In-situ photothermal catalyst and application thereof in catalyzing methane dry reforming reaction

Abstract

This invention belongs to the field of functional catalyst technology, specifically relating to a photo-in-situ heating catalyst and its application in catalyzing the dry reforming reaction of methane, as well as a method for catalyzing the dry reforming reaction of methane. The photo-in-situ heating catalyst of this invention includes a support and an active metal element supported on the support; wherein the active metal element includes a plasma photothermal metal that can generate heat through plasma effect irradiation; the support includes a composite metal oxide. The active metal element nanoparticles in the catalyst exhibit a strong localized surface plasmon resonance effect, allowing light to be directly converted into heat energy at the metal active sites under illumination. Since the heat-generating region is the region where the DRM reaction occurs, a complete heat transfer path, no thermal resistance, and no heat transfer lag can be achieved, effectively ensuring the heat supply for the entire process.

Description

Technical Field

[0001] This invention belongs to the field of functional catalyst technology, specifically relating to a photo-in-situ heating catalyst and its application in catalyzing the dry reforming reaction of methane, as well as a method for catalyzing the dry reforming reaction of methane. Background Technology

[0002] With the increasingly severe global climate change problem, controlling greenhouse gas emissions, primarily composed of carbon dioxide (CO2) and methane (CH4), has become a common challenge facing the international community. Compared to the impact of CO2, the single-molecule greenhouse effect potential of CH4 far exceeds that of CO2, and it has made a significant contribution to recent global warming. Therefore, exploring the resource-based conversion of CH4 and CO2, these two major greenhouse gases, in this field can not only help alleviate environmental pressure but also transform them into high-value-added chemicals or fuels, achieving "turning waste into treasure," which is an important direction in line with the sustainable development strategy.

[0003] Among the numerous CH4 and CO2 conversion pathways, dry reforming (DRM: CH4 + CO2 → 2CO + 2H2) has attracted much attention due to its ability to simultaneously and efficiently convert two greenhouse gases and produce syngas (CO + H2). Methane-carbon dioxide dry reforming can simultaneously utilize methane and carbon dioxide to produce syngas, which, as a key platform feedstock, can be further converted into liquid fuels or bulk chemicals, occupying a core position in the modern chemical industry chain. Therefore, developing efficient DRM technology has significant environmental and economic benefits.

[0004] However, since both CH4 and CO2 are inert molecules with high dissociation energies and low polarizability, high operating temperatures above 800°C are usually required to drive the dry reforming reaction from a thermodynamic and kinetic perspective. This inevitably leads to catalyst deactivation due to sintering of active metal sites, as well as carbon deposition caused by the disproportionate dissociation of CH4 and the generation of CO.

[0005] More importantly, because the dry reforming of methane is a strongly endothermic reaction with a standard molar enthalpy change ΔH = +247 kJ / mol, and because this reaction occurs at the active sites of the catalyst metal, it undergoes intense endothermic reactions within milliseconds. Traditional external furnace heating and the currently mainstream bed-type photothermal catalysis both employ a multi-stage heat conduction mode of "reactor wall → inert packing → catalyst support → active sites," which inherently involves thermal resistance and heat transfer hysteresis. When the instantaneous endothermic rate of the reaction is much greater than the external heat conduction rate, it will cause a sudden drop in the local instantaneous temperature of the active sites (site cooling). Conventional thermocouples can only detect the macroscopic average temperature of the reaction bed and cannot identify low-temperature anomalies at the nanoscale active sites. Typically, site cooling will cause three major problems: firstly, the apparent activation energy of the reaction increases, and the instantaneous conversion rate decreases significantly; secondly, reaction intermediates tend to accumulate at low-temperature sites, exacerbating catalyst carbon deposition; and thirdly, repeated fluctuations in site temperature accelerate the sintering and deactivation of the metal active components. In traditional reaction systems, the common industry problem of mismatched heat transfer and endothermic rates and microscopic site temperature loss has long been overlooked and is a core bottleneck restricting further improvement in DRM reaction efficiency, which has not yet been completely solved. Although existing technologies have gradually developed various photothermal catalysis technologies that can reduce the reaction temperature to some extent, the overall process still belongs to the "externally heated bed" and has not broken away from the heat conduction system.

[0006] Therefore, the field expects to develop a more direct heat conduction reaction system to circumvent the heat conduction process and specifically address the pain point of temperature loss at the entire process site, which is of positive significance for the development and application of methane dry reforming reaction. Summary of the Invention

[0007] The first objective of this invention is to provide a photo-in-situ heating catalyst, wherein under light irradiation, light energy can be directly converted into heat energy at the metal active sites, and the heat-generating region is the region where the DRM reaction occurs, enabling in-situ heating reaction with no heat transfer path, no thermal resistance, and no heat transfer lag throughout the process.

[0008] The second objective of this invention is to provide a method for catalytic dry reforming of methane based on the aforementioned photo-in-situ heating catalyst. This method leverages the photo-in-situ heating advantage of the catalyst, ensuring that the heat absorbed instantaneously by the active sites during the entire DRM reaction is replenished in real time and in sufficient quantity by the heat generated in situ through photo-irradiation. This achieves dynamic matching between the heat absorption rate and the in-situ heat generation rate, fundamentally eliminating the instantaneous temperature loss phenomenon caused by heat transfer lag in traditional systems, while significantly reducing overall heat loss.

[0009] To address the aforementioned technical problems, this invention provides a photo-in-situ heating catalyst, the catalyst comprising a support and an active metal element supported on the support; wherein... The active metal element includes plasma photothermal metal, which is a plasma photothermal metal that generates heat by irradiation using the plasma effect. The carrier comprises a composite metal oxide.

[0010] Specifically, the active metal element in the photo-in-situ heating catalyst includes Ni, Co, Fe, or a noble metal element.

[0011] Specifically, the photo-in-situ heating catalyst is characterized in that the metal element contained in the composite metal oxide in the support is selected from at least two of Mg, Zn, Al or Ti.

[0012] Specifically, the photo-in-situ heating catalyst has a support comprising MgAlO x ZnAlO x MgAlTiO x or ZnAlTiO x At least one of them; Preferably, in the carrier, the molar ratio of Mg / Zn to Al is (2-5):1; Preferably, in the carrier, the molar ratio of Al to Ti is (1-x):x, where x = 0.05-0.2.

[0013] Specifically, in the photo-in-situ heating catalyst, the active metal element is loaded at a rate of less than 30 wt% based on the support.

[0014] The present invention also provides a method for preparing the photo-in-situ heating catalyst as described above, comprising the following steps: (1) Prepare the corresponding metal salt solution according to the selected active metal element, the metal element of the carrier, and their respective proportions, and add an OH- oxidant. - and CO3 2- The mixture of alkaline solutions was followed by a crystallization reaction, and the precipitate was collected to obtain LDH precursors. (2) The LDHs precursor is subjected to high-temperature reduction calcination under a reducing atmosphere, and the reduction products are collected to obtain the desired catalyst.

[0015] In step (1), the synthesis method of the LDHs precursor can be selected from known processes in the art, such as nucleation crystallization isolation method, pH double drop method or urea method.

[0016] Specifically, in step (1), the metal salt includes at least one of metal nitrates, metal chlorides, metal sulfates, metal phosphates, metal carbonates, metal alkoxides, and organometallic ammonium salts. For example, when the metal element (including active metal elements or metal elements in the support) is selected from elements such as Ni, Mg, Al, and Zn, inorganic salts such as nitrates, which are conventional in the art, are preferred. If Ti needs to be added to the support, titanium salts such as tetrabutyl titanate, titanium isopropoxide, or titanium ammonium lactate chelates can be selected.

[0017] Specifically, in step (1), the mixed alkaline solution provides OH... - Substances include inorganic or organic bases; for example, NaOH, KOH, LiOH, and ammonia (NH3). H2O, urea (CO(NH2)2), metal alkoxides, etc.

[0018] Specifically, in step (1), the mixed alkaline solution provides CO3. 2- The substances include inorganic carbonates or organic hydrochlorides; for example, potassium carbonate, sodium carbonate, ammonium carbonate / ammonium bicarbonate, sodium citrate, sodium oxalate, sodium phosphotungstenate, etc.

[0019] Specifically, in step (1), the mixed alkaline solution contains OH... - The molar ratio of the substance to the total amount of metal ions is 1-5:1. For example, when OH is provided... - When choosing inorganic bases such as NaOH or KOH, the molar ratio of the inorganic base to the total amount of metal ions can be adjusted to 1-3:1; while when providing OH... - When choosing urea as the material, the molar ratio of urea to the total amount of all metal ions can be adjusted to 3-5:1.

[0020] In step (1), the mixed alkaline solution provides CO3. 2- The molar ratio of the substance to the total amount of trivalent metal ions in the metal ions is 1-2:3; and / or, In step (1), the temperature of the crystallization reaction is 60-120℃; and / or, In step (1), the crystallization reaction takes 12-24 hours; and / or, In step (1), the crystallization reaction includes dynamic crystallization or static crystallization; and / or, Step (1) further includes centrifuging, washing, and / or drying the precipitate; and / or, In step (2), the reducing atmosphere includes a hydrogen atmosphere or a mixed atmosphere of H2 / inert gas (preferably with H2 accounting for 10%-20%); and / or, In step (2), the flow rate of the reducing atmosphere is 40-60 mL / min; and / or, In step (2), the temperature of the high-temperature reduction calcination step is 600-900℃; and / or, In step (2), the heating rate of the high-temperature reduction calcination step is 1-10℃ / min; and / or, In step (2), the duration of the high-temperature reduction calcination and heat preservation step is less than 6 hours; and / or, Step (2) further includes cooling and / or purging the reduction product with nitrogen.

[0021] The present invention also provides the application of the photo-in-situ heating catalyst or the photo-in-situ heating catalyst prepared by the method in the catalytic dry reforming reaction process of methane.

[0022] The present invention also provides a method for photo-in-situ heating catalyzed dry reforming of methane, comprising the steps of using methane and carbon dioxide as raw materials and providing a light source through concentrated light irradiation in the presence of the photo-in-situ heating catalyst or the photo-in-situ heating catalyst prepared by the method, to carry out the dry reforming reaction.

[0023] Specifically, the method for photocatalytic in-situ heating of methane dry reforming includes the following steps: S1, the catalyst is loaded, a selected light source is used to irradiate the catalyst with a first focused light, and a reducing atmosphere is introduced to reduce the catalyst in situ by light irradiation; S2, the reducing atmosphere is turned off, a mixed reaction gas of CH4, CO2 and N2 is introduced, and the catalyst is irradiated with a second focused light to catalyze the CH4 and CO2 to undergo a dry reforming reaction.

[0024] Specifically, the method for photocatalytic in-situ heating of methane dry reforming reaction: In step S1, the catalyst loading container includes a quartz reaction tube; and / or, In step S1, the light source includes a xenon lamp, an LED light source, simulated sunlight, etc.; and / or, In step S1, the parameters for the first focused illumination step include: adjusting the light intensity of the light source to 5-40 W / cm². 2 ; Usually adjusted to maximum light intensity (specific parameters depend on the light source); and / or, In step S1, the reducing atmosphere includes a mixed atmosphere of H2 and inert gas (preferably H2 accounting for 10%-20%); and / or, In step S1, the in-situ illumination restoration step takes 15-20 minutes; and / or, In step S2, the volume ratio of CH4, CO2, and N2 in the mixed reaction gas is 1:1:1-1.5; and / or, In step S2, the space velocity of the mixed reaction gas is 1000-13000 h⁻¹. -1 ; and / or, In step S2, the parameters of the second focusing irradiation step include: adjusting the light intensity of the light source to control the system temperature to 100-800℃; usually adjusting the light intensity from high to low or from low to high to control temperature changes; In step S2, the dry reforming reaction is carried out at atmospheric pressure.

[0025] The photo-in-situ heating catalyst of this invention comprises a support and an active metal element supported on the support; wherein the active metal element includes a plasma photothermal metal that can generate heat by irradiation using the plasma effect; the support comprises a composite metal oxide. The active metal element nanoparticles in the catalyst exhibit a strong localized surface plasmon resonance effect, allowing light to be directly converted into heat energy at the metal active sites under illumination. Since the heat-generating region is the same as the DRM reaction site, a complete heat transfer path, thermal resistance, and heat transfer hysteresis can be achieved, effectively ensuring the heat supply for the entire process.

[0026] The photo-in-situ heating catalyst of this invention innovatively forms a photo-in-situ heating mechanism. Utilizing the localized surface plasmon resonance (LSPR) effect of metal nanoparticles in the catalyst, light energy is instantaneously converted into heat energy in situ at the active site under illumination. Without the need for external heat transfer, it can directly meet the strong endothermic requirements of DRM and completely solve the defect of "site temperature loss-heat transfer mismatch" caused by heat conduction in traditional DRM reaction.

[0027] The photo-in-situ heating catalyst of this invention generates heat in situ at the reaction site, eliminating the need for multi-stage heat conduction. Even during the transient phase of intense endothermic reaction, the temperature of the active site does not decrease significantly, resulting in a substantial improvement in microscopic temperature stability. The isothermal site keeps the apparent activation energy of the reaction at a low level, preventing drastic fluctuations in the instantaneous conversion rate of raw materials and the reaction rate, thus enhancing the continuity of the reaction and completely solving the problem of instantaneous temperature loss at the active site.

[0028] The photo-in-situ heating catalyst of this invention is based on the photo-in-situ heating mechanism. Under this mode, the temperature of the active site remains stable. Especially during the DRM reaction, the heat absorbed instantaneously by the active site is replenished in real time and in full by the heat generated in situ by the light, realizing the dynamic matching of the heat absorption rate and the in-situ heat generation rate. This fundamentally eliminates the instantaneous temperature loss phenomenon caused by heat transfer lag in traditional systems, while significantly reducing the overall heat loss.

[0029] The photo-in-situ heating catalyst of this invention is based on an innovative "photo-in-situ heating" strategy. This heat generation method avoids heat transfer and realizes in-situ energy supply at the reaction site, ensuring that the heat demand of the endothermic reaction can be met in time. This is expected to avoid the reduction in reaction efficiency due to "temperature loss" at the active site, and can fundamentally solve the problem of heat transfer mismatch, providing a new idea for developing low-energy-consumption and high-efficiency greenhouse gas conversion technologies.

[0030] The photo-in-situ heating catalyst of this invention effectively eliminates the periodic low-temperature range of active sites, reducing the adsorption of carbon precursors; it can inhibit carbon deposition and sintering from the source, while avoiding repeated temperature fluctuations, effectively inhibiting the sintering of metal nanoparticles, and extending the service life of the catalyst.

[0031] The method for preparing the photo-in-situ heating catalyst of the present invention uses common metal salts and alkaline solutions to prepare a hydrotalcite precursor, which can be obtained by calcination and reduction. It does not require complex equipment or harsh conditions, and the preparation process is simple and easy to scale up, which is conducive to large-scale industrial production.

[0032] The method for catalytic dry reforming of methane described in this invention, based on the advantages of the catalyst, realizes a photo-enhanced in-situ heating method for DRM, which can completely eliminate the external heat transfer process, reduce heat loss to an extremely low level, and further reduce the overall energy consumption of the reaction by combining clean solar energy, making it more suitable for the requirements of continuous industrial production.

[0033] The method for catalytic dry reforming of methane described in this invention employs a light-transmitting reactor to construct a mixed bed, ensuring uniform light transmission and bed temperature; it uses a light source for directional irradiation, enabling in-situ heat generation of the photothermal catalyst, resulting in a concentrated heat field, fast response, and no heat loss; the entire process is based on photothermal coupling for catalysis, reducing the reaction activation energy, inhibiting carbon deposition and sintering, and improving conversion rate and stability.

[0034] The catalyst of this invention, in synergy with the photo-in-situ heating mode, can simultaneously solve three common industry problems in traditional methane dry reforming reactions: catalyst coking, sintering, and low heat transfer efficiency. Firstly, the catalyst prepared by the hydrotalcite precursor method has small particle size and high dispersion of Ni active sites. Combined with the strong metal-support interaction and basic sites of the support, it intrinsically inhibits coking and metal sintering. Secondly, the photo-in-situ heating mode completely eliminates the instantaneous temperature loss of active sites caused by the strong endothermic reaction. This avoids the aggravation of CO disproportionation and coking in the low-temperature region and reduces thermal shock sintering caused by temperature fluctuations. Simultaneously, it enhances the carbon gasification reaction to achieve in-situ removal of coking. This system significantly extends catalyst lifespan while improving catalytic activity, and it boasts high energy utilization and low equipment requirements, making it more suitable for large-scale, low-carbon methane dry reforming industrial production.

[0035] The method for catalytic dry reforming of methane described in this invention breaks with the traditional heating approach. It utilizes the localized surface plasmon resonance (LSPR) effect of metals to achieve in-situ heat generation at active sites, completely avoiding the heat transfer process and specifically addressing the pain point of site temperature loss. It effectively overcomes the shortcomings of existing technologies and has high industrial application value. Attached Figure Description

[0036] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 This is a schematic diagram of a feasible device for the photo-in-situ thermal DRM reaction described in this invention, wherein the flat square area in the middle of the quartz tube is filled with catalyst, and the two sides are irradiated by xenon lamps. Figure 2 The XRD patterns are of the LDHs samples prepared in Examples 1 and 2 of this invention. Figure 3 The XRD patterns are of the composite oxide samples prepared in Examples 1 and 2 of this invention. Figure 4 Ni-MgAlO with different Ni contents x At 12.5W / cm 2 Temperature rise and fall curves under illumination; Figure 5 The conversion rates of methane and carbon dioxide in the DRM reaction at different light powers in Example 1 and Comparative Example 1 are shown. Figure 6 For solar heating, Ni-MgAlO under conventional heat x The conversion rates of methane in the DRM reaction were compared with those at equilibrium. Figure 7 The pulse signal curve and temperature loss curve are shown in Comparative Example 2 under conventional thermal reaction conditions. Figure 8 The pulse signal curve and temperature curve of the sample in Example 1 under the photothermal reaction are shown. Detailed Implementation

[0037] In the following embodiments of the present invention, in order to solve the problem of heat transfer mismatch in the traditional methane-carbon dioxide dry reforming reaction, an innovative "photo-in-situ heating" strategy is proposed, aiming to fundamentally solve the above-mentioned heat transfer mismatch problem.

[0038] In the following embodiments of the present invention, a photo-in-situ heating catalyst is provided, the catalyst comprising a support and an active metal element supported on the support; wherein, The active metal element includes plasma photothermal metals that can generate heat through plasma effect illumination, such as Ni, Co, Fe, or noble metal elements. The carrier includes a composite metal oxide, for example, a composite metal oxide containing at least two metal elements selected from Mg, Zn, Al or Ti. The active metal element is loaded at a rate of less than 30 wt% based on the carrier.

[0039] In some specific embodiments, the carrier is preferably MgAlO x ZnAlO x MgAlTiO x or ZnAlTiO x At least one of them.

[0040] In some specific embodiments, the preferred molar ratio of Mg / Zn to Al in the above-mentioned feasible carrier is (2-5):1.

[0041] In some specific embodiments, in the above-mentioned feasible carrier, the preferred molar ratio of Al to Ti is (1-x):x, where x = 0.05-0.2.

[0042] In the following embodiments of the present invention, a method for preparing the photo-in-situ heating catalyst as described above is also provided, comprising the following steps: (1) Prepare LDHs precursors, for example, by using nucleation crystallization isolation method, pH double drop method or urea method; in some feasible embodiments, according to the selected active metal element, the metal element of the carrier and their respective proportions, prepare the corresponding metal salt solution, and add OH- - and CO3 2- The mixture of alkaline solutions was followed by a crystallization reaction, and the precipitate was collected to obtain LDH precursors. (2) The LDHs precursor is subjected to high-temperature reduction calcination under a reducing atmosphere, wherein the added active metal element is reduced to form elemental components through a reduction reaction, while the metal that cannot be reduced under this condition constitutes the metal element in the support. The reduced active metal element is loaded inside and on the surface of the support, thus obtaining the desired catalyst.

[0043] As an exemplary embodiment, in the following examples of the present invention, the method for preparing the catalyst includes the following steps: (1) Preparation of LDH precursors Using the nucleation crystallization isolation method, pH double drop method, or urea method, weigh a certain amount of metal salt into a beaker (the total amount of metal ions should be 50-80 mmol), add 200-300 mL of deionized water and stir until homogeneous to obtain a mixed salt solution; then take a certain amount of sodium hydroxide solid (100-150 mmol) and sodium carbonate (about 1 / 2 of the amount of trivalent metal) and add them into another beaker, add 200-300 mL of deionized water, and stir until fully dissolved to obtain an alkaline solution; Pour both solutions into a four-necked flask containing 200-300 mL of deionized water simultaneously, and stir at the maximum speed for 2-3 minutes. Then, crystallize dynamically or statically at 60-100℃ for 12-24 hours to obtain a precipitate. Centrifuge and wash the precipitate, and then dry it in an oven at 60-80℃ for 12-24 hours to obtain the LDHs precursor. (2) Preparation of composite oxides The LDHs sample prepared above was subjected to high-temperature reduction calcination in a reducing atmosphere (hydrogen atmosphere) at a flow rate of 40-60 mL / min and a heating rate of 1-10℃ / min to raise the furnace temperature to 600-900℃. The temperature was held for less than 6 hours and then naturally cooled to room temperature. Nitrogen was then purged for 1-2 hours, and the final powder sample was collected to obtain the desired composite oxide.

[0044] In the following embodiments of the present invention, a method for catalytic dry reforming of methane with carbon dioxide based on the aforementioned catalyst is also provided, that is, the aforementioned catalyst is used for in-situ photothermal heating to carry out the dry reforming of methane.

[0045] As an exemplary embodiment, a small amount of catalyst and quartz sand can be mixed evenly and filled into an inner flat quartz photothermal reaction tube. Two xenon lamps are used as light sources to focus light on both sides of the catalyst. Simultaneously, H2 and Ar are introduced, and the light sources are turned on for in-situ photoluminescence reduction of the catalyst. Then, a mixed reaction gas of CH4 / CO2 / N2 = 1:1:1-1.5 (volume ratio) is introduced into the reactor. The light power density is controlled by adjusting the lamp current of the xenon lamp light source, while the reaction temperature is monitored. The products of the entire reaction are CO and H2, with an initial conversion rate of 50-100% for both CH4 and CO2.

[0046] As an exemplary embodiment, a quartz reaction tube can be selected as the reactor for carrying out the above-mentioned methane-carbon dioxide dry reforming reaction.

[0047] As an exemplary embodiment, the mass ratio of the catalyst to the quartz sand can be selected as 1:30-50, and the quartz sand is preferably 40-60 mesh quartz sand.

[0048] The technical solution of the present invention will be described in detail below with reference to specific embodiments of the present invention. The described embodiments are only a part of the present invention, and the present invention is not limited to the embodiments described below.

[0049] Preparation Example 1 This preparation example provides a catalyst for photo-in-situ heating catalytic dry reforming of methane, wherein the molar ratio of Ni, Mg, and Al in the catalyst is 0.83:3:1.

[0050] The preparation method of the catalyst for photo-in-situ heating catalytic dry reforming of methane described in this preparation example includes the following steps: (1) Preparation of NiMgAl-LDHs According to the above molar ratio of Ni, Mg and Al elements, weigh appropriate amounts of Ni(NO3)2·6H2O, Mg(NO3)2·6H2O and Al(NO3)3·9H2O and dissolve them in 200mL of deionized water and stir evenly to obtain a metal salt solution. Weigh 4.8g of NaOH and 6.53g of Na2CO3 and dissolve them in 200mL of deionized water. Stir well to obtain a mixed alkaline solution. The metal salt solution and the mixed alkaline solution were simultaneously poured into a four-necked flask. The crystallization temperature was controlled at 85°C and the crystallization time was 20h. The reaction precipitate was collected, centrifuged, washed, and then dried in an oven at 60°C for 12h to obtain NiMgAl-LDH. (2) Preparation of Ni-MgAlO x Weigh 1g of the NiMgAl-LDHs obtained above and calcine it under a pure H2 atmosphere. The calcine temperature is set to 850℃, the initial temperature is room temperature, the heating rate is 2℃ / min, no heat preservation is required, and the gas flow rate is controlled at 40mL / min. During the entire reduction process, the Ni in the Ni salt solution... 2+ It is reduced to form metallic Ni, while Mg cannot be reduced under these conditions. 2+ Al 3+ It will then form the desired support MgAlO in the form of oxides. x The reduced metallic Ni element is loaded inside and on the surface of the support to obtain the desired catalyst Ni-MgAlO. x .

[0051] In this preparation example, the Ni content in the catalyst was 20 wt% as determined by ICP testing.

[0052] Preparation Example 2 This preparation example provides a catalyst for photo-in-situ heating catalytic dry reforming of methane, wherein the molar ratio of Ni, Mg, Al, and Ti in the catalyst is 0.83:3:0.85:0.15.

[0053] The preparation method of the catalyst for photo-in-situ heating catalytic dry reforming of methane described in this preparation example includes the following steps: (1) Preparation of NiMgAlTi-LDHs According to the above molar ratio of Ni, Mg, Al and Ti elements, weigh appropriate amounts of Ni(NO3)2·6H2O, Mg(NO3)2·6H2O, Al(NO3)3·9H2O and titanium ammonium salt and dissolve them in 200mL of deionized water, and stir evenly to obtain a metal salt solution. Weigh 4.8g of NaOH and 5.55g of Na2CO3 and dissolve them in 200mL of deionized water. Stir well to obtain a mixed alkaline solution. The metal salt solution and the mixed alkaline solution were simultaneously poured into a four-necked flask. The crystallization temperature was controlled at 85°C and the crystallization time was 20h. After centrifugation and washing, the precipitate was dried in an oven at 60°C for 12h to obtain NiMgAlTi-LDHs. (2) Preparation of Ni-MgAlTiO x Weigh 1g of the previously prepared NiMgAlTi-LDHs and perform high-temperature reduction calcination under a pure H2 atmosphere. The temperature is set at 850℃, the initial temperature is room temperature, the heating rate is 2℃ / min, no heat preservation is required, and the gas flow rate is controlled at 40mL / min. During the entire reduction process, the Ni in the Ni salt solution... 2+ It is reduced to form metallic Ni, while Mg cannot be reduced under these conditions. 2+ Al 3+ Ti 2+ It will then form the desired support MgAlTiO in the form of oxides. x Reduced metallic Ni elements are loaded inside and on the surface of the support to obtain Ni-MgAlTiO. x .

[0054] In this preparation example, the Ni content in the catalyst was 20 wt% as determined by ICP testing.

[0055] Preparation Example 3 This preparation example provides a catalyst for photo-in-situ heating catalytic dry reforming of methane, wherein the molar ratio of Co, Mg, and Al in the catalyst is 0.83:3:1.

[0056] The preparation method of the catalyst for photo-in-situ heating catalytic dry reforming of methane described in this preparation example includes the following steps: (1) Preparation of CoMgAl-LDHs According to the above molar ratio of Ni, Mg and Al elements, weigh appropriate amounts of Co(NO3)2·6H2O, Mg(NO3)2·6H2O and Al(NO3)3·9H2O and dissolve them in 200mL of deionized water and stir evenly to obtain a metal salt solution. Weigh 4.8g of NaOH and 6.53g of Na2CO3 and dissolve them in 200mL of deionized water. Stir well to obtain a mixed alkaline solution. The metal salt solution and the mixed alkaline solution were simultaneously poured into a four-necked flask. The crystallization temperature was controlled at 60°C and the crystallization time was 24h. The reaction precipitate was collected, centrifuged, washed, and then dried in an oven at 60°C for 12h to obtain CoMgAl-LDHs. (2) Preparation of Co-MgAlO x Weigh 1g of the obtained CoMgAl-LDHs and calcine it under a pure H2 atmosphere. The calcine temperature is set at 850℃, the initial temperature is room temperature, the heating rate is 2℃ / min, no heat preservation is required, and the gas flow rate is controlled at 40mL / min. During the entire reduction process, the Co in the Co salt solution... 2+ It is reduced to form metallic Co, while Mg cannot be reduced under these conditions. 2+ Al 3+ It will then form the desired support MgAlO in the form of oxides. x The reduced metallic Co element is loaded inside and on the surface of the support to obtain the desired catalyst Co-MgAlO. x .

[0057] Preparation Example 4 This preparation example provides a catalyst for photo-in-situ heating catalytic dry reforming of methane, wherein the molar ratio of Fe, Mg, and Al in the catalyst is 0.83:3:1.

[0058] The preparation method of the catalyst for photo-in-situ heating catalytic dry reforming of methane described in this preparation example includes the following steps: (1) Preparation of FeMgAl-LDHs According to the above molar ratio of Ni, Mg and Al elements, weigh appropriate amounts of Fe(NO3)3·6H2O, Mg(NO3)2·6H2O and Al(NO3)3·9H2O and dissolve them in 200mL of deionized water and stir evenly to obtain a metal salt solution. Weigh 4.8g of NaOH and 6.5g of Na2CO3 and dissolve them in 200mL of deionized water. Stir well to obtain a mixed alkaline solution. The metal salt solution and the mixed alkaline solution were simultaneously poured into a four-necked flask. The crystallization temperature was controlled at 120°C and the crystallization time was 12 h. The reaction precipitate was collected, centrifuged, washed, and then dried in an oven at 60°C for 12 h to obtain FeMgAl-LDH. (2) Preparation of Fe-MgAlO x Weigh 1g of the FeMgAl-LDHs obtained above and calcine it under a pure H2 atmosphere. The calcine temperature is set to 850℃, the initial temperature is room temperature, the heating rate is 2℃ / min, no heat preservation is required, and the gas flow rate is controlled at 40mL / min. During the entire reduction process, the Fe in the Fe salt solution... 3+ It is reduced to form metallic Fe, while Mg cannot be reduced under these conditions. 2+ Al 3+ It will then form the desired support MgAlO in the form of oxides. x Reduced metallic Fe is loaded onto the inside and surface of the support to obtain the desired catalyst Fe-MgAlO. x .

[0059] Preparation Example 5 This preparation example provides a catalyst for photo-in-situ heating catalytic dry reforming of methane, wherein the molar ratio of Ni, Mg, and Al in the catalyst is 0.83:3:1.

[0060] The preparation method of the catalyst for photo-in-situ heating catalytic dry reforming of methane described in this preparation example includes the following steps: (1) Preparation of NiMgAl-LDHs According to the above molar ratio of Ni, Mg and Al elements, weigh appropriate amounts of Ni(NO3)2·6H2O, Mg(NO3)2·6H2O and Al(NO3)3·9H2O and dissolve them in 200mL of deionized water and stir evenly to obtain a metal salt solution. Weigh 4.8g of NaOH and 6.53g of Na2CO3 and dissolve them in 200mL of deionized water. Stir well to obtain a mixed alkaline solution. The metal salt solution and the mixed alkaline solution were simultaneously poured into a four-necked flask. The crystallization temperature was controlled at 85°C and the crystallization time was 20h. The reaction precipitate was collected, centrifuged, washed, and then dried in an oven at 60°C for 12h to obtain NiMgAl-LDHs. (2) Preparation of Ni-MgAlO x Weigh 1g of the NiMgAl-LDHs obtained above and calcine it under a pure H2 atmosphere. The calcine temperature is set to 850℃, the initial temperature is room temperature, the heating rate is 5℃ / min, no heat preservation is required, and the gas flow rate is controlled at 40mL / min. During the entire reduction process, the Ni in the Ni salt solution... 2+ It is reduced to form metallic Ni, while Mg cannot be reduced under these conditions. 2+ Al 3+ It will then form the desired support MgAlO in the form of oxides. x The reduced metallic Ni element is loaded inside and on the surface of the support to obtain the desired catalyst Ni-MgAlO. x .

[0061] In this preparation example, the Ni content in the catalyst was 20 wt% as determined by ICP testing.

[0062] Comparative Preparation Example 1 This comparative preparation example provides a catalyst for the dry reforming of methane, wherein the molar ratio of Ni, Mg, and Al in the catalyst is 0.83:3:1.

[0063] The preparation method of the methane dry reforming catalyst described in this comparative preparation example includes the following steps: (1) Preparation of MgAl-LDH According to the above molar ratio of Mg and Al elements, weigh appropriate amounts of Mg(NO3)2·6H2O and Al(NO3)3·9H2O and dissolve them in 200mL of deionized water, and stir evenly to obtain a metal salt solution. Weigh 4.8g of NaOH and 6.53g of Na2CO3 and dissolve them in 200mL of deionized water. Stir well to obtain a mixed alkaline solution. The metal salt solution and the mixed alkaline solution were simultaneously poured into a four-necked flask. The crystallization temperature was controlled at 85°C and the crystallization time was 20h. The reaction precipitate was collected, centrifuged, washed, and then dried in an oven at 60°C for 12h to obtain MgAl-LDH. (2) Preparation of Ni 2+ / MgAl-LDHs Weigh 1g of the aforementioned MgAl-LDH and immerse it in 1mL of an aqueous solution containing an appropriate amount of Ni(NO3)2·6H2O. After vortexing for 2min, place it in a 120℃ forced-air drying oven for drying to obtain Ni with a loading of 20wt%. 2+ / MgAl-LDH; (3) Preparation of Ni / MgAlO x Take the Ni sample obtained above 2+ / MgAl-LDH was calcined under a pure H2 atmosphere at a set temperature of 850℃, with an initial temperature of room temperature and a heating rate of 2℃ / min. No heat preservation was required, and the gas flow rate was 40mL / min, to obtain the desired Ni-MgAlO. x .

[0064] In this comparative preparation example, the Ni content in the catalyst was 20 wt% as determined by ICP testing.

[0065] Comparative Preparation Example 2 This comparative preparation example provides a catalyst for the dry reforming of methane, wherein the molar ratio of Fe, Mg, and Al in the catalyst is 0.83:3:1.

[0066] The preparation method of the methane dry reforming catalyst described in this comparative preparation example includes the following steps: (1) Preparation of MgAl-LDH According to the above molar ratio of Mg and Al elements, weigh appropriate amounts of Mg(NO3)2·6H2O and Al(NO3)3·9H2O and dissolve them in 200mL of deionized water, and stir evenly to obtain a metal salt solution. Weigh 4.8g of NaOH and 6.53g of Na2CO3 and dissolve them in 200mL of deionized water. Stir well to obtain a mixed alkaline solution. The metal salt solution and the mixed alkaline solution were simultaneously poured into a four-necked flask. The crystallization temperature was controlled at 85°C and the crystallization time was 20h. The reaction precipitate was collected, centrifuged, washed, and then dried in an oven at 60°C for 12h to obtain MgAl-LDH. (2) Preparation of Fe 2+ / MgAl-LDHs Weigh 1g of the aforementioned MgAl-LDH and immerse it in 1mL of an aqueous solution containing an appropriate amount of Ni(NO3)2·6H2O. After vortexing for 2min, place it in a 120℃ forced-air drying oven for drying to obtain Fe with a loading of 20wt%. 2+ / MgAl-LDH; (3) Preparation of Fe / MgAlO x Take the Fe sample obtained above 2+ / MgAl-LDH was calcined under a pure H2 atmosphere at a set temperature of 850℃, with an initial temperature of room temperature and a heating rate of 2℃ / min. No heat preservation was required, and the gas flow rate was 40mL / min to obtain the desired Fe / MgAlO₂. x .

[0067] In this comparative preparation example, the Fe element content in the catalyst was 20 wt% as determined by ICP testing.

[0068] Example 1 This embodiment uses the catalyst prepared in Preparation Example 1 above to carry out the catalytic dry reforming reaction of methane and carbon dioxide.

[0069] As attached Figure 1 The quartz reaction tube shown can serve as a schematic diagram of a feasible device for the photo-in-situ thermal DRM reaction described in this invention. The flat, square area in the center of the quartz tube is filled with catalyst, and xenon lamps irradiate the two sides. (See attached diagram.) Figure 1 The quartz reaction tube shown is used for catalytic reaction in a quartz tube reactor with a length of 400 mm and an inner diameter of 4 mm.

[0070] Weigh 10 mg of the catalyst obtained in Preparation Example 1 and 400 mg of 40-60 mesh quartz sand, mix them evenly, and load them into the quartz reaction tube, fixing them with quartz wool.

[0071] A mixture of hydrogen and argon (hydrogen volume ratio 20%) was introduced into the above reaction system, and the xenon lamp light source was turned on for the first focused irradiation, adjusted to the maximum light intensity of 12.5 W / cm². 2 The catalyst temperature rises rapidly, and the catalyst is subjected to photoreduction for 20 minutes.

[0072] The gas inlet was then shut off, and a CH4 / CO2 / N2 mixed reaction gas with a volume ratio of 3:3:4 was switched in at a space velocity of 8000 h⁻¹. -1 The reaction is a normal pressure reaction, and the xenon lamp light source is adjusted for a second focused irradiation. During the second focused irradiation, the light intensity is adjusted by regulating the current, thereby controlling the temperature. For example, at a light intensity of 12.5 W / cm², 2 When the temperature reaches 620℃, methane and carbon dioxide undergo a dry reforming reaction under the action of a catalyst.

[0073] In this embodiment, the reaction temperature was monitored by a thermocouple, and the content of reaction product components was measured by gas chromatography (GC). According to the 2014 test, the exhaust gas was discharged after being treated by an absorption device.

[0074] Example 2 This embodiment is based on the catalyst prepared in Preparation Example 2 above for catalytic dry reforming of methane with carbon dioxide.

[0075] As attached Figure 1 The quartz reaction tube shown was prepared by weighing 10 mg of the catalyst obtained in Preparation Example 1 and 400 mg of 40-60 mesh quartz sand, mixing them evenly, and then loading them into the quartz reaction tube and fixing them with quartz wool.

[0076] A mixture of hydrogen and argon (hydrogen volume ratio 20%) was introduced into the above reaction system, and the xenon lamp light source was turned on for the first focused irradiation, adjusted to the maximum light intensity of 12.5 W / cm². 2 The catalyst temperature rises rapidly, and the catalyst is subjected to photoreduction for 20 minutes.

[0077] The gas inlet was then shut off, and a CH4 / CO2 / N2 mixed reaction gas with a volume ratio of 1:1:1 was switched in at a space velocity of 8000 h⁻¹. -1 The reaction is a normal pressure reaction. The xenon lamp light source is adjusted to perform a second focused irradiation. The light intensity is adjusted by adjusting the current to control the temperature to about 600℃. Methane and carbon dioxide undergo a dry reforming reaction under the action of a catalyst.

[0078] Example 3 This embodiment uses the catalyst prepared in Preparation Example 3 above to carry out the catalytic dry reforming reaction of methane and carbon dioxide.

[0079] As attached Figure 1 The quartz reaction tube shown was prepared by weighing 10 mg of the catalyst obtained in Preparation Example 1 and 400 mg of 40-60 mesh quartz sand, mixing them evenly, and then loading them into the quartz reaction tube and fixing them with quartz wool.

[0080] A mixture of hydrogen and argon (20% v / v H2) was introduced into the above reaction system, and the xenon lamp light source was turned on for the first focused irradiation, adjusted to the maximum light intensity of 12.5 W / cm². 2 The catalyst temperature rises rapidly, and the catalyst is subjected to photoreduction for 20 minutes.

[0081] The gas inlet was then shut off, and a CH4 / CO2 / N2 mixed reaction gas with a volume ratio of 1:1:1.5 was switched in at a space velocity of 8000 h⁻¹. -1 The reaction is a normal pressure reaction. The xenon lamp light source is adjusted to perform a second focused irradiation. The light intensity is adjusted by adjusting the current, thereby controlling the temperature. Methane and carbon dioxide undergo a dry reforming reaction under the action of a catalyst.

[0082] Example 4 This embodiment uses the catalyst prepared in Preparation Example 4 above to carry out the catalytic dry reforming reaction of methane and carbon dioxide.

[0083] As attached Figure 1 The quartz reaction tube shown can serve as a schematic diagram of a feasible device for the photo-in-situ thermal DRM reaction described in this invention. The flat, square area in the center of the quartz tube is filled with catalyst, and xenon lamps irradiate the two sides. (See attached diagram.) Figure 1 The quartz reaction tube shown is used for catalytic reaction in a quartz tube reactor with a length of 400 mm and an inner diameter of 4 mm.

[0084] Weigh 10 mg of the catalyst obtained in Preparation Example 1 and 400 mg of 40-60 mesh quartz sand, mix them evenly, and load them into the quartz reaction tube, fixing them with quartz wool.

[0085] A mixture of hydrogen and argon (20% hydrogen) was introduced into the above reaction system, and the xenon lamp light source was turned on for the first focused irradiation, adjusted to the maximum light intensity of 12.5 W / cm². 2 The catalyst temperature rises rapidly, and the catalyst is subjected to photoreduction for 20 minutes.

[0086] The gas inlet was then shut off, and a CH4 / CO2 / N2 mixed reaction gas with a volume ratio of 3:3:4 was switched in at a space velocity of 8000 h⁻¹. -1 The reaction is a normal pressure reaction. The xenon lamp light source is adjusted to perform a second focused irradiation. The light intensity is adjusted by adjusting the current, thereby controlling the temperature. Methane and carbon dioxide undergo a dry reforming reaction under the action of a catalyst.

[0087] In this embodiment, the reaction temperature was monitored by a thermocouple, and the content of reaction product components was measured by gas chromatography (GC). According to the 2014 test, the exhaust gas was discharged after being treated by an absorption device.

[0088] Comparative Example 1 The method for the dry reforming reaction of methane and carbon dioxide described in this comparative example is the same as that in Example 1, except that the catalyst prepared in Comparative Preparation Example 1 is selected for catalysis.

[0089] Comparative Example 2 The method for the dry reforming reaction of methane and carbon dioxide described in this comparative example is the same as that in Example 1, except that instead of using light-based heat transfer, a traditional external tube furnace is used to heat the entire mixture to the preset reaction temperature.

[0090] Experimental Example 1. XRD pattern The LDHs samples (NiMgAl-LDHs and NiMgAlTi-LDHs) prepared in Examples 1 and 2 above were subjected to XRD analysis, and the results are shown in the appendix. Figure 2 As shown.

[0091] As can be seen in the XRD patterns of the above samples, at 2θ = 11.7... o 23.6 o 35.4 o 39.6 o 47.0 o 60.3 o 61.2 oCharacteristic diffraction peaks appeared, which corresponded to the characteristic diffraction peaks of magnesium aluminum hydrotalcite (PDF#54-1030) in Jade card (003), (006), (012), (015), (018), (110), (113), respectively, and no other impurity peaks appeared, indicating that the prepared precursor has a good hydrotalcite structure and good crystal form.

[0092] Take the composite oxide samples (Ni-MgAlO) prepared in Examples 1 and 2 above, respectively. x and Ni-MgAlTiO x XRD pattern testing was performed, and the results are attached. Figure 3 As shown.

[0093] As can be seen in the XRD pattern of the above samples, at 2θ = 36.6... o 43.5 o and 63.1 o Observed at [location] belongs to MgAlO x Characteristic diffraction peaks of crystal planes (111), (200), and (220) (PDF#45-0946); at 44.5 o 51.9 o and 76.4 o The characteristic diffraction peaks of the corresponding metal Ni (111), (200), and (220) were observed at the point (PDF#04-0850).

[0094] 2. Effect of different Ni contents In this experimental example, based on the catalyst preparation scheme described in Preparation Example 1, the performance of the catalyst products with different Ni contents was investigated.

[0095] Following the method described in Preparation Example 1, Ni-MgAlO4 was prepared with Ni contents of 5, 10, 20, and 30 wt% by adjusting the amount of Ni salt. x Meanwhile, the catalyst from the comparative preparation example 1 was used, and the dry reforming reaction process was performed according to Example 1 at 12.5 W / cm². 2 Under illumination, the temperature rise and fall curves of each catalyst product were tested.

[0096] The results are attached. Figure 4 As shown.

[0097] The results show that for Ni-MgAlO derived in situ from hydrotalcite precursors xWithin the Ni loading range of 5-30 wt%, the photothermal heating rate of the catalyst gradually increases with increasing Ni loading, the steady-state equilibrium temperature gradually rises, and the photothermal conversion efficiency increases with the increase in the number of Ni active sites with plasmon effects. At the same Ni loading, the catalyst prepared by the hydrotalcite precursor method of this invention exhibits a faster photothermal response rate and a higher steady-state temperature compared to the comparative traditional impregnation method sample. This is attributed to the more uniform dispersion of Ni nanoparticles, stronger interaction with the support, and a more significant local surface plasmon resonance effect, which can provide efficient and stable local thermal field support for the methane dry reforming reaction under photo-in-situ heating mode.

[0098] 3. DRM reaction conversion rate In this experimental example, the performance of the DRM reaction under the schemes of Example 1 and Comparative Example 1 was investigated, and the methane and carbon dioxide conversion rates of the respective DRM reactions were examined at different light powers. The results are shown in the appendix. Figure 5 As shown.

[0099] It is evident that the CH4 and CO2 conversion rates of both catalysts gradually increase with increasing light power density; under the same light intensity conditions, the Ni-MgAlO prepared by the hydrotalcite precursor method of this invention... x The catalyst exhibits a significantly higher feed conversion rate than the Ni / MgAlO catalyst prepared by the conventional impregnation method compared to the control sample. x Furthermore, the reaction can be initiated even under low light intensity, exhibiting superior photoresponse performance. This performance advantage stems from the catalyst prepared by the precursor method, which possesses uniformly dispersed Ni particles and stronger interactions between the metal support. This enhances the localized surface plasmon resonance effect, improves photothermal conversion efficiency, and strengthens electron transfer. It can fully leverage the technical advantages of in-situ photothermal heating, providing sufficient thermal driving force and active sites for the methane dry reforming reaction, thus achieving highly efficient greenhouse gas conversion.

[0100] In this experimental example, the performance of the DRM reaction under the schemes of Example 1 and Comparative Example 2 was investigated, and the methane conversion rate and equilibrium conversion rate of the DRM reaction were examined under different heating methods. The results are shown in the appendix. Figure 6 As shown.

[0101] It is evident that, under the same macroscopic bed temperature, the CH4 conversion rate of the photo-in-situ heating system of this invention is far higher than that of the traditional external heating system, and the reaction start-up temperature is lower. This performance advantage stems from the photo-in-situ heating mode: utilizing the local surface plasmon resonance effect of metal nanoparticles, light energy is converted into heat energy in situ at the reactive active site, completely avoiding the hysteresis and loss caused by multi-stage heat conduction, eliminating the problem of active site temperature loss caused by strong endothermic reaction, and significantly improving the actual site temperature and reaction heat driving force; at the same time, the photothermal coupling effect can reduce the apparent activation energy of the reaction, realizing a highly efficient methane dry reforming reaction under mild conditions.

[0102] 4. Effects of catalyst temperature loss In this experimental example, the DRM reaction was tested using the schemes of Example 1 and Comparative Example 2, respectively.

[0103] According to the schemes of Example 1 and Comparative Example 2, inert gas Ar was introduced into both reaction systems. After the heating program stabilized, the initial steady-state temperature was recorded. Then, the corresponding CH4 / CO2 reaction gas was introduced instantaneously (strong endothermic start) and the system was run for 20-60 seconds, and the temperature change was recorded. The system was then switched back to inert gas, and this cycle was repeated. At the same time, the CO / H2 signal of the product was qualitatively detected by mass spectrometry throughout the process.

[0104] The pulse signal curves and temperature loss curves under the conventional thermal reaction in Comparative Example 2 are shown in the attached figure. Figure 7 As shown in the attached figure, the pulse signal curve and temperature curve under the photothermal response in Example 1 are as follows. Figure 8 As shown.

[0105] As can be seen, in traditional thermal systems, after a pulsed reaction, the catalyst temperature drops rapidly, resulting in a severe temperature loss of over 30°C within 10 seconds, and requiring more than 30 seconds to slowly recover. In contrast, the in-situ photothermal system of this invention allows for immediate in-situ reheating at the site, resulting in a pulsed reaction temperature drop of less than 10°C, with rapid recovery, thus completely eliminating the site-specific temperature loss phenomenon.

[0106] In summary, this invention constructs a catalyst system based on the localized surface plasmon resonance (LSPR) effect of metals to achieve in-situ heat generation at active sites. When applied to the DRM reaction, it can achieve in-situ photothermal heating, completely avoiding the heat transfer process of the entire process, and specifically solving the pain point of site cooling, effectively ensuring the efficiency and performance of the entire DRM reaction.

[0107] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A photocatalyst for in-situ photothermal heating, characterized in that, The catalyst comprises a support and an active metal element supported on the support; wherein... The active metal element includes plasma photothermal metal; The carrier comprises a composite metal oxide.

2. The photo-in-situ heating catalyst according to claim 1, characterized in that, The active metal element includes Ni, Co, Fe, or a noble metal element.

3. The photo-in-situ heating catalyst according to claim 1, characterized in that, In the carrier, the metal element contained in the composite metal oxide is selected from at least two of the elements Mg, Zn, Al or Ti.

4. The photo-in-situ heating catalyst according to claim 3, characterized in that, The carrier includes MgAlO x ZnAlO x MgAlTiO x or ZnAlTiO x At least one of them; Preferably, in the carrier, the molar ratio of Mg / Zn to Al is (2-5):1; Preferably, in the carrier, the molar ratio of Al to Ti is (1-x):x, where x = 0.05-0.

2.

5. The photo-in-situ heating catalyst according to any one of claims 1-4, characterized in that, In the catalyst, the active metal element is less than 30 wt% based on the loading of the support.

6. A method for preparing a photo-in-situ heating catalyst as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Prepare the corresponding metal salt solution according to the selected active metal element, the metal element of the carrier, and their respective proportions, and add an OH- oxidant. - and CO3 2- The mixture of alkaline solutions was followed by a crystallization reaction, and the precipitate was collected to obtain LDH precursors. (2) The LDHs precursor is subjected to high-temperature reduction calcination under a reducing atmosphere, and the reduction products are collected to obtain the desired catalyst.

7. The method for preparing the photo-in-situ heating catalyst according to claim 6, characterized in that: In step (1), the metal salt includes at least one of metal nitrates, metal chlorides, metal sulfates, metal phosphates, metal carbonates, metal alkoxides, and organometallic ammonium salts; and / or, In step (1), the mixed alkaline solution provides OH- - Substances include inorganic or organic bases; and / or, In step (1), CO3 is provided in the mixed alkaline solution. 2- The substances include inorganic carbonates or organic hydrochlorides; and / or, In step (1), the mixed alkaline solution provides OH... - The molar ratio of the substance to the total amount of metal ions is 1-5:1; and / or, In step (1), the mixed alkaline solution provides CO3. 2- The molar ratio of the substance to the total amount of trivalent metal ions in the metal ions is 1-2:3; and / or, In step (1), the temperature of the crystallization reaction is 60-120℃; and / or, In step (1), the crystallization reaction takes 12-24 hours; and / or, In step (1), the crystallization reaction includes dynamic crystallization or static crystallization; and / or, Step (1) further includes centrifuging, washing, and / or drying the precipitate; and / or, In step (2), the reducing atmosphere includes a hydrogen atmosphere or a mixed atmosphere of H2 / inert gas; and / or, In step (2), the flow rate of the reducing atmosphere is 40-60 mL / min; and / or, In step (2), the temperature of the high-temperature reduction calcination step is 600-900℃; and / or, In step (2), the heating rate of the high-temperature reduction calcination step is 1-10℃ / min; and / or, In step (2), the high-temperature reduction calcination step lasts for less than 6 hours; and / or, Step (2) further includes cooling and / or purging the reduction product with nitrogen.

8. A method for photocatalytic in-situ heating catalyzes the dry reforming reaction of methane, characterized in that, The step includes a dry reforming reaction carried out using methane and carbon dioxide as raw materials, with concentrated light irradiation as a light source, in the presence of the photo-in-situ heating catalyst as described in any one of claims 1-5 or the photo-in-situ heating catalyst prepared by the method described in claim 6 or 7.

9. The method for photocatalytic in-situ heating of methane dry reforming according to claim 8, characterized in that, Includes the following steps: S1, the catalyst is loaded, a selected light source is used to irradiate the catalyst with a first focused light, and a reducing atmosphere is introduced to reduce the catalyst in situ by light irradiation; S2, the reducing atmosphere is turned off, a mixed reaction gas of CH4, CO2 and N2 is introduced, and the catalyst is irradiated with a second focused light to catalyze the CH4 and CO2 to undergo a dry reforming reaction.

10. The method for photocatalytic in-situ heating of methane dry reforming according to claim 9, characterized in that: In step S1, the catalyst loading container includes a quartz reaction tube; and / or, In step S1, the light source includes a xenon lamp, an LED light source, a simulated sunlight source, etc.; and / or, In step S1, the parameters for the first focused illumination step include: adjusting the light intensity of the light source to 5-40 W / cm². 2 ; and / or, In step S1, the reducing atmosphere includes a mixture of H2 and an inert gas; and / or, In step S1, the in-situ illumination restoration step takes 15-20 minutes; and / or, In step S2, the volume ratio of CH4, CO2, and N2 in the mixed reaction gas is 1:1:1-1.5; and / or, In step S2, the space velocity of the mixed reaction gas is 1000-13000 h⁻¹. -1 ; and / or, In step S2, the parameters of the second focusing irradiation step include: adjusting the light intensity of the light source to control the temperature of the system to reach 100-800℃; In step S2, the dry reforming reaction is carried out at atmospheric pressure.

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