Anchored anti-sintering supported noble metal catalyst, its preparation method and application in hcl catalytic oxidation

Abstract

The present application relates to a kind of anchoring type anti-sintering supported noble metal catalyst and its preparation method and application in HCl catalytic oxidation, by preparing porous ceramic material carrier and introducing auxiliary agent La, K, Li in carrier, its surface is modified and alkali treatment, active component noble metal precursor is simultaneously acidified, can make carrier and active component noble metal have stronger force, anchor noble metal in the surface of porous material carrier, to obtain high dispersion and excellent high-temperature anti-sintering ability of anchoring type anti-sintering supported noble metal catalyst.This catalyst can be used in HCl catalytic oxidation and simultaneously has higher catalytic activity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of catalysts, and relates to a supported noble metal catalyst, in particular to an anchoring type sintering-resistant supported noble metal catalyst and a preparation method thereof, and application of the catalyst in HCl catalytic oxidation. BACKGROUND

[0002] In the supported noble metal catalyst, the unsaturated d electron orbit of the noble metal can make the catalyst surface conducive to adsorbing HCl gas, so that a catalytic reaction occurs, and very high catalytic activity is exhibited.

[0003] The noble metal is the active site of the catalytic reaction, and most of it exists on the surface of the catalyst, so that a small-particle nano-catalyst often exhibits higher catalytic activity. However, when the nanoparticle is less than 10 nm, the specific surface energy is large and unstable, and the noble metal particles are prone to agglomeration under high-temperature conditions, thereby causing the catalyst to be deactivated.

[0004] At present, the common methods for preparing the supported noble metal catalyst mainly include sol-gel method, precipitation method, impregnation method, liquid-phase chemical reduction method, ion exchange method, etc., and the prepared catalyst has the defects of larger noble metal particle size (Appl Catal B Environ, 2020, 266: 118598), poor dispersibility, utilization rate and repeatability.

[0005] Researchers have made a lot of work to improve the stability of the supported metal catalyst, such as: in the patent CN, 101357337 and the literature (ChemCatChem., 2013, 5(3): 748-756.), the authors confine the metal components in the pores of specific porous materials, so that the nanoparticles are isolated from each other, thereby inhibiting the particle growth caused by migration and improving the sintering resistance of the catalyst; Jooh et al. (Nat. Mater., 2009, 9: 75) prepared a Pt@mSiO2 catalyst with a core-shell structure, coated an oxide shell on the surface of the noble metal, isolated the active components, prevented the particle growth caused by the contact between the particles, and thereby improved the thermal stability of the catalyst.

[0006] In the HCl catalytic oxidation reaction, on the one hand, due to the high concentration of HCl gas (about 80%) in the raw material gas, Cl is prone to combining with the active component / support of the catalyst under the oxidation atmosphere, thereby causing the catalyst to be poisoned and deactivated; on the other hand, the noble metal is slowly sintered during the continuous high-temperature (350℃-450℃) operation of the catalyst, which eventually causes the catalyst to be deactivated.

[0007] Therefore, the stability and service life of the noble metal catalyst inevitably become a key problem restricting its industrialization and production. SUMMARY

[0008] Therefore, the present application aims to provide an anchored anti-sintering supported noble metal catalyst and a preparation method thereof to solve the problems of low dispersion and poor high-temperature resistance of supported noble metal nanoparticle catalysts, and to provide a high-activity long-life catalyst for efficient catalytic preparation of chlorine from HCl.

[0009] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0010] In the method of the present application, the porous ceramic material carrier is prepared, and the surface thereof is modified and treated with alkali by introducing the additives La, K and Li, and the active component noble metal precursor is acid-treated, so that the carrier and the active component noble metal have stronger action, the noble metal is anchored on the surface of the porous material carrier, and thus an anchored anti-sintering supported noble metal catalyst with high dispersion and excellent high-temperature sintering resistance is obtained. In particular, the catalyst can be used for the reaction of catalytic oxidation of HCl to prepare chlorine while having high catalytic activity.

[0011] The present application provides a preparation method of an anchored anti-sintering supported noble metal catalyst, comprising the following steps:

[0012] 1) uniformly mixing diatomite, alumina powder, pore-forming agent, binder, dispersing agent and additive to obtain a premix, mixing the premix with water, and then pressing and molding to obtain a porous ceramic, and then drying and calcining to obtain the porous ceramic;

[0013] 2) soaking the porous ceramic prepared in step 1) in a weak alkaline solution, and then drying to obtain a pretreated porous ceramic carrier;

[0014] 3) soaking a noble metal precursor in an acid solution for acid treatment, then adding the pretreated porous ceramic carrier of step 2) for impregnation, and then drying and calcining to obtain an anchored anti-sintering supported noble metal catalyst.

[0015] In the present application, the particle size of the alumina powder in step 1) is 80-120 um.

[0016] In the present application, the pore-forming agent in step 1) is selected from any one or more of starch, urea, polyvinyl alcohol, polymethyl methacrylate and ammonium carbonate, and is preferably starch.

[0017] In the present application, the binder in step 1) is selected from any one or more of gelatin, kaolin and polycarbosilane, and is preferably gelatin.

[0018] In the present application, the dispersing agent in step 1) is selected from any one or more of citric acid, sodium silicate, sodium tripolyphosphate and sodium dodecyl sulfate, and is preferably citric acid.

[0019] In the present application, the auxiliary agent in step 1) is selected from any one or more of lanthanum (La), potassium (K), lithium (Li) and compounds thereof, preferably any one or more of lanthanum (La) and compounds thereof;

[0020] wherein the lanthanum, potassium, lithium compound is selected from lanthanum salt, potassium salt, lithium salt, preferably any one or more of La(NO3)3, K2CO3 and lithium acetate, further preferably La(NO3)3.

[0021] In the present application, the mass ratio of diatomite to alumina powder in step 1) is 1:0.34-2.94, preferably 1:0.87-0.89;

[0022] The mass ratio of diatomite to pore-forming agent, binder, dispersing agent is 1:0.13-1.61:0.28-0.3:1.47-2.78, preferably 1:0.4-0.5:0.290-0.295:1.7-1.8;

[0023] The mass ratio of diatomite to auxiliary agent is 1:0.055-0.074, preferably 1:0.069-0.070.

[0024] In the present application, the mass ratio of the premix in step 1) to water is 1:1-3, preferably 1:1.8-2.2.

[0025] In the present application, the pressing forming in step 1) is cylindrical long strip, preferably the size is 4-6 mm in length and 2-3 mm in diameter.

[0026] In the present application, the drying in step 1) is at a temperature of 60-80℃, preferably 65-75℃, for a time of 12-24h, preferably 17-19h;

[0027] The calcination is at a temperature of 1000-1500℃, preferably 1230-1270℃, for a time of 3-7h, preferably 4.5-5.5h;

[0028] Preferably, the heating rate during the calcination process is 2-6℃ / min.

[0029] In the present application, the weak alkaline solution in step 2) has a pH value of 8-9, and the base therein is selected from any one or more of ammonia, sodium bicarbonate, dimethylamine and sodium acetate, preferably ammonia;

[0030] Preferably, the weak alkaline solution is an aqueous solution with a concentration of 0.045-0.055 mol / L.

[0031] In the present application, the porous ceramic prepared in step 1) is soaked in a weak alkaline solution in step 2), the soaking temperature is 26-34℃, preferably 29-31℃, and the soaking time is 2-10h, preferably 5-7h;

[0032] The soaking is a conventional operation in the art, and the amount of the weak alkaline solution is not particularly limited, and the porous ceramic can be immersed therein; preferably, the mass ratio of the porous ceramic to the weak alkaline solution is 1:1-3.

[0033] In the present application, the drying in step 2) is carried out at a temperature of 60-80℃, preferably 65-75℃, for a time of 12-24h, preferably 17-19h.

[0034] In the present application, the noble metal precursor in step 3) is selected from any one or more of Pt, Pd, Ru, Rh and Au, preferably Pt;

[0035] Preferably, the noble metal precursor is selected from a soluble salt of a noble metal, more preferably any one or more of a hydrochloride, a nitrate and a carbonate of a noble metal, preferably a hydrochloride.

[0036] In the present application, the acid solution in step 3) is selected from any one or more of phosphoric acid, hydrochloric acid, nitric acid, sulfuric acid and acetic acid, preferably phosphoric acid;

[0037] Preferably, the acid solution is an aqueous solution with a concentration of 0.045-0.055mol / L;

[0038] Preferably, the mass ratio of the noble metal precursor to the acid solution is 1:1-3, preferably 1:1.5-2.5.

[0039] In the present application, the acidification treatment in step 3) is carried out at a temperature of 26-34℃, preferably 29-31℃, for a time of 2-10h, preferably 5-7h;

[0040] In the present application, the impregnation in step 3) is carried out at a temperature of 26-34℃, preferably 29-31℃, for a time of 12-24h, preferably 17-19h;

[0041] Preferably, the mass ratio of the noble metal precursor to the porous ceramic carrier is 1:25-135, preferably 1:70-80.

[0042] In the present application, the drying in step 3) is carried out at a temperature of 60-80℃, preferably 65-75℃, for a time of 12-24h, preferably 17-19h.

[0043] The calcination is carried out at a temperature of 200-500℃, preferably 340-360℃, for a time of 3-7h, preferably 4.5-5.5h.

[0044] The roasting is carried out in a gas atmosphere selected from one or more than two of nitrogen, inert gas atmosphere such as argon, helium and the like, or selected from oxidizing gas atmosphere such as oxygen, air and the like;

[0045] Preferably, the gas atmosphere inlet flow rate is 500-2500 mL / min, preferably 1400-1600 mL / min.

[0046] The present application also provides an anchoring type anti-sintering supported noble metal catalyst prepared by the above method, comprising a porous ceramic carrier and a supported noble metal active component; wherein the chemical composition of the porous ceramic in the carrier comprises silicon dioxide, diatomic aluminum and an auxiliary agent; and the loading amount of the noble metal active component is 0.5-2 wt%.

[0047] The catalyst has a noble metal dispersion of 40-45%, a particle size of 2-6 mm, a pore size of 40-100 nm, a surface area of 20-60 m 2 / g, and a catalyst strength of 50-80 N / cm.

[0048] The present application also provides the application of the above-mentioned anchoring type anti-sintering supported noble metal catalyst, which is suitable for the fields of ammonia oxidation, unsaturated hydrocarbon oxidation, petroleum hydrocarbon reforming, nitrogen oxide removal, and the like, and is particularly suitable for the catalytic oxidation of chlorine-containing organic matter and hydrogen chloride.

[0049] As a preferred embodiment, the present application provides a method for preparing chlorine gas by catalytic oxidation of hydrogen chloride, which can be based on the method disclosed in the prior art and uses the above-mentioned catalyst of the present application for the catalytic oxidation of hydrogen chloride.

[0050] As a preferred embodiment, in the method, the molar ratio of hydrogen chloride to oxygen is 1:0.25-1, preferably 1:0.4-0.6; the temperature during the catalytic oxidation reaction process is 280-340°C, preferably 305-315°C; and the pressure is 0.1-0.3 MPag, preferably 0.15-0.25 MPag.

[0051] In the method, the reaction of hydrogen chloride catalytic oxidation for preparing chlorine gas is carried out in a fixed bed reactor, and the volume space velocity of hydrogen chloride is 0.6-0.7 h -1 .

[0052] The anchoring type anti-sintering supported noble metal catalyst of the present application exhibits excellent high-temperature resistance in long-period stability experiments, and does not have problems such as catalyst sintering deactivation under long-time high-temperature environment, for example, after 7000 h of degradation treatment under a 500°C high-temperature environment, the reaction activity does not decrease significantly when used in the above-mentioned reaction of hydrogen chloride catalytic oxidation for preparing chlorine gas.

[0053] Compared with the prior art, the technical scheme of the present application has the beneficial effects that:

[0054] The present application uses acid-base treatment of the carrier and active components to embed noble metals in the inside of the pore structure of the porous ceramic, and through the metal additives La, K and Li, the free hydroxyl groups on the surface of the carrier are combined in the form of hydrogen bonds, which plays a role in blocking the noble metal particles to prevent their migration and agglomeration, and causes the electron shift between the noble metal and the carrier, improves the binding force between the noble metal and the carrier, promotes the high dispersion of the noble metal on the carrier, and at the same time, through the chemical bond action of M-P-O-Si / Al between the noble metal M and the carrier, the noble metal is further anchored, so that the active components can still maintain uniform dispersion at high temperature, effectively prevent the sintering and chlorine poisoning of the noble metal, and finally show excellent HCl oxidation reaction activity and stability.

[0055] The porous ceramic supported noble metal catalyst of the present application is applied to the HCl catalytic oxidation reaction for preparing chlorine gas, and has good activity and stability. The reaction conversion rate of HCl can be as high as 90% or more, and the reaction activity of the catalyst does not decrease significantly after 7000 hours of degradation treatment at a high temperature of 500 DEG C. DETAILED DESCRIPTION

[0056] The following will be described in detail: The present embodiment is implemented on the premise of the technical scheme of the present application, and gives a detailed implementation manner and specific operation process, but the protection scope of the present application is not limited to the following examples.

[0057] The main raw material source information in the present embodiment and comparative examples is as follows, and other materials not specifically mentioned are obtained from ordinary commercial channels:

[0058] Diatomaceous earth, alumina powder (particle size 80-120um), starch, urea, polyvinyl alcohol, polymethyl methacrylate, gelatin, kaolin, citric acid, sodium silicate, sodium tripolyphosphate, sodium dodecyl sulfate, lanthanum nitrate, lithium acetate, dimethylamine, sodium acetate, platinum chloride: Beijing Inokai Technology Co., Ltd.;

[0059] Polycarbosilane: Ningbo Zhongxing New Material Co., Ltd. PCS. The main instrument analysis method used in the present embodiment and comparative examples is as follows:

[0060] Specific surface area analyzer: ASAP2020, BET, American Micromeritics Corporation;

[0061] X-ray fluorescence spectrometer: Epsilon4, XRF, Fujian Jingan Instrument Co., Ltd.;

[0062] Particle strength tester: KC-4, strength tester, Taizhou Jiangyan Analytical Instrument Factory.

[0063] Automatic chemisorption instrument: AutoChem II 2920 of Merck-Merital Instruments Co., Ltd., noble metal dispersion test.

[0064] Example 1

[0065] A preparation method of an anchored anti-sintering supported noble metal catalyst, comprising the following steps:

[0066] 1) First, 1.8 g of diatomaceous earth, 5.3 g of alumina powder, 2.9 g of urea are continuously stirred for 20 min using a magnetic stirrer to mix and disperse uniformly, then 0.5 g of kaolin, 5 g of sodium silicate and 0.1 g of K2CO3 are added to obtain a premix, then the premix is mixed uniformly with 15.6 g of water, and then a tablet press is used to press into a ceramic wet embryo under a pressure of 3 MPa, into a cylindrical strip with a length of 4-6 mm and a diameter of 2-3 mm, after drying at 60℃ for 12 h, finally calcined in a muffle furnace at a heating rate of 2℃ / min from room temperature 30℃ to 1000℃ and then calcined for 3 h to obtain 12.7 g of porous ceramic.

[0067] 2) The porous ceramic prepared in step 1) is immersed in 12.2 g of a NaHCO3 aqueous solution with a concentration of 0.05 mol / L (pH 8-9) at 26℃ for 2 h, and after taking out, it is dried at 60℃ for 12 h to obtain a pretreated porous ceramic carrier.

[0068] 3) 0.47 g of PtCl3 precursor is placed in 0.47 g of hydrochloric acid with a concentration of 0.05 mol / L, and acidification treatment is carried out at 26℃ for 2 h, then the pretreated porous ceramic carrier in step 2) is added for impregnation, and after standing at 26℃ for 12 h, it is dried at 60℃ for 12 h, and finally calcined at 200℃ for 3 h under a nitrogen atmosphere of 500 mL / min to obtain an anchored anti-sintering supported noble metal catalyst.

[0069] The physical properties of the catalyst are as follows: Pt loading is 2.5 wt%, Pt metal dispersion is 40%, particle size is 6 mm, pore size is 70 nm, surface area is 45 m 2 / g, catalyst strength is 60 N / cm.

[0070] The above catalyst is used for hydrogen chloride catalytic oxidation to prepare chlorine gas reaction, which is carried out in a fixed bed reactor, and the catalytic reaction conditions are as follows: reaction temperature 314℃, reaction pressure 0.1 MPa, molar ratio of hydrogen chloride to oxygen 1:0.5, hydrogen chloride volume space velocity 0.67h -1 , the initial hydrogen chloride conversion rate is 90%.

[0071] Evaluation of the catalyst's high temperature resistance: the catalyst was treated at 500℃ for 7000h, then reduced to 314℃, and the reaction was continued under the above conditions. The hydrogen chloride conversion rate was 89.3%, and the activity decreased by 0.7% compared to the previous reaction.

[0072] Example 2

[0073] A method for preparing an anchoring anti-sintering supported noble metal catalyst, comprising the following steps:

[0074] 1) First, 3.0g of diatomaceous earth, 4.5g of alumina powder, 2.4g of polyvinyl alcohol were continuously stirred for 30min using a magnetic stirrer, then 0.9g of kaolin, 6.2g of sodium tripolyphosphate and 0.2g of K2CO3 were added to obtain a premix, then the premix was mixed uniformly with 24.3g of water, and then a ceramic wet embryo was prepared by using a tablet press under a pressure of 4MPa, which was a cylindrical strip with a length of 4-6mm and a diameter of 2-3mm. After drying at 60℃ for 15h, the ceramic was finally calcined at a temperature rising rate of 3℃ / min from room temperature 30℃ to 1100℃ and then calcined for 4h to obtain 14.8g of porous ceramic.

[0075] 2) The porous ceramic prepared in step 1) was immersed in 13.9g of NaHCO3 aqueous solution with a concentration of 0.05mol / L (pH 8-9) at 28℃ for 4h, and then dried at 60℃ for 15h to obtain the pretreated porous ceramic carrier.

[0076] 3) 0.27g of PtCl3 precursor was placed in 0.27g of hydrochloric acid with a concentration of 0.05mol / L and soaked in the acid at 28℃ for 4h, then the pretreated porous ceramic carrier of step 2) was added to the solution for impregnation, and then the mixture was placed at 28℃ for 15h, dried at 60℃ for 15h, and finally calcined at 275℃ for 4h under an argon gas atmosphere of 1000mL / min to obtain the anchoring anti-sintering supported noble metal catalyst.

[0077] The physical properties of the catalyst are as follows: Pt loading is 1.25wt%, Pt metal dispersion is 42%, particle size is 5mm, pore size is 90nm, surface area is 53m 2 / g, and catalyst strength is 70N / cm.

[0078] The above catalyst was used for the reaction of hydrogen chloride catalytic oxidation to produce chlorine gas, which was carried out in a fixed bed reactor. The catalytic reaction conditions were as follows: reaction temperature 306℃, reaction pressure 0.1MPa, molar ratio of hydrogen chloride to oxygen 1:0.5, hydrogen chloride volume space velocity 0.67h -1 , and the initial hydrogen chloride conversion rate was 90.5%.

[0079] Evaluation of catalyst high temperature resistance: the catalyst was treated at 500℃ for 7000h, then reduced to 306℃, and the reaction was continued under the above conditions. The hydrogen chloride conversion rate was 90%, and the activity decreased by 0.5% before and after the reaction.

[0080] Example 3

[0081] A method for preparing an anchored anti-sintering supported noble metal catalyst, comprising the following steps:

[0082] 1) First, 4.3g of diatomaceous earth, 3.8g of alumina powder, 1.9g of starch were continuously stirred for 40min using a magnetic stirrer, then 1.25g of gelatin, 7.5g of citric acid and 0.3g of La(NO3)3 were added to obtain a premix, then the premix was mixed with 38.1g of water, and a ceramic wet body was prepared by using a tablet press under a pressure of 5MPa, which was a cylindrical strip with a length of 4-6mm and a diameter of 2-3mm. After drying at 70℃ for 18h, the final calcination was carried out in a muffle furnace at a heating rate of 4℃ / min from room temperature 30℃ to 1250℃, and then calcined for 5h to obtain 8.4g of porous ceramic.

[0083] 2) The porous ceramic prepared in step 1) was immersed in 16.8g of NaHCO3 aqueous solution with a concentration of 0.05mol / L (pH 8-9) at 30℃ for 6h, and then dried at 70℃ for 18h to obtain the pretreated porous ceramic carrier.

[0084] 3) 0.11g of PtCl3 precursor was placed in 0.22g of hydrochloric acid with a concentration of 0.05mol / L, and acidification treatment was carried out at 30℃ for 6h, then the pretreated porous ceramic carrier in step 2) was added for impregnation, and the loading was carried out at 30℃ for 18h, then dried at 70℃ for 18h, and finally calcined at 350℃ for 5h under a helium gas flow of 1500mL / min to obtain the anchored anti-sintering supported noble metal catalyst.

[0085] The physical properties of the catalyst are as follows: Pt loading is 0.83wt%, Pt metal dispersion is 45%, particle size is 4mm, pore size is 100nm, surface area is 60m 2 / g, and catalyst strength is 80N / cm.

[0086] The above catalyst was used for hydrogen chloride catalytic oxidation to prepare chlorine gas reaction, which was carried out in a fixed bed reactor, and the catalytic reaction conditions were as follows: reaction temperature 282℃, reaction pressure 0.1MPa, molar ratio of hydrogen chloride to oxygen 1:0.5, hydrogen chloride volume space velocity 0.67h -1 , and the initial hydrogen chloride conversion rate was 91.5%.

[0087] Evaluation of the catalyst's high temperature resistance: the catalyst was treated at 500°C for 7000h, then reduced to 282°C, and the reaction was continued under the above conditions. The hydrogen chloride conversion rate was 91.4%, and the activity decreased by 0.1% compared to the previous reaction.

[0088] Example 4

[0089] A method for preparing an anchoring anti-sintering supported noble metal catalyst, comprising the following steps:

[0090] 1) First, 5.5g of diatomaceous earth, 3.0g of alumina powder, 1.4g of polymethyl methacrylate were continuously stirred for 50min using a magnetic stirrer, then 1.6g of polycarbosilane, 8.7g of sodium silicate and 0.4g of lithium acetate were added to obtain a premix, then the premix was mixed uniformly with 50.5g of water, and then a tablet press was used to press the ceramic wet embryo under a pressure of 6MPa to form a cylindrical strip with a length of 4-6mm and a diameter of 2-3mm. After drying at 80°C for 21h, the final calcination was carried out in a muffle furnace at a heating rate of 5°C / min from room temperature 30°C to 1300°C, and then calcined for 6h to obtain 17.6g of porous ceramic.

[0091] 2) The porous ceramic prepared in step 1) was immersed in 52.8g of a 0.05mol / L (pH 8-9) sodium acetate solution at 32°C for 8h, and then dried at 80°C for 21h to obtain the pretreated porous ceramic carrier.

[0092] 3) 0.17g of PtCl3 precursor was placed in 0.51g of 0.05mol / L hydrochloric acid and soaked at 32°C for 8h, then the pretreated porous ceramic carrier of step 2) was added to the solution for impregnation, and then placed at 32°C for 21h, dried at 80°C for 21h, and finally calcined at 425°C for 6h under an oxygen atmosphere of 2000mL / min to obtain the anchoring anti-sintering supported noble metal catalyst.

[0093] The physical properties of the catalyst are as follows: Pt loading is 0.63wt%, Pt metal dispersion is 43%, particle size is 3mm, pore size is 80nm, surface area is 50m 2 / g, and catalyst strength is 60N / cm.

[0094] The above catalyst was used for the reaction of hydrogen chloride catalytic oxidation to produce chlorine gas in a fixed bed reactor, and the catalytic reaction conditions were as follows: reaction temperature 298°C, reaction pressure 0.1MPa, molar ratio of hydrogen chloride to oxygen 1:0.5, hydrogen chloride volume space velocity 0.67h -1 , and the initial hydrogen chloride conversion rate was 90.3%.

[0095] Evaluation of the catalyst's high temperature resistance: the catalyst was treated at 500℃ for 7000h, then reduced to 298℃, and the reaction was continued under the above conditions. The hydrogen chloride conversion rate was 89.9%, and the activity decreased by 0.4% before and after the reaction.

[0096] Example 5

[0097] A method for preparing an anchoring anti-sintering supported noble metal catalyst, comprising the following steps:

[0098] 1) First, 6.8g of diatomaceous earth, 2.3g of alumina powder, 0.9g of ammonium carbonate were continuously stirred for 60min using a magnetic stirrer, then 2.0g of polycarbosilane, 10g of sodium silicate and 0.5g of lithium acetate were added to obtain a premix, then the premix was mixed with 67.5g of water, and then a tablet press was used to press the mixture into a ceramic wet embryo body under a pressure of 7MPa, which was in the shape of a cylindrical strip with a length of 4-6mm and a diameter of 2-3mm. After drying at 80℃ for 24h, the ceramic was finally calcined at a temperature rising rate of 6℃ / min from room temperature 30℃ to 1500℃ and then calcined for 7h to obtain 19.6g of porous ceramic.

[0099] 2) The porous ceramic prepared in step 1) was immersed in a 58.8g aqueous solution of NaHCO3 with a concentration of 0.05mol / L (pH 8-9) at 34℃ for 10h, and then dried at 80℃ for 24h to obtain the pretreated porous ceramic carrier.

[0100] 3) 0.15g of PtCl3 precursor was placed in 0.47g of acetic acid with a concentration of 0.05mol / L and soaked in the acid at 34℃ for 10h, then the pretreated porous ceramic carrier from step 2) was added to the solution for impregnation, and then the mixture was placed at 34℃ for 24h, dried at 80℃ for 24h, and finally calcined at 500℃ under an air atmosphere of 2500mL / min for 7h to obtain the anchoring anti-sintering supported noble metal catalyst.

[0101] The physical properties of the catalyst were as follows: Pt loading was 0.5wt%, Pt metal dispersion was 41%, particle size was 2mm, pore size was 60nm, surface area was 40m 2 / g, and catalyst strength was 50N / cm.

[0102] The above catalyst was used for the reaction of hydrogen chloride catalytic oxidation to produce chlorine gas, which was carried out in a fixed bed reactor. The catalytic reaction conditions were as follows: reaction temperature was 310℃, reaction pressure was 0.1MPa, molar ratio of hydrogen chloride to oxygen was 1:0.5, and hydrogen chloride volume space velocity was 0.67h -1 The initial hydrogen chloride conversion rate was 89.8%.

[0103] The high temperature resistance of the catalyst was evaluated: the catalyst was treated at 500°C for 7000h, then reduced to 310°C, and the reaction was continued under the above conditions. The conversion of hydrogen chloride was 89%, and the decrease in the activity of the catalyst before and after the reaction was 0.8%.

[0104] Comparative Example 1

[0105] The catalyst was prepared according to the method of Example 3, except that in step 1) no additive La was added, and other operations and parameters were unchanged. The physical properties of the catalyst were as follows: Pt loading was 0.83wt%, Pt metal dispersion was 28%, particle size was 4mm, pore size was 50nm, surface area was 30m 2 / g, and catalyst strength was 60N / cm.

[0106] The catalyst was used in the reaction of hydrogen chloride catalytic oxidation to produce chlorine according to the method of Example 3, and the conversion of hydrogen chloride was 85% at the beginning of the reaction.

[0107] The high temperature resistance of the catalyst was evaluated: the catalyst was treated at 500°C for 7000h, then reduced to 325°C, and the reaction was continued under the above conditions. The conversion of hydrogen chloride was 83%, and the decrease in the activity of the catalyst before and after the reaction was 2%.

[0108] Comparative Example 2

[0109] The catalyst was prepared according to the method of Example 3, except that after the porous ceramic was prepared according to the method of step 1), step 2) was omitted, i.e. the carrier was not treated with alkali, and in step 3) the acid treatment of the active component precursor PtCl3was omitted. The PtCl3precursor was prepared into an aqueous solution and then impregnated onto the prepared porous ceramic carrier in an equal volume. Other operations and parameters were unchanged.

[0110] The physical properties of the catalyst were as follows: Pt loading was 0.83wt%, Pt metal dispersion was 25%, particle size was 4mm, pore size was 40nm, surface area was 20m 2 / g, and catalyst strength was 50N / cm.

[0111] The catalyst was used in the reaction of hydrogen chloride catalytic oxidation to produce chlorine according to the method of Example 3, and the conversion of hydrogen chloride was 80% at the beginning of the reaction.

[0112] The high temperature resistance of the catalyst was evaluated: the catalyst was treated at 500°C for 7000h, then reduced to 332°C, and the reaction was continued under the above conditions. The conversion of hydrogen chloride was 77%, and the decrease in the activity of the catalyst before and after the reaction was 3%.

[0113] Comparative Example 3

[0114] The catalyst was prepared according to the catalyst preparation method of Example 3, except that step 2) was omitted, i.e. the carrier was not subjected to alkali treatment, and other operations and parameters were unchanged.

[0115] The physical properties of the catalyst were as follows: Pt loading was 0.83 wt%, Pt metal dispersion was 23%, particle size was 5 mm, pore size was 43 nm, and surface area was 25 m 2 / g, and catalyst strength was 55 N / cm.

[0116] The catalyst was used for the reaction of catalytic oxidation of hydrogen chloride to produce chlorine according to the method of Example 3, and the initial hydrogen chloride conversion rate was 83%;

[0117] The high-temperature resistance of the catalyst was evaluated: the catalyst was subjected to degradation treatment at 500°C for 7000 h, and then the temperature was lowered to 328°C, and the reaction was continued under the above conditions. The hydrogen chloride conversion rate was 79.4%, and the decrease in reaction activity before and after was 2.6%.

[0118] Comparative Example 4

[0119] The catalyst was prepared according to the catalyst preparation method of Example 3, except that in step 3), the acid treatment of the active component precursor PtCl3was omitted, and the PtCl3precursor was prepared into an aqueous solution and then impregnated onto the prepared porous ceramic carrier in an equal volume, and other operations and parameters were unchanged.

[0120] The physical properties of the catalyst were as follows: Pt loading was 0.83 wt%, Pt metal dispersion was 22%, particle size was 5 mm, pore size was 45 nm, and surface area was 27 m 2 / g, and catalyst strength was 58 N / cm.

[0121] The catalyst was used for the reaction of catalytic oxidation of hydrogen chloride to produce chlorine according to the method of Example 3, and the initial hydrogen chloride conversion rate was 82%;

[0122] The high-temperature resistance of the catalyst was evaluated: the catalyst was subjected to degradation treatment at 500°C for 7000 h, and then the temperature was lowered to 328°C, and the reaction was continued under the above conditions. The hydrogen chloride conversion rate was 79.4%, and the decrease in reaction activity before and after was 2.6%.

[0123] Comparative Example 5

[0124] The catalyst was prepared according to the catalyst preparation method of Example 3, except that according to the method of step 1), the porous ceramic was prepared, and the alkali treatment of step 2) and the acid treatment of step 3) were interchanged, i.e. step 2) NaHCO3was replaced with an equal amount of hydrochloric acid to acidify the carrier for pretreatment, and step 3) hydrochloric acid was replaced with an equal amount of NaHCO3to alkali treat the active component precursor PtCl3, and other operations and parameters were unchanged.

[0125] The physical properties of the catalyst are as follows: Pt loading 0.83wt%, Pt metal dispersion 20%, particle size 6mm, pore size 47nm, surface area 24m 2 / g, catalyst strength 51N / cm.

[0126] The above catalyst was used in the reaction of hydrogen chloride catalytic oxidation for preparing chlorine according to the method of Example 3, and the initial hydrogen chloride conversion rate was 78% measured in the reaction;

[0127] The high temperature resistance of the catalyst was evaluated: the catalyst was treated at 500℃ for 7000h, and then reduced to 335℃, and the reaction was continued according to the above conditions, and the hydrogen chloride conversion rate was 74% measured, and the activity decreased by 4% compared with the previous reaction.

[0128] The anchoring anti-sintering noble metal catalyst prepared by the method has obviously improved anti-sintering performance compared with ordinary noble metal catalyst, and still maintains high catalytic activity after 7000h of high temperature treatment at 500℃, and the reaction activity does not decrease obviously, wherein the anti-sintering performance of Example 3 is the best, and the HCl reaction conversion rate at 282℃ can be maintained at 91.5%.

[0129] Although the anchoring anti-sintering supported noble metal catalyst and its preparation and application have been described in detail and specifically in the specification, it is obvious that other obvious changes and contents can be deduced by researchers in the art after reading the description in the foregoing specification. Therefore, the present application is not limited to the specific embodiments, and any content not inconsistent with the spirit and scope of the present application should also be included in the present application.

Claims

1. A process for the preparation of an anchored anti-sintering supported noble metal catalyst, characterized in that, The method comprises the following steps: 1) mixing diatomite, alumina powder, pore-forming agent, binder, dispersing agent and auxiliary agent to obtain a premix, wherein the auxiliary agent is selected from any one or more of lanthanum, potassium, lithium and compounds thereof, mixing the premix with water, and then pressing to form a shape, and then drying and calcining to obtain the porous ceramic; 2) soaking the porous ceramic prepared in step 1) in a weak alkaline solution, and then drying to obtain a pretreated porous ceramic carrier; 3) soaking a noble metal precursor in an acid solution for acidification treatment, wherein the acid is selected from any one or more of phosphoric acid, hydrochloric acid, nitric acid and sulfuric acid, then adding the pretreated porous ceramic carrier prepared in step 2) to the acid solution for impregnation, and then drying and calcining to obtain an anchoring type sintering-resistant supported noble metal catalyst.

2. The production method according to claim 1, characterized by, In step 1), the particle size of the alumina powder is 80-120 μm; and / or In step 1), the pore-forming agent is selected from any one or more of starch, urea, polyvinyl alcohol, polymethyl methacrylate and ammonium carbonate; and / or In step 1), the binder is selected from any one or more of gelatin, kaolin and polycarbosilane; and / or In step 1), the dispersing agent is selected from any one or more of citric acid, sodium silicate, sodium tripolyphosphate and sodium dodecyl sulfate; and / or In step 1), the auxiliary agent is any one or more of lanthanum and compounds thereof; and / or In step 1), the lanthanum, potassium and lithium compounds are selected from lanthanum salts, potassium salts and lithium salts; and / or In step 1), the mass ratio of diatomite to alumina powder is 1:0.34-2.94; and / or In step 1), the mass ratio of diatomite to pore-forming agent, binder and dispersing agent is 1:0.13-1.61:0.28-0.3:1.47-2.78; and / or In step 1), the mass ratio of diatomite to auxiliary agent is 1:0.055-0.074; and / or In step 1), the mass ratio of the premix to water is 1:1-3.

3. The production method according to claim 2, characterized by, In step 1), the lanthanum, potassium and lithium compounds are selected from any one or more of La(NO3)3, K2CO3 and lithium acetate.

4. The preparation method according to claim 2, characterized in that, In step 1), the mass ratio of diatomite to alumina powder is 1:0.87-0.

89.

5. The preparation method according to claim 2, characterized in that, In step 1), the mass ratio of diatomite to pore-forming agent, binder and dispersing agent is 1:0.4-0.5:0.290-0.295:1.7-1.

8.

6. The preparation method according to claim 2, characterized in that, In step 1), the mass ratio of diatomite to auxiliary agent is 1:0.069-0.

070.

7. The preparation method according to claim 2, characterized in that, In step 1), the mass ratio of the premix to water is 1:1.8-2.

2.

8. The method of claim 1, wherein, In step 1), the pressing is performed to form a cylindrical long strip; and / or In step 1), the drying is performed at a temperature of 60-80 ℃ for 12-24 h; and / or In step 1), the calcining is performed at a temperature of 1000-1500 ℃ for 3-7 h.

9. The production method according to claim 8, characterized by, In step 1), the carrier is formed into a cylindrical long strip with a length of 4-6 mm and a diameter of 2-3 mm.

10. The preparation method according to claim 8, characterized in that, In step 1), the drying is performed at a temperature of 65-75 ℃ for 17-19 h.

11. The preparation method according to claim 8, characterized in that, In step 1), the calcining is performed at a temperature of 1230-1270 ℃ for 4.5-5.5 h.

12. The method of claim 1, wherein, The heating rate of the calcination process in step 1) is 2-6℃ / min.

13. The method of claim 1, wherein, The pH value of the weak alkaline solution in step 2) is 8-9; and / or The soaking temperature of the porous ceramic prepared in step 1) in the weak alkaline solution in step 2) is 26-34℃, and the soaking time is 2-10h; and / or The drying temperature in step 2) is 60-80℃, and the drying time is 12-24h.

14. The method of claim 13, wherein, The weak alkaline solution in step 2) is selected from any one or more of ammonia, sodium bicarbonate, dimethylamine and sodium acetate.

15. The preparation method according to claim 13, characterized in that, The concentration of the weak alkaline solution in step 2) is 0.045-0.055mol / L.

16. The method of claim 13, wherein, The soaking temperature of the porous ceramic prepared in step 1) in the weak alkaline solution in step 2) is 29-31℃, and the soaking time is 5-7h.

17. The method of claim 13, wherein, The drying temperature in step 2) is 65-75℃, and the drying time is 17-19h.

18. The method of claim 1, wherein, The noble metal precursor in step 3) is selected from any one or more of Pt, Pd, Ru, Rh and Au; and / or The mass ratio of the noble metal precursor to the acid solution in step 3) is 1:1-3.

19. The method of claim 1, wherein, The noble metal precursor in step 3) is selected from a soluble salt of a noble metal.

20. The method of claim 19, wherein, The noble metal precursor is selected from any one or more of a hydrochloride, a nitrate and a carbonate of a noble metal.

21. The method of claim 1, wherein, The concentration of the acid solution in step 3) is 0.045-0.055mol / L.

22. The method of claim 1, wherein, The mass ratio of the noble metal precursor to the acid solution in step 3) is 1:1.5-2.

5.

23. The method of claim 1, wherein, The acidification temperature in step 3) is 26-34℃, and the acidification time is 2-10h; and / or The soaking temperature in step 3) is 26-34℃, and the soaking time is 12-24h; and / or The mass ratio of the noble metal precursor to the porous ceramic carrier in step 3) is 1:25-135; and / or The drying temperature in step 3) is 60-80℃, and the drying time is 12-24h; and / or The calcination temperature in step 3) is 200-500℃, and the calcination time is 3-7h.

24. The method of claim 23, wherein, The acidification temperature in step 3) is 29-31℃, and the acidification time is 5-7h.

25. The preparation method of claim 23, wherein the soaking temperature in step 3) is 29-31℃, and the soaking time is 17-19h.

26. The preparation method of claim 23, wherein the mass ratio of the noble metal precursor to the porous ceramic carrier in step 3) is 1:70-80.

27. The preparation method of claim 23, wherein the drying temperature in step 3) is 65-75℃, and the drying time is 17-19h.

28. The preparation method of claim 23, wherein the calcination temperature in step 3) is 340-360℃, and the calcination time is 4.5-5.5h.

29. The preparation method of claim 1, wherein the calcination in step 3) is performed in a gas selected from one or more of nitrogen, an inert atmosphere, or an oxidizing gas.

30. The preparation method of claim 29, wherein the gas flow rate is 500-2500mL / min.

31. The preparation method of claim 30, wherein the gas inlet flow rate is 1400-1600 mL / min.

32. An anchored, anti-sintering, supported noble metal catalyst prepared by the method of any one of claims 1-31, wherein, The porous ceramic carrier and the supported noble metal active component; wherein the chemical composition of the porous ceramic carrier comprises silica, alumina and additives; and the loading of the noble metal active component is 0.5-2 wt%.

33. The anchored anti-sintering supported noble metal catalyst of claim 32, wherein, The catalyst has a noble metal dispersion of 40-45%, a particle size of 2-6mm, a pore size of 40-100nm, a specific surface area of 20-60m 2 / g, and a catalyst strength of 50-80N / cm.

34. Use of an anchored, anti-sintering supported noble metal catalyst prepared by the method of any one of claims 1-31, characterized in that, The catalyst is used in the fields of ammonia oxidation, unsaturated hydrocarbon oxidation, petroleum hydrocarbon reforming and nitrogen oxide removal.

35. Use of an anchored, anti-sintering, supported noble metal catalyst prepared according to the method of any one of claims 1 to 31, characterized in that, The catalyst is used in the catalytic oxidation of chlorine-containing organic compounds and hydrogen chloride.

36. A process for the catalytic oxidation of hydrogen chloride to produce chlorine, characterized in that, The anchored anti-sintering supported noble metal catalyst prepared by the method of any one of claims 1-31 is used in the catalytic oxidation of hydrogen chloride.

37. The method of claim 36, wherein, The molar ratio of hydrogen chloride to oxygen is 1:0.25-1; the temperature of the catalytic oxidation reaction process is 280-340℃, and the pressure is 0.1-0.3 MPag. The reaction is carried out in a fixed bed reactor at a volume hourly space velocity of hydrogen chloride of 0.6 to 0.7 h -1 .

38. The method of claim 37, wherein, The molar ratio of hydrogen chloride to oxygen is 1:0.4-0.

6.

39. The method of claim 37, wherein, The temperature of the catalytic oxidation reaction process is 305-315℃, and the pressure is 0.15-0.25 MPag.