from one or a combination of CeO2, TiO2, ZnO, Bi2O3, In2O3, and g-C3N4.

[0058] Preferably, the semiconductor additive M3 is CeO2 or TiO2. As an example, the semiconductor additive in the catalyst is selected as...

[0059] The mass ratio between Mg and Al is 1:8 to 8:1 (e.g., 1:8, 1:4, 1:2, 1:1, 2:1, 3:1, 4:1, 8:1, etc.).

[0060] Preferably, the mass ratio of Mg to Al in the catalyst is 1:4 to 4:1.

[0061] This invention also provides a method for preparing the above-mentioned multifunctional additive-modified composite catalyst, which is prepared by co-precipitation and ultraviolet-assisted deposition, specifically including the following steps:

[0062] S1. Provide Mg salt, Al salt, and salt of the second metal auxiliary M2. Dissolve the Mg salt, Al salt, and salt of the second metal auxiliary M2 in deionized water or ethanol according to the mass percentage of the catalyst to obtain a mixed metal salt solution.

[0063] S2. Disperse semiconductor additive M3 in deionized water or ethanol to obtain mother liquor;

[0064] S3. The mixed metal salt solution and the alkaline solution are simultaneously added dropwise to the mother liquor to cause co-precipitation and obtain a co-precipitation solution;

[0065] S4. After aging, centrifuging, washing and drying the coprecipitation solution, the MgAlM2M3 precursor is obtained.

[0066] S5. Dissolve the salt of the first metal additive M1 in deionized water to obtain a first metal salt solution;

[0067] S6. According to the mass percentage of the catalyst, the first metal salt solution is added to the MgAlM2M3 precursor and irradiated with ultraviolet light to cause a precipitation reaction, thus obtaining the M1-MgAlM2M3 precursor; that is, the first metal salt with LSPR effect is loaded onto the MgAlM2M3 precursor by ultraviolet light-assisted deposition.

[0068] S7. After aging, rotary evaporation, calcination and reduction treatment of the M1-MgAlM2M3 precursor, the M1-MgAlM2M3 catalyst is obtained.

[0069] Specifically, this invention employs co-precipitation and ultraviolet (UV) light-assisted deposition to prepare multifunctional additive-modified composite catalysts. This method offers advantages such as simple preparation processes, mild operating conditions, and high reaction controllability. Utilizing a light source, MgAlM2M3 precursor molecules are deposited under specific conditions to form catalyst clusters, achieving precise control over the catalyst. Compared to traditional methods, photo-assisted deposition can prepare smaller, more uniformly dispersed cluster-supported catalysts with higher catalytic activity and selectivity. The entire preparation process is simple and can be scaled up. By loading a first metal additive with localized surface plasmon resonance effect using UV light-assisted deposition, and combining it with a second metal additive and a semiconductor additive, the efficiency and stability of the photothermal methane dry reforming reaction can be effectively improved. Furthermore, by optimizing the catalyst's composition and structure, this invention enhances its selectivity and specificity for CO2 and methane, achieving high product purity and yield while reducing energy consumption and costs in subsequent product purification processes.

[0070] As an example, in step S1, the Mg salt is selected from one or a combination of Mg chloride, nitrate, sulfate, carbonate, and acetate.

[0071] As an example, in step S1, the Al salt is selected from one or a combination of chloride, nitrate, sulfate, carbonate, and acetate of Al.

[0072] As an example, in step S1, the salt of the second metal auxiliary M2 is selected from one or a combination of chloride, nitrate, sulfate, carbonate, and acetate of element M2.

[0073] Specifically, the second metal additive M2 is selected from one or a combination of Ca, Sr, and Ba.

[0074] As an example, the total molar concentration of the metal in the mixed metal salt solution obtained in step S1 is 1 mol / L to 5 mol / L.

[0075] Specifically, the total molar concentration of metals in a mixed metal salt solution can be any value within the range of 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, etc., and can be adjusted according to the actual situation.

[0076] As an example, in the mother liquor of step S2, the mass concentration of semiconductor additive M3 is 5 g / L to 40 g / L.

[0077] Specifically, semiconductor additive M3 is selected from one or a combination of CeO2, TiO2, ZnO, Bi2O3, In2O3, and g-C3N4; the mass concentration of the mother liquor may be any value within any range such as 5 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, and 40 g / L.

[0078] As an example, the alkaline solution in step S3 is a NaOH solution or a KOH solution with a molar concentration of 6 mol / L.

[0079] As an example, the temperature for co-precipitation in step S3 is 30℃~80℃, and the pH of the solution is maintained at 6~10 during the co-precipitation process.

[0080] Specifically, the temperature for coprecipitation can be any value within the range of 30℃, 40℃, 60℃, 80℃, etc., and can be adjusted according to the actual situation; the pH value of the solution during coprecipitation can be any value within the range of 6, 7, 8, 9, 10, etc.

[0081] As an example, the aging temperature in step S4 is 30℃~80℃, and the aging time is 12h~48h.

[0082] Specifically, the aging temperature can be any value within the range of 30℃, 40℃, 60℃, 80℃, etc., and can be adjusted according to the actual situation; the aging time can be any value within the range of 12h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 48h, etc., and can be adjusted according to the actual situation.

[0083] In addition, the number of centrifugal washing cycles in step S4 is 0 to 20. When the number of centrifugal washing cycles is 0, it indicates that the centrifugal washing step is not required.

[0084] As an example, the drying temperature in step S4 is 80℃~120℃, and the drying time is 12h~48h.

[0085] Specifically, the drying temperature can include any value within the range of 80℃, 90℃, 100℃, 110℃, 120℃, etc.; the drying time can include any value within the range of 12h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 48h, etc.

[0086] As an example, in step S5, the salt of the first metal auxiliary M1 is selected from one or a combination of the chloride, nitrate, sulfate, carbonate, and acetate of M1, and the first metal auxiliary M1 is selected from one or a combination of Cu, Au, Ag, Ni, and Ru.

[0087] Specifically, this invention utilizes a first metal promoter M1 with LSPR effect to improve photothermal catalytic efficiency, enhance the photothermal activity of the catalyst surface, and achieve efficient conversion of light energy into heat energy, thereby promoting the photothermal dry reforming reaction of methane.

[0088] As an example, in step S5, the molar concentration of the first metal auxiliary agent M1 in the first metal salt solution is 2 mol / L to 5 mol / L.

[0089] Specifically, the molar concentration of the first metal auxiliary agent M1 in the first metal salt solution can be any value within the range of 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, etc., and can be adjusted according to actual conditions.

[0090] As an example, the temperature of ultraviolet irradiation in step S6 is 30℃~80℃.

[0091] Specifically, the temperature for ultraviolet light irradiation can be any value within a range such as 30℃, 40℃, 60℃, or 80℃, and can be adjusted according to actual conditions.

[0092] As an example, the wavelength of ultraviolet light irradiation in step S6 is 300nm to 420nm.

[0093] Specifically, the wavelength of ultraviolet light irradiation can be any value within the range of 300nm, 320nm, 350nm, 400nm, 420nm, etc.

[0094] As an example, the precipitation reaction time caused by ultraviolet light irradiation in step S6 is 4h to 24h.

[0095] Specifically, the time for precipitation reaction to occur under ultraviolet light irradiation can be any value within a range such as 4h, 10h, 15h, 20h, 22h, 24h.

[0096] As an example, the aging temperature in step S7 is 30℃~80℃, and the aging time is 8h~48h.

[0097] Specifically, the aging temperature can be any value within the range of 30℃, 40℃, 60℃, 80℃, etc.; the aging time can be any value within the range of 8h, 12h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 48h, etc.

[0098] As an example, the rotary evaporation step in step S7 is specifically performed by vacuum rotary evaporation at 50℃~100℃, with a rotation speed of 50r / min~120r / min.

[0099] Specifically, the rotary evaporation temperature can be any value within the range of 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, etc.; the rotation speed can be any value within the range of 50r / min, 80r / min, 100r / min, 120r / min, etc.

[0100] As an example, the calcination step in step S7 is specifically calcined in a static or flowing atmosphere at 200℃ to 600℃ for 0.5h to 10h.

[0101] Specifically, the calcination temperature can be any value within the range of 200℃, 300℃, 400℃, 500℃, 600℃, etc.; the calcination time can be any value within the range of 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, etc.

[0102] Preferably, the static atmosphere is static air; the flowing atmosphere includes one or a combination of flowing air, flowing N2 gas, flowing Ar gas, flowing NO / Ar mixture, flowing H2O / Ar mixture, flowing H2O / air mixture, flowing CO2 / Ar mixture, and flowing CO2 / air mixture.

[0103] As an example, in step S7, the reduction is a high-temperature reduction, with a reduction temperature of 200℃~600℃, a reduction time of 4h~16h, and the reduction atmosphere is one of pure H2 gas, H2 / Ar mixture, or H2 / CO2 mixture.

[0104] Specifically, the reduction temperature can be any value within the range of 200℃, 300℃, 400℃, 500℃, 600℃, etc.; the reduction time can be any value within the range of 4h, 6h, 8h, 10h, 12h, 16h, etc.

[0105] Preferably, the atmosphere for high-temperature reduction is pure H2 gas.

[0106] In addition, the present invention also provides an application of a multifunctional additive-modified composite catalyst, wherein the catalyst is applied to a solar-driven photothermal catalytic dry reforming reaction of methane, wherein the catalyst is the aforementioned multifunctional additive-modified composite catalyst.

[0107] Specifically, the catalyst in the specific embodiments of the present invention exhibits excellent comprehensive catalytic performance. When applied to photothermal catalytic dry reforming of methane, it demonstrates highly efficient activation of CO2 and CH4 under photothermal conditions, and can stably generate syngas with an H2 / CO ratio of approximately 1:1 for 120 hours. The CO2 conversion rate can reach up to 40%, and the catalyst exhibits good stability and is not easily deactivated.

[0108] The multifunctional additive-modified composite catalyst in the specific embodiments of the present invention has the synergistic effect of multiple active phases. The first metal additive with LSPR effect can absorb light energy and convert it into heat energy, and at the same time can serve as an active site for CH bond dissociation and C=O bond activation. The addition of the second metal additive M2 realizes the efficient adsorption and activation of CO2, thereby improving the reaction rate. Meanwhile, the semiconductor additive M3 realizes the ability of photothermal absorption and conversion in photothermal catalytic reaction, effectively improving photothermal efficiency and helping to overcome the thermodynamic limitations of methane reforming reaction. The magnesium-aluminum structure has a large number of active sites, which can effectively promote the reaction and effectively support the M1-MgAlM2M3 catalyst.

[0109] As an example, the feed gas used in the dry reforming reaction of methane is CH4 and CO2, with a volume ratio of 1:1 to 3:1.

[0110] Specifically, the volume ratio of CH4 to CO2 in the feed gas can be any value within a range such as 1, 2, or 3.

[0111] As an example, the space velocity of the feed gas is 10,000–97,000 ml / g. cat -1 ·h -1 .

[0112] Specifically, the space velocity of the feed gas can include 10000 ml / (g) cat ·h), 50000ml / (g cat ·h), 70000ml / (g cat ·h), 97000ml / (g cat ·h) and other specific parameters can be adjusted according to actual conditions.

[0113] As an example, the surface temperature of the methane dry reforming reaction is 300–800 °C, and the pressure of the methane dry reforming reaction is 0.1 MPa.

[0114] Specifically, the surface temperature of the methane dry reforming reaction can be any value within the range of 300℃, 400℃, 500℃, 600℃, 700℃, 800℃, etc. This temperature is provided by light. Applying a certain current to the light can generate heat on the one hand and have a photocatalytic function on the other.

[0115] To better understand the multifunctional additive-modified composite catalyst, its preparation method, and its application in this invention, specific embodiments are described below. It should be noted that these embodiments are merely descriptive and do not limit the invention in any way.

[0116] In the following examples, the preparation of multifunctional additive-modified composite catalysts is measured as 4g of M1-MgAlM2M3 catalyst.

[0117] Example 1

[0118] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCeO2 catalyst, comprising a first metal additive Ni, Mg, Al and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 25 wt% of Mg, 25 wt% of Al and 48 wt% of the semiconductor additive CeO2.

[0119] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The catalyst is prepared by co-precipitation and ultraviolet-assisted deposition, specifically including the following steps:

[0120] S1. Provide magnesium nitrate and aluminum nitrate. Dissolve 25 wt% of magnesium nitrate (measured by the mass of Mg element) and 25 wt% of aluminum nitrate (measured by the mass of Al element) of the total catalyst mass in deionized water to obtain a 2 mol / L mixed metal salt solution.

[0121] S2. Disperse 48wt% of CeO2, which accounts for 48wt% of the total mass of the catalyst, in deionized water to obtain a mother liquor with a mass concentration of 20g / mL.

[0122] S3. The above mixed metal salt solution and NaOH solution with a molar concentration of 6 mol / L are simultaneously added dropwise to the mother liquor. The temperature at which co-precipitation occurs is 60℃, and a co-precipitation solution is obtained.

[0123] S4. The coprecipitate solution was aged at 60℃ for 6 hours, centrifuged and washed 10 times, and then dried in an oven at 100℃ for 48 hours to obtain the MgAlCeO2 precursor.

[0124] S5. Dissolve 2 wt% of nickel nitrate, which accounts for 2 wt% of the total mass of the catalyst, in deionized water to obtain a Ni salt solution with a molar concentration of 2 mol / L.

[0125] S6. Add the Ni salt solution to the above MgAlCeO2 precursor and irradiate with ultraviolet light at 50°C for 4 hours until sufficient precipitation is obtained to obtain Ni-MgAlCeO2 precursor.

[0126] S7. The Ni-MgAlCeO2 precursor was aged at 60℃ for 4h, vacuum rotary evaporated at 60℃ and 100r / min, calcined in air at 400℃ for 4h, and reduced in pure H2 atmosphere at 400℃ to obtain the Ni-MgAlCeO2 catalyst.

[0127] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is packed in a fixed bed and applied to a photothermal catalytic dry reforming reaction of methane. The performance of the catalyst in this embodiment is then evaluated. Specifically, 20 mg of the catalyst is weighed and reacted in a feed gas with CH4 / CO2 = 1, a space velocity (WHSV) of 19400 ml / (gcat·h), a reaction pressure of 0.1 MPa, and a photocurrent of 18 A. The performance results are shown in Table 1.

[0128] Example 2

[0129] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Cu-MgAlCeO2 catalyst, comprising a first metal additive Cu, Mg, Al and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Cu, 25 wt% of Mg, 25 wt% of Al and 48 wt% of the semiconductor additive CeO2.

[0130] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 1 is that: in step S5, 2 wt% of copper nitrate, accounting for the total mass of the catalyst, is weighed and dissolved in deionized water to obtain a Cu salt solution with a molar concentration of 2 mol / L; in step S6, the Cu salt solution is added to the above-mentioned MgAlCeO2 precursor; other steps and methods are the same as those in Example 1, and will not be repeated here.

[0131] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 1, and will not be repeated here. The performance results are shown in Table 1.

[0132] Example 3

[0133] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ru-MgAlCeO2 catalyst, comprising a first metal additive Ru, Mg, Al and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ru, 25 wt% of Mg, 25 wt% of Al and 48 wt% of the semiconductor additive CeO2.

[0134] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 1 is that: in step S5, 2 wt% of ruthenium nitrate, accounting for the total mass of the catalyst, is weighed and dissolved in deionized water to obtain a Ru salt solution with a molar concentration of 2 mol / L; in step S6, the Ru salt solution is added to the above-mentioned MgAlCeO2 precursor; other steps and methods are the same as those in Example 1, and will not be repeated here.

[0135] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 1, and will not be repeated here. The performance results are shown in Table 1.

[0136] Example 4

[0137] This embodiment provides a multifunctional additive-modified composite catalyst, which is an Au-MgAlCeO2 catalyst, comprising a first metal additive Au, Mg, Al and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Au, 25 wt% of Mg, 25 wt% of Al and 48 wt% of the semiconductor additive CeO2.

[0138] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 1 is that: in step S5, 2 wt% of chloroauric acid, accounting for the total mass of the catalyst, is dissolved in deionized water to obtain an Au salt solution with a molar concentration of 2 mol / L; in step S6, the Au salt solution is added to the above-mentioned MgAlCeO2 precursor; other steps and methods are the same as those in Example 1, and will not be repeated here.

[0139] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 1, and will not be repeated here. The performance results are shown in Table 1.

[0140] Example 5

[0141] This embodiment provides a multifunctional additive-modified composite catalyst, which is an Ag-MgAlCeO2 catalyst, comprising a first metal additive Ag, Mg, Al and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ag, 25 wt% of Mg, 25 wt% of Al and 48 wt% of the semiconductor additive CeO2.

[0142] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 1 is that: in step S5, 2 wt% of silver chloride, accounting for the total mass of the catalyst, is weighed and dissolved in deionized water to obtain an Ag salt solution with a molar concentration of 2 mol / L; in step S6, the Ag salt solution is added to the above-mentioned MgAlCeO2 precursor; other steps and methods are the same as those in Example 1, and will not be repeated here.

[0143] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 1, and will not be repeated here. The performance results are shown in Table 1.

[0144] Example 6

[0145] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 25 wt% of Mg, 25 wt% of Al, 8 wt% of Ca, and 40 wt% of the semiconductor additive CeO2.

[0146] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The catalyst is prepared by co-precipitation and ultraviolet-assisted deposition, specifically including the following steps:

[0147] S1. Dissolve 25 wt% magnesium nitrate (measured by the mass of Mg), 25 wt% aluminum nitrate (measured by the mass of Al), and 8 wt% calcium nitrate (measured by the mass of Ca) in deionized water to obtain a 2 mol / L mixed metal salt solution.

[0148] S2. Disperse 40wt% of CeO2, which accounts for 40wt% of the total mass of the catalyst, in deionized water to obtain a mother liquor with a mass concentration of 20g / mL.

[0149] S3. The above mixed metal salt solution and NaOH solution with a molar concentration of 6 mol / L are simultaneously added dropwise to the mother liquor. The temperature at which co-precipitation occurs is 60℃, and a co-precipitation solution is obtained.

[0150] S4. The coprecipitate solution was aged at 60℃ for 6 hours, centrifuged and washed 10 times, and then dried in an oven at 100℃ for 48 hours to obtain the MgAlCaCeO2 precursor.

[0151] S5. Dissolve 2 wt% of nickel nitrate, which accounts for 2 wt% of the total mass of the catalyst, in deionized water to obtain a Ni salt solution with a molar concentration of 2 mol / L.

[0152] S6. Add the Ni salt solution to the above MgAlCaCeO2 precursor and irradiate with ultraviolet light at 50°C for 4 hours until sufficient precipitation is obtained to obtain Ni-MgAlCaCeO2 precursor.

[0153] S7. The Ni-MgAlCaCeO2 precursor was aged at 60℃ for 4h, vacuum rotary evaporation was performed at 60℃ and 100r / min, calcined in air at 400℃ for 4h, and reduced in pure H2 atmosphere at 400℃ to obtain the Ni-MgAlCaCeO2 catalyst.

[0154] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 1, and will not be repeated here. The performance results are shown in Table 1.

[0155] See Figure 1 The figure shows the catalytic performance of the catalyst in the photothermal catalytic dry reforming of methane in this embodiment. As can be seen from the figure, the catalyst in this embodiment has a high product yield in the photothermal catalytic dry reforming of methane. The catalyst still has good catalytic activity after 120 h of reaction. The pentagram curve represents the H / C ratio. It can stably generate syngas with H2 / CO≈1:1 for 120 h, which indicates that the catalyst has excellent stability.

[0156] Example 7

[0157] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlSrCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Sr and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 25 wt% of Mg, 25 wt% of Al, 8 wt% of Sr and 40 wt% of the semiconductor additive CeO2.

[0158] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that: in step S1, 25 wt% of magnesium nitrate (measured by the mass of Mg), 25 wt% of aluminum nitrate (measured by the mass of Al), and 8 wt% of strontium nitrate (measured by the mass of Sr) are dissolved in deionized water to obtain a 2 mol / L mixed metal salt solution; in step S4, a MgAlSrCeO2 precursor is obtained; in steps S6 and S7, the second metal additive is adapted to be Sr; other steps and methods are the same as in Example 6 and will not be repeated here.

[0159] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0160] Example 8

[0161] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlBaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ba, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 25 wt% of Mg, 25 wt% of Al, 8 wt% of Ba, and 40 wt% of the semiconductor additive CeO2.

[0162] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that: in step S1, 25 wt% magnesium nitrate (measured by the mass of Mg), 25 wt% aluminum nitrate (measured by the mass of Al), and 8 wt% barium nitrate (measured by the mass of Ba) are dissolved in deionized water to obtain a 2 mol / L mixed metal salt solution; in step S4, a MgAlBaCeO2 precursor is obtained; in steps S5, S6, and S7, the second metal additive is adapted to be Ba; other steps and methods are the same as in Example 6 and will not be repeated here.

[0163] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0164] Example 9

[0165] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive TiO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 25 wt% of Mg, 25 wt% of Al, 8 wt% of Ca, and 40 wt% of the semiconductor additive TiO2.

[0166] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that: in step S2, 40 wt% of TiO2, accounting for the total mass of the catalyst, is dispersed in deionized water to obtain a mother liquor with a mass concentration of 20 g / mL; in step S4, a MgAlCaTiO2 precursor is obtained; in steps S6 and S7, the semiconductor additive is adapted to TiO2; other steps and methods are the same as those in Example 6, and will not be repeated here.

[0167] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0168] Example 10

[0169] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaZnO catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive ZnO; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 25 wt% of Mg, 25 wt% of Al, 8 wt% of Ca, and 40 wt% of the semiconductor additive ZnO.

[0170] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that: in step S2, 40 wt% of ZnO, accounting for the total mass of the catalyst, is dispersed in deionized water to obtain a mother liquor with a mass concentration of 20 g / mL; in step S4, a MgAlCaZnO precursor is obtained; in steps S6 and S7, the semiconductor additive is adapted to ZnO; other steps and methods are the same as in Example 6 and will not be repeated here.

[0171] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0172] Example 11

[0173] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaBi2O3 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive Bi2O3; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 25 wt% of Mg, 25 wt% of Al, 8 wt% of Ca, and 40 wt% of the semiconductor additive Bi2O3.

[0174] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that: in step S2, 40 wt% of Bi2O3, accounting for the total mass of the catalyst, is dispersed in deionized water to obtain a mother liquor with a mass concentration of 20 g / mL; in step S4, a MgAlCaBi2O3 precursor is obtained; in steps S6 and S7, the semiconductor additive is adapted to Bi2O3; other steps and methods are the same as those in Example 6 and will not be repeated here.

[0175] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0176] Example 12

[0177] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCag-C3N4 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive g-C3N4; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 25 wt% of Mg, 25 wt% of Al, 8 wt% of Ca, and 40 wt% of the semiconductor additive g-C3N4.

[0178] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that: in step S2, 40 wt% of g-C3N4, accounting for the total mass of the catalyst, is dispersed in deionized water to obtain a mother liquor with a mass concentration of 20 g / mL; in step S4, a MgAlCag-C3N4 precursor is obtained; in steps S6 and S7, the semiconductor additive is adapted to g-C3N4; other steps and methods are the same as in Example 6 and will not be repeated here.

[0179] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0180] Example 13

[0181] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaIn2O3 catalyst, comprising a first metal additive Ni, Mg, Al, Ca and a semiconductor additive In2O3; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 25 wt% of Mg, 25 wt% of Al, 8 wt% of Ca and 40 wt% of the semiconductor additive In2O3.

[0182] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that: in step S2, 40 wt% of In2O3, accounting for the total mass of the catalyst, is dispersed in deionized water to obtain a mother liquor with a mass concentration of 20 g / mL; in step S4, a MgAlCaIn2O3 precursor is obtained; in steps S6 and S7, the semiconductor additive is adapted to In2O3; other steps and methods are the same as in Example 6 and will not be repeated here.

[0183] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0184] Example 14

[0185] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 27 wt% of Mg, 27 wt% of Al, 4 wt% of Ca, and 40 wt% of the semiconductor additive CeO2.

[0186] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this preparation method and that in Example 6 is that in step S1, calcium nitrate accounts for 4 wt% of the total mass of the catalyst (measured by the mass of Ca element), magnesium nitrate accounts for 27 wt% of the total mass of the catalyst (measured by the mass of Mg element), and aluminum nitrate accounts for 27 wt% of the total mass of the catalyst (measured by the mass of Al element); other steps and methods are the same as in Example 6, and will not be repeated here.

[0187] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0188] Example 15

[0189] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 24 wt% of Mg, 24 wt% of Al, 10 wt% of Ca, and 40 wt% of the semiconductor additive CeO2.

[0190] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that in step S1, calcium nitrate accounts for 10 wt% of the total mass of the catalyst (measured by the mass of Ca element), magnesium nitrate accounts for 24 wt% of the total mass of the catalyst (measured by the mass of Mg element), and aluminum nitrate accounts for 24 wt% of the total mass of the catalyst (measured by the mass of Al element); other steps and methods are the same as those in Example 6, and will not be repeated here.

[0191] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0192] Example 16

[0193] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 21 wt% of Mg, 21 wt% of Al, 16 wt% of Ca, and 40 wt% of the semiconductor additive CeO2.

[0194] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that in step S1, calcium nitrate accounts for 16 wt% of the total mass of the catalyst (measured by the mass of Ca element), magnesium nitrate accounts for 21 wt% of the total mass of the catalyst (measured by the mass of Mg element), and aluminum nitrate accounts for 21 wt% of the total mass of the catalyst (measured by the mass of Al element); other steps and methods are the same as those in Example 6, and will not be repeated here.

[0195] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0196] Example 17

[0197] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 19 wt% of Mg, 19 wt% of Al, 20 wt% of Ca, and 40 wt% of the semiconductor additive CeO2.

[0198] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this preparation method and that in Example 6 is that in step S1, calcium nitrate accounts for 20 wt% of the total mass of the catalyst (measured by the mass of Ca element), magnesium nitrate accounts for 19 wt% of the total mass of the catalyst (measured by the mass of Mg element), and aluminum nitrate accounts for 19 wt% of the total mass of the catalyst (measured by the mass of Al element); other steps and methods are the same as in Example 6, and will not be repeated here.

[0199] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0200] Example 18

[0201] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 10 wt% of Mg, 40 wt% of Al, 8 wt% of Ca, and 40 wt% of the semiconductor additive CeO2.

[0202] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this preparation method and that in Example 6 is that: in step S1, magnesium nitrate accounts for 10 wt% of the total mass of the catalyst (measured by the mass of Mg element) and aluminum nitrate accounts for 40 wt% of the total mass of the catalyst (measured by the mass of Al element); other steps and methods are the same as in Example 6, and will not be repeated here.

[0203] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0204] Example 19

[0205] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 40 wt% of Mg, 10 wt% of Al, 8 wt% of Ca, and 40 wt% of the semiconductor additive CeO2.

[0206] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that in step S1, magnesium nitrate accounts for 40 wt% of the total mass of the catalyst (measured by the mass of Mg element) and aluminum nitrate accounts for 10 wt% of the total mass of the catalyst (measured by the mass of Al element); other steps and methods are the same as in Example 6, and will not be repeated here.

[0207] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0208] Example 20

[0209] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 10 wt% of the first metal additive Ni, 25 wt% of Mg, 25 wt% of Al, 8 wt% of Ca, and 32 wt% of the semiconductor additive CeO2.

[0210] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that: in step S1, 32 wt% of CeO2 is added; in step S5, 10 wt% of nickel nitrate is dissolved in deionized water to obtain a Ni salt solution with a molar concentration of 2 mol / L; other steps and methods are the same as in Example 6 and will not be repeated here.

[0211] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0212] Example 21

[0213] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 40 wt% of Mg, 40 wt% of Al, 8 wt% of Ca, and 10 wt% of the semiconductor additive CeO2.

[0214] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that: in step S1, 40 wt% magnesium nitrate (measured by the mass of Ca) and 40 wt% aluminum nitrate (measured by the mass of Al) of the total catalyst mass are added; in step S2, 10 wt% CeO2 of the total catalyst mass is dispersed in deionized water to obtain a mother liquor with a mass concentration of 20 g / mL; other steps and methods are the same as in Example 6 and will not be repeated here.

[0215] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0216] Example 22

[0217] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 35 wt% of Mg, 35 wt% of Al, 8 wt% of Ca, and 20 wt% of the semiconductor additive CeO2.

[0218] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that: in step S1, magnesium nitrate (measured by the mass of Mg) accounting for 35 wt% of the total mass of the catalyst is added, and aluminum nitrate (measured by the mass of Al) accounting for 35 wt% of the total mass of the catalyst is added; in step S2, CeO2 accounting for 20 wt% of the total mass of the catalyst is dispersed in deionized water to obtain a mother liquor with a mass concentration of 20 g / mL; other steps and methods are the same as in Example 6, and will not be repeated here.

[0219] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0220] Example 23

[0221] This embodiment provides a multifunctional additive-modified composite catalyst, which is a Ni-MgAlCaCeO2 catalyst, comprising a first metal additive Ni, Mg, Al, Ca, and a semiconductor additive CeO2; wherein, by mass percentage, the catalyst comprises 2 wt% of the first metal additive Ni, 30 wt% of Mg, 30 wt% of Al, 8 wt% of Ca, and 30 wt% of the semiconductor additive CeO2.

[0222] This embodiment also provides a method for preparing a multifunctional additive-modified composite catalyst. The difference between this method and that in Example 6 is that: in step S1, magnesium nitrate (measured by the mass of Mg) accounting for 30 wt% of the total mass of the catalyst is added, and aluminum nitrate (measured by the mass of Al) accounting for 30 wt% of the total mass of the catalyst is added; in step S2, CeO2 accounting for 30 wt% of the total mass of the catalyst is dispersed in deionized water to obtain a mother liquor with a mass concentration of 20 g / mL; other steps and methods are the same as those in Example 6, and will not be repeated here.

[0223] In addition, this embodiment also provides an application of a multifunctional additive-modified composite catalyst. The catalyst in this embodiment is applied to a photothermal catalytic dry reforming reaction of methane, and the performance of the catalyst in this embodiment is evaluated. The specific evaluation method is the same as that in Example 6, and will not be repeated here. The performance results are shown in Table 1.

[0224] Table 1. Results of applying the multifunctional additive-modified composite catalysts from Examples 1-13 to the photothermal catalytic dry reforming reaction of methane.

[0225]

[0226]

[0227] The data above show that Examples 1-5 compared the effects of different LSPR first metal promoters M1 on the photothermal dry reforming performance of methane. The results indicate that Ni is the LSPR metal component with the best activity. Examples 1 and 6-8 compared the effects of adding second metal promoter M2 on the photothermal dry reforming activity of methane. The results show that adding second metal Ca can effectively improve catalytic activity and exhibits the best photothermal conversion ability during the experiment. Examples 9-13 compared the effects of different semiconductor promoters M3 on the photothermal dry reforming performance of methane. The results show that adding semiconductor CeO2 has higher catalytic activity. Examples 6 and 14-17 compared the effects of the amount of second metal promoter M2 added on the photothermal dry reforming activity of methane. The results show that adding 8% second metal Ca can effectively improve the catalytic activity of the catalyst, but increasing the content inhibits the catalytic performance. Examples 6, 18, and 19 compared the effects of adding different Mg:Al ratios on the photothermal dry reforming of methane. The results show that the catalytic activity is best when the ratio is 1:1. Examples 6 and 20 compared the effect of Ni loading on the catalytic activity of photothermal methane dry reforming in LSPR, and the catalyst with a Ni content of 2 wt% exhibited the best activity. Examples 6 and 20-23 compared the effect of adding different amounts of semiconductor additives on the catalytic reaction activity, and the results showed that the greater the amount of semiconductor additive added, the more beneficial it was to improving the activity of photothermal methane dry reforming.

[0228] In summary, the multifunctional modified composite catalyst M1-MgAlM2M3 of this invention comprises, by mass percentage, the following components: 0.1wt%–10wt% of a first metal promoter M1, 5wt%–40wt% of Mg, 5wt%–40wt% of Al, 0–20wt% of a second metal promoter M2, and 0–40wt% of a semiconductor promoter M3. Furthermore, this catalyst is prepared using a co-precipitation method and an ultraviolet-assisted deposition method. The preparation method is simple, the operating conditions are mild, and the reaction is highly controllable, which can reduce preparation costs, improve preparation efficiency, and facilitate large-scale production. The first metal promoter with localized surface plasmon resonance (LSPR) effect is introduced through ultraviolet-assisted deposition. Metal promoter M1 enables the catalyst to absorb light energy and convert it into heat energy within a specific wavelength range, significantly improving the photothermal catalytic activity of the catalyst surface and achieving efficient conversion of light energy to heat energy. Combined with the composite structure of the second metal promoter M2 and the semiconductor promoter M3, the catalyst effectively improves the reaction efficiency and stability in the photothermal methane dry reforming reaction. The introduction of the second metal promoter M2 enables efficient CO2 adsorption and activation, while the introduction of the semiconductor promoter M3 improves the efficiency of photothermal conversion, further promoting the reaction. Furthermore, the magnesium-aluminum structure design not only improves the catalyst's resistance to sintering and carbon deposition but also enhances the stability of the catalyst structure, thereby improving the catalyst's recyclability. The multifunctional modified composite catalyst of this invention, applied in a solar-driven photothermal catalytic dry reforming reaction of methane, exhibits excellent comprehensive catalytic performance. The optimized catalyst composition and structure improve its selectivity and specificity for CO2 and CH4, achieving high purity and high yield of the product while reducing energy consumption and cost in subsequent product purification processes. Under photothermal conditions, it possesses highly efficient activation capabilities for CO2 and CH4, with a CH4 conversion rate reaching up to 38.8%, and can stably generate syngas with an H2 / CO ratio of approximately 1:1 for 120 hours. This catalyst exhibits good stability and is not easily deactivated, enabling large-scale scale-up. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and possesses high industrial application value.

[0229] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing a multifunctional additive-modified composite catalyst, characterized in that, The catalyst is an M1-MgAlM2M3 catalyst, comprising a first metal promoter M1, Mg element, Al element, a second metal promoter M2, and a semiconductor promoter M3, wherein the first metal promoter M1 is a metal with local surface plasmon resonance effect; the second metal promoter M2 is selected from one or a combination of Ca, Sr, and Ba. The catalyst comprises, by mass percentage, 0.1 wt% to 10 wt% of a first metal promoter M1, 5 wt% to 40 wt% of Mg, 5 wt% to 40 wt% of Al, 0 to 20 wt% of a second metal promoter M2 and 0 to 50 wt% of a semiconductor promoter M3, wherein the mass percentages of the second metal promoter M2 and the semiconductor promoter M3 are both not 0. The catalyst was prepared by co-precipitation and ultraviolet-assisted deposition, specifically including the following steps: S1. Provide Mg salt, Al salt, and salt of the second metal auxiliary M2. Dissolve the Mg salt, Al salt, and salt of the second metal auxiliary M2 in deionized water or ethanol according to the mass percentage of the catalyst to obtain a mixed metal salt solution. S2. Disperse semiconductor additive M3 in deionized water or ethanol to obtain mother liquor; S3. The mixed metal salt solution and the alkaline solution are simultaneously added dropwise to the mother liquor to cause co-precipitation and obtain a co-precipitation solution; S4. After aging, centrifuging, washing and drying the coprecipitation solution, the MgAlM2M3 precursor is obtained. S5. Dissolve the salt of the first metal additive M1 in deionized water to obtain a first metal salt solution; S6. According to the mass percentage of the catalyst, the first metal salt solution is added to the MgAlM2M3 precursor, and ultraviolet light is used to irradiate it to cause a precipitation reaction, so as to obtain M1-MgAlM2M3 precursor. S7. After aging, rotary evaporation, calcination and reduction treatment of the M1-MgAlM2M3 precursor, the M1-MgAlM2M3 catalyst is obtained.

2. The preparation method of the multifunctional additive-modified composite catalyst according to claim 1, characterized in that: Includes one or a combination of the following conditions: The first metal additive M1 is selected from one or a combination of Cu, Au, Ag, Ni, and Ru; The semiconductor additive M3 is selected from one or a combination of CeO2, TiO2, ZnO, Bi2O3, In2O3, and g-C3N4.

3. The preparation method of the multifunctional additive-modified composite catalyst according to claim 1, characterized in that: Step S1 includes one or a combination of the following conditions: The Mg salt is selected from one or a combination of Mg chloride, nitrate, sulfate, carbonate, and acetate. The Al salt is selected from one or a combination of Al chloride, nitrate, sulfate, carbonate, and acetate. The salt of the second metal auxiliary M2 is selected from one or a combination of chloride, nitrate, sulfate, carbonate, and acetate of element M2; The total molar concentration of the metal in the obtained mixed metal salt solution is 1 mol / L to 5 mol / L.

4. The preparation method of the multifunctional additive-modified composite catalyst according to claim 1, characterized in that: In the mother liquor of step S2, the mass concentration of the semiconductor additive M3 is 5 g / L to 40 g / L.

5. The preparation method of the multifunctional additive-modified composite catalyst according to claim 1, characterized in that: Step S3 includes one or a combination of the following conditions: The alkaline solution is a NaOH solution or a KOH solution with a molar concentration of 6 mol / L; The coprecipitation temperature is 30℃~80℃, and the pH of the solution is maintained at 6~10 during the coprecipitation process.

6. The preparation method of the multifunctional additive-modified composite catalyst according to claim 1, characterized in that: Step S4 includes one or a combination of the following conditions: The aging temperature is 30℃~80℃, and the aging time is 12h~48h; The drying temperature is 80℃~120℃, and the drying time is 12h~48h.

7. The preparation method of the multifunctional additive-modified composite catalyst according to claim 1, characterized in that: Step S5 includes one or a combination of the following conditions: The salt of the first metal additive M1 is selected from one or a combination of the chloride, nitrate, sulfate, carbonate, and acetate of M1, and the first metal additive M1 is selected from one or a combination of Cu, Au, Ag, Ni, and Ru. The molar concentration of the first metal auxiliary agent M1 in the first metal salt solution is 2 mol / L to 5 mol / L.

8. The preparation method of the multifunctional additive-modified composite catalyst according to claim 1, characterized in that: Step S6 includes one or a combination of the following conditions: The temperature of the ultraviolet light irradiation is 30℃~80℃; The wavelength of the ultraviolet light irradiation is 300nm~420nm; The precipitation reaction time caused by ultraviolet light irradiation is 4h~24h.

9. The preparation method of the multifunctional additive-modified composite catalyst according to claim 1, characterized in that: Step S7 includes one or a combination of the following conditions: The aging temperature is 30℃~80℃, and the aging time is 8h~48h; The rotary evaporation step specifically involves performing vacuum rotary evaporation at 50℃~100℃ with a rotation speed of 50r / min~120r / min. The calcination step specifically involves calcining at 200℃~600℃ in a static or flowing atmosphere for 0.5h~10h. The reduction is a high-temperature reduction, the reduction temperature is 200℃~600℃, the reduction time is 4h~16h, and the reduction atmosphere is one of pure H2 gas, H2 / Ar mixture, or H2 / CO2 mixture.

10. The application of a multifunctional additive-modified composite catalyst, characterized in that, The catalyst is used in the photothermal catalytic dry reforming reaction of methane, wherein the catalyst is the multifunctional additive-modified composite catalyst prepared by the preparation method of the multifunctional additive-modified composite catalyst according to claim 1 or 2.

11. The application of the multifunctional additive-modified composite catalyst according to claim 10, characterized in that: Includes one or a combination of the following conditions: The feed gas used in the dry reforming reaction of methane is CH4 and CO2, with a volume ratio of 1:1 to 3:

1. The space velocity of the raw material gas is 10000~97000 ml / g cat -1 ·h -1 ; The surface temperature of the methane dry reforming reaction is 300~800℃, and the pressure of the methane dry reforming reaction is 0.1 MPa.

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