Cobalt-containing composite metal oxides and their preparation methods, catalysts and their preparation methods and applications

Abstract

This invention discloses a cobalt-containing composite metal oxide and its preparation method, a catalyst and its preparation method, and their applications, belonging to the field of catalyst technology. The cobalt-containing composite metal oxide comprises cobalt, M1, and M2; M1 is selected from at least one element of Group VIB; M2 is selected from at least one element of the lanthanides; in the H2-TPR spectrum of the cobalt-containing composite metal oxide, at least one H2 reduction peak has a peak value below 275℃. In the preparation process of the monolithic catalyst, a dispersant is added to ensure uniform distribution of the active component and the coating carrier, and a binder is added to ensure tight bonding, resulting in a slurry with a certain viscosity range. The catalyst prepared by coating with this slurry exhibits a reduced shedding rate, thereby significantly improving the stability of the prepared honeycomb catalyst.

Description

Technical Field

[0001] This invention relates to cobalt-containing composite metal oxides and their preparation methods, catalysts and their preparation methods and applications, belonging to the field of catalyst technology. Background Technology

[0002] Petrochemical production processes frequently generate waste gases containing volatile organic compounds (VOCs). Direct release of these gases into the atmosphere can cause significant harm to the atmospheric environment. Most VOCs have unpleasant odors and can cause illness or even cancer in humans; in particular, VOCs containing halogens are not only highly toxic themselves but can also undergo photochemical reactions with ozone to produce photochemical smog, which severely damages the Earth's environment. Therefore, the effective treatment of organic waste gases generated during petrochemical production is an important issue in environmental science.

[0003] Catalytic combustion, with the help of a catalyst, lowers the operating temperature to 280–450℃, significantly reducing energy consumption. It is safe, stable, and inexpensive to operate, and produces no nitrogen oxides, thus avoiding secondary pollution. Therefore, catalytic combustion is a relatively ideal method for treating organic waste gas.

[0004] Catalysts used for treating organic waste gases are often prepared using a coating method, which involves coating a carrier with a slurry containing the desired active components. For example:

[0005] Chinese Patent ZL201510434338.2 protects a CoMn composite oxide catalyst for eliminating benzene-based volatile organic compounds (VOCs) from the air and its preparation method. The active component of the catalyst is CoMn spinel oxide. Using a spinel composite oxide formed from non-precious metals Co and Mn as the active component significantly reduces the catalyst cost. The spinel phase of the catalyst provides the active species MnCo2O4 for the catalytic combustion reaction of benzene-based VOC reactants, exhibiting good low-temperature catalytic combustion activity for benzene-based VOCs. The CoMn composite oxide protected by this patent shows good catalytic combustion activity for benzene, toluene, ethylbenzene, and xylene.

[0006] Chinese invention patent application 201911298212.1 discloses an adsorption / catalytic material for waste gas treatment. The adsorption / catalytic material includes an active coating composed of a honeycomb carrier, a molecular sieve, a surfactant, a transition metal solution, and a binder. By using a SiO2-Al2O3-ZrO2 composite sol as a binder, the adhesion between the components of the active coating and the honeycomb carrier is effectively enhanced. By making the mass ratio of the honeycomb carrier to the active coating 8:1-5:1, the loading of the molecular sieve active coating on the honeycomb carrier is significantly increased. This invention mainly evaluates the removal effect of the adsorption / catalytic material on nitrogen oxides.

[0007] Chinese invention patent application 201910790560.4 discloses a catalyst for catalytic combustion of VOCs and its preparation method. The catalyst uses cordierite honeycomb ceramic or porous metal material as a support, and a nano-coating material is coated on the support. The active component is a combination of noble metal and transition metal, and the catalyst is a combination of rare earth oxides as a catalyst promoter. The catalyst is a solid solution made of alkaline earth metal compound and main group metal oxide as a support modifier. However, this invention does not evaluate the activity of the prepared catalyst in specific components of the waste gas.

[0008] Chinese invention patent application 201811568947.7 discloses an oxidizing catalyst for catalytic combustion of VOCs and its preparation method. The oxidizing catalyst of this invention includes a support coated with a coating at a concentration of 60-180 g / L. The coating contains 0.2-5.0 g / L of noble metals Pt and Pd, with a mass ratio of Pt to Pd of 0.1:1-10:1. The coating comprises activated alumina, cobalt-cerium composite oxide, and manganese oxide. This invention only evaluated the catalyst's treatment effect on waste gas containing 1000 ppm ethyl acetate.

[0009] Chinese invention patent application 201811120312.0 discloses a catalyst for treating volatile chlorinated aromatic hydrocarbon pollutants, comprising a porous support and at least one of an active component supported on the porous support, selected from noble metals, including perovskite-type composite oxides, pyrochlore-type composite oxides, and hydrotalcite-derived composite oxides. This invention primarily evaluates the catalyst's removal efficiency for chlorobenzene pollutants. Summary of the Invention

[0010] This invention prepares cobalt-containing composite metal oxides through stepwise precipitation, complexation, and hydrothermal synthesis, and then prepares a highly active catalyst based on this oxide for industrial waste gas treatment.

[0011] The present invention provides a cobalt-containing composite metal oxide, wherein the metal in the cobalt-containing composite metal oxide includes cobalt, M1 and M2;

[0012] M1 is selected from at least one element in group VIB;

[0013] M2 is selected from at least one of the lanthanide elements;

[0014] In the H2-TPR spectrum of the cobalt-containing composite metal oxide, at least one H2 reduction peak has a peak value below 275℃.

[0015] Optionally, the H2-TPR spectrum of the cobalt-containing composite metal oxide has two H2 reduction peaks; the peak value of the first H2 reduction peak is below 275℃, and the peak value of the second H2 reduction peak is below 340℃.

[0016] Alternatively, the peak value of the first H2 reduction peak is between 250℃ and 275℃, and the peak value of the second H2 reduction peak is between 320℃ and 340℃.

[0017] The peak value of the H2 reduction peak mentioned in this invention refers to the temperature value corresponding to the peak apex of each H2 reduction peak.

[0018] Optionally, the VIB family elements are selected from W and / or Mo.

[0019] Optionally, the lanthanide element is selected from Nd and / or Sm.

[0020] Optionally, in the cobalt-containing composite metal oxide, the molar ratio of cobalt, M1, and M2 is 1:(0.02-0.12):(0.03-0.18).

[0021] Another aspect of the present invention provides a method for preparing the above-mentioned cobalt-containing composite metal oxide, comprising:

[0022] Step (1): Provide a mixture containing a cobalt source, an M1 source and water, and mix the mixture with a precipitant to obtain material I;

[0023] Step (2): Provide material II containing M2 source, ligand and water;

[0024] Step (3): Mix material II with material I and perform a hydrothermal reaction to obtain material III;

[0025] Step (4): Separate the material III to obtain a precipitate, and after calcining I, obtain the composite oxide.

[0026] Optionally, the cobalt source is selected from at least one of the inorganic acid salts of cobalt; the inorganic acid salt is preferably selected from at least one of nitrates and chlorides;

[0027] Optionally, the M1 source is selected from at least one of ammonium metatungstate, ammonium tungstate, tungstic acid, and sodium tungstate.

[0028] Optionally, the M2 source is selected from at least one of the inorganic acid salts of lanthanides; the inorganic acid salt is preferably selected from at least one of nitrates and chlorides.

[0029] Optionally, the ligand is selected from at least one of ethylenediaminetetraacetic acid, ethylenediamine, ethylenediaminetetraacetic acid, and N-methylethylenediamine.

[0030] Optionally, the precipitant is selected from at least one of sodium hydroxide, potassium hydroxide, and ammonia.

[0031] Optionally, in step (1), the mass ratio of cobalt source, M1 source, and water is 1:(0.02~0.12):(10~20);

[0032] Optionally, in step (1), the mixing conditions each independently include: 50–70°C.

[0033] Optionally, in step (1), the amount of precipitant added is such that the pH of the mixture is adjusted to 10-11;

[0034] Optionally, in step (2), the mass ratio of M2 source, ligand, and water is 1:(1.5-3):(3-6);

[0035] Optionally, in step (3), the ratio of material II to material I is (0.03 to 0.18):1, based on the molar ratio of M2 source to Co source, and the hydrothermal reaction conditions include: temperature 120 to 140°C and time 8 to 12 hours.

[0036] Optionally, in step (4), the drying process is further included before the calcination I. The drying conditions include: temperature 90-110°C, time 8-12 hours; and / or, the calcination I conditions include: temperature 350-550°C, time 2-4 hours; and / or the atmosphere of calcination I is air.

[0037] Another aspect of the present invention provides a catalyst, wherein the active component of the catalyst contains any of the cobalt-containing composite metal oxides described above.

[0038] Optionally, the catalyst includes a honeycomb support and a coating; the coating contains the cobalt-containing composite metal oxide.

[0039] Optionally, the coating content is 10-20% of the total mass of the catalyst.

[0040] And / or, based on the total mass of the coating, the content of the cobalt-containing composite metal oxide is 26 to 50 wt% of the coating, preferably 32 to 42 wt%.

[0041] Optionally, the coating is located on the inner and / or outer surface of the cellular carrier.

[0042] Optionally, the cellular carrier is selected from at least one of cordierite cellular carrier, mullite cellular carrier, and aluminum titanate ceramic cellular carrier.

[0043] Optionally, the aluminum oxide is selected from at least one of alumina and boehmite.

[0044] Optionally, the ultrasonic shedding rate of the catalyst is ≤2.8%.

[0045] Optionally, the coating may further include a coating carrier and an oxide of M3.

[0046] Optionally, M3 is selected from at least one of the noble metal elements in group VIIIB.

[0047] Optionally, the coating carrier is selected from at least one of aluminum oxides.

[0048] And / or, based on the total mass of the coating, the coating carrier accounts for 44 to 72 wt% of the coating, preferably 50 to 60 wt%.

[0049] And / or, based on the total mass of the coating, the oxide of M3 accounts for 2 to 6 wt% of the total mass of the coating, preferably 2 to 4 wt%.

[0050] Optionally, M3 is Pd and / or Ru.

[0051] Optionally, the oxide of M3 satisfies CXPS / CICP = 0.4 to 0.9.

[0052] Among them, CXPS is the molar content of Group VIIIB noble metal elements in the catalyst characterized by X-ray photoelectron spectroscopy; CICP is the molar content of Group VIIIB noble metal elements in the catalyst characterized by plasmonic coupling.

[0053] Another aspect of the present invention provides a method for preparing any of the above-mentioned catalysts, comprising:

[0054] Step a: Provide a coating slurry; the viscosity of the coating slurry is 180-320 mPa·s; the coating slurry contains cobalt-containing composite metal oxides; if the viscosity is too low, the peeling rate will increase; if the viscosity is too high, it will be inconvenient to prepare.

[0055] Step b: Apply a coating slurry to the inner and / or outer surfaces of the honeycomb carrier, and then calcine it to obtain the catalyst.

[0056] Optionally, the concentration of the cobalt-containing composite metal oxide in the coating slurry is 2.6 wt% to 5.3 wt%.

[0057] Optionally, the coating slurry may further contain an adhesive, a dispersant, a solvent, a coating carrier, and an M3 source.

[0058] Optionally, by weight, the coating slurry contains: 13-25 parts of cobalt-containing composite metal oxide; 2.4-4.6 parts of adhesive; 0.6-1.4 parts of dispersant; 22-36 parts of coating carrier; 1-3 parts of M3 source; and 330-470 parts of solvent.

[0059] Optionally, the concentration of the M3 source in the coating slurry is 0.2wt% to 0.8wt%.

[0060] Optionally, the M3 source is selected from at least one of palladium chloride and ruthenium chloride.

[0061] Optionally, in step b, the coating carrier undergoes a pretreatment of calcination III, preferably in an inactive atmosphere at a temperature of 200–400°C for 2–4 hours; preferably, the inactive atmosphere is selected from at least one of nitrogen and argon.

[0062] Optionally, in step b, the method of attaching the coating slurry to the inner and / or outer surfaces of the cellular carrier includes coating the slurry onto the inner and / or outer surfaces of the cellular carrier or immersing the cellular carrier in the coating slurry.

[0063] Optionally, the adhesive is aluminum sol.

[0064] Optionally, the dispersant is selected from at least one of P123 and F127.

[0065] Optionally, the solvent is water.

[0066] Optionally, in step b, the conditions for calcination II include: a temperature of 450–550°C and a time of 2–4 hours.

[0067] Optionally, before the calcination II step, a drying step is further included, wherein the drying conditions include 80-110°C and drying for 0.5-2 hours.

[0068] Optionally, the roasting II step further includes a reduction step, wherein the reduction is carried out in a reducing atmosphere at 200-300°C for 2-3 hours, and the reducing atmosphere is preferably a hydrogen atmosphere.

[0069] Preferably, a multi-coating method is used, repeating the impregnation, drying, and firing steps at least three times, until the coating amount on the unit volume of the honeycomb ceramic skeleton is 120-200 g / L.

[0070] Preferably, the method for obtaining the coating slurry includes the following specific steps:

[0071] The coating carrier is provided, which is divided into a first coating carrier and a second coating carrier;

[0072] The adhesive is provided in two portions: a first adhesive and a second adhesive.

[0073] Provide material 4 containing M3 source, dispersant and solvent;

[0074] Step 1: Mix the first coating carrier with material 4, stir for 1-2 hours, and then grind for 0.5-1 hours to obtain material 5;

[0075] Step 2: Mix the second coating carrier, the first adhesive and material 5, stir for 1-2 hours, and then grind for 0.5-1 hours to obtain material 6;

[0076] Step 3: Mix the cobalt-containing composite metal oxide, the second adhesive, and material 6, stir for 1-2 hours, and then grind for 1-2 hours to obtain the coating slurry.

[0077] Another aspect of the present invention provides a method for treating industrial waste gas, wherein the waste gas is contacted with any of the above-described catalysts or catalysts obtained by any of the above-described preparation methods to undergo a catalytic reaction.

[0078] Optionally, the conditions for the catalytic reaction include: a reaction atmosphere of air; a reaction pressure of 0.05 MPa to 0.1 MPa; a reaction temperature of 100 to 400 °C; and a reaction time of 10 to 100 h. Preferably, the reaction temperature is 300 °C and the reaction time is 100 h.

[0079] Preferably, starting from 20°C, the temperature is increased to 100°C at a rate of 10°C / min and held for 0.5 hours; then increased to 150°C at a rate of 10°C / min and held for 0.5 hours; then increased to 160°C at a rate of 5°C / min and held for 5 minutes; then increased to 165°C at a rate of 5°C / min and held for 5 minutes; then increased to 170°C at a rate of 5°C / min and held for 5 minutes; and so on, with each increase in temperature increment being 5°C, and each increment being held for 5 minutes, until the temperature reaches 400°C.

[0080] Optionally, the content of epichlorohydrin in the exhaust gas is 2000 ppm; the T99 temperature of the epichlorohydrin is 260°C.

[0081] Wherein, T99 represents the reaction temperature at which the purification rate of epichlorohydrin in the waste gas reaches 99%. The cobalt-containing composite metal oxide prepared in this invention was characterized for its redox performance using H2-TPR. The number of reduction peaks and the temperature of the reduction peaks were used to define the catalyst, and comparisons were made with comparative examples. For the same series of catalysts, generally speaking, the lower the temperature of the reduction peak, the better the redox performance and the better the catalytic combustion activity.

[0082] In the preparation of the monolithic catalyst, this invention involves adding a dispersant to ensure uniform distribution of the active components and the coating carrier, and adding an adhesive to ensure tight bonding, resulting in a slurry with a specific viscosity range. The catalyst coated with this slurry exhibits a lower detachment rate, thus significantly improving the stability of the prepared honeycomb catalyst. By adding the adhesive and coating carrier in stages, and by progressively grinding the slurry, the surface content of the first additive is limited, preventing the noble metal components of the monolithic catalyst from being completely exposed on the surface, thereby improving the catalyst's resistance to poisoning. Attached Figure Description

[0083] Figure 1 The H2-TPR analysis comparison diagrams of the cobalt-containing composite metal oxides prepared in Example 1 and the comparative example are shown. Detailed Implementation

[0084] The testing method of this invention embodiment:

[0085] H2-TPR analysis was performed using a Micromeritics AutoChemⅡ2920 chemisorption analyzer. The procedure was as follows: 0.1 g of 20-40 mesh sample particles were weighed and placed in a sample U-tube. The sample was purged with Ar at 100°C for 1 hour, then cooled to room temperature. The sample tube was then purged with a 10% H2-90% Ar (volume percentage) mixture at room temperature for 10 min. The temperature was then programmed to 600°C at a rate of 10°C / min, and the hydrogen consumption peak was detected using a TCD detector.

[0086] X-ray photoelectron spectroscopy (XPS) was measured using the Nexsa™ X-ray photoelectron spectrometer from Thermo Fisher Scientific.

[0087] Plasma coupling (ICP, also known as inductively coupled plasma) was measured using the THERMO IRIS IntrepidXSP inductively coupled plasma atomic emission spectrometer.

[0088] CXPS is the molar content of Group VIIIB noble metal elements in a catalyst characterized by X-ray photoelectron spectroscopy.

[0089] CICP is the molar content of Group VIIIB noble metal elements in a catalyst characterized by plasma coupling.

[0090] Coating slurry viscosity test: The viscosity was measured using a Bollerfeld DV2T viscometer. The test method was as follows: at 25℃, 50mL of the liquid to be tested was poured into the measuring cup, and the measurement time was 300s.

[0091] Coating stability of the exhaust gas treatment catalyst: It was evaluated by ultrasonic vibration test. The sample was placed in an ultrasonic cleaner with water as the medium. The ultrasonic working frequency was 53KHz. The peeling rate was calculated after 30 minutes of ultrasonication.

[0092] Ultrasonic shedding rate = (total mass of catalyst before ultrasound - total mass of catalyst after ultrasound) / (total mass of catalyst before ultrasound - mass of honeycomb carrier before coating) * 100%.

[0093] Example 1

[0094] Preparation of cobalt-containing composite metal oxides

[0095] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0096] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0097] 3) Mix material 1 and material 2, and synthesize them hydrothermally at 120°C for 8 hours under sealed conditions to obtain material 3;

[0098] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide A.

[0099] The cobalt-containing composite metal oxide A was tested by H2-TPR, and the results are as follows: Figure 1 As shown, the cobalt-containing composite metal oxide A has two H2 reduction peaks, one with a peak temperature of around 330℃ and the other with a peak temperature of around 270℃.

[0100] Preparation of coating slurry

[0101] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 Weigh out 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0102] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0103] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0104] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide A), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain a coating slurry, denoted as coating slurry A. The viscosity of coating slurry A was measured to be 180 mPa·s.

[0105] Preparation of industrial waste gas treatment catalysts

[0106] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0107] 2) The pretreated carrier from 1) is immersed in coating slurry A for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0108] 3) Repeat the steps of soaking, drying and roasting in 2) at least 3 times.

[0109] 4) Catalyst A was obtained by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0110] The ultrasonic shedding rate of catalyst A was 2.8%; the CXPS / CICP ratio of ruthenium in catalyst A was 0.6.

[0111] Example 2

[0112] Preparation of cobalt-containing composite metal oxides

[0113] 1) A mixed solution of 58.20g cobalt nitrate, 6.12g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0114] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0115] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0116] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide B.

[0117] Preparation of coating slurry

[0118] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0119] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0120] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0121] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide B), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain the coating slurry, which is denoted as coating slurry B. The viscosity of the coating slurry was measured to be 185 mPa·s.

[0122] Preparation of industrial waste gas treatment catalysts

[0123] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0124] 2) The carrier pretreated in 1) is immersed in coating slurry B for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0125] 3) Repeat the steps of soaking, drying and roasting in 2) at least 3 times.

[0126] 4) Catalyst B was prepared by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0127] The ultrasonic shedding rate of catalyst B was 2.74%; the CXPS / CICP ratio of ruthenium in catalyst B was 0.65.

[0128] Example 3

[0129] Preparation of cobalt-containing composite metal oxides

[0130] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0131] 2) Mix 11.89g of neodymium nitrate, 1.75g ​​of ethylenediaminetetraacetic acid and 30ml of water to obtain material 2;

[0132] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0133] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide C.

[0134] Preparation of coating slurry

[0135] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0136] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0137] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0138] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide C), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain a coating slurry, denoted as coating slurry C. The viscosity of coating slurry C was measured to be 188 mPa·s.

[0139] Preparation of industrial waste gas treatment catalysts

[0140] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0141] 2) The carrier pretreated in 1) is immersed in coating slurry C for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0142] 3) Repeat the steps of soaking, drying and roasting in 2) at least 3 times.

[0143] 4) Catalyst C was obtained by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0144] The ultrasonic shedding rate of catalyst C was tested to be 2.75%; the CXPS / CICP ratio of ruthenium in catalyst C was 0.71.

[0145] Example 4

[0146] Preparation of cobalt-containing composite metal oxides

[0147] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0148] 2) Mix 1.98g neodymium nitrate, 3.50g ethylenediaminetetraacetic acid and 30ml water to obtain material 2;

[0149] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0150] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide D.

[0151] Preparation of coating slurry

[0152] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0153] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0154] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0155] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide D), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain a coating slurry, denoted as coating slurry D. The viscosity of coating slurry D was measured to be 192 mPa·s.

[0156] Preparation of industrial waste gas treatment catalysts

[0157] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0158] 2) The pretreated carrier from 1) is immersed in coating slurry D for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0159] 3) Repeat the steps of soaking, drying and roasting in 2) at least 3 times.

[0160] 4) Catalyst D was obtained by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0161] The ultrasonic shedding rate of catalyst D was 2.6%; the CXPS / CICP ratio of ruthenium in catalyst D was 0.66.

[0162] Example 5

[0163] Preparation of cobalt-containing composite metal oxides

[0164] 1) A mixed solution of 58.20g cobalt nitrate, 3.06g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0165] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0166] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0167] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide E.

[0168] Preparation of coating slurry

[0169] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0170] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0171] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0172] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide E), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain the coating slurry, denoted as coating slurry E. The viscosity of coating slurry E was measured to be 196 mPa·s.

[0173] Preparation of industrial waste gas treatment catalysts

[0174] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0175] 2) The pretreated carrier from 1) is immersed in coating slurry E for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0176] 3) Repeat steps 2) impregnation, drying and roasting at least 3 times.

[0177] 4) Catalyst E was obtained by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0178] The ultrasonic shedding rate of catalyst E was measured to be 2.52%; the CXPS / CICP ratio of ruthenium in catalyst E was 0.68.

[0179] Example 6

[0180] Preparation of cobalt-containing composite metal oxides

[0181] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0182] 2) Mix 7.93g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid and 30ml water to obtain material 2;

[0183] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0184] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide F.

[0185] Preparation of coating slurry

[0186] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0187] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0188] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0189] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide F), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain the coating slurry, denoted as coating slurry F. The viscosity of coating slurry F was measured to be 194 mPa·s.

[0190] Preparation of industrial waste gas treatment catalysts

[0191] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0192] 2) The pretreated carrier is immersed in the coating slurry F for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0193] 3) Repeat the steps of impregnation, drying and roasting at least 3 times.

[0194] 4) Catalyst F was obtained by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0195] The ultrasonic shedding rate of catalyst F was measured to be 2.53%; the CXPS / CICP ratio of ruthenium in catalyst F was 0.62.

[0196] Example 7

[0197] Preparation of cobalt-containing composite metal oxides

[0198] 1) A mixed solution of 58.20g cobalt nitrate, 0.71g ammonium molybdate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, thus obtaining material 1;

[0199] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0200] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0201] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide G.

[0202] Preparation of coating slurry

[0203] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0204] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0205] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0206] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide G), the second part of aluminum sol and material 6, stir for 1 hour, and then grind for 1 hour to obtain the coating slurry, which is denoted as coating slurry G; the viscosity of coating slurry G is measured to be 182 mPa·s.

[0207] Preparation of industrial waste gas treatment catalysts

[0208] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0209] 2) The pretreated carrier is immersed in the coating slurry G for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0210] 3) Repeat the steps of impregnation, drying and roasting at least 3 times.

[0211] 4) Catalyst G was prepared by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0212] The ultrasonic shedding rate of catalyst G was 2.76%; the CXPS / CICP ratio of ruthenium in catalyst G was 0.68.

[0213] Example 8

[0214] Preparation of cobalt-containing composite metal oxides

[0215] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0216] 2) Mix 2.02g samarium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0217] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0218] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide H.

[0219] Preparation of coating slurry

[0220] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0221] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0222] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0223] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide H), the second part of aluminum sol and material 6, stir for 1 hour, and then grind for 1 hour to obtain the coating slurry, which is denoted as coating slurry H; the viscosity of the coating slurry was measured to be 184 mPa·s.

[0224] Preparation of industrial waste gas treatment catalysts

[0225] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0226] 2) The pretreated carrier is immersed in the coating slurry H for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0227] 3) Repeat the steps of impregnation, drying and roasting at least 3 times.

[0228] 4) The catalyst H was prepared by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0229] The ultrasonic shedding rate of catalyst H was 2.76%; the CXPS / CICP ratio of ruthenium in catalyst H was 0.72.

[0230] Example 9

[0231] Preparation of cobalt-containing composite metal oxides

[0232] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0233] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0234] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0235] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, which is denoted as cobalt-containing composite metal oxide I.

[0236] Preparation of coating slurry

[0237] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0238] 2) Mix 20 ml of palladium chloride standard solution with a Pd content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0239] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0240] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide I), the second part of aluminum sol and material 6, stir for 1 hour, and then grind for 1 hour to obtain the coating slurry; the viscosity of the coating slurry was measured to be 190 mPa·s.

[0241] Preparation of industrial waste gas treatment catalysts

[0242] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0243] 2) The pretreated carrier was immersed in the coating slurry for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0244] 3) Repeat the steps of impregnation, drying and roasting at least 3 times.

[0245] 4) Catalyst I was prepared by reduction at 200°C for 2 hours in a hydrogen atmosphere.

[0246] The ultrasonic shedding rate of catalyst I was tested to be 2.78%; the CXPS / CICP ratio of palladium in catalyst I was 0.61.

[0247] Example 10

[0248] Preparation of cobalt-containing composite metal oxides

[0249] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0250] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0251] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0252] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide J.

[0253] Preparation of coating slurry

[0254] 1) Weigh 36g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0255] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 470 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0256] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0257] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide J), ​​the second part of aluminum sol and material 6, stir for 1 hour, and then grind for 1 hour to obtain the coating slurry; the viscosity of the coating slurry was measured to be 285 mPa·s.

[0258] Preparation of industrial waste gas treatment catalysts

[0259] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0260] 2) The pretreated carrier was immersed in the coating slurry for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0261] 3) Repeat the steps of impregnation, drying and roasting at least 3 times.

[0262] 4) Catalyst J was prepared by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0263] The ultrasonic shedding rate of catalyst J was 2.38%; the CXPS / CICP ratio of ruthenium in catalyst J was 0.40.

[0264] Example 11

[0265] Preparation of cobalt-containing composite metal oxides

[0266] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0267] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0268] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0269] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide K.

[0270] Preparation of coating slurry

[0271] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0272] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 450 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0273] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0274] 4) Mix 25g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide K), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain coating slurry K. The viscosity of coating slurry K was measured to be 262 mPa·s.

[0275] Preparation of industrial waste gas treatment catalysts

[0276] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0277] 2) The pretreated carrier is immersed in the coating slurry K for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0278] 3) Repeat the steps of impregnation, drying and roasting at least 3 times.

[0279] 4) Catalyst K was prepared by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0280] The ultrasonic shedding rate of catalyst K was 2.46%; the CXPS / CICP ratio of ruthenium in catalyst K was 0.51.

[0281] Example 12

[0282] Preparation of cobalt-containing composite metal oxides

[0283] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0284] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0285] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0286] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide L.

[0287] Preparation of coating slurry

[0288] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0289] 2) Mix 60 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 290 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0290] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0291] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide L), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain the coating slurry. The viscosity of the coating slurry was measured to be 225 mPa·s.

[0292] Preparation of industrial waste gas treatment catalysts

[0293] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0294] 2) The pretreated carrier was immersed in the coating slurry for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0295] 3) Repeat the steps of impregnation, drying and roasting at least 3 times.

[0296] 4) Catalyst L was prepared by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0297] The ultrasonic shedding rate of catalyst J was 2.68%; the CXPS / CICP ratio of ruthenium in catalyst L was 0.9.

[0298] Example 13

[0299] Preparation of cobalt-containing composite metal oxides

[0300] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0301] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0302] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0303] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide M.

[0304] Preparation of coating slurry

[0305] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two parts. Weigh 4.6g of aluminum sol with a solid content of 20wt% and divide it into two parts.

[0306] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0307] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0308] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide M), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain a coating slurry, denoted as coating slurry M. The viscosity of coating slurry M was measured to be 320 mPa·s.

[0309] Preparation of industrial waste gas treatment catalysts

[0310] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0311] 2) The pretreated carrier is immersed in the coating slurry M for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0312] 3) Repeat the steps of impregnation, drying and roasting at least 3 times.

[0313] 4) Catalyst M was prepared by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0314] The ultrasonic shedding rate of catalyst J was 2.35%; the CXPS / CICP ratio of ruthenium in catalyst M was 0.82.

[0315] Example 14

[0316] Preparation of cobalt-containing composite metal oxides

[0317] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0318] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0319] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0320] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide N.

[0321] Preparation of coating slurry

[0322] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0323] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 1.4 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0324] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0325] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide N), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain a coating slurry, denoted as coating slurry N. The viscosity of coating slurry N was measured to be 205 mPa·s.

[0326] Preparation of industrial waste gas treatment catalysts

[0327] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0328] 2) The carrier pretreated in 1) is immersed in coating slurry N for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0329] 3) Repeat the steps of soaking, drying and roasting in 2) at least 3 times.

[0330] 4) Catalyst N was obtained by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0331] The ultrasonic shedding rate of catalyst N was 2.76%; the CXPS / CICP ratio of ruthenium in catalyst N was 0.75.

[0332] Comparative Example 1

[0333] 1) Obtain a mixed solution of 58.20g cobalt nitrate and 300ml water. At 50℃, add sodium hydroxide dropwise to adjust the pH of the mixed solution to 11, and obtain material 1;

[0334] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0335] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0336] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide X.

[0337] The cobalt-containing composite metal oxide X was tested by H2-TPR, and the results are as follows: Figure 1 As shown, the cobalt-containing composite metal oxide X has only one H2 reduction peak, with a peak value around 370℃.

[0338] Preparation of coating slurry

[0339] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0340] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0341] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0342] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide X), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain the coating slurry, which is denoted as coating slurry X. The viscosity of coating slurry X was measured to be 160 mPa·s.

[0343] Preparation of industrial waste gas treatment catalysts

[0344] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0345] 2) The pretreated carrier from 1) was immersed in the coating slurry for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0346] 3) Repeat the steps of soaking, drying and roasting in 2) at least 3 times.

[0347] 4) Catalyst X was obtained by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0348] The measured ultrasonic shedding rate of catalyst X was 3.5%. The CXPS / CICP ratio of ruthenium in catalyst X was 1.1.

[0349] Comparative Example 2

[0350] Preparation of cobalt-containing composite metal oxides

[0351] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0352] 2) The materials were hydrothermally synthesized at 120°C for 8 hours under sealed conditions to obtain material 2;

[0353] 3) Centrifuge material 2 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide Y.

[0354] The cobalt-containing composite metal oxide Y was tested by H2-TPR, and the results are as follows: Figure 1 As shown, the cobalt-containing composite metal oxide Y has two H2 reduction peaks, one with a peak temperature of around 290℃ and the other with a peak temperature of around 400℃.

[0355] Preparation of coating slurry

[0356] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0357] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0358] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0359] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide Y), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain the coating slurry, denoted as coating slurry Y. The viscosity of the coating slurry was measured to be 155 mPa·s.

[0360] Preparation of industrial waste gas treatment catalysts

[0361] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0362] 2) The carrier pretreated in 1) is immersed in the coating slurry Y for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0363] 3) Repeat the steps of soaking, drying and roasting in 2) at least 3 times.

[0364] 4) Catalyst Y was prepared by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0365] The ultrasonic shedding rate of catalyst Y was 3.8%; the CXPS / CICP ratio of ruthenium in catalyst Y was 1.2.

[0366] Comparative Example 3

[0367] Preparation of cobalt-containing composite metal oxides

[0368] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0369] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0370] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0371] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide A.

[0372] Preparation of coating slurry

[0373] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0374] 2) Mix 0.6g P123 with 330g water to obtain material 4. Mix the first part of pseudoboehmite with material 4, stir for 1 hour, and then grind for 0.5 hours to obtain material 5.

[0375] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0376] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide A), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain a coating slurry, denoted as coating slurry Z. The viscosity of coating slurry Z was measured to be 170 mPa·s.

[0377] Preparation of industrial waste gas treatment catalysts

[0378] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0379] 2) The pretreated carrier from 1) is immersed in the coating slurry Z for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0380] 3) Repeat the steps of soaking, drying and roasting in 2) at least 3 times.

[0381] 4) Catalyst Z was prepared by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0382] The ultrasonic shedding rate of catalyst Z was tested to be 3.35%.

[0383] Comparative Example 4

[0384] Preparation of cobalt-containing composite metal oxides

[0385] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0386] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0387] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0388] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide A.

[0389] Preparation of coating slurry

[0390] 1) Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 / g), and divide it into two equal parts. Weigh 2.4g of aluminum sol with a solid content of 20wt% and divide it into two equal parts.

[0391] 2) Mix 20 ml of ruthenium chloride standard solution with Ru content of 50 g / L, 0.6 g of P123 and 330 g of water to obtain material 4. Mix the first part of boehmite with material 4, stir for 1 h, and then grind for 0.5 h to obtain material 5.

[0392] 3) Mix the second part of the pseudo-boehmite, the first part of the aluminum sol and material 5, stir for 1 hour, and then grind for 0.5 hours to obtain material 6;

[0393] 4) Mix 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide A), the second part of aluminum sol, and material 6, stir for 1 hour, and then grind for 1 hour to obtain the coating slurry, which is denoted as coating slurry A. The viscosity of coating slurry R was measured to be 180 mPa·s.

[0394] Preparation of industrial waste gas treatment catalysts

[0395] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0396] 2) The pretreated carrier is immersed in coating slurry A for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0397] 3) The catalyst R is obtained by repeating the impregnation, drying and calcination steps at least 3 times.

[0398] The ultrasonic shedding rate of catalyst R was measured to be 3.05%; the CXPS / CICP ratio of ruthenium in catalyst R was 0.3.

[0399] Comparative Example 5

[0400] Preparation of cobalt-containing composite metal oxides

[0401] 1) A mixed solution of 58.20g cobalt nitrate, 1.02g ammonium metatungstate and 300ml water was obtained. Sodium hydroxide was added dropwise at 50℃ to adjust the pH of the mixed solution to 11, and material 1 was obtained.

[0402] 2) Mix 1.98g neodymium nitrate, 1.75g ​​ethylenediaminetetraacetic acid, and 30ml water to obtain material 2;

[0403] 3) Mix material 2 with material 1 and perform hydrothermal synthesis at 120°C for 8 hours under sealed conditions to obtain material 3;

[0404] 4) Centrifuge material 3 to obtain precipitate, dry it overnight at 110℃, and then calcine it in air at 550℃ for 2 hours to obtain cobalt-containing composite metal oxide, denoted as cobalt-containing composite metal oxide A.

[0405] Preparation of coating slurry

[0406] Weigh 22g of pseudoboehmite as the coating carrier (Jiangsu Sanji Co., Ltd., specific surface area 300-400m²). 2 13g of cobalt-containing composite metal oxide (cobalt-containing composite metal oxide A), 2.4g of aluminum sol with a solid content of 20wt%, 20ml of ruthenium chloride standard solution with a Ru content of 50g / L, 0.6g of P123, and 330g of water were mixed to obtain material 4. After stirring for 1 hour and then gel milling for 1 hour, a coating slurry was obtained, denoted as coating slurry S. The viscosity of the coating slurry was measured to be 150 mPa·s.

[0407] Preparation of industrial waste gas treatment catalysts

[0408] 1) The honeycomb cordierite carrier was calcined at 200°C for 2 hours in a nitrogen atmosphere;

[0409] 2) The pretreated carrier is immersed in the coating slurry S for 0.5 hours, dried overnight at 110°C, and then calcined in air at 550°C for 4 hours before being weighed.

[0410] 3) Repeat the steps of impregnation, drying and roasting at least 3 times.

[0411] 4) Catalyst S was obtained by reduction at 300°C for 3 hours in a hydrogen atmosphere.

[0412] The ultrasonic shedding rate of catalyst S was 3.2%; the CXPS / CICP ratio of ruthenium in catalyst S was 2.1.

[0413] Test Example 1

[0414] The catalytic performance of the examples and comparative examples was evaluated under the same conditions in a fixed-bed reactor catalytic reaction apparatus, and the results are shown in Table 1. In this experimental example, waste gas containing 2000 ppm epichlorohydrin was contacted with the catalyst for catalytic combustion.

[0415] The evaluated process conditions were as follows: under an air atmosphere, a reaction pressure of 0.05 MPa-0.1 MPa, a tail gas flow rate of 15 L / h per gram of catalyst, and a programmed temperature ramp to the reaction temperature until complete conversion. The temperature ramping program was as follows: from 20°C to 100°C at a ramp rate of 10°C / min, hold for 0.5 hours; to 150°C at a ramp rate of 10°C / min, hold for 0.5 hours; to 160°C at a ramp rate of 5°C / min, hold for 5 minutes; to 165°C at a ramp rate of 5°C / min, hold for 5 minutes; to 170°C at a ramp rate of 5°C / min, hold for 5 minutes, and so on, until the temperature reached 400°C.

[0416] The reactivity of the catalyst in this invention is evaluated by the reaction temperature at which the components of the exhaust gas are completely converted; the lower the temperature of complete conversion, the better the catalyst performance. Here, T99 represents the reaction temperature at which the purification rate of epichlorohydrin in the exhaust gas is 99%. 400(Tn) represents the purification rate of epichlorohydrin at 400℃ as n%. In Example 1, T99 is 260℃, and in Comparative Example 4, the purification rate at 400℃ is 85%.

[0417] Table 1

[0418]

[0419] Test Example 2

[0420] The catalytic performance of Examples 1, 6, and Comparative Examples 1-5 was evaluated under the same conditions in a fixed-bed reactor catalytic reaction device. The reaction results are shown in Table 2.

[0421] In this test example, waste gas containing 2000 ppm epichlorohydrin was contacted with a catalyst for catalytic combustion. The evaluation process conditions were as follows: under an air atmosphere, the reaction pressure was 0.05 MPa-0.1 MPa, the tail gas flow rate treated per gram of catalyst was 15 L per hour, the temperature was increased to 300 °C at a rate of 5 °C / min, and maintained for 100 hours. The conversion rate at 10 minutes after reaching 300 °C was the pre-reaction conversion rate, and the conversion rate after 100 hours of reaction was the post-reaction conversion rate.

[0422] Conversion rate before reaction Conversion rate after reaction Example 1 100％ 100％ Example 6 100％ 100％ Comparative Example 1 65％ 50％ Comparative Example 2 70％ 45％ Comparative Example 3 45％ 25％ Comparative Example 4 40％ 30％ Comparative Example 5 75％ 55％

Claims

1. A catalyst, characterized in that, The catalyst includes a honeycomb support and a coating; The coating slurry comprises a cobalt-containing composite metal oxide, an M3 source, a coating carrier, an adhesive, a dispersant, and a solvent; wherein the M3 is selected from at least one of the noble metal elements in Group VIIIB; The metals in the cobalt-containing composite metal oxide include cobalt, M1, and M2; M1 is selected from at least one element in Group VIB; M2 is selected from at least one lanthanide element; in the H2-TPR spectrum of the cobalt-containing composite metal oxide, at least one H2 reduction peak has a peak value below 275℃. The preparation method of the coating slurry includes: dividing the coating carrier into a first coating carrier and a second coating carrier; dividing the homogenizing adhesive into a first adhesive and a second adhesive; obtaining material 4 containing M3 source, dispersant and solvent; mixing the first coating carrier with material 4, stirring for 1-2 hours, and then grinding for 0.5-1 hours to obtain material 5; mixing the second coating carrier, the first adhesive and material 5, stirring for 1-2 hours, and then grinding for 0.5-1 hours to obtain material 6; mixing the cobalt-containing composite metal oxide, the second adhesive and material 6, stirring for 1-2 hours, and then grinding for 1-2 hours to obtain the coating slurry.

2. The catalyst according to claim 1, characterized in that, The coating contains the cobalt-containing composite metal oxide, the coating carrier, and the oxide of M3; And / or, based on the total mass of the catalyst, the coating comprises 10 wt% to 20 wt% of the catalyst; And / or, based on the total mass of the coating, the cobalt-containing composite metal oxide accounts for 26-50 wt% of the coating; And / or, the coating is located on the inner surface and / or outer surface of the cellular carrier; And / or, the cellular carrier is selected from at least one of cordierite cellular carrier, mullite cellular carrier and aluminum titanate ceramic cellular carrier; And / or, the ultrasonic shedding rate of the catalyst is ≤2.8%; And / or, the coating carrier is selected from at least one aluminum oxide; And / or, based on the total mass of the coating, the coating carrier accounts for 44-72 wt% of the coating; And / or, based on the total mass of the coating, the oxide of M3 accounts for 2-6 wt% of the coating; And / or, the M3 is Pd and / or Ru; And / or, the oxide of M3 satisfies CXPS / CICP=0.4~0.9, where CXPS is the molar content of Group VIIIB noble metal elements in the catalyst characterized by X-ray photoelectron spectroscopy; CICP is the molar content of Group VIIIB noble metal elements in the catalyst characterized by plasmonic coupling.

3. The catalyst according to claim 2, characterized in that, Based on the total mass of the coating, the cobalt-containing composite metal oxide accounts for 32-42 wt% of the coating. And / or, the aluminum oxide is selected from at least one of alumina and boehmite; And / or, based on the total mass of the coating, the coating carrier accounts for 50-60 wt% of the coating; And / or, based on the total mass of the coating, the oxide of M3 accounts for 2 to 4 wt% of the coating.

4. The catalyst according to claim 1, characterized in that, The H2-TPR spectrum of the cobalt-containing composite metal oxide has two H2 reduction peaks; The peak value of the first H2 reduction peak is below 275℃, and the peak value of the second H2 reduction peak is below 340℃; or, the peak value of the first H2 reduction peak is between 250℃ and 275℃, and the peak value of the second H2 reduction peak is between 320℃ and 340℃. And / or, the VIB group elements are selected from W and / or Mo; And / or, the lanthanide element is selected from Nd and / or Sm; And / or, in the cobalt-containing composite metal oxide, the molar ratio of cobalt, M1, and M2 is 1:(0.02-0.12):(0.03-0.18).

5. The catalyst according to any one of claims 1-4, characterized in that, The preparation method of the cobalt-containing composite metal oxide includes: Step (1): Provide a mixture containing a cobalt source, an M1 source and water, and mix the mixture with a precipitant to obtain material I; Step (2): Provide material II containing M2 source, ligand and water; Step (3): Mix material II with material I and carry out a hydrothermal reaction to obtain material III; Step (4): Separate the material III to obtain a precipitate. After roasting I, the precipitate is used to obtain the cobalt-containing composite metal oxide.

6. The catalyst according to claim 5, characterized in that, The cobalt source is selected from at least one of the inorganic acid salts of cobalt; And / or, the M1 source is selected from at least one of ammonium metatungstate, ammonium tungstate, tungstic acid, sodium tungstate, and ammonium molybdate; And / or, the M2 source is selected from at least one of the inorganic acid salts of lanthanides; And / or, the ligand is selected from at least one of ethylenediaminetetraacetic acid, ethylenediamine, and N-methylethylenediamine; And / or, the precipitant is selected from at least one of sodium hydroxide, potassium hydroxide and ammonia water; And / or, in step (1), the mass ratio of cobalt source, M1 source, and water is 1:(0.02~0.12):(74~82); And / or, in step (1), the mixing conditions each independently include: Temperature 50~70℃; And / or, in step (1), the amount of precipitant added is such that the pH of the mixture is adjusted to 10-11; And / or, in step (2), the mass ratio of M2 source, ligand, and water is 1:(1~2):(30~185); And / or, in step (3), the ratio of material II to material I is (0.03~0.18):1 based on the molar ratio of M2 source to Co source, and the conditions for hydrothermal reaction include: temperature 120~140℃, time 8~12 hours; And / or, in step (4), the drying process is further included before the calcination I, and the drying conditions include: temperature 90~110℃, time 8~12 hours; and / or, the calcination I conditions include: temperature 350~550℃, time 2~4 hours; and / or the atmosphere of calcination I is air.

7. The catalyst according to claim 6, characterized in that, The inorganic acid salt of cobalt is selected from at least one of cobalt nitrate and cobalt chloride; And / or, the inorganic acid salt of the lanthanide element is selected from at least one of the lanthanide nitrates and lanthanide chlorides.

8. The method for preparing the catalyst according to any one of claims 1-7, characterized in that, include: Step a: Provide the coating paste; The viscosity of the coating slurry is 180–320 mPa·s; Step b: Apply a coating slurry to the inner and / or outer surfaces of the honeycomb carrier, and then calcine it to obtain the catalyst.

9. The preparation method according to claim 8, characterized in that, The concentration of cobalt composite metal oxide in the coating slurry is 2.6wt%~5.3wt%; And / or, by using multiple coatings, the coating slurry is adhered to the inner and / or outer surfaces of the honeycomb carrier; And / or, by weight, the coating slurry contains: 13-25 parts of cobalt-containing composite metal oxide; and 2.4-4.6 parts of adhesive; Dispersant 0.6~1.4 parts; coating carrier 22~36 parts; M3 source 1~3 parts; solvent 330~470 parts; And / or, the concentration of the M3 source in the coating slurry is 0.2wt%~0.8wt%; And / or, the M3 source is selected from at least one of palladium chloride and ruthenium chloride; And / or, in step b, the cellular carrier undergoes a calcination III pretreatment; And / or, the method of attaching a coating slurry to the inner and / or outer surfaces of a cellular carrier includes: applying the coating slurry to the inner and / or outer surfaces of the cellular carrier or immersing the cellular carrier in the coating slurry; And / or, the adhesive is aluminum sol; And / or, the dispersant is selected from at least one of P123 and F127; And / or, the solvent is water; And / or, the conditions for calcination II include: a temperature of 450~550°C and a time of 2~4 hours; and / or the atmosphere for calcination I is air; And / or, before the calcination II, a drying step is further included, wherein the drying conditions include: temperature 80~110℃, time 0.5~2 hours; And / or, the preparation method further includes a reduction step after the calcination II.

10. The preparation method according to claim 9, characterized in that, In step b, the honeycomb carrier is pretreated by calcination III in an inactive atmosphere at a temperature of 200-400°C for 2-4 hours. And / or, the reduction is carried out in a reducing atmosphere at 200~300℃ for 2~3 hours.

11. The preparation method according to claim 10, characterized in that, The inactive atmosphere is selected from at least one of nitrogen and argon; And / or, the reducing atmosphere is a hydrogen atmosphere.

12. A method for treating waste gas, characterized in that, The catalyst prepared by any one of claims 1-7 or by any one of the preparation methods of claims 8-11 is brought into contact with the waste gas to undergo a catalytic reaction.

13. The method according to claim 12, characterized in that, The conditions for the catalytic reaction include: an air atmosphere; a reaction pressure of 0.05 MPa to 0.1 MPa; a reaction temperature of 100 to 400 °C; and a reaction time of 10 to 100 h. And / or, the content of epichlorohydrin in the exhaust gas is 2000 ppm; the T99 temperature of the epichlorohydrin is 260°C.

14. The method according to claim 13, characterized in that, The conditions for the catalytic reaction include: a reaction temperature of 300°C and a reaction time of 100 h.

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