Method for preparing sulfur-tolerant noble metal catalyst, catalyst and application thereof

Abstract

The invention relates to the technical field of catalytic materials, and discloses a method for preparing a sulfur-tolerant noble metal catalyst, the catalyst and application of the catalyst. The catalyst contains a carrier and an active component loaded on the carrier, the active component contains Ru element and / or Au element, and the carrier is an M-ZSM-5 molecular sieve with an MFI structure; wherein M is a Co element and / or a Ni element; and the active component and Co element and / or Ni element in the carrier form alloy particles. The sulfur-tolerant noble metal CO catalytic oxidation catalyst provided by the invention can realize high conversion rate of low-concentration CO at a relatively low temperature, and is good in sulfur resistance and high in stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalytic materials, in particular to a method for preparing a sulfur-tolerant noble metal catalyst, the catalyst and application thereof. BACKGROUND

[0002] Carbon monoxide is one of the common pollutants in the atmosphere, mainly from incomplete combustion of carbon-containing substances. Very low concentration of carbon monoxide can enter the human body through the respiratory tract and cause poisoning. Therefore, controlling the concentration of carbon monoxide in the atmospheric environment is of great significance to human survival and health and environmental protection.

[0003] In some chemical production processes, the waste gas produced contains low concentration of CO gas (<20000 ppmv). For such waste gas, the recovery cost is high. In order to meet the emission requirements, the methods reported so far are to use Pt, Pd, Au and other noble metals as active components to prepare catalysts for catalytic oxidation of waste gas.

[0004] CN108067294A discloses an Au@ZSM-5 molecular sieve catalyst with gold nanoparticles wrapped in the molecular sieve crystal, which exhibits high sintering resistance and reaction stability in the high-temperature oxidation reaction of carbon monoxide.

[0005] CN110180582A discloses a low-noble-metal-loaded modified hierarchical pore zeolite molecular sieve catalyst for automobile exhaust treatment, which can achieve efficient adsorption of CO and C3H8 at room temperature and efficient catalytic oxidation of CO and C3H8 at 300℃ or below.

[0006] However, the CO-containing waste gas of many chemical plants also contains a certain concentration of sulfides (including H2S, COS, etc.) due to the influence of the previous process. Such sulfur compounds have a strong poisoning effect on noble metal catalysts and can easily cause catalyst deactivation. The above two catalysts cannot solve the above catalyst poisoning phenomenon caused by sulfides.

[0007] CN114177932A discloses a carbon monoxide low-temperature combustion catalyst, which can treat CO waste gas containing 50 ppm of sulfur at a relatively low reaction temperature. However, there is a problem of high removal temperature of non-noble metal catalyst system, and the ability to tolerate H2S and other sulfides is not clear.

[0008] Therefore, it is of great significance to develop a CO catalytic oxidation catalyst with high carbon monoxide oxidation activity, good sulfur tolerance and excellent reaction stability. SUMMARY

[0009] The present application aims to overcome the problem that the existing CO catalytic oxidation catalyst cannot remove CO with high efficiency while having good sulfur resistance, low removal temperature and high stability.

[0010] To achieve the above-mentioned object, the present application provides a sulfur-tolerant noble metal CO catalytic oxidation catalyst, which comprises a carrier and an active component supported on the carrier, wherein the active component comprises Ru element and / or Au element, the carrier is M-ZSM-5 molecular sieve with MFI structure, M is Co element and / or Ni element, and the active component and the Co element and / or Ni element in the carrier form alloy particles.

[0011] Preferably, the content of the Co element and / or Ni element in terms of metal elements is 2-5 wt%.

[0012] Preferably, the content of the Co element and / or Ni element in terms of metal elements is 2-5 wt%.

[0013] The present application provides a method for preparing a sulfur-tolerant noble metal CO catalytic oxidation catalyst, which comprises:

[0014] (1) impregnating M-ZSM-5 molecular sieve with MFI structure with an aqueous solution of noble metal precursor, and obtaining a catalyst precursor after calcination I; wherein M is Co element and / or Ni element;

[0015] (2) reducing the catalyst precursor at 300-500℃ in the presence of reducing atmosphere to obtain a sulfur-tolerant noble metal CO catalytic oxidation catalyst;

[0016] The control conditions are such that in the obtained sulfur-tolerant noble metal CO catalytic oxidation catalyst, the content of the active component in terms of metal elements is 0.1-0.7 wt% and the content of the Co element and / or Ni element in terms of metal elements is 0.5-8 wt% based on the total weight of the sulfur-tolerant noble metal CO catalytic oxidation catalyst; preferably, the content of the Co element and / or Ni element in terms of metal elements is 2-5 wt%.

[0017] Preferably, the content of the Co element and / or Ni element in terms of metal elements is 2-5 wt%.

[0018] The noble metal precursor is RuCl3 and / or chloroauric acid;

[0019] The preparation method of the M-ZSM-5 molecular sieve with MFI structure comprises:

[0020] S1, contacting and mixing ZSM-5 molecular sieve, an aluminum source, a silicon source and a precursor of transition metal M I to obtain a mixture I;

[0021] S2, in the presence of n-butylamine, the mixture I is sequentially subjected to first crystallization and second crystallization, and after calcination II, the M-ZSM-5 molecular sieve with MFI structure is obtained.

[0022] The third aspect of the present application provides the use of the sulfur-tolerant noble metal CO catalytic oxidation catalyst prepared by the method of the second aspect as a catalyst for carbon monoxide oxidation reaction.

[0023] Compared with the prior art, the technical scheme of the present application has at least the following advantages:

[0024] (1) The method provided by the present application is simple in process, low in cost, good in repeatability, can be mass-produced, and improves the dispersion degree of transition metal heteroatoms;

[0025] (2) The sulfur-tolerant noble metal CO catalytic oxidation catalyst prepared by the present application has high dispersion degree, and the catalyst exhibits good catalytic activity for low-temperature catalytic removal in carbon monoxide oxidation reaction, has high stability and excellent sulfur poisoning resistance. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a SEM image of a preferred sulfur-tolerant noble metal CO catalytic oxidation catalyst provided by the present application;

[0027] Figure 2 is a TEM image of a preferred sulfur-tolerant noble metal CO catalytic oxidation catalyst provided by the present application;

[0028] Figure 3 is an XRD image of a preferred sulfur-tolerant noble metal CO catalytic oxidation catalyst provided by the present application;

[0029] Figure 4 is a conversion rate graph of a preferred sulfur-tolerant noble metal CO catalytic oxidation catalyst catalytic oxidation CO provided by the present application. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0031] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0032] As described above, the first aspect of the present invention provides a sulfur-resistant noble metal CO catalytic oxidation catalyst, which comprises a carrier and an active component supported on the carrier, wherein the active component comprises Ru and / or Au, and the carrier is an M-ZSM-5 molecular sieve having an MFI structure; wherein M is Co and / or Ni; and the active component forms alloy particles with the Co and / or Ni elements in the carrier;

[0033] Based on the total weight of the sulfur-resistant noble metal CO catalytic oxidation catalyst, the content of the active component calculated as metal element is 0.1-0.7 wt%, and the content of the Co element and / or Ni element calculated as metal element is 0.5-8 wt%;

[0034] Preferably, the content of the Co element and / or Ni element calculated as metal elements is 2-5 wt%.

[0035] As mentioned above, the second aspect of the present invention provides a method for preparing a sulfur-resistant noble metal CO catalytic oxidation catalyst, comprising:

[0036] (1) impregnating an M-ZSM-5 molecular sieve having an MFI structure with an aqueous solution of a noble metal precursor, and calcining the mixture to obtain a catalyst matrix; wherein M is Co and / or Ni;

[0037] (2) reducing the catalyst precursor at 300-500° C. in the presence of a reducing atmosphere to obtain a sulfur-resistant noble metal CO catalytic oxidation catalyst;

[0038] The conditions are controlled so that in the obtained sulfur-resistant precious metal CO catalytic oxidation catalyst, the content of the active component as a metal element is 0.1-0.7 wt%, and the content of the Co element and / or the Ni element as a metal element is 0.5-8 wt%, based on the total weight of the sulfur-resistant precious metal CO catalytic oxidation catalyst; preferably, the content of the Co element and / or the Ni element as a metal element is 2-5 wt%;

[0039] Wherein, the active component contains Ru element and / or Au element;

[0040] The noble metal precursor is RuCl3 and / or chloroauric acid;

[0041] The preparation method of the M-ZSM-5 molecular sieve with MFI structure comprises:

[0042] S1, contacting and mixing ZSM-5 molecular sieve, aluminum source, silicon source and precursor of transition metal M I to obtain mixture I;

[0043] S2, in the presence of n-butylamine, the mixture I is sequentially subjected to first crystallization and second crystallization, and after calcination II, the M-ZSM-5 molecular sieve with MFI structure is obtained.

[0044] Preferably, in step S1, the weight ratio of the use amount of the ZSM-5 molecular sieve, the aluminum source, the silicon source and the precursor of the transition metal M is 1:2-10:50-70:0.2-2.

[0045] Preferably, in step S1, the weight ratio of the use amount of the n-butylamine and the mixture I is 1:30-45.

[0046] Preferably, in step S1, the precursor of the transition metal M is selected from at least one of sulfate of metal M, chloride of metal M and nitrate of metal M.

[0047] Preferably, the silicon-aluminum ratio of the ZSM-5 molecular sieve is 18-46. The inventors found that in this preferred case, the prepared sulfur-tolerant noble metal CO catalytic oxidation catalyst has better sulfur-tolerant catalytic performance.

[0048] Preferably, the aluminum source is aluminum sulfate and / or aluminum chloride.

[0049] More preferably, the aluminum source is Al2(SO4)3·18H2O.

[0050] Preferably, the silicon source is sodium silicate with a modulus of 1.5-3.5.

[0051] Preferably, in step S1, the operation of contacting and mixing I comprises:

[0052] SS1, first contacting the aluminum source with water I, then adding a 95.0-98.0wt% sulfuric acid solution for second contacting, and then adding the ZSM-5 molecular sieve for third contacting to obtain mixture II;

[0053] SS2, adding silicon source and water II to the mixture II for fourth contacting to obtain mixture III;

[0054] SS3, fifth contacting the precursor of the transition metal M with the mixture III to obtain the mixture I.

[0055] Preferably, in step SS1, the weight ratio of the amount of the aluminum source, the water I and the sulfuric acid solution is 1:8-15:0.5-1.5.

[0056] Preferably, in step SS2, the weight ratio of the amount of the silicon source and the water II is 1:0.2-1.2.

[0057] It should be noted that, in the present application, the water I and the water II are both water.

[0058] Preferably, in step SS2, the silicon source is added to the mixture II in the form of dropwise addition, and the dropwise addition speed of the silicon source is 20-40 mL / min per 1 L of the mixture II.

[0059] According to a preferred embodiment, the first contact, the second contact, the third contact, the fourth contact and the fifth contact each independently satisfy the following conditions: being carried out under stirring, and at least satisfying the following conditions: temperature is 20-30℃, rotation speed is 300-500 rpm, and time is 5-35 min.

[0060] Preferably, the temperature of the first crystallization is 60-70℃ lower than that of the second crystallization. The inventors have found that, in this preferred case, the sulfur-resistant noble metal CO catalytic oxidation catalyst prepared has better sulfur-resistant reaction performance.

[0061] Preferably, in step S2, the conditions of the first crystallization at least satisfy the following conditions: temperature is 120-140℃, and time is 4-6h.

[0062] Preferably, in step S2, the conditions of the second crystallization at least satisfy the following conditions: temperature is 160-220℃, and time is 14-16h.

[0063] Preferably, the method further comprises: in step S2, before the first crystallization, mixing the n-butylamine with the mixture I at a rotation speed of 300-500 rpm for 1-3h, and then carrying out the first crystallization on the obtained product.

[0064] It should be noted that, in the present application, the reactor for the first crystallization and the second crystallization is not specifically limited, and can be carried out using the technical means commonly used in the art, for example, in a crystallization kettle with a polytetrafluoroethylene lining.

[0065] Preferably, the method of the present application further comprises: in step S2, after the second crystallization is completed, washing the product of the second crystallization with deionized water to a pH of 6.5-7.5, and then drying it at 90-120℃ for 6-12h to obtain mixture IV, and finally applying the mixture IV to the calcination II.

[0066] Preferably, the calcination I and / or the calcination II is carried out in a muffle furnace.

[0067] Preferably, the method of the present application further comprises: in step S2, raising the temperature of the mixture IV to 450-550℃ at a rate of 1-3℃ / min, and then carrying out the calcination II at 450-550℃ for 3-6h.

[0068] According to a preferred embodiment, the method of the present application further comprises: in step (1), the impregnation treatment is carried out by an equal volume impregnation method, which comprises: impregnating the M-ZSM-5 molecular sieve with MFI structure in a diluted aqueous solution of noble metal precursor at room temperature for 12-24h.

[0069] Preferably, the impregnation treatment is carried out under sealed conditions, and the temperature is 20-30℃.

[0070] Preferably, the concentration of the diluted aqueous solution of noble metal precursor is 0.02-0.05mol / L.

[0071] Preferably, before the impregnation treatment is carried out, the M-ZSM-5 molecular sieve with MFI structure is subjected to a saturated water absorption rate determination, which comprises:

[0072] The M-ZSM-5 molecular sieve with MFI structure with a mass of m1 is placed in a graduated cylinder to obtain its bulk volume V1, and deionized water with a volume of V2 and a mass of m2 is added, and after stirring and standing for 12-24h, the volume of the mixed liquid in the graduated cylinder is read as V3, and the saturated water absorption rate ω of the M-ZSM-5 molecular sieve with MFI structure can be calculated by the following formula:

[0073]

[0074] Then, using the saturated water absorption rate (ω) calculated as described above, the total volume of the diluted aqueous solution of noble metal precursor is calculated by the following formula: t :

[0075] V t = m 2* ω (mL)

[0076] m2: mass of the M-ZSM-5 molecular sieve with MFI structure to be impregnated, g.

[0077] Preferably, the method of the present application further comprises: in step (1), before performing the calcination I, the temperature of the product after the impregnation treatment is increased to the temperature of the calcination I at a rate of 1-3 ℃ / min, and then the calcination I is performed.

[0078] Preferably, the temperature of the calcination I is 450-500 ℃.

[0079] Preferably, the time of the calcination I is 3-6 h.

[0080] According to a preferred embodiment, in step (2), the reducing atmosphere is a mixed gas atmosphere of H2 / Ar with a H2 content of 5-15 vol%.

[0081] Preferably, in step (2), the time of the reduction is 0.5-2 h.

[0082] According to a preferred embodiment, the reduction is performed in a fixed bed reactor.

[0083] As mentioned above, the third aspect of the present application provides the use of the sulfur-tolerant noble metal CO catalytic oxidation catalyst prepared by the method of the second aspect as a catalyst for carbon monoxide oxidation reaction.

[0084] Preferably, the reaction raw gas used in the process of the carbon monoxide oxidation reaction contains 0.4 vol% or less of CO.

[0085] Preferably, the reaction raw gas used in the process of the carbon monoxide oxidation reaction contains 0.02 vol% or less of sulfide.

[0086] Preferably, the temperature of the carbon monoxide oxidation reaction is 150-300 ℃.

[0087] The sulfur-tolerant noble metal CO catalytic oxidation catalyst of the present application, the preparation method thereof and the use thereof will be further illustrated by the following examples. The examples are implemented on the premise of the technical solutions of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0088] In the present application, unless otherwise specified, the normal temperature or room temperature involved in the following examples is 25±5 ℃.

[0089] In the following examples, unless otherwise specified, the experimental methods are all conventional methods in the art.

[0090] The experimental materials used in the following examples are all of analytical purity grade and commercially available, for example, purchased from the National Pharmaceutical Group Chemical Reagent Co., Ltd., unless otherwise specified.

[0091] ZSM-5 molecular sieve I: with a silicon-aluminum ratio of 38, purchased from Tianjin Nanhua Catalyst Co., Ltd., with a brand of NKF-5D-38H;

[0092] ZSM-5 molecular sieve II: with a silicon-aluminum ratio of 60, purchased from Tianjin Nanhua Catalyst Co., Ltd., with a brand of NKF-5-60H;

[0093] Aluminum source: Al2(SO4)3·18H2O;

[0094] Silicon source: sodium silicate with a modulus of 1.5, purchased from Shandong Huixin Chemical Technology Co., Ltd., with a brand of NS-2;

[0095] Precursor of transition metal M: Ni(NO3)2·6H2O;

[0096] Diluted aqueous solution of noble metal precursor: chloroauric acid with a concentration of 0.02 mol / L;

[0097] Gas chromatograph: model Agilent 8890A, purchased from Agilent Technologies, USA;

[0098] Fixed bed reactor: model TD-501, purchased from Qingdao Jetian Electrical Equipment Co., Ltd.;

[0099] Inductively coupled plasma emission spectrometer: model PerkinElmer ICP 2100, purchased from PerkinElmer Inc.;

[0100] In the following examples, the inductively coupled plasma emission spectrometer is used to determine the element content, unless otherwise specified.

[0101] Preparation Example 1

[0102] This example is used to illustrate a preferred method for preparing M-ZSM-5 molecular sieve with MFI structure provided by the present application, which comprises:

[0103] S1, at 27℃, ZSM-5 molecular sieve I (0.75g), aluminum source, silicon source and precursor of transition metal M are contacted and mixed I with a weight ratio of 1:3:67:0.37:

[0104] SS1, first contact the aluminum source with water I at 300 rpm for 5 min at a weight ratio of 1:13, then add 3 g of 98.0 wt% sulfuric acid solution at 300 rpm for 10 min for the second contact, and then add the ZSM-5 molecular sieve for the third contact for 10 min to obtain mixture II;

[0105] SS2, add the silicon source and water II to the mixture II at 300 rpm for 30 min at a weight ratio of 1:0.2 for the fourth contact to obtain mixture III;

[0106] wherein the silicon source is added to the mixture II in the form of drops, and the dropwise addition rate of the silicon source is 20 mL / min per 1 L of the mixture II;

[0107] SS3, contact the precursor of the transition metal M with the mixture III at 300 rpm for 10 min for the fifth contact to obtain the mixture I;

[0108] S2, add 1.5 g of n-butylamine to the mixture I at 300 rpm for 2 h, then load it into a crystallization kettle with a polytetrafluoroethylene liner, and then place it in a forced air oven, and perform the first crystallization at 120°C for 5 h, and then perform the second crystallization at 180°C for 15 h, wash the product of the second crystallization with deionized water until the pH is 7.0, and then place it in an oven at 100°C for 12 h to obtain mixture IV, and then increase the temperature of the mixture IV to 550°C at a rate of 3°C / min in a muffle furnace, and then perform the calcination II at 550°C for 4 h to obtain the M-ZSM-5 molecular sieve with MFI structure, which is named as a1.

[0109] Preparation Example 2

[0110] This example is used to illustrate a preferred method for preparing the M-ZSM-5 molecular sieve with MFI structure provided by the present application, which comprises:

[0111] S1, contact and mix I the ZSM-5 molecular sieve I (0.75 g), the aluminum source, the silicon source, and the precursor of the transition metal M at 25°C at a weight ratio of 1:5:60:1:

[0112] SS1, first contact the aluminum source with water I at 450 rpm for 5 min at a weight ratio of 1:15, then add 3.75 g of 98.0 wt% sulfuric acid solution at 450 rpm for 10 min for the second contact, and then add the ZSM-5 molecular sieve for the third contact for 10 min to obtain mixture II;

[0113] SS2, the silicon source and water II are added to the mixture II in a weight ratio of 1:0.5 at 500 rpm for the fourth contact for 30 min to obtain mixture III;

[0114] wherein the silicon source is added to the mixture II in the form of drops, and the dropwise adding speed of the silicon source is 30 mL / min per 1 L of the mixture II;

[0115] SS3, the precursor of the transition metal M is contacted with the mixture III at 350 rpm for the fifth contact for 30 min to obtain the mixture I;

[0116] S2, 1.5 g of n-butylamine is added to the mixture I at 400 rpm for mixing for 2 h, and then the mixture is loaded into a crystallization kettle with a polytetrafluoroethylene liner and placed in a blast oven, and the first crystallization is carried out at 120℃ for 5 h, and the second crystallization is carried out at 180℃ for 15 h, the product of the second crystallization is washed with deionized water until the pH is 7.0, and then it is placed in an oven at 100℃ for drying for 12 h to obtain mixture IV, and the temperature of the mixture IV is increased to 450℃ at a rate of 2℃ / min in a muffle furnace, and then the calcination II is carried out at 450℃ for 6 h to obtain the M-ZSM-5 molecular sieve with MFI structure, which is named as a2.

[0117] Preparation Example 3

[0118] The present preparation example is carried out by using the similar method of Preparation Example 1, except that the temperature of the first crystallization is 100℃, and the temperature of the second crystallization is 180℃, to obtain the M-ZSM-5 molecular sieve with MFI structure, which is named as a3.

[0119] Preparation Example 4

[0120] The present preparation example is carried out by using the similar method of Preparation Example 1, except that the ZSM-5 molecular sieve used is ZSM-5 molecular sieve II, to obtain the M-ZSM-5 molecular sieve with MFI structure, which is named as a4.

[0121] Preparation Example 5

[0122] The present preparation example is carried out by using the similar method of Preparation Example 1, except that no ZSM-5 molecular sieve is used in the contact mixing I in S1, and the specific operation steps of S1 are as follows:

[0123] At 27℃, 2.25 g of an aluminum source, 50.3 g of a silicon source, and 0.28 g of a precursor of a transition metal M are subjected to contact mixing I:

[0124] SS1, first contact the aluminum source with water I at 300 rpm for 5 min with a use amount weight ratio of 1:13, then add a 98.0 wt% sulfuric acid solution at 300 rpm for a second contact of 10 min to obtain mixture II;

[0125] SS2, add the silicon source and water II to the mixture II at 300 rpm for a fourth contact of 30 min with a use amount weight ratio of 1:0.2 to obtain mixture III;

[0126] wherein the silicon source is added to the mixture II in the form of drops, and the dropwise addition rate of the silicon source is 20 mL / min per 1 L of the mixture II;

[0127] SS3, contact the precursor of the transition metal M with the mixture III at 300 rpm for a fifth contact of 10 min to obtain the mixture I;

[0128] Finally, a molecular sieve is obtained, designated as a5.

[0129] Preparation Example 6

[0130] The present preparation example is carried out by using a method similar to that of Preparation Example 1, except that the ZSM-5 molecular sieve, the aluminum source, the silicon source and the precursor of the transition metal M are not contacted in contact mixture I in S1 with a use amount weight ratio of 1:3:67:0.1.

[0131] The M-ZSM-5 molecular sieve with MFI structure is obtained, designated as a6.

[0132] Example 1

[0133] The present example is used to illustrate a preferred method for preparing a sulfur-tolerant noble metal CO catalytic oxidation catalyst provided by the present application, which is carried out according to the following steps, specifically comprising:

[0134] (1) At room temperature, 10 g of the M-ZSM-5 molecular sieve with MFI structure (a1) is weighed, the saturated water absorption rate of a1 is determined to be 0.7 mL / g, and the total volume of the diluted noble metal precursor aqueous solution is calculated to be 7.0 mL, and an equal volume impregnation method is used to immerse the M-ZSM-5 molecular sieve with MFI structure in the diluted noble metal precursor aqueous solution for 12 h under sealed conditions;

[0135] Then the product after the immersion treatment is placed in a blast drying oven at 80℃ for drying, and then the temperature is raised to 500℃ at a rate of 3℃ / min in a muffle furnace, and then the catalyst precursor is obtained after the calcination I for 4 h; wherein M is Ni element;

[0136] (2) the catalyst precursor is reduced in a fixed bed reactor at 500 DEG C in the presence of a reducing atmosphere (H2 / Ar mixed atmosphere with 10 vol% H2) for 1 h to obtain a sulfur-tolerant noble metal CO catalytic oxidation catalyst, named P1;

[0137] wherein the content of the active component Au is 0.52 wt% in terms of metal elements, and the content of Ni element is 4.2 wt% in terms of metal elements;

[0138] Figure 1 The SEM image of P1 is shown in FIG. 1, Figure 1 As can be seen in FIG. 1, P1 has a typical cubic structure;

[0139] Figure 2 The TEM image of P1 is shown in FIG. 2, Figure 2 As can be seen in FIG. 2, nanoparticles with uniform size and good dispersion are formed on P1, and the line scan result shows that the nanoparticles are in Au-Ni alloy state, which is beneficial to improving the sulfur-tolerant carbon monoxide oxidation reaction capacity of the catalyst;

[0140] Figure 3 The XRD image of P1 is shown in FIG. 3, Figure 3 As can be seen in FIG. 3, the synthesized catalyst has a typical MFI structure and good crystallinity.

[0141] Example 2

[0142] This example is used to illustrate a preferred method for preparing a sulfur-tolerant noble metal CO catalytic oxidation catalyst provided by the present application, which is carried out according to the following steps and specifically comprises:

[0143] (1) 10 g of M-ZSM-5 molecular sieve with MFI structure (a2) is weighed at room temperature, the saturated water absorption rate of a2 is determined to be 0.75 mL / g, and the total volume of the diluted noble metal precursor aqueous solution is calculated to be 7.5 mL, and the M-ZSM-5 molecular sieve with MFI structure is immersed in the diluted noble metal precursor aqueous solution under sealed conditions for 15 h by using the equal-volume impregnation method;

[0144] Then the product after the impregnation treatment is placed in a blast drying oven at 80 DEG C for drying, and then the temperature is raised to 500 DEG C at a rate of 3 DEG C / min in a muffle furnace, and then the catalyst precursor is obtained after the first calcination for 5 h; wherein M is Ni element;

[0145] (2) the catalyst precursor is reduced in a fixed bed reactor at 500 DEG C in the presence of a reducing atmosphere (H2 / Ar mixed atmosphere with 10 vol% H2) for 1 h to obtain a sulfur-tolerant noble metal CO catalytic oxidation catalyst, named P2;

[0146] The content of the active component Au is 0.37wt% as measured by metal elements, and the content of Ni element is 3.2wt% as measured by metal elements.

[0147] Example 3

[0148] The present preparation example is carried out by using the similar method as in Preparation Example 1, except that in step (1), the M-ZSM-5 molecular sieve with MFI structure used is a3, to obtain a sulfur-tolerant noble metal CO catalytic oxidation catalyst, named as P3;

[0149] The content of the active component Au is 0.50wt% as measured by metal elements, and the content of Ni element is 4.0wt% as measured by metal elements.

[0150] Example 4

[0151] The present preparation example is carried out by using the similar method as in Preparation Example 1, except that in step (1), the M-ZSM-5 molecular sieve with MFI structure used is a4, to obtain a sulfur-tolerant noble metal CO catalytic oxidation catalyst, named as P4;

[0152] The content of the active component Au is 0.53wt% as measured by metal elements, and the content of Ni element is 3.2wt% as measured by metal elements.

[0153] Example 5

[0154] The present preparation example is carried out by using the similar method as in Preparation Example 1, except that in step (1), the temperature of the calcination I is 600℃, to obtain a sulfur-tolerant noble metal CO catalytic oxidation catalyst, named as P5;

[0155] The content of the active component Au is 0.52wt% as measured by metal elements, and the content of Ni element is 4.2wt% as measured by metal elements.

[0156] Example 6

[0157] The present preparation example is carried out by using the similar method as in Preparation Example 1, except that in step (1), the M-ZSM-5 molecular sieve with MFI structure used is a6, to obtain a sulfur-tolerant noble metal CO catalytic oxidation catalyst, named as P6;

[0158] The content of the active component Au is 0.1wt% as measured by metal elements, and the content of Ni element is 1.4wt% as measured by metal elements.

[0159] Comparative Example 1

[0160] The comparative example was carried out in a similar manner to Preparation Example 1, except that in step (1), equal mass (10 g) of ZSM-5 molecular sieve I was used instead of M-ZSM-5 molecular sieve (a1) having MFI structure for impregnation treatment, to obtain a CO catalytic oxidation catalyst, designated as DP1;

[0161] The content of active component Au was measured as 0.54wt% in terms of metal elements, and the content of Ni element was 4.4wt% in terms of metal elements.

[0162] Comparative Example 2

[0163] The comparative example was carried out in a similar manner to Preparation Example 1, except that in step (1), molecular sieve a5 was used instead of M-ZSM-5 molecular sieve (a1) having MFI structure for impregnation treatment, to obtain a CO catalytic oxidation catalyst, designated as DP2;

[0164] The content of active component Au was measured as 0.52wt% in terms of metal elements, and the content of Ni element was 4.1wt% in terms of metal elements.

[0165] Comparative Example 3

[0166] The comparative example was carried out in a similar manner to Preparation Example 1, except that in step (2), the temperature of reduction was 600℃, and finally a CO catalytic oxidation catalyst was obtained, designated as DP3;

[0167] The content of active component Au was measured as 0.52wt% in terms of metal elements, and the content of Ni element was 4.2wt% in terms of metal elements.

[0168] Test Example 1

[0169] The catalyst prepared in the above examples was placed in a fixed bed reactor (reaction tube inner diameter of 6 mm), and heated to 250℃ at a heating rate of 5℃ / min, and then the catalyst was subjected to catalytic oxidation reaction with raw material gas for 200h, wherein

[0170] The composition of the reaction raw material gas was: 0.4vol% CO (C0), 0.005vol% H2S, 5vol% O2 and 94.395vol% CO2, and the reaction space velocity was 10000h -1 .

[0171] The concentration of CO at the outlet of the reactor at time t (C t ) was detected by a gas chromatograph, and the CO conversion rate was calculated according to the following formula: CO conversion rate t / %=(C t- C0) / C0*100%;

[0172] The change of CO conversion rate of the product P1 with time within 200h was monitored, and the results are shown in Table 1. Figure 4 As can be seen from Figure 4 , the CO conversion rate of P1 can be maintained above 99% during the long-period carbon monoxide oxidation reaction process of 200h.

[0173] The CO conversion rate of the catalyst prepared in the above examples after 200h of reaction at 250℃ was calculated, and the results are shown in Table 1.

[0174] T 50 , which is the temperature corresponding to a CO conversion rate of 50%;

[0175] T 90 , which is the temperature corresponding to a CO conversion rate of 90%.

[0176] Table 1

[0177]

[0178] As can be seen from the above results, the sulfur-tolerant noble metal CO catalytic oxidation catalyst provided by the present application can achieve high conversion rate of low-concentration CO at a lower temperature, has good sulfur resistance and high stability, and the CO conversion rate can still be maintained above 99% during the long-period carbon monoxide oxidation reaction process of 200h.

[0179] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A sulfur-resistant noble metal CO catalytic oxidation catalyst, characterized in that: The catalyst comprises a carrier and an active component supported on the carrier, wherein the active component comprises Ru and / or Au, and the carrier is an M-ZSM-5 molecular sieve having an MFI structure; wherein M is Co and / or Ni; and the active component forms alloy particles with the Co and / or Ni elements in the carrier. Based on the total weight of the sulfur-resistant noble metal CO catalytic oxidation catalyst, the content of the active component calculated as metal element is 0.1-0.7 wt%, and the content of the Co element and / or Ni element calculated as metal element is 0.5-8 wt%; Preferably, the content of the Co element and / or Ni element calculated as metal elements is 2-5 wt%.

2. A method for preparing a sulfur-resistant noble metal CO catalytic oxidation catalyst, characterized in that: include: (1) impregnating an M-ZSM-5 molecular sieve having an MFI structure with an aqueous solution of a noble metal precursor, and calcining the mixture to obtain a catalyst matrix; wherein M is Co and / or Ni; (2) reducing the catalyst precursor at 300-500° C. in the presence of a reducing atmosphere to obtain a sulfur-resistant noble metal CO catalytic oxidation catalyst; The conditions are controlled so that in the obtained sulfur-resistant precious metal CO catalytic oxidation catalyst, the content of the active component as a metal element is 0.1-0.7 wt%, and the content of the Co element and / or the Ni element as a metal element is 0.5-8 wt%, based on the total weight of the sulfur-resistant precious metal CO catalytic oxidation catalyst; preferably, the content of the Co element and / or the Ni element as a metal element is 2-5 wt%; Wherein, the active component contains Ru element and / or Au element; The noble metal precursor is RuCl3 and / or chloroauric acid; The preparation method of the M-ZSM-5 molecular sieve having an MFI structure comprises: S1, contacting and mixing a ZSM-5 molecular sieve, an aluminum source, a silicon source, and a precursor of a transition metal M to obtain a mixture I; S2. In the presence of n-butylamine, the mixture I is subjected to a first crystallization and a second crystallization in sequence, and the M-ZSM-5 molecular sieve having an MFI structure is obtained after calcination II.

3. The method according to claim 2, wherein: The temperature of the first crystallization is 60-70° C. lower than that of the second crystallization.

4. The method according to claim 3, wherein: In step S2, the first crystallization conditions at least meet the following requirements: temperature of 120-140° C., time of 4-6 h; and / or In step S2, the second crystallization conditions at least meet the following requirements: temperature of 160-220°C and time of 14-16 hours.

5. The method according to any one of claims 2 to 4, wherein: In step S1, the precursor of the transition metal M is selected from at least one of a sulfate of metal M, a chloride of metal M and a nitrate of metal M; Preferably, the silicon to aluminum ratio of the ZSM-5 molecular sieve is 18-46.

6. The method according to any one of claims 2 to 5, wherein: The method further comprises: in step (1), before performing the roasting I, first raising the temperature of the product after the impregnation treatment to the roasting temperature of the roasting I at a rate of 1-3°C / min, and then performing the roasting I; Preferably, the temperature of the calcination I is 450-500°C; Preferably, the roasting time is 3-6 hours.

7. Use of the sulfur-resistant noble metal CO catalytic oxidation catalyst prepared by the method according to any one of claims 2 to 6 as a catalyst for carbon monoxide oxidation reaction.

8. The use according to claim 7, wherein: The reaction raw gas used in the carbon monoxide oxidation reaction contains less than 0.4 vol% of CO.

9. The use according to claim 7 or 8, wherein: The reaction raw gas used in the carbon monoxide oxidation reaction contains sulfides in an amount of less than 0.02 vol%.

10. The use according to any one of claims 7 to 8, wherein: The temperature of the carbon monoxide oxidation reaction is 150-300°C.

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