Nickel-based catalyst as well as preparation method and application thereof

Abstract

The invention discloses a nickel-based catalyst as well as a preparation method and application thereof, relates to the field of catalysts, and solves the problems of poor sintering resistance and carbon deposition resistance, harsh reaction conditions, high cost and the like of a traditional nickel-based catalyst. A site separation structure is introduced to prepare the Pd (at) CeO2 (at) Ni / S1 catalyst, S1 serves as a carrier, small particles with Pd as a core are loaded on the S1, the outer layer of Pd is sequentially wrapped with a CeO2 shell layer and a Ni shell layer, Pd-Ni alloy state sites and NiO-Ni anti-reduction sites are formed, and then the reaction capacity of the Pd (at) CeO2 (at) Ni / S1 catalyst with CH4 and CO2 is improved. In the preparation process of the catalyst, a small amount of noble metal is used, an expensive organic ligand reagent is not needed, the preparation process is simple and convenient, and the synthesis cost is low. The catalyst can be applied to a methane dry reforming reaction, the catalyst can stably react for a long time under the condition of 750 DEG C, the hydrogen yield is high, the conversion rate of CH4 and CO2 is high, sintering and carbon deposition are not generated in the reaction, and the catalyst is suitable for large-scale industrial application.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and in particular to a nickel-based catalyst and a preparation method and application thereof. Background Art

[0002] With the rapid development of the global economy, the chemical industry's demand for sustainable energy is increasing day by day, and countries are facing tremendous pressure to reduce emissions. In this context, the methane dry reforming reaction has attracted widespread attention due to its ability to efficiently convert methane and carbon dioxide into synthesis gas, and is expected to replace the traditional technology route that relies on fossil fuels such as coal. Catalysts play a role in reducing activation energy, accelerating reaction rate, and affecting reaction selectivity in the methane dry reforming reaction. At present, nickel-based catalysts have attracted much attention due to their low price and high initial activity for methane. However, traditional supported nickel-based catalysts have poor resistance to sintering and carbon deposition, and are difficult to be stable for a long time at high temperatures, which greatly limits the industrial promotion of methane dry reforming technology.

[0003] In order to solve the shortcomings of the above-mentioned nickel-based catalysts in the dry reforming reaction of methane, optimizing the reaction process of Ni-based catalysts has become a key research direction. At present, some researchers have successfully constructed atomic-level dispersed sites by regulating the dispersion of active sites. This strategy effectively improves the anti-carbon deposition performance of Ni-based catalysts by cutting off the CC coupling process. However, this method is in a metastable state because the isolated sites are inevitably agglomerated and sintered under high temperature conditions. When the reaction temperature exceeds 600°C, the catalyst will quickly deactivate, resulting in its relatively low reaction activity, which seriously restricts the industrial application of the catalyst. In addition, some researchers have adopted the liquid metal strategy to effectively circumvent the problems of carbon deposition and sintering, but this strategy has strict requirements on reaction conditions and needs to maintain a reaction temperature above 900°C to ensure the state of liquid metal, which significantly increases the reaction energy consumption and catalytic cost, limiting its feasibility in large-scale industrial applications.

[0004] Site separation technology can effectively separate the active sites of the catalyst through a unique structural design, avoid excessive aggregation and interaction between active sites, reduce the sintering tendency of the catalyst under harsh reaction conditions such as high temperature, optimize the contact path between the reaction molecules and the active sites, make the reactants more accurately adsorbed and converted, and improve the catalyst's ability to resist carbon deposition. Although site separation technology has shown certain application potential in the field of catalytic materials, research on the application of site separation technology in the preparation of nickel-based catalysts is still limited. Therefore, developing a method to reduce side reactions such as sintering and carbon deposition, optimize reaction conditions, and accurately control the performance of nickel-based catalysts has vital application value and practical significance for promoting the industrialization of methane dry reforming reactions, reducing production costs, and improving energy efficiency. Summary of the invention

[0005] In order to solve the problems of poor sintering and carbon deposition resistance, harsh reaction conditions and high cost of traditional nickel-based catalysts in the prior art, the present invention proposes a nickel-based catalyst and a preparation method and application thereof.

[0006] A nickel-based catalyst uses S1 molecular sieve as a carrier and comprises the following element loadings in parts by weight: 0.3-0.8 wt% nickel, 0.05-0.2 wt% palladium, and 0.1-5.0 wt% cerium.

[0007] A method for preparing a nickel-based catalyst comprises the following steps:

[0008] P1: Tetraethyl silicate (TEOS), tetraisopropylammonium hydroxide (TPAOH) and water are mixed and stirred, and after the liquid is clarified, it is transferred to a polytetrafluoroethylene kettle for hydrothermal treatment. After the reaction is completed, it is cooled, and the product is centrifuged, washed and dried overnight, and then calcined to prepare S1 molecular sieve;

[0009] P2: Add sodium chloropalladate (Na 2 PdCl 4 ) aqueous solution, urotropine (HMT) are stirred, the pH is adjusted, the mixed solution is oil bathed, and then washed, centrifuged, dried and calcined in sequence; the obtained solid powder is dispersed in the aqueous solution, and cerium acetate (Ce(Ac) 3 ) and stirred, the mixed solution was placed in an oil bath, and then washed, centrifuged, dried and calcined in sequence; the obtained solid product was dispersed in an aqueous solution, and nickel nitrate (Ni(NO 3 ) 2 ) aqueous solution and HMT were stirred, the pH was adjusted, the mixed solution was put into an oil bath, and then washed, centrifuged, dried and calcined in sequence to prepare Pd@CeO 2 @Ni / S1 catalyst.

[0010] Further, the volume ratio of TEOS, TPAOH and water in P1 is 1-2:11-14:4-6;

[0011] Further, the stirring time in P1 is 4 to 6 hours;

[0012] Further, the temperature of the hydrothermal treatment in P1 is 140-180°C;

[0013] Further, the hydrothermal treatment time in P1 is 24 to 96 hours;

[0014] Further, the calcination temperature in P1 is 500-600°C;

[0015] Further, the calcination time in P1 is 6 to 8 hours;

[0016] Further, the calcination atmosphere in P1 is an air atmosphere;

[0017] Further, the pH in P2 is adjusted to 8-10;

[0018] Further, the temperature of the oil bath in P2 is 60-90°C;

[0019] Furthermore, the oil bath time in P2 is 4 to 8 h;

[0020] Further, the calcination temperature in P2 is 200-500°C;

[0021] Furthermore, the calcination atmosphere in P2 is air atmosphere;

[0022] Furthermore, the calcination time in P2 is 1 to 3 hours.

[0023] A nickel-based catalyst is used in methane dry reforming reaction.

[0024] Compared with the prior art, the present invention solves the problems of poor sintering and carbon deposition resistance, harsh reaction conditions and high cost of traditional nickel-based catalysts, and has the following specific beneficial effects:

[0025] 1. Introducing site separation structure to improve catalytic performance: Pd@CeO prepared by the present invention 2 @Ni / S1 catalyst, with S1 molecular sieve as carrier, loaded with small particles with Pd as the core, and the outer layer of Pd successively wrapped with CeO 2 and Ni. Ni is wrapped in the outermost layer, and only a small amount of Ni will pass through CeO 2 The gaps between particles enter the inner layer, causing Pd to alloy and generate Pd-Ni alloy sites. Ni and Ce have a strong interaction, so that the outer layer Ni exists mainly in the form of NiO, forming NiO-Ni anti-reduction sites. Therefore, the outermost NiO-Ni shell will be reduced to Ni and directly react with CH 4 and CO 2 reaction, increasing CH 4 and CO 2 The conversion rate of Ni 2+ It can weaken the Oswald ripening effect of Ni and greatly increase the energy barrier of deep cracking of methane, stabilize the particle size, and endow Pd@CeO 2 @Ni / S1 catalyst has excellent resistance to sintering and carbon deposition.

[0026] 2. Low preparation cost: The present invention prepares Pd@CeO by aqueous phase synthesis method 2@Ni / S1 catalyst does not require the use of expensive organic ligand reagents, and the amount of precious metal Pd used is less than 0.2wt%. The preparation process is simple and the synthesis cost is low, which can be applied in large-scale industrial applications.

[0027] 3. Mild reaction conditions: Pd@CeO prepared by the present invention 2 @Ni / S1 catalyst is used in methane dry reforming reaction. It can react stably for a long time at 750℃, with high hydrogen yield and CH 4 The conversion rate can reach 97.7%, CO 2 The conversion rate can reach 98%, and there is no sintering and carbon deposition in the reaction, which is suitable for industrial production of synthesis gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Pd@CeO 2 @TEM image of Ni / S1 catalyst;

[0029] Figure 2 Pd@CeO 2 HAADF-STEM and EDS characterization images of @Ni / S1 catalyst;

[0030] Figure 3 Pd@CeO 2 @XRD pattern of Ni / S1 catalyst;

[0031] Figure 4 Pd@CeO 2 @Ni / S1 catalyst and NiPd-CeO 2 / The catalytic performance diagram of S1 catalyst applied to methane dry reforming reaction. DETAILED DESCRIPTION

[0032] In order to make the technical solution of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the specification of the present invention. It should be noted that the following embodiments are only used to better understand the technical solution of the present invention and should not be understood as a limitation to the present invention.

[0033] Example 1.

[0034] In this embodiment, S1 molecular sieve is used as the catalyst carrier, Na 2 PdCl 4 、Ce(Ac) 3 and Ni(NO 3 ) 2 6H 2 O as the metal salt precursor, with Pd loading of 0.1wt%, Ce loading of 0.45wt%, and Ni loading of 0.4wt%;

[0035] P1: 6.4 mL of TPAOH (25 wt%) aqueous solution and 7.8 mL of deionized water were mixed and stirred, 4.5 mL of TEOS was added dropwise, and the mixture was stirred at room temperature for 6 h, then transferred to a 50 ml polytetrafluoroethylene reactor, and hydrothermally treated at 170 ° C for 72 h. After the reaction was completed, it was completely cooled, centrifuged and washed with deionized water for 3 times, then dried overnight, calcined at 200 ° C for 2 h in an air atmosphere, and then calcined at 550 ° C for 6 h to prepare S1 molecular sieve;

[0036] P2: 294.22 mg Na 2 PdCl 4 The solid powder was diluted to 10 mL with deionized water to obtain a concentration of 0.1 M Na 2 PdCl 4 aqueous solution; 100 mg Ni(NO 3 ) 2 6H 2 The solid powder was diluted to 10 mL with deionized water to obtain a concentration of 10 mg mL -1 Ni(NO 3 ) 2 6H 2 O aqueous solution;

[0037] P3: 400 mg of S1 molecular sieve was dispersed in 20 mL of deionized water, and 40 μL of Na prepared in P2 was added. 2 PdCl 4 The aqueous solution and 0.56 g HMT were stirred for 30 min, the pH was adjusted to 9, the mixed solution was placed in an oil bath at 80 °C for 6 h, then washed with water and ethanol in sequence and centrifuged, dried overnight, and calcined at 300 °C for 2 h in an air atmosphere; the obtained solid product was dispersed in 40 mL of deionized water, and 25 mg of Ce(Ac) was added. 3 The solid powder was stirred for 30 min and placed in an oil bath at 80 °C for 6 h to prepare Pd@CeO 2 Products of core-shell structure;

[0038] P4: will have Pd@CeO 2 The core-shell structured product was washed with water and ethanol in turn and centrifuged, dried overnight, and calcined at 300 °C for 2 h in an air atmosphere. The obtained solid product was dispersed in 20 mL of deionized water, and 0.2 mL of L P2 prepared Ni(NO 3 ) 2 6H 2O aqueous solution and 0.56g HMT were stirred for 30min, the pH was adjusted to 9, and the mixture was in an oil bath at 80℃ for 6h. The mixture was washed with water and ethanol in sequence and centrifuged, dried overnight, and calcined at 300℃ in air for 2h to prepare Pd@CeO 2 @Ni / S1 catalyst.

[0039] Methane dry reforming reaction:

[0040] Pd@CeO 2 @Ni / S1 catalyst was pressed into tablets and sieved with 40-mesh and 60-mesh screens to obtain particles with a particle size of 0.25-0.425 mm. 50 mg Pd@CeO 2 @Ni / S1 catalyst particles were placed in a fixed bed reactor with an inlet flow rate of 50 mL min -1 CH 4 , CO 2 and Ar(CH 4 , CO 2 The volume ratio of Ar is 1:1:8), and the mass space velocity is WHSV=6000mL CH4 g cat -1 h -1 , the reaction was carried out continuously at 750℃ and atmospheric pressure, with Ar as the internal standard gas, and CH 4 The conversion rate was 92%, CO 2 The conversion rate was 93.6%, H 2 The ratio of CO to CO was 0.97. The product was treated with a cold trap and analyzed online at normal pressure using a gas chromatograph equipped with a thermal conductivity detector (TCD), using a 5A molecular sieve packed column and a Porapak Q packed column as the chromatographic column, and the evaluation time was set to 100 h.

[0041] like Figure 1 Pd@CeO prepared in Example 1 2 @ TEM image of Ni / S1 catalyst. It can be seen from the image that the catalyst is in a polyhedral shape with tiny particles loaded on the surface. Figure 2 Pd@CeO prepared in Example 1 2 HAADF-STEM and EDS characterization of @Ni / S1 catalyst, from Figure 2 It can be analyzed in Figure 1 The tiny particles seen in the figure are multi-level core-shell structures, in which the core is Pd and the outer layers are successively wrapped with CeO 2 shell and Ni shell. The formation of this structure is due to the Na 2 PdCl 4Under alkaline conditions, it will hydrolyze and attach to the rich pore structure on the surface of S1 molecular sieve to form ultra-small PdO x (x ranges from 0 to 2) particles, PdO x Particles and Ce 3+ There is a redox potential that can generate Pd 0 Metal particle core and CeO 2 Small particles, these small particles will be enriched around the Pd particles to form an attached shell layer, forming Pd@CeO 2 Semi-encapsulated structure; on this basis, Ni(NO 3 ) 2 6H 2 O, due to the abundant silanol groups and pore structure on the surface of S1 molecular sieve, ultra-small NiO can be formed on the surface of S1 molecular sieve x (x ranges from 0 to 2) particles, under the action of thermal effect and reducing atmosphere, due to the low Tammann temperature of Ni, NiO x There is no strong interaction between S1 molecular sieve and Ni particles, so Ni will migrate on the surface, while CeO 2 There is a strong metal-support interaction with Ni, which can capture Ni atoms. 2 A Ni shell will be formed outside the shell, eventually forming Pd@CeO 2 @Ni's core-shell structure.

[0042] like Figure 3 Pd@CeO prepared in Example 1 2 @XRD spectrum of Ni / S1 catalyst. In the figure, the diffraction peaks are concentrated between 10° and 30°. The catalyst has good crystallinity, catalytic activity and stability.

[0043] Example 2.

[0044] The difference between this embodiment and embodiment 1 is that the content of Ce is 0.29 wt %. Other experimental conditions and steps are the same as those in embodiment 1.

[0045] In the methane dry reforming reaction, CH 4 The conversion rate was 91.10%, CO 2 The conversion rate was 92.5%, H 2 The ratio to CO is 0.94.

[0046] Example 3.

[0047] The difference between this embodiment and embodiment 1 is that the content of Ce is 0.18 wt %. Other experimental conditions and steps are the same as those in embodiment 1.

[0048] In the methane dry reforming reaction, CH4 The conversion rate was 90.70%, CO 2 The conversion rate was 92.3%, H 2 The ratio to CO is 0.94.

[0049] Example 4.

[0050] The difference between this embodiment and embodiment 1 is that the content of Ce is 0.08 wt %. Other experimental conditions and steps are the same as those in embodiment 1.

[0051] In the methane dry reforming reaction, CH 4 The conversion rate was 88.5%, CO 2 The conversion rate was 90.1%, H 2 The ratio to CO is 0.94.

[0052] Example 5.

[0053] The difference between this embodiment and embodiment 1 is that the content of Ce is 3.26 wt %. Other experimental conditions and steps are the same as those in embodiment 1.

[0054] In the methane dry reforming reaction, CH 4 The conversion rate was 87.2%, CO 2 The conversion rate was 87.2%, H 2 The ratio to CO is 0.92.

[0055] Example 6.

[0056] The difference between this embodiment and embodiment 1 is that the Ni content is 0.45wt%, the Pd content is 0.05wt%, and the other experimental conditions and steps are the same as those in embodiment 1.

[0057] In the methane dry reforming reaction, CH 4 The conversion rate was 94.3%, CO 2 The conversion rate was 96.6%, H 2 The ratio to CO is 0.97.

[0058] Example 7.

[0059] The difference between this embodiment and embodiment 1 is that the Ni content is 0.35wt%, the Pd content is 0.15wt%, and the other experimental conditions and steps are the same as those in embodiment 1.

[0060] In the methane dry reforming reaction, CH 4 The conversion rate was 93.2%, CO 2 The conversion rate was 94.3%, H 2 The ratio to CO is 0.94.

[0061] Example 8.

[0062] The difference between this embodiment and embodiment 1 is that the Ni content is 0.3wt%, the Pd content is 0.2wt%, and the other experimental conditions and steps are the same as those in embodiment 1.

[0063] In the methane dry reforming reaction, CH 4 The conversion rate was 91.1%, CO 2 The conversion rate was 91.6%, H 2 The ratio to CO is 0.93.

[0064] Example 9.

[0065] The difference between this embodiment and embodiment 1 is that the mass space velocity in the methane dry reforming reaction is WHSV=3000mL CH4 g cat -1 h -1 , other experimental conditions and steps are the same as those in Example 1, and it is calculated that CH 4 The conversion rate was 97.7%, CO 2 The conversion rate was 98.0%, H 2 The ratio to CO is 0.98.

[0066] Example 10.

[0067] The difference between this embodiment and embodiment 1 is that the mass space velocity in the methane dry reforming reaction is WHSV=12000mL CH4 g cat -1 h -1 , other experimental conditions and steps are the same as those in Example 1, and it is calculated that CH 4 The conversion rate was 88.3%, CO 2 The conversion rate was 90.2%, H 2 The ratio to CO is 0.93.

[0068] Comparative Example 1.

[0069] 400 mg of the S1 molecular sieve prepared in Example 1 was dispersed in 20 mL of deionized water and 40 μL of Na 2 PdCl 4 Aqueous solution, 0.2 mL Ni(NO 3 ) 2 6H 2 O aqueous solution, 3.96 mg Ce(Ac) 3 The solid powder and 0.56 g HMT were stirred for 30 min, in an oil bath at 80 °C for 6 h, then washed with water and ethanol, centrifuged, dried overnight, and calcined at 300 °C in air atmosphere for 2 h to prepare NiPd-CeO2 / S1 catalyst.

[0070] NiPd-CeO 2 / S1 catalyst was pressed into tablets and sieved with 40-mesh and 60-mesh screens to obtain particles with a particle size of 0.25-0.425 mm. 50 mg NiPd-CeO 2 / S1 catalyst particles were placed in a fixed bed reactor and fed at a flow rate of 50 mL min -1 CH 4 , CO 2 and Ar(CH 4 , CO 2 The volume ratio of Ar is 1:1:8), and the mass space velocity is WHSV=6000mL CH4 g cat -1 h -1 , the reaction was carried out continuously at 750℃ and atmospheric pressure, with Ar as the internal standard gas, and CH 4 The conversion rate was 85.4%, CO 2 The conversion rate was 90.8%, H 2 The ratio to CO is 0.97.

[0071] like Figure 4 Pd@CeO prepared in Example 1 2 @Ni / S1 catalyst and NiPd-CeO prepared in Comparative Example 1 2 The catalytic performance of Pd@CeO / S1 catalyst in methane dry reforming reaction is shown in the figure. 2 The activity of @Ni / S1 catalyst did not decay significantly, while NiPd-CeO 2 / S1 catalyst lost 25% of its activity within 40 h. This is mainly due to the 2 NiPd alloy particles were formed in the S1 catalyst, and CeO 2 The NiPd particles adhere to the alloy particles, but the interaction force with the alloy particles is weak. During the reaction, the NiPd particles sinter and grow, and carbon deposits are generated, resulting in a continuous attenuation of activity. 2 The Ni / S1 catalyst is formed with Pd as the core and CeO as the outer layer. 2 shell and Ni shell, due to CeO 2 The isolation effect of the shell prevents Pd from migrating outward and is encapsulated in the inner layer as the core, while Ni mainly exists in the outer layer, and only a small amount will pass through CeO 2The particle gaps enter the inner layer, causing Pd to alloy and form a Pd-Ni alloy. At the same time, due to the strong interaction between Ni and Ce, the outer layer Ni has a stronger anti-alloying ability and exists mainly in the form of NiO. Therefore, two separate sites are formed, namely the inner layer Pd-Ni alloy state site and the outer layer NiO-Ni anti-reduction site. During the methane dry reforming reaction, the outermost Ni species participates in the activation of methane and carbon dioxide through redox reactions, while the anti-reduction Ni 2+ It can weaken the Oswald ripening effect of Ni, stabilize the particle size, and achieve anti-sintering effect. 2+ It will greatly increase the energy barrier of deep cracking of methane, making it impossible for carbon deposits to form. In addition, the inner Pd species can accelerate the H 2 generation process and improve the reaction activity.

[0072] The following table shows the Pd@CeO prepared in Examples 1-10. 2 @Ni / S1 catalyst catalytic results in methane dry reforming reaction, from the data in the table, it can be seen that with the decrease of Ce content, CH 4 and CO 2 The conversion rate showed a downward trend. This is mainly because the decrease in Ce content will lead to an incomplete shell layer, causing Pd to migrate outward, resulting in alloying of the outer Ni species, which is prone to sintering. At the same time, the anti-carbon deposition ability is weakened, and the active sites are covered by carbon deposition. 4 The conversion rate also decreases, which ultimately leads to a decrease in the overall catalytic efficiency of the methane dry reforming reaction. Excessive CeO may cause the Pd site to be completely blocked and unable to participate in the H species overflow desorption process, and the active metal site Ni is partially covered, reducing the metal exposure on the catalyst surface that can be used for CH and CO activation, thereby reducing the catalytic efficiency. Compared with Example 1, Examples 6-8 change the content of Pd and Ni, and their CH 4 and CO 2 The conversion rate changes slightly, but its stability decreases significantly. This is mainly due to the destruction of the synergistic effect of Pd and Ni in the catalyst, which causes changes in the distribution of active centers and electronic effects, thereby reducing the stability of the catalyst. In the methane dry reforming reaction provided in Example 9, the mass space velocity is reduced (i.e., the feed flow rate is reduced), and the conversion rate and stability of CH and CO are increased compared with Example 1. This is because the lower mass space velocity prolongs the residence time of the reactants on the catalyst surface, thereby increasing the degree of complete conversion of the reaction, and at the same time helps to promote the full reaction of the intermediates on the catalyst surface, reduce the occurrence of carbon deposition and side reactions, thereby improving the stability of the catalyst; on the contrary, in Example 10, the mass space velocity is increased (i.e., the feed flow rate is increased), and the conversion rate and stability of CH and CO are reduced. The Pd@CeO prepared in the example 2The catalytic performance of @Ni / S1 catalyst is due to the NiPd-CeO prepared in Comparative Example 1. 2 / S1 catalyst.

[0073]

[0074] The present invention introduces a site separation structure to prepare Pd@CeO 2 @Ni / S1 catalyst, with S1 molecular sieve as carrier, loaded with small particles with Pd as the core, and the outer layer of Pd successively wrapped with CeO 2 and Ni shell, forming Pd-Ni alloy sites and NiO-Ni anti-reduction sites, thereby improving the 4 and CO 2 The responsiveness of Pd@CeO 2 @Ni / S1 catalyst stability, endowing Pd@CeO 2 @Ni / S1 catalyst has excellent anti-sintering and anti-carbon deposition capabilities. 2 In the preparation process of @Ni / S1 catalyst, there is no need to use expensive organic ligand reagents, and the amount of precious metal Pd is less than 0.2wt%, the preparation process is simple and the synthesis cost is low. 2 @Ni / S1 catalyst can react stably for a long time at 750℃, with high hydrogen yield and CH 4 and CO 2 The conversion rate is high, and there is no sintering and carbon deposition in the reaction, which is suitable for large-scale industrial applications.

[0075] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0076] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A nickel-based catalyst, characterized in that The S1 molecular sieve is used as a carrier, and the element loading amounts are as follows: 0.3-0.8 wt % nickel, 0.05-0.2 wt % palladium, and 0.1-5.0 wt % cerium.

2. A method for preparing a nickel-based catalyst as claimed in claim 1, characterized in that: The following steps are involved: P1: Tetraethyl silicate, tetraisopropylammonium hydroxide and water are mixed and stirred, and after the liquid is clarified, it is transferred to a polytetrafluoroethylene kettle for hydrothermal treatment. After the reaction is completed, it is cooled, and the product is washed, centrifuged and dried overnight, and then calcined to prepare S1 molecular sieve; P2: Add sodium chloropalladate aqueous solution and urotropine to the S1 molecular sieve aqueous dispersion, stir, adjust the pH, put the mixed solution into an oil bath, and then wash, centrifuge, dry and calcine in sequence; The obtained solid product is dispersed in an aqueous solution, cerium acetate is continuously added and stirred, the mixed solution is subjected to an oil bath, and then the mixture is washed, centrifuged, dried and calcined in sequence; the obtained solid product is dispersed in an aqueous solution, nickel nitrate aqueous solution and urotropine are added and stirred, the pH value is adjusted, the mixed solution is subjected to an oil bath, and then the mixture is washed, centrifuged, dried and calcined in sequence to prepare a Pd@CeO2@Ni / S1 catalyst.

3. The method for preparing a nickel-based catalyst according to claim 2, characterized in that: The volume ratio of tetraethyl silicate, tetraisopropylammonium hydroxide and water in P1 is: 1-2: 11-14: 4-6; the stirring time is 4-6h.

4. The method for preparing a nickel-based catalyst according to claim 2, characterized in that: The temperature of the hydrothermal treatment in P1 is 140-180° C., and the time of the hydrothermal treatment is 24-96 hours.

5. The method for preparing a nickel-based catalyst according to claim 2, characterized in that: The calcination temperature in P1 is 500-600° C., the calcination time is 6-8 hours, and the calcination atmosphere is air atmosphere.

6. The method for preparing a nickel-based catalyst according to claim 2, characterized in that: The pH in P2 was adjusted to 8-10.

7. The method for preparing a nickel-based catalyst according to claim 2, characterized in that: The temperature of the oil bath in P2 is 60-90°C, and the time of the oil bath is 4-8h.

8. The method for preparing a nickel-based catalyst according to claim 2, characterized in that: The calcination temperature in P2 is 200-500°C.

9. The method for preparing a nickel-based catalyst according to claim 2, characterized in that: The calcination time in P2 is 1 to 3 hours, and the calcination atmosphere is air atmosphere.

10. Use of the nickel-based catalyst according to claim 1 or the nickel-based catalyst prepared by the method according to any one of claims 2 to 9, characterized in that: Applied to methane dry reforming reaction.

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