Rhodium-based catalyst taking nano spherical alpha-alumina as carrier, preparation method of rhodium-based catalyst and application of rhodium-based catalyst in photo-thermal catalysis

Abstract

The invention belongs to the field of photo-thermal catalysis, and relates to a rhodium-based catalyst taking nano spherical alpha-aluminum oxide as a carrier, a preparation method of the rhodium-based catalyst and application of the rhodium-based catalyst in photo-thermal catalysis. Comprising a nano spherical alpha-alumina carrier and rhodium nanoparticles loaded on the carrier, and the preparation method comprises the following steps: uniformly mixing an aqueous solution of a rhodium-based precursor with nano spherical alpha-alumina, then removing water to obtain powder, and then carrying out a reduction reaction by adopting hydrogen to reduce rhodium in the powder, thereby obtaining the rhodium nano-particles. The rhodium-based photo-thermal catalyst provided by the invention has the characteristics of high dispersion of active components and excellent thermal stability of a catalytic carrier, significantly enhances the adsorption activation ability of CO2 molecules, further improves the reaction efficiency and selectivity of photo-thermal catalysis of CO2 methanation and the stability of the catalyst, and provides an efficient and sustainable solution for realizing CO2 resource utilization.

Description

Technical Field

[0001] The invention belongs to the field of photothermal catalysis, and relates to a rhodium-based catalyst using nano-spherical alpha-alumina as a carrier, a preparation method thereof, and an application thereof in photothermal catalysis. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Carbon dioxide (CO2) is a major greenhouse gas, and its concentration continues to rise, becoming one of the important driving factors of global climate change. CO2 methanation can produce high calorific value fuels while alleviating the problem of global warming, providing new solutions for energy supply and chemical production, and is an effective way to achieve "turning waste into treasure".

[0004] Traditional CO2 methanation technology mostly uses nickel-based catalysts at high temperatures (>300℃), which face the problems of low activity, easy sintering, carbon deposition and high energy consumption. Photothermal catalysis can combine light energy and thermal energy, and has the advantages of low energy consumption and high efficiency. Therefore, the development of efficient photothermal catalysts is the key to promoting the development of CO2 methanation technology. Rhodium (Rh) has become the preferred precious metal for CO2 methanation due to its efficient catalytic activity, especially its significant role in the adsorption and activation of CO2 molecules and the formation of CH bonds (a key step to improve methane selectivity). In particular, Rh can produce a localized photothermal effect under light conditions through the surface plasmon resonance (SPR) effect to reduce the activation energy of the reaction; at the same time, the SPR effect also promotes the generation of hot electrons, significantly enhances the activation and conversion ability of intermediates, and further improves the efficiency of photothermal catalysis. However, due to the scarcity and high price of Rh resources, achieving its efficient dispersion and stable loading on the basis of ensuring photothermal catalytic performance is a key technical bottleneck. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a rhodium-based catalyst with nano-spherical α-alumina as a carrier, a preparation method thereof, and an application thereof in photothermal catalysis. The present invention selects nano-spherical α-alumina with excellent thermal stability and good surface structure regulation ability as a catalytic carrier, and obtains a rhodium-based photothermal catalyst with highly dispersed catalytic active components, excellent photothermal catalytic CO2 methanation activity, high methane selectivity and good stability through simple impregnation, drying, calcination and other processes, which is of great significance to the fields of energy, environment and catalytic materials.

[0006] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0007] In a first aspect, a rhodium-based catalyst using nano-spherical α-alumina as a carrier comprises a nano-spherical α-alumina carrier and rhodium nanoparticles loaded on the carrier.

[0008] Nano-spherical α-alumina has excellent thermal stability and good surface structure regulation ability. At the same time, research has shown that nano-spherical α-alumina as a carrier for loading rhodium nanoparticles, a photothermal catalytic active material, can not only achieve efficient dispersion and stable loading of rhodium nanoparticles, but also the catalyst formed by it has excellent photothermal catalytic CO2 methanation activity.

[0009] The particle size of the nano-spherical α-alumina carrier described in the present invention is 50-200nm. The rhodium nanoparticles described in the present invention are nanoparticles of rhodium metal element. The particle size of the rhodium nanoparticles described in the present invention is 0.5-8nm. In the catalyst provided by the present invention, the mass of the rhodium nanoparticles is 0.2-5% of the mass of the nano-spherical α-alumina carrier.

[0010] In the second aspect, a method for preparing the above-mentioned rhodium-based catalyst with nano-spherical α-alumina as a carrier is provided, wherein an aqueous solution of a rhodium-based precursor is evenly mixed with the nano-spherical α-alumina, and then water is removed to obtain a powder, and then a reduction reaction is carried out using hydrogen to reduce the rhodium in the powder.

[0011] Mixing an aqueous solution of a rhodium-based precursor with nano-spherical α-alumina is beneficial to the uniform dispersion of the rhodium-based precursor and the nano-spherical α-alumina, so that the rhodium-based precursor can be uniformly adsorbed on the nano-spherical α-alumina, and then through hydrogen reduction, efficient dispersion and stable loading of rhodium nanoparticles can be achieved.

[0012] The rhodium-based precursor described in the present invention is a precursor of rhodium nanoparticles, which is generally a rhodium salt, and can be rhodium trichloride, rhodium nitrate, rhodium sulfate, etc.

[0013] In a third aspect, a rhodium-based catalyst with nano-spherical α-alumina as a carrier is used in photothermal catalysis.

[0014] Specifically, the photothermal catalysis is photothermal catalytic CO2 methanation.

[0015] The rhodium-based photothermal catalyst provided by the present invention has the characteristics of highly dispersed active components and excellent thermal stability of the catalytic carrier, which significantly enhances the adsorption and activation ability of CO2 molecules, further improves the reaction efficiency, selectivity and catalyst stability of photothermal catalytic CO2 methanation, and provides an efficient and sustainable solution for realizing the resource utilization of CO2.

[0016] In a fourth aspect, a method for photothermal catalytic CO2 methanation comprises the following steps:

[0017] The rhodium-based catalyst is placed in a fixed-bed photothermal reactor, activated in a high-temperature hydrogen atmosphere and cooled to a reaction temperature, CO2 and H2 are introduced as reaction gases, and photothermal catalytic CO2 methanation is carried out under light conditions.

[0018] The fixed bed photothermal reactor described in the present invention refers to a fixed bed reactor provided with a light source.

[0019] The beneficial effects of the present invention are:

[0020] 1. The rhodium-based photothermal catalyst provided by the present invention can produce a localized photothermal effect through the surface plasmon resonance (SPR) effect under illumination conditions, significantly reducing the activation energy of the reaction and enhancing the activation and conversion capacity of the reaction intermediates. The photothermal synergistic effect allows the catalytic reaction to proceed at a lower temperature, thereby improving the overall photothermal catalytic efficiency and reducing energy consumption.

[0021] 2. Using nano-spherical α-alumina as a carrier can effectively improve the dispersibility of rhodium, reduce agglomeration, and make it have a longer service life. The rhodium-based photothermal catalyst of the present invention exhibits excellent anti-carbon deposition ability and high-temperature stability during the reaction process, can maintain stable catalytic activity, and adapt to multiple cycles without significant deactivation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0023] Figure 1 The high-magnification transmission electron microscope images of the rhodium-based photothermal catalyst 0.5wt% Rh / α-Al2O3 prepared in the embodiment of the present invention at different magnifications ( Figure 1 a and Figure 1 b) and elemental mapping ( Figure 1 c).

[0024] Figure 2 This is the X-ray diffraction pattern of the rhodium-based photothermal catalyst 0.5wt% Rh / α-Al2O3 prepared in an example of the present invention.

[0025] Figure 3 These are the results of the evaluation of the thermal catalytic CO2 methanation performance of the rhodium-based photothermal catalyst 0.5wt% Rh / α-Al2O3 prepared in the embodiment of the present invention under different temperature conditions, including the methane generation rate and selectivity.

[0026] Figure 4These are the results of the photothermal catalytic CO2 methanation performance evaluation of the rhodium-based photothermal catalyst 0.5wt% Rh / α-Al2O3 prepared in an embodiment of the present invention under different temperature conditions, including the methane generation rate and selectivity.

[0027] Figure 5 This is a stability test of the rhodium-based photothermal catalyst 0.5wt% Rh / α-Al2O3 prepared in an example of the present invention in the photothermal catalytic CO2 methanation reaction.

[0028] Figure 6 These are the results of the photothermal catalytic CO2 methanogenesis performance evaluation at 350°C of the rhodium-based photothermal catalysts with different loading amounts prepared in the examples of the present invention, including the methane generation rate and selectivity. DETAILED DESCRIPTION

[0029] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0030] A typical embodiment of the present invention provides a rhodium-based catalyst with nano-spherical α-alumina as a carrier, comprising a nano-spherical α-alumina carrier and rhodium nanoparticles loaded on the carrier.

[0031] Nano-spherical α-alumina has excellent thermal stability and good surface structure regulation ability. At the same time, research has shown that nano-spherical α-alumina as a carrier for loading rhodium nanoparticles, a photothermal catalytic active material, can not only achieve efficient dispersion and stable loading of rhodium nanoparticles, but also the catalyst formed by it has excellent photothermal catalytic CO2 methanation activity.

[0032] In some embodiments, the particle size of the nano-spherical α-alumina carrier is 50-200 nm, preferably 50-100 nm.

[0033] In some embodiments, the particle size of the rhodium nanoparticles is 0.5-8 nm, preferably 0.5-5 nm. The particle size of the rhodium nanoparticles can be characterized and determined by transmission electron microscopy (TEM) images.

[0034] In some embodiments, the mass of the rhodium nanoparticles is 0.2-5%, preferably 0.5-4%, of the mass of the nano-spherical α-alumina support.

[0035] Another embodiment of the present invention provides a method for preparing the above-mentioned rhodium-based catalyst with nano-spherical α-alumina as a carrier, wherein an aqueous solution of a rhodium-based precursor and the nano-spherical α-alumina are evenly mixed, and then water is removed to obtain a powder, and then a reduction reaction is carried out using hydrogen to reduce the rhodium in the powder.

[0036] Specifically, an aqueous solution of a rhodium-based precursor is mixed with nano-spherical α-alumina, and the mixture is stirred thoroughly and then allowed to stand to ensure that the rhodium-based precursor is fully adsorbed on the surface of the nano-spherical α-alumina carrier. Water is removed by evaporation to obtain a uniform dry powder. The dried powder is reduced in a hydrogen atmosphere to ensure that the rhodium-based precursor is completely reduced to metallic rhodium nanoparticles and is uniformly dispersed on the surface of the nano-spherical α-alumina to obtain a target product. The present invention removes water by evaporation, which can not only improve the loading efficiency of the nano-spherical α-alumina on the rhodium-based precursor and avoid waste of the rhodium-based precursor, but also improve the dispersion uniformity of the rhodium-based precursor in the nano-spherical α-alumina.

[0037] In some embodiments, the concentration of the aqueous solution of the rhodium-based precursor is 0.01-0.15 mol / L.

[0038] In some embodiments, the mass of the rhodium element in the rhodium-based precursor is 0.2-5%, preferably 0.5-4%, of the mass of the nano-spherical α-alumina support.

[0039] In some embodiments, the drying temperature after removing water is 80-120° C., preferably 110° C. Specifically, the drying time is 12 hours.

[0040] In some embodiments, the reduction temperature is 500-800° C., preferably 600° C. Under this condition, the reduced rhodium can be guaranteed to be rhodium alone, while avoiding the reduction of aluminum oxide.

[0041] In some embodiments, the reduction time is 2-6 hours, preferably 3 hours.

[0042] A third embodiment of the present invention provides an application of the above-mentioned rhodium-based catalyst with nano-spherical α-alumina as a carrier in photothermal catalysis.

[0043] Specifically, the photothermal catalysis is photothermal catalytic CO2 methanation. Rhodium-based photothermal catalysts can significantly improve the efficiency and methane selectivity of CO2 methanation reaction through photothermal synergy, providing an efficient solution for carbon resource utilization.

[0044] A fourth embodiment of the present invention is a method for photothermal catalytic CO2 methanation, comprising the following steps:

[0045] The rhodium-based catalyst is placed in a fixed-bed photothermal reactor, activated in a high-temperature hydrogen atmosphere and cooled to a reaction temperature, CO2 and H2 are introduced as reaction gases, and photothermal catalytic CO2 methanation is carried out under light conditions.

[0046] The activity of the catalyst is calculated based on the methane generation rate.

[0047] Before the catalytic reaction, the rhodium-based photothermal catalyst needs to be activated in a high-temperature hydrogen atmosphere to remove metal oxides on the surface.

[0048] In some embodiments, the activation temperature is 350-600° C., preferably 400° C. Specifically, the heating rate is 10° C. / min.

[0049] In some embodiments, the activation time is 0.5-1.5 h, preferably 1 h.

[0050] In some embodiments, the hydrogen flow rate during the activation process is 35-45 ml / min, preferably 40 ml / min.

[0051] In some embodiments, the reaction temperature is 150-350°C.

[0052] In some embodiments, the ratio of the CO2 and H2 reaction gases is 1:1-4, preferably 1:4.

[0053] In some embodiments, the ratio of the mass of the rhodium-based catalyst to the total flow rate of the reaction gas is 10-30 mg:45-55 ml / min, preferably 10-30 mg:50 ml / min, preferably 20 mg:45-55 ml / min, preferably 20 mg:50 ml / min.

[0054] In some embodiments, the light condition is 1.0-5.0 W / cm -2 . Provided by 300w xenon lamp and ZF2 plano-convex lens.

[0055] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0056] Example 1

[0057] A method for preparing a nano-spherical α-alumina-supported rhodium-based photothermal catalyst 0.5wt% Rh / α-Al2O3 comprises the following steps:

[0058] Weigh 500 mg of nano-spherical α-alumina powder and add it to 2.5 ml of deionized water. Measure 2.453 ml of rhodium chloride aqueous solution (0.01 mol L -1) Add the above suspension, stir well and let it stand to allow the rhodium-based precursor to be fully adsorbed on the carrier surface. Place the suspension in a 110°C sand bath and stir for 12 hours until it is completely dry. Reduce the dried powder in a hydrogen atmosphere with a hydrogen reduction gas flow rate of 40 ml / min, a reduction temperature of 600°C, and a reduction time of 3 hours. After the reduction is completed, cool naturally to room temperature. The resulting catalyst is named 0.5wt% Rh / α-Al2O3.

[0059] Example 2

[0060] A method for preparing a nano-spherical α-alumina-supported rhodium-based photothermal catalyst 2wt% Rh / α-Al2O3 comprises the following steps:

[0061] Weigh 500 mg of nano-spherical α-alumina powder and add it to 4 ml of deionized water. Measure 1 ml of rhodium chloride aqueous solution (0.1 mol L -1 ) Add the above suspension, stir well and let stand to allow the rhodium-based precursor to be fully adsorbed on the carrier surface. Place the suspension in a 110°C sand bath and stir for 12 hours until completely dry. Reduce the dried powder in a hydrogen atmosphere with a hydrogen reduction gas flow rate of 40 ml / min, a reduction temperature of 600°C, and a reduction time of 3 hours. After the reduction is completed, cool naturally to room temperature. The resulting catalyst is named 2wt% Rh / α-Al2O3.

[0062] Example 3

[0063] A method for preparing a nano-spherical α-alumina-supported rhodium-based photothermal catalyst 4wt% Rh / α-Al2O3 comprises the following steps:

[0064] Weigh 500 mg of nano-spherical α-alumina powder and add it to 2.9 ml of deionized water. Measure 2.1 ml of rhodium chloride aqueous solution (0.1 mol L -1 ) Add the above suspension, stir well and let it stand to allow the rhodium-based precursor to be fully adsorbed on the carrier surface. Place the suspension in a 110°C sand bath and stir for 12 hours until it is completely dry. Reduce the dried powder in a hydrogen atmosphere with a hydrogen reduction gas flow rate of 40 ml / min, a reduction temperature of 600°C, and a reduction time of 3 hours. After the reduction is completed, cool naturally to room temperature. The resulting catalyst is named 4wt% Rh / α-Al2O3.

[0065] Product analysis and performance testing:

[0066] Morphological and phase analysis of rhodium-based photothermal catalysts:

[0067] The TEM spectrum of the rhodium-based photothermal catalyst 0.5wt% Rh / α-Al2O3 prepared in Example 1 is as follows Figure 1As shown in a, the particle size of nano-spherical α-alumina is 50-100nm, and nanoparticles (particle size is 0.5-5nm) are evenly distributed on the catalytic carrier. Figure 1 The further magnified image in b shows that the lattice spacing of the nanoparticles is 0.218nm, which corresponds to the (111) crystal plane of metallic rhodium. This indicates that the rhodium nanoparticles are successfully loaded on the surface of the nanospherical α-alumina and retain typical metallic properties. Figure 1 The element distribution diagram of c further confirms the high dispersibility of Rh nanoparticles, indicating that the preparation method adopted effectively avoids the particle agglomeration phenomenon. Overall, the lattice characteristics of Rh nanoparticles in the rhodium-based photothermal catalyst 0.5wt% Rh / α-Al2O3 are clear, and the particles are evenly distributed, providing an ideal structural basis for the subsequent improvement of photothermal catalytic performance.

[0068] XRD spectrum Figure 2 As shown. All samples showed typical diffraction peaks at 35.16°, 37.8°, 43.39°, 52.57°, 57.51°, 66.53° and 68.19°, corresponding to the (104), (110), (113), (024), (116), (214) and (300) crystal planes of the nano-spherical α-Al2O3 support, respectively. However, the Rh diffraction peak intensity in the rhodium-based photothermal catalyst samples with different loading amounts was not obvious, which can be explained by the low loading amount and high dispersion of metal Rh. In addition, with the increase of Rh metal loading, the diffraction peak intensity attributed to the α-Al2O3 support was observed to gradually decrease. This phenomenon indicates that with the increase of loading amount, Rh nanoparticles gradually covered the surface of the α-Al2O3 support, which may partially shield the diffraction signal of the support, resulting in the weakening of the diffraction peak intensity of the support crystal plane characteristics. In addition, this may also reflect the enhanced interaction between the support surface and Rh, which further changes the surface properties and electronic structure of the crystal, providing important supporting evidence for the subsequent improvement of catalytic performance.

[0069] Performance evaluation of photothermal catalytic CO2 methanation:

[0070] (1) Experimental method: Weigh 20 mg of the photothermal catalyst prepared in the embodiment (0.5wt% Rh / α-Al2O3, 2wt% Rh / α-Al2O3) and place it in a fixed bed photothermal reactor, and evenly disperse and cover the quartz wool. Before the catalytic reaction, the photothermal catalyst was activated in a hydrogen atmosphere for 1 h to remove the surface metal oxides. The hydrogen flow rate was 40 ml / min and the activation temperature was 400 ° C. After the activation, it was naturally cooled to the catalytic reaction temperature (150 ° C, 250 ° C, 350 ° C), and then the reaction gas was introduced for 30 min. The total flow rate of the reaction gas was 50 ml / min, and CO2 / H2 = 1:4. During the photothermal catalytic process, a 300W xenon lamp equipped with a ZF2 plano-convex lens was used as the light source, and full-spectrum irradiation was performed on the top of the reactor. For the thermal catalytic process, no light was added, and other conditions were consistent with the photothermal catalytic conditions. During the catalytic reaction, 0.2 ml of gas was taken at regular intervals (25 minutes, 50 minutes, and 75 minutes) to test the composition of the generated gas through gas chromatography. Four cycle experiments were carried out at 350°C to test the cycle stability of the photothermal catalyst. After each test, the reaction gas was used to exhaust for 1 hour before the next cycle.

[0071] (2) Experimental results: The results of the comparison of the thermal catalytic CO2 methanation and photothermal catalytic CO2 methanation activities of 0.5 wt% Rh / α-Al2O3 prepared in Example 1 under different temperature conditions are as follows: Figure 3 and Figure 4 As shown. Figure 3 It can be seen that under the condition of 150℃ thermal catalysis, the catalyst has almost no catalytic performance. As the temperature of the thermal catalytic reaction increases, the catalytic activity gradually increases, especially at 350℃, the catalytic activity is significantly enhanced. This shows that the CO2 methanation reaction is limited by a high reaction energy barrier, and high temperature conditions are conducive to the full activation of the reactant molecules and the acceleration of the surface reaction kinetics. Figure 4 The photothermal catalytic activity was better than that of pure thermal catalytic conditions at all tested temperatures, indicating the significant effect of light. At 150 °C, the reaction rate under photothermal catalytic conditions reached 3.205 mmol·g -1 ·h -1 , indicating that even at low temperatures, the introduction of light can still significantly stimulate the activity of the catalyst. At 250°C, the photothermal catalytic performance was 57 times higher than the thermal catalytic performance under dark conditions, further verifying the key role of light in the reaction process. This significant performance improvement is mainly due to the hot electrons and photothermal effects generated by rhodium nanoparticles under SPR excitation, which significantly promote the adsorption and activation of CO2 molecules, reduce the activation energy of the reaction, and thus improve the efficiency of the photothermal catalytic CO2 methanation reaction. Figure 5The effects of catalysts with different loading amounts on photothermal catalytic CO2 methanation were compared. The results showed that the increase in metal loading was positively correlated with the catalytic activity, but the selectivity decreased, which may be related to the particle size. Figure 6 It is proved that 0.5wt% Rh / α-Al2O3 photothermal catalyst has good photothermal catalytic cycle stability, and the methane selectivity remains at around 98.7%.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A rhodium-based catalyst with nano-spherical α-alumina as a carrier, characterized in that: The invention comprises a nano-spherical alpha-alumina carrier and rhodium nanoparticles loaded on the carrier.

2. The rhodium-based catalyst according to claim 1, characterized in that: The particle size of the nano-spherical α-alumina carrier is 50-200 nm, preferably 50-100 nm. Alternatively, the particle size of the rhodium nanoparticles is 0.5-8 nm, preferably 0.5-5 nm.

3. The rhodium-based catalyst according to claim 1, characterized in that: The mass of the rhodium nanoparticles is 0.2-5% of the mass of the nano-spherical α-alumina carrier, preferably 0.5-4%.

4. A method for preparing a rhodium-based catalyst with nano-spherical α-alumina as a carrier as claimed in claim 1, characterized in that: The aqueous solution of rhodium-based precursor and nano-spherical α-alumina are mixed evenly, and then the water is removed to obtain powder, and then hydrogen is used for reduction reaction to reduce the rhodium in the powder.

5. The preparation method according to claim 4, characterized in that: The concentration of the aqueous solution of the rhodium-based precursor is 0.01-0.15 mol / L; Alternatively, the mass of the rhodium element in the rhodium-based precursor is 0.2-5% of the mass of the nano-spherical α-alumina support, preferably 0.5-4%.

6. The preparation method according to claim 4, characterized in that: Remove water by evaporation; The drying temperature after removing water is 80-120°C; Or, the reduction temperature is 500-800°C; Or, the reduction time is 2-6h.

7. Use of a rhodium-based catalyst with nano-spherical α-alumina as a carrier as claimed in any one of claims 1 to 3 in photothermal catalysis.

8. The use according to claim 7, characterized in that: The photothermal catalysis is photothermal catalytic CO2 methanation.

9. A method for photothermal catalytic CO2 methanation, characterized in that: The steps include: The rhodium-based catalyst described in any one of claims 1 to 3 is placed in a fixed-bed photothermal reactor, the catalyst is activated in a high-temperature hydrogen atmosphere and cooled to the reaction temperature, CO2 and H2 are introduced as reaction gases, and photothermal catalytic CO2 methanation is carried out under light conditions.

10. The method according to claim 9, characterized in that: The activation temperature is 350-600°C, preferably 400°C; Or, the activation time is 0.5-1.5h; Or, the hydrogen flow rate during activation is 35-45 ml / min; Or, the reaction temperature is 150-350°C; Or, the ratio of CO2 and H2 reaction gases is 1:1-4; Or, the ratio of the mass of the rhodium-based catalyst to the total flow rate of the reaction gas is 10-30 mg: 45-55 ml / min; Or, the light condition is 1.0-5.0W / cm -2 .

Images