Preparation method of nickel catalyst for hydrogenation reaction

Abstract

According to the preparation method of the nickel catalyst for hydrogenation reaction of the present invention, the nickel catalyst is subjected to a two-step passivation step after reduction, whereby the nickel catalyst for hydrogenation reaction of petroleum resin has excellent safety and reaction activity.

Description

Technical Field

[0001] Cross - reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2022-0120131, filed on September 22, 2022, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

[0003] The present invention relates to a method for preparing a nickel catalyst for a hydrogenation reaction, and more particularly, to a method for preparing a nickel catalyst in which the safety and reactivity of the catalyst are improved through a two-step passivation process. Background Art

[0004] Generally, the hydrogenation reaction of organic compounds applied to reduce specific functional groups or convert unsaturated compounds into saturated compounds can be applied to various compounds by reducing compounds having unsaturated functional groups (such as ketones, aldehydes, imines, and the like) to compounds such as alcohols, amines, and the like, or saturating the unsaturated bonds of olefin compounds and the like, and is one of the commercially very important reactions.

[0005] Lower olefins (i.e., ethylene, propylene, butene, and butadiene) and aromatic compounds (i.e., benzene, toluene, and xylene) are basic intermediates widely used in the petrochemical and chemical industries. Thermal cracking or steam pyrolysis is the main type of process typically used to form these materials in the presence of steam and in the absence of oxygen. The raw materials can include petroleum gases such as naphtha, kerosene, and gas oil, as well as distillates. Among them, through the thermal cracking of naphtha and the like, C4 fractions including ethylene, propylene, butane, and butadiene, C5 fractions including dicyclopentadiene (DCPD), cracked gasoline (including benzene, toluene, and xylene), cracked kerosene (C9+ fractions), cracked heavy oil (ethylene residue, bottom oil), and hydrogen can be produced, and petroleum resins can be prepared by polymerization from these fractions and the like.

[0006] However, the polymerized petroleum resin partially contains double bonds in the aromatic part (hereinafter referred to as 'aromatic double bonds') and double bonds in the aliphatic part (hereinafter referred to as 'olefin double bonds'), and the higher the content of olefin double bonds, the lower the quality of the petroleum resin. Among them, if a hydrogenation process of adding hydrogen to the olefin double bonds is carried out, the unsaturated double bonds can be saturated, so the color can become bright, and the unique odor of the petroleum resin can be reduced, thereby improving the quality.

[0007] During the hydrogenation reaction of petroleum resin, in order to control the content of aromatic double bonds, it is necessary to selectively hydrogenate the olefin bonds of the polymeric resin. The selective hydrogenation reaction of olefin double bonds can generally be carried out by bringing hydrogen and the reaction target to be hydrogenated into contact with a noble metal catalyst such as palladium (Pd), platinum (Pt) and their analogues. However, noble metal catalysts are extremely expensive and are the main cause of cost increase. Therefore, commercially, a nickel (Ni)-based catalyst is used for the hydrogenation reaction of petroleum resin.

[0008] For the nickel powder catalyst used in the hydrogenation reaction of petroleum resin, due to its self-heating property, a method for ensuring safe transportation, storage and use is required. To achieve this method, a process for ensuring the safety of the nickel catalyst is applied. For nickel catalysts, generally, a passivation process is used after the reduction process, and the passivation process uses a nitrogen mixed gas containing part of air. Through the passivation process, the highly reactive nickel component reacts with air and is converted into nickel oxide (NiO), thereby ensuring the safety of using the nickel catalyst.

[0009] However, since a part of the formed nickel oxide is not regenerated into nickel during the hydrogenation reaction, the reaction activity decreases, so the amount of the catalyst used increases. If the rate of conversion of nickel in the nickel catalyst into nickel oxide decreases, the hydrogenation reaction performance can be improved and the amount of the catalyst used can be reduced, but the risk of rapid heating may increase during the transportation, storage and use of the catalyst, thus causing environmental safety problems during use. Summary of the Invention

[0010] [Technical Problem]

[0011] An object of the present invention is to provide a method for preparing a nickel catalyst for hydrogenation reaction, which nickel catalyst has increased safety and excellent hydrogenation reaction activity at the same time.

[0012] [Technical Solution]

[0013] To achieve the above object, there is provided a method for preparing a nickel catalyst, which includes: a step of preparing a catalyst precursor mixture containing a nickel precursor (step 1); a step of precipitating the catalyst precursor mixture to obtain a catalyst precursor (step 2); a step of drying, calcining and reducing the catalyst precursor to prepare a catalyst (step 3); a first passivation step of passivating the catalyst using a mixed gas containing air and nitrogen (step 4); and a second passivation step of passivating the catalyst using a mixed gas containing air and nitrogen at a temperature different from the temperature of the first passivation step after the first passivation step (step 5).

[0014] The present invention also provides a nickel catalyst, which contains nickel on a solid support and has H at 120 to 200 °C 2- The maximum value of the TPR peak, where the H 2 - The half-width of the TPR peak is 90 or less, and the degree of stabilization calculated by the following calculation formula 1 is 55% to 70%:

[0015] [Calculation formula 1]

[0016] Degree of stabilization (%) = ((peak area of the TPR graph of the catalyst ÷ sample weight) / (peak area of the TPR graph of the oxidized catalyst ÷ sample weight)) × 100.

[0017] As used herein, the terms "first", "second" and the like are used to explain various elements, and are only used to distinguish one element from other elements.

[0018] In addition, the terms used herein are only used to explain specific embodiments, and are not intended to limit the present invention.

[0019] Unless explicitly stated or obvious from a situation not contemplated, singular expressions include their plural expressions.

[0020] Throughout this specification, the terms "comprising", "equipped with" or "having" and the like are intended to mean the presence of practicing features, numbers, steps, components or combinations thereof, and are not intended to exclude the possibility of the presence or addition of one or more other features, numbers, steps, components or combinations thereof.

[0021] In addition, in the case of stating that each layer or component is formed "on" or "above" each layer or component, it means that each layer or component is formed directly above each layer or component, or other layers or components may additionally be formed between these layers or on an object or substrate.

[0022] Although various modifications can be made to the present invention and the present invention can have various forms, specific examples will be shown and explained in detail below. However, it should be understood that it is not intended to limit the present invention to the specific disclosure, and without departing from the spirit and technical scope of the present invention, the present invention includes all its modifications, equivalents or alternatives.

[0023] As used herein, the term "nickel catalyst" represents a structure in which metal nickel particles and a carrier are physically and chemically combined, and the "nickel" in the "nickel catalyst" includes both nickel metal and nickel oxide.

[0024] Hereinafter, the present invention will be explained in detail.

[0025] The present disclosure relates to a method for passivating a catalyst after reduction during the preparation of a nickel catalyst, and to a method for preparing a nickel catalyst, wherein the passivation step is carried out in a two-step process at different temperatures.

[0026] Nickel catalysts typically undergo a passivation step to ensure safety, and the degree of passivation affects the safety or reactivity of the catalyst when used in subsequent reactions. In the present disclosure, the nickel catalyst is prepared via a two-step passivation method and is thus characterized by excellent safety and reactivity.

[0027] Hereinafter, the present invention will be explained in detail according to the steps.

[0028] (Step 1)

[0029] Step 1 of the present invention is a step of preparing a catalyst precursor mixture containing a nickel precursor.

[0030] The nickel catalyst used in the present disclosure can be prepared using a variety of nickel precursors. As examples of nickel precursors, nickel nitrates, acetates, sulfates, chlorides can be used, and preferably, nickel sulfate can be used, but the nickel precursor is not limited thereto.

[0031] According to one embodiment of the present invention, the catalyst precursor mixture of Step 1 may further contain one or more of a carrier and a promoter precursor. The type of the carrier is not particularly limited. For example, it can be selected from SiO 2 , Al 2 O 3 , MgO, MgCl 2 , CaCl 2 , ZrO 2 , TiO 2 , B 2 O 3 , CaO, ZnO, BaO, ThO 2 , SiO 2 -Al 2 O 3 , SiO 2 -MgO, SiO 2 -TiO 2 , SiO 2 -V 2 O 5 , SiO 2 -CrO 2 O 3 , SiO 2 -TiO 2 -MgO and zeolites, and one or more of them. Among them, a carrier containing silica (SiO 2 ) can be typically used.

[0032] In addition, the type of the promoter precursor is not particularly limited. For example, it can be oxides, nitrates, acetates, sulfates, chlorides or combinations thereof containing copper, potassium, sulfur and the like, and preferably, copper sulfate can be used, but the promoter precursor is not limited thereto.

[0033] Meanwhile, the catalyst precursor mixture can be prepared by mixing in a solvent, and the type of the solvent is not particularly limited, but water, methanol, ethanol or their analogues can be used, and preferably, water can be used. In addition, the mixing method of the catalyst precursor mixture is not particularly limited. For example, it can be prepared by dissolving nickel and the promoter precursor in a solvent and then adding a carrier, or it can be prepared by adding a carrier to a solvent to prepare a suspension solution and then adding nickel and the cocatalyst precursor.

[0034] (Step 2)

[0035] Step 2 of the present invention is a step of using a precipitant to prepare a catalyst precursor from the catalyst precursor mixture prepared in Step 1.

[0036] In Step 2, the method of preparing a catalyst precursor from the catalyst precursor mixture is not particularly limited, and it can generally be prepared by a precipitation method. Specifically, coprecipitation, impregnation, deposition-precipitation methods or their analogues can be used.

[0037] For example, after introducing a nickel precursor, a promoter precursor and a carrier into a solvent in Step 1 to prepare a catalyst precursor mixture, a precipitant can be added to the catalyst precursor mixture so that nickel and the promoter components are deposited in the solid carrier suspended in the solvent.

[0038] In addition, the precipitant that can be used can be selected considering the nickel carrier amount, the size of nickel crystals and the dispersion of nickel of the prepared catalyst, etc. Preferably, as the precipitant in Step 2, one or more of sodium carbonate and sodium bicarbonate can be used.

[0039] (Step 3)

[0040] Step 3 of the present invention is a step of drying, calcining and reducing the catalyst precursor prepared in Step 2 to prepare a catalyst.

[0041] First, drying is a step of drying the solvent of the catalyst precursor to prepare a dried substance. Among them, a drying temperature and time sufficient to remove the solvent can be selected, and although not particularly limited, drying can be carried out at a temperature of 80 to 200 °C for 5 to 30 hours. In addition, before drying, the step of further washing and filtering the catalyst precursor prepared via Step 2 can be carried out.

[0042] After preparing the dried substance, calcination of the catalyst precursor is carried out. Calcination can be carried out in an air atmosphere, and can be carried out at 180 to 500 °C, 200 to 450 °C or 250 to 400 °C. If the calcination temperature is lower than the above range, the dispersion of the active species nickel may deteriorate, and if it exceeds the above range, sintering of nickel may occur, thus deteriorating the reaction activity.

[0043] Since calcination is usually carried out in air, the nickel included in the catalyst precursor mainly exists in the form of nickel oxide, and nickel oxide generally has lower hydrogenation reaction activity compared with nickel. Therefore, generally speaking, nickel oxide is reduced again before use. Thus, after calcining the catalyst precursor, reduction is carried out and then it is used as a catalyst.

[0044] The reduction in step 3 can be carried out at a temperature of 300 to 600 °C in a hydrogen atmosphere. If the reduction temperature is lower than the above range, the reduction of the catalyst may not be properly achieved, and if the reduction temperature exceeds the above range, sintering of the active metal may occur. More preferably, the reduction can be carried out at a temperature of 350 to 550 °C or 400 to 500 °C.

[0045] (Step 4)

[0046] As explained above, the nickel catalyst prepared by reducing the catalyst precursor is subjected to a passivation step to ensure safety during transportation, storage and use. Step 4 corresponds to the first passivation step of the two-step passivation process of the present disclosure.

[0047] Existing passivation steps have been carried out by converting a part of the nickel of the catalyst into nickel oxide or depositing the prepared catalyst in an organic solvent capable of blocking air. However, it is difficult for the existing methods to meet both the safety and the reaction activity of the catalyst. The researchers of the present disclosure have confirmed through continuous experiments that by carrying out the passivation process in two steps at different temperatures, a catalyst with excellent reaction activity and safety during transportation, storage and use can be prepared.

[0048] The first passivation step is a step of passivating the catalyst using a mixed gas containing air and nitrogen. Among them, air may include nitrogen, oxygen, carbon monoxide, carbon dioxide, argon, etc. More specifically, in air, it may include about 78 vol% of nitrogen, about 21 vol% of oxygen, about 0.93 vol% of argon. In addition, carbon dioxide, carbon monoxide and water vapor etc. may be further included.

[0049] Preferably, based on the total volume of the mixed gas of air and nitrogen in step 4, 0.1 to 2 vol% of air may be included. If the proportion of air in the mixed gas is less than the above range, the conversion of nickel to nickel oxide may not be properly achieved, and if it exceeds the above range, the catalyst activity may deteriorate. More preferably, based on the total volume of the mixed gas, air may be included in an amount of 0.15 vol% or more, 0.2 vol% or more, or 0.3 vol% or more and 1.7 vol% or less, 1.5 vol% or less, or 1.2 vol% or less.

[0050] Preferably, the first passivation step of step 4 can be carried out at a temperature of 15 to 50 °C. Preferably, the first passivation step of the present disclosure is carried out at a temperature lower than that of the second passivation step. In the first passivation step, the catalyst can be stably passivated by carrying out passivation relatively slowly via contact with air under mild conditions. More preferably, the first passivation step can be carried out at a temperature above 17 °C, above 20 °C or above 22 °C and below 45 °C, below 40 °C, below 35 °C or below 30 °C.

[0051] In addition, preferably, the first passivation step of step 4 can be carried out for 5 to 24 hours. The running time of the first passivation step can affect the stability of the passivated catalyst. If the running time of the first passivation step is less than 5 hours or greater than 24 hours, the safety and reactivity of the catalyst may deteriorate.

[0052] (Step 5)

[0053] Step 5 of the present disclosure is a step of carrying out a second passivation step using a mixed gas including air and nitrogen after the first passivation step of the catalyst.

[0054] Meanwhile, the mixed gas used in this step is a mixed gas including air and nitrogen, and has the same composition as the mixed gas used in the first passivation step of step 4. Regarding the composition of air and the volume of air in the mixed gas, reference can be made to the explanation in step 4.

[0055] Preferably, the second passivation step of step 5 can be carried out at a temperature higher than that of the first passivation step. As explained above, in the second passivation step, by carrying out the passivation step again after the first passivation step, the surface of unpassivated nickel or passivated nickel oxide can be further passivated. Therefore, when the prepared nickel catalyst is passivated in two steps, the safety of the prepared catalyst can become suitable for commercial use, and the prepared catalyst can also have excellent activity in the hydrogenation reaction. More specifically, the second passivation step of step 5 can be carried out at a temperature above 50 °C or above 60 °C and below 150 °C, below 140 °C, below 130 °C or below 120 °C.

[0056] In addition, according to the present invention, there is provided a nickel catalyst comprising nickel on a solid support and having a maximum value of the H 2 -TPR peak at 120 to 200 °C, wherein the half-width of the H 2 -TPR peak is 90 or less, and the degree of stabilization calculated by the following calculation formula 1 is 55% to 70%:

[0057] [Calculation formula 1]

[0058] Degree of stabilization (%) = ((peak area of the TPR graph of the catalyst ÷ sample weight) / (peak area of the TPR graph of the oxidized catalyst ÷ sample weight)) × 100

[0059] Regarding the nickel contained in the nickel catalyst and the support, refer to the above explanation.

[0060] H 2 -TPR (Temperature Programmed Reduction) is a measurement method used to evaluate the reduction ability of a catalyst using hydrogen. TPR increases the temperature to the target temperature at a given temperature ramp rate while flowing a gas to the catalyst sample and evaluates the degree of reduction of the catalyst. Among them, if the catalyst sample is reduced by the reducing gas, a peak is generated, and the peak maximum represents the point where the hydrogen consumption is the highest at a specific temperature. In addition, the smaller the half-width of the peak, the higher the homogeneity of the active components of the prepared nickel catalyst. Preferably, the nickel catalyst of the present invention has an H 2 -TPR peak maximum at 120 to 200 °C, 125 to 195 °C, 130 to 190 °C, or 135 to 185 °C. If the H 2 -TPR peak value is less than 120 °C, the safety of using the catalyst may be significantly reduced, so it may easily get hot, thus increasing the risk of accidents. If the H 2 -TPR peak value is greater than 200 °C, the activity during the reaction may be reduced, so the amount of the catalyst used may increase.

[0061] In addition, the half-width of the H 2 -TPR peak is 90 or less. If the half-width of the H 2 -TPR peak is wide, the performance homogeneity of the catalyst may deteriorate, and because it is small, it is more favorable for ensuring the homogeneity of the catalyst activity and life performance. The reaction process can be safely controlled, and the catalyst performance is more excellent. Therefore, the lower limit is not particularly limited, but for example, it may be 85 or less, 80 or less, or 75 or less and may be 30 or more, 35 or more, or 40 or more.

[0062] In addition, the nickel catalyst according to the present invention has a degree of stabilization of 55% to 70% calculated by the following calculation formula 1. The H 2 -TPR graph peak area (base area) represents the hydrogen consumption during the catalyst reduction process. At the same time, in the following calculation formula 1, the "TPR graph of the catalyst" represents the TPR graph measured without pretreatment, and the "TPR graph of the oxidized catalyst" represents the TPR graph of the catalyst that has undergone oxidation pretreatment before TPR measurement.

[0063] [Calculation formula 1]

[0064] Degree of stabilization (%) = ((peak area of the TPR graph of the catalyst ÷ sample weight) / (peak area of the TPR graph of the oxidized catalyst ÷ sample weight)) × 100

[0065] The degree of stabilization is calculated by analyzing each TPR graph and represents the change in hydrogen consumption with increasing temperature (i.e., the degree of change in the reducing power of the catalyst). If the calculated degree of stabilization is high, the safety of using the catalyst can be increased, but the activity and life performance of the catalyst may deteriorate. If the degree of stabilization is low, when the catalyst is exposed to air, it can easily self-heat, thus increasing the danger, but the activity and life performance of the catalyst can be increased. Therefore, the degree of stabilization preferably has a specific range that simultaneously satisfies the safety of using the catalyst and its activity and life performance. In the measurement of the H 2 -TPR graph, the pretreatment method of the sample, the TPR measurement conditions, and the calculation method of the peak area of the graph will be specifically shown in the examples described below.

[0066] [Effect]

[0067] As explained above, according to the method for preparing a nickel catalyst for hydrogenation reaction of the present disclosure, a two-step passivation process is carried out, so the safety and reaction activity of the catalyst are excellent. Description of the Drawings

[0068] Figure 1 It is an image of the H 2 -TPR graph of the nickel catalyst prepared in Example 1. Detailed Description of the Invention

[0069] Hereinafter, preferred embodiments will be presented to help understand the present invention. However, the following embodiments are only presented as illustrations of the present invention, and the present invention is not limited thereto.

[0070] <Example>

[0071] Example 1

[0072] 1.5 kg of amorphous silica powder, 20 kg of nickel sulfate, 222 g of copper sulfate, and 60 L of distilled water were placed in a precipitation container, and the temperature was raised to 75 °C with stirring. Using a diaphragm pump, 75 L of a precipitant solution containing 12.5 kg of sodium carbonate was injected into the reactor of the raw material solution in 1 hour. After precipitation was completed, the solution was filtered with a filter press and washed with 600 L of distilled water. After washing, it was dried in a drying oven at 120 °C for 24 hours. It was divided into small pieces, and then calcined at a temperature of 300 °C in an air atmosphere. It was divided into small pieces again, and then reduced at a temperature of 400 °C in a hydrogen atmosphere.

[0073] After reduction, it was pretreated with a nitrogen mixed gas containing 1% by volume of air at 25°C for 12 hours, and the temperature was raised to 60°C, followed by an additional heat treatment for 1 hour. After the air concentration was gradually increased, the catalyst was safely recovered.

[0074] Based on the weight of the catalyst, the active material content of the recovered catalyst was 78.2 parts by weight of NiO and 0.8 parts by weight of CuO, and the average size of the nickel crystals was measured to be 4.1 nm. In addition, its BET specific surface area was 245 m 2 / g, the total pore volume was 0.33 m 3 / g and the average pore size was 5.5 nm.

[0075] Example 2

[0076] A catalyst was prepared by the same method as in Example 1, except that after reduction, it was treated with a nitrogen mixed gas containing 1% by volume of air at 25°C for 12 hours, and the temperature was raised to 80°C, followed by an additional heat treatment of the catalyst for 1 hour.

[0077] Example 3

[0078] A catalyst was prepared by the same method as in Example 1, except that after reduction, it was treated with a nitrogen mixed gas containing 1% by volume of air at 25°C for 12 hours, and the temperature was raised to 100°C, followed by an additional heat treatment of the catalyst for 1 hour.

[0079] Example 4

[0080] A catalyst was prepared by the same method as in Example 1, except that after reduction, it was treated with a nitrogen mixed gas containing 1% by volume of air at 25°C for 12 hours, and the temperature was raised to 120°C, followed by an additional heat treatment of the catalyst for 1 hour.

[0081] Comparative Example 1

[0082] A catalyst was prepared by the same method as in Example 1, except that after reduction, it was heat-treated with a nitrogen mixed gas containing 1% by volume of air at 25°C for 12 hours, and the air concentration was gradually increased to safely recover the catalyst.

[0083] Comparative Example 2

[0084] A catalyst was prepared by the same method as in Comparative Example 1, except that after reduction, it was heat-treated with a nitrogen mixed gas containing 1% by volume of air at 60°C for 12 hours.

[0085] Comparative Example 3

[0086] The catalyst was prepared by the same method as in Comparative Example 1, except that after reduction, it was heat-treated at 80 °C for 12 hours using a nitrogen mixed gas containing 1% by volume of air.

[0087] Comparative Example 4

[0088] The catalyst was prepared by the same method as in Comparative Example 1, except that after reduction, it was heat-treated at 100 °C for 12 hours using a nitrogen mixed gas containing 1% by volume of air.

[0089] Comparative Example 5

[0090] The catalyst was prepared by the same method as in Comparative Example 1, except that after reduction, it was heat-treated at 120 °C for 12 hours using a nitrogen mixed gas containing 1% by volume of air.

[0091] <Experimental Example>

[0092] For the catalysts prepared above, the following analysis, characterization, and measurement of reaction activity were carried out.

[0093] (1) H 2 -TPR analysis

[0094] The characteristics of the catalyst were analyzed using a Belcat II device from MicrotracBEL. Typically, the H Figure 1 -TPR graph of the catalyst prepared in Example 1 is shown in 2 . During the reduction of the oxidized catalyst and the reduced catalyst, the hydrogen consumption was measured, and based on the ratio, the degree of stabilization of the catalyst was calculated according to the following Calculation Formula 1.

[0095] Among them, the weight of the sample was 50 mg, the analysis conditions of the oxidized catalyst were as described in Table 1 below, and the analysis conditions of the catalyst were as described in Table 2 below. The TPR graph was obtained by the non-linear curve fitting (Gauss) method using the Origin 9.1 program, and the results are shown in Table 3 below.

[0096] [Calculation Formula 1]

[0097] Degree of stabilization (%) = ((peak area of the TPR graph of the catalyst ÷ sample weight) / (peak area of the TPR graph of the oxidized catalyst ÷ sample weight)) × 100

[0098] [Table 1]

[0099]

[0100] 1 5% H 2 / Ar balance gas (H 21.5 mL / min, Ar 28.5 mL / min) [Table 2]

[0101]

[0102] 1 5% H 2 / Ar balance gas (H 2 1.5 mL / min, Ar 28.5 mL / min)

[0103] (2) Evaluate the catalyst activity

[0104] Use a 300 mL autoclave, which includes a hollow shaft stirrer and has a stirring speed of 1600 rpm. Dissolve non-hydrogenated petroleum resin (Hanwha solution DCPD polymerization resin: 20 wt% styrene monomer and 80 wt% DCPD) in cyclohexane at a concentration of 30 wt% to prepare 75 g of a mixed solution. Then, at 200 °C and 50 bar, add a catalyst at a content of 2% based on the mass of the petroleum resin for hydrogenation, and 1 hour after the start of the reaction, analyze the NMR of the petroleum resin and calculate the hydrogenation rate compared to the non-hydrogenated petroleum resin, as shown in Table 3.

[0105] [Table 3]

[0106]

[0107] As confirmed in Table 3, the nickel catalyst prepared by the preparation method according to the embodiments of the present disclosure has excellent stabilization and reaction activity. At the same time, the catalysts of Comparative Examples 1 to 4 have a lower degree of stabilization compared to the catalyst of the example, so when exposed to air during the experiment, they involve rapid self-heating and cannot be tested for activity reaction. It can be confirmed that the catalysts of Comparative Example 4 and Comparative Example 5 have improved stabilization, but the activity is significantly reduced. The catalyst of the present invention can achieve the safety and excellent reaction activity of the catalyst through a two-step passivation process.

Claims

1. A method for preparing a nickel catalyst, which comprises: a step of preparing a catalyst precursor mixture containing a nickel precursor (step 1); a step of precipitating the catalyst precursor mixture to obtain a catalyst precursor (step 2); a step of drying, calcining and reducing the catalyst precursor to prepare a catalyst (step 3); a first passivation step of passivating the catalyst using a mixed gas containing air and nitrogen (step 4); and after the first passivation step, a second passivation step of passivating the catalyst using a mixed gas containing air and nitrogen at a temperature different from the temperature of the first passivation step (step 5).

2. The method for preparing a nickel catalyst according to claim 1, wherein the catalyst precursor mixture in step 1 further comprises one or more of a support and a promoter precursor.

3. The method for preparing a nickel catalyst according to claim 1, wherein one or more of sodium carbonate and sodium bicarbonate are used as the precipitating agent in step 2.

4. The method for preparing a nickel catalyst according to claim 1, wherein the drying in step 3 is carried out at a temperature of 80 to 200 °C.

5. The method for preparing a nickel catalyst according to claim 1, wherein the calcining in step 3 is carried out in an air atmosphere at a temperature of 180 to 500 °C.

6. The method for preparing a nickel catalyst according to claim 1, wherein the reduction in step 3 is carried out in a hydrogen atmosphere at a temperature of 300 to 600 °C.

7. The method for preparing a nickel catalyst according to claim 1, wherein based on the total volume of the mixed gas of air and nitrogen in step 4, it contains 0.1 to 2% by volume of air.

8. The method for preparing a nickel catalyst according to claim 1, wherein the first passivation step in step 4 is carried out at a temperature of 15 to 50 °C.

9. The method for preparing a nickel catalyst according to claim 1, wherein the first passivation step in step 4 is carried out for 5 to 24 hours.

10. The method for preparing a nickel catalyst according to claim 1, wherein the second passivation step in step 5 is carried out at a temperature higher than the temperature of the first passivation step.

11. The method for preparing a nickel catalyst according to claim 1, wherein the second passivation step in step 5 is carried out at a temperature of 50 to 150 °C.

12. A nickel catalyst, which comprises nickel on a solid support, and Having an H 2 -TPR peak maximum at 120 to 200 °C, wherein the H 2 -TPR peak has a half-width of 90 or less, and the degree of stabilization calculated by the following calculation formula 1 is 55% to 70%: [Calculation formula 1] Degree of stabilization (%) = ((peak area of the TPR graph of the catalyst ÷ sample weight) / (peak area of the TPR graph of the oxidized catalyst ÷ sample weight)) × 100.

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