Platinum carbon catalysts, methods for their preparation and use

Abstract

This invention relates to the field of catalysis technology, and discloses a platinum-carbon catalyst, its preparation method, and its application. The platinum-carbon catalyst comprises sulfur-containing conductive carbon black and platinum metal supported thereon. The sulfur-containing conductive carbon black comprises conductive carbon black and sulfur elements incorporated therein. The total sulfur content in the sulfur-containing conductive carbon black is greater than or equal to the surface sulfur content, and the platinum content in the platinum-carbon catalyst is 0.1-5% by mass. This invention employs a simple method to incorporate sulfur into conductive carbon black. When applied to the dehydrogenation reaction of low-carbon alkanes, it significantly improves the activity and stability of the catalyst. It can efficiently catalyze the dehydrogenation of low-carbon alkanes to olefins under relatively low temperature and platinum loading conditions, reducing catalyst cost, reaction temperature, and energy consumption, and has good prospects for industrial application.

Description

Technical Field

[0001] This invention relates to the field of catalysis technology, specifically to a platinum-carbon catalyst, its preparation method, and its application. Background Technology

[0002] Ethylene, propylene, butene, and other low-carbon olefins are important organic chemical raw materials. Their sources include petroleum refining products and byproducts, as well as specialized olefin production processes. For example, crude oil undergoes distillation and refining processes to produce finished oil products while simultaneously generating low-carbon olefins as byproducts; naphtha undergoes steam cracking to produce ethylene while simultaneously generating propylene and butene as byproducts; coal or methanol-to-olefins processes; and catalytic dehydrogenation to produce olefins. Traditional petroleum-based separation processes are complex, energy-intensive, and involve large investments and high costs in olefin production, with low olefin yields, making it difficult to meet the growing market demand for olefins. Therefore, non-petroleum-based technologies for producing low-carbon olefins have become a research hotspot. Low-carbon alkanes exhibit significant advantages due to their wide availability, low price, and the short process flow and lower investment and operating costs of catalytic dehydrogenation units. Alkane dehydrogenation is a strongly endothermic, reversible reaction involving an increase in the number of molecules; high temperature and low pressure favor the dehydrogenation reaction. However, high temperatures can lead to the aggregation of active catalyst particles, resulting in reduced catalyst activity. Furthermore, conventional industrial carriers such as molecular sieves and alumina are inherently highly acidic, easily leading to deep cracking of alkanes and further reducing catalyst activity. Therefore, designing and controlling catalysts to effectively improve alkane conversion and olefin selectivity is the main research direction.

[0003] In the field of alkane dehydrogenation, noble metal catalysts have demonstrated excellent catalytic activity. Among them, platinum group catalysts are commonly used in the dehydrogenation of low-carbon alkanes, and some platinum group catalysts have already been applied in commercial production. Reducing costs and improving performance have always been important directions in the research of noble metal catalysts.

[0004] The selection of the support is crucial for the development of high-performance noble metal catalysts. In recent years, carbon materials have gradually become a research hotspot as catalyst supports, possessing characteristics not found in traditional catalyst supports, such as resistance to acid and alkali media and controllable surface physicochemical properties. Introducing heteroatoms such as N, B, P, and S into the carbon framework can control the physicochemical properties of carbon materials, such as electron transport rate, specific surface area, pore structure, wettability, and surface acidity / alkalinity, which helps expand the application of carbon materials in fuel cells, water electrolysis, supercapacitors, and heterogeneous catalysis. Compared to N composites with atomic diameters similar to C atoms, incorporating S, with its larger atomic radius, into the carbon lattice is much more difficult. This is mainly because S composites cannot maintain the planar structure of carbon materials, resulting in significant stress and tension. Currently reported S composite methods in composite carbon materials are complex, and achieving efficient and controllable S composites remains a challenge. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of manufacturing highly active platinum-carbon catalysts at low cost, and to provide a platinum-carbon catalyst, its preparation method, and its applications. This invention employs a simple method to incorporate sulfur into conductive carbon black, which, when applied to the dehydrogenation reaction of low-carbon alkanes, significantly improves the catalyst's activity and stability. It can efficiently catalyze the dehydrogenation of low-carbon alkanes to olefins under relatively low temperature and platinum loading conditions, reducing catalyst cost, reaction temperature, and energy consumption, and has good prospects for industrial application.

[0006] To achieve the above objectives, the present invention provides a platinum-carbon catalyst comprising sulfur-containing conductive carbon black and platinum metal supported thereon. The sulfur-containing conductive carbon black comprises conductive carbon black and sulfur element incorporated therein. The total sulfur content in the sulfur-containing conductive carbon black is greater than or equal to the surface sulfur content, preferably more than 1.2 times the surface sulfur content, and more preferably more than 1.5 times. The platinum content in the platinum-carbon catalyst is 0.1-5% by mass, preferably 0.2-1% by mass.

[0007] Preferably, the total sulfur content in the sulfur-containing conductive carbon black is 3% by mass or more, and more preferably 5-15% by mass.

[0008] Preferably, the surface sulfur content in the sulfur-containing conductive carbon black is 2-15% by mass, more preferably 3-14% by mass.

[0009] Preferably, the characteristic peak of Pt 4f 7 / 2 in the XPS spectrum of the platinum-carbon catalyst is located above 71.9 eV.

[0010] Preferably, the conductive carbon black is one or more of EC-300J, EC-600JD, ECP600JD, VXC72, VXC72R, Blackpearls 2000, PRINTEX XE2-B, PRINTEX L6, and HIBLAXK40B2.

[0011] Preferably, the oxygen content in the conductive carbon black, as determined by XPS analysis, is greater than 4% by mass.

[0012] Preferably, the specific surface area of ​​the conductive carbon black is 200-2000 m². 2 / g.

[0013] A second aspect of the present invention provides a method for preparing a platinum-carbon catalyst, the method comprising:

[0014] (1) Impregnate conductive carbon black with a sulfur-containing solution at 10-80℃ for 1-5 hours, and then dry the impregnated product to obtain sulfur-containing conductive carbon black.

[0015] (2) Remove the solvent from the homogeneous mixture containing sulfur-containing conductive carbon black, platinum source and solvent obtained in step (1) to obtain the precursor material;

[0016] (3) In a reducing atmosphere, the precursor material obtained in step (2) is heat-treated at 80-200℃ for 1-4 hours to obtain a platinum carbon catalyst.

[0017] In step (2), the amount of platinum source used relative to 1g of sulfur-containing conductive carbon black is 0.001-0.055g, preferably 0.001-0.011g, based on the elemental platinum.

[0018] Preferably, the conductive carbon black is one or more of EC-300J, EC-600JD, ECP600JD, VXC72, VXC72R, Blackpearls 2000, PRINTEX XE2-B, PRINTEX L6, and HIBLAXK40B2.

[0019] Preferably, the oxygen content in the conductive carbon black, as determined by XPS analysis, is greater than 4% by mass.

[0020] Preferably, the specific surface area of ​​the conductive carbon black is 200-2000 m². 2 / g.

[0021] Preferably, in step (1), the solvent in the sulfur-containing solution is one or more of CCl4, CS2, cyclohexane, and n-hexane.

[0022] Preferably, in step (1), the concentration of sulfur in the sulfur-containing solution is 0.0004-0.02 g / mL.

[0023] Preferably, in step (1), the amount of sulfur used is 0.005-0.15g relative to 1g of conductive carbon black.

[0024] Preferably, in step (1), the drying conditions include a temperature of 20-100℃ and a time of 5-10h.

[0025] Preferably, in step (2), the platinum source is one or more of chloroplatinic acid, chloroplatinate, tetraammineplatinum acetate, and platinum acetylacetonate.

[0026] Preferably, in step (2), the solvent is one or more of water, alcohol solvents or ketone solvents.

[0027] Preferably, in step (2), the solvent is water and / or ethanol, more preferably a mixture of water and ethanol.

[0028] Preferably, in step (2), after the homogeneous mixture is allowed to stand, the solvent is removed, and the standing time is more than 10 hours, preferably 15-24 hours.

[0029] Preferably, in step (2), the drying temperature during solvent removal is below 100°C.

[0030] Preferably, in step (3), the reducing atmosphere includes hydrogen, preferably a mixture of hydrogen and an inert gas, more preferably a mixture of hydrogen and nitrogen; preferably, hydrogen accounts for 5-30% of the total gas volume.

[0031] A third aspect of the present invention provides a platinum-carbon catalyst, which is prepared by the preparation method of the second aspect of the present invention described above.

[0032] The fourth aspect of the present invention provides the application of the platinum-carbon catalyst described in the first or third aspect of the present invention in the dehydrogenation of low-carbon alkanes to olefins.

[0033] Preferably, the low-carbon alkane is selected from one or more C2-C8 alkane compounds.

[0034] Preferably, the reaction conditions for the dehydrogenation of the low-carbon alkane include: a temperature of 400-650℃, preferably 400-550℃, a reaction space velocity of 1000-6000 mL of reaction gas / (h·g catalyst), and a pressure of 0.01-0.5 MPa.

[0035] Preferably, the content of the low-carbon alkanes in the reaction gas is 1-5% by volume; more preferably, the molar ratio of low-carbon alkanes to hydrogen in the reaction gas is 1:(0.5-5).

[0036] A fifth aspect of the present invention provides a method for the dehydrogenation of alkane to olefins, the method comprising: contacting a reaction gas containing low-carbon alkanes and hydrogen with a platinum-carbon catalyst under dehydrogenation reaction conditions; wherein the platinum-carbon catalyst comprises sulfur-containing conductive carbon black and platinum metal supported thereon, the sulfur-containing conductive carbon black comprising conductive carbon black and sulfur element incorporated therein, the total sulfur content in the sulfur-containing conductive carbon black being greater than or equal to the surface sulfur content, preferably the total sulfur content being more than 1.2 times the surface sulfur content, more preferably more than 1.5 times; the platinum content in the platinum-carbon catalyst being 0.1-5% by mass, preferably 0.2-1% by mass.

[0037] Preferably, the low-carbon alkane is selected from one or more C2-C8 alkane compounds.

[0038] Preferably, the conditions for the dehydrogenation reaction include: a temperature of 400-650℃, more preferably 400-550℃, a reaction space velocity of 1000-6000 mL of reaction gas / (h·g catalyst), and a pressure of 0.01-0.5 MPa.

[0039] Preferably, the content of the low-carbon alkanes in the reaction gas is 1-5% by volume; more preferably, the molar ratio of low-carbon alkanes to hydrogen in the reaction gas is 1:(0.5-5).

[0040] A sixth aspect of the present invention provides a platinum-carbon catalyst comprising sulfur-containing conductive carbon black and platinum metal supported thereon, wherein the sulfur-containing conductive carbon black comprises conductive carbon black and sulfur element incorporated therein, and the total sulfur content in the platinum-carbon catalyst is greater than or equal to the surface sulfur content, preferably more than 1.2 times the surface sulfur content, more preferably more than 1.5 times; the platinum content in the platinum-carbon catalyst is 0.1-5% by mass, preferably 0.2-1% by mass.

[0041] Compared with the prior art, the present invention has the following beneficial technical effects through the above technical solution.

[0042] I. The present invention utilizes a novel sulfur-modified conductive carbon black to manufacture a platinum-carbon catalyst, which can significantly improve the catalytic activity, lifetime, or selectivity of the catalyst.

[0043] Second, the present invention improves the dispersion of Pt by controlling the sulfur distribution in sulfur-modified conductive carbon black. Attached Figure Description

[0044] Figure 1 XPS spectrum of the platinum-carbon catalyst in Example 1;

[0045] Figure 2 The image shows the XPS spectrum of the platinum-carbon catalyst in Comparative Example 1. Detailed Implementation

[0046] The endpoints and any values ​​of the ranges 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 endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0047] The first aspect of the present invention provides a platinum-carbon catalyst comprising sulfur-containing conductive carbon black and platinum metal supported thereon, wherein the sulfur-containing conductive carbon black comprises conductive carbon black and sulfur element incorporated therein, the total sulfur content in the sulfur-containing conductive carbon black is greater than or equal to the surface sulfur content, preferably the total sulfur content is more than 1.2 times the surface sulfur content, more preferably more than 1.5 times; the platinum content in the platinum-carbon catalyst is 0.1-5% by mass, preferably 0.2-1% by mass.

[0048] In the sulfur-containing conductive carbon black according to the present invention, preferably, the total sulfur content in the sulfur-containing conductive carbon black can be more than 1.2 times, 1.5 times, 1.7 times, 2 times, or 3 times the surface sulfur content, for example, 1.5-10 times. Here, the surface sulfur content represents the sulfur mass fraction measured by XPS analysis, and the total sulfur content represents the sulfur mass fraction measured by a sulfur-carbon analyzer.

[0049] According to the present invention, on the one hand, the inventors have discovered that by incorporating more sulfur elements into the interior of conductive carbon black, it is suitable to prepare catalysts that are more conducive to platinum being supported inside conductive carbon black and provide better catalytic performance; on the other hand, the inventors have discovered that by introducing elemental sulfur into conductive carbon black by impregnation, it is possible to produce platinum-carbon catalysts with superior performance.

[0050] Preferably, the total sulfur content in the sulfur-containing conductive carbon black can be 3% by mass or more, preferably 5-15% by mass. Furthermore, preferably, the surface sulfur content in the sulfur-containing conductive carbon black can be 2-15% by mass, preferably 3-14% by mass. By giving the sulfur-containing conductive carbon black the above-mentioned sulfur content and sulfur distribution, the effect of the platinum-carbon catalyst in alkane dehydrogenation can be further improved.

[0051] According to other specific embodiments of the present invention, the total sulfur content in the sulfur-containing conductive carbon black can be 3-10% by mass, and the surface sulfur content can be 0.5-6% by mass.

[0052] According to the present invention, the total sulfur content in the sulfur-containing conductive carbon black can be, for example, 3% by mass, 4% by mass, 5% by mass, 6% by mass, 7% by mass, 8% by mass, 9% by mass, 10% by mass, 11% by mass, 12% by mass, 13% by mass, 14% by mass, or 15% by mass; the surface sulfur content in the sulfur-containing conductive carbon black can be, for example, 0.5% by mass, 1% by mass, 2% by mass, 3% by mass, 4% by mass, 5% by mass, 6% by mass, 7% by mass, 8% by mass, 9% by mass, 10% by mass, 11% by mass, 12% by mass, 13% by mass, 14% by mass, or 15% by mass.

[0053] According to the present invention, the sulfur-containing conductive carbon black preferably comprises conductive carbon black and sulfur and oxygen elements compounded therein. The oxygen content in the sulfur-containing conductive carbon black of the present invention is 4-15% by mass, preferably 6-10% by mass. Furthermore, the sulfur-containing conductive carbon black of the present invention preferably does not contain any other composite elements besides sulfur. Here, "composite elements" in the present invention refer to nitrogen, phosphorus, boron, sulfur, fluorine, chlorine, bromine, and iodine. More preferably, the sulfur-containing conductive carbon black is composed of conductive carbon black and sulfur and oxygen elements compounded therein.

[0054] The conductive carbon black that can be used in this invention may be one or more of ordinary conductive blacks, super conductive blacks, or extra conductive blacks, such as Ketjen black, Cabot conductive black (Cabot, Black Pearls, etc.), Orion conductive black (HIBLACK, PRINTEX, etc.), etc. Specifically, it may be one or more of EC-300J, EC-600JD, ECP600JD, VXC72, VXC72R, Black Pearls 2000, PRINTEX XE2-B, PRINTEX L6, and HIBLAXK 40B2.

[0055] This invention does not restrict the method of preparation or source of conductive carbon black. The conductive carbon black may be acetylene black, furnace black, etc.

[0056] Preferably, the oxygen content in the conductive carbon black, as determined by XPS analysis, is greater than 4% by mass.

[0057] Preferably, the specific surface area of ​​the conductive carbon black can be 200-2000 m². 2 / g, preferably 220-1500m 2 / g. Specific surface area can be determined by the BET method.

[0058] According to the present invention, in the synchrotron X-ray absorption spectroscopy characterization of the platinum-carbon catalyst, sulfur characteristic peaks are present at 2474±2 eV, 2481±2 eV, and 2483±2 eV. In the synchrotron X-ray absorption spectroscopy characterization, the sulfur characteristic peak at 2474±2 eV represents the sulfur characteristic peak in the CSC structure, the sulfur characteristic peak at 2483±2 eV represents the PtS2 characteristic peak, and the sulfur characteristic peak at 2481±2 eV represents the characteristic peak of elemental sulfur.

[0059] According to the present invention, the characteristic peak of Pt 4f 7 / 2 in the XPS spectrum of the platinum-carbon catalyst is located at 71.8 eV or higher, preferably 71.9 eV or higher, for example 71.9-72.2 eV. The aforementioned XPS spectrum refers to the XPS spectrum corrected to a C1s peak at 284.3 eV. Typically, for example, when platinum is supported on a carbon support without composite elements, the characteristic peak of Pt 4f 7 / 2 is located around 71.5 eV. This indicates that the characteristic peak of Pt 4f 7 / 2 in the XPS spectrum of the platinum-carbon catalyst of the present invention is shifted to a higher electron volt level by 0.3 eV or higher, preferably 0.4 eV or higher.

[0060] According to the present invention, the platinum content in the platinum-carbon catalyst can be 0.1% by mass, 0.2% by mass, 0.5% by mass, 1% by mass, 1.5% by mass, 2% by mass, 2.5% by mass, 3% by mass, 3.5% by mass, 4% by mass, 4.5% by mass, or 5% by mass.

[0061] A second aspect of the present invention provides a method for preparing a platinum-carbon catalyst, the method comprising:

[0062] (1) Impregnate conductive carbon black with a sulfur-containing solution at 10-80℃ for 1-5 hours, and then dry the impregnated product to obtain sulfur-containing conductive carbon black.

[0063] (2) Remove the solvent from the homogeneous mixture containing sulfur-containing conductive carbon black, platinum source and solvent obtained in step (1) to obtain the precursor material;

[0064] (3) In a reducing atmosphere, the precursor material obtained in step (2) is heat-treated at 80-200℃ for 1-4 hours to obtain a platinum carbon catalyst.

[0065] In step (2), the amount of platinum source used relative to 1g of sulfur-containing conductive carbon black is 0.001-0.055g, preferably 0.001-0.011g, based on the elemental platinum.

[0066] According to the present invention, the conductive carbon black used in step (1) can be the same as that in the first aspect, and will not be described again here.

[0067] Preferably, in step (1), the solvent in the sulfur-containing solution only needs to be able to dissolve the sulfur. From the perspective of better preparing sulfur-containing conductive carbon black, it can be one or more of CCl4, CS2, cyclohexane, and n-hexane, more preferably cyclohexane and n-hexane. The concentration of sulfur in the sulfur-containing solution is 0.0004-0.02 g / mL, preferably 0.0005-0.01 g / mL. The impregnation temperature is preferably 10-40℃, more preferably 20-30℃, particularly preferably room temperature (25℃), and the time is preferably 2-4 h. In addition, there is no particular limitation on the drying method, as long as the solvent in the sulfur-containing solution can be removed, vacuum drying is preferred.

[0068] According to the present invention, in step (1), in order to obtain a suitable sulfur loading and sulfur distribution, the amount of sulfur used is preferably 0.005-0.15g, more preferably 0.05-0.14g, relative to 1g of the conductive carbon black.

[0069] By performing sulfur modification treatment on conductive carbon black under the above conditions, the sulfur-containing conductive carbon black required by this invention can be obtained. Furthermore, the obtained sulfur-containing conductive carbon black can be more easily dispersed in an aqueous phase.

[0070] According to the present invention, in step (2), the platinum source can be one or more of chloroplatinic acid, chloroplatinate, tetraammineplatinum acetate, and platinum acetylacetonate. The chloroplatinate can be potassium chloroplatinate or sodium chloroplatinate, etc. Preferably, relative to 1g of the sulfur-containing conductive carbon black, the amount of the platinum source, calculated in terms of elemental platinum, is 0.001-0.055g, more preferably 0.001-0.011g, and more preferably 0.003-0.011g.

[0071] According to the present invention, the precursor material is obtained by dissolving conductive carbon black and a platinum source in a solvent to form a homogeneous mixture, and then removing the solvent from the homogeneous mixture. There is no particular limitation on the type of solvent; for example, one or more of water, alcohol solvents, or ketone solvents can be used. The alcohol solvent can be, for example, ethanol, and the ketone solvent can be, for example, acetone. More preferably, the solvent is water, ethanol, or a homogeneous mixture of ethanol and water (the volume ratio of ethanol to water can be, for example, 0.1-10:1, preferably 1-5:1). The present invention also does not particularly limit the amount of solvent used; for example, it can be 3-20 mL relative to 1 g of conductive carbon black.

[0072] This invention involves mixing conductive carbon black, a platinum source, and a solvent to obtain the aforementioned homogeneous mixture, preferably with stirring. The invention does not impose particular limitations on the stirring rate and time, as long as the homogeneous mixture is formed. Furthermore, to further accelerate the dissolution process by heating, a homogeneous mixture can also be formed.

[0073] As a method for removing the solvent from the homogeneous mixture, evaporation can be used to remove the solvent. The evaporation temperature and process can employ existing techniques known to those skilled in the art. According to the present invention, the drying temperature for solvent removal is below 100°C, for example, 20-100°C, and the time is 5-10 hours, specifically drying in an oven at 60-95°C for 12-24 hours to remove the solvent from the homogeneous mixture. According to a preferred embodiment of the present invention, the homogeneous mixture is allowed to stand before the solvent is removed. The standing time is 10 hours or more, preferably 12-72 hours, and more preferably 15-24 hours.

[0074] According to the present invention, the heat treatment is carried out in a reducing atmosphere. The reducing atmosphere preferably includes hydrogen, more preferably a mixture of hydrogen and an inert gas, wherein the inert atmosphere can be nitrogen and / or argon, specifically a mixture of hydrogen and nitrogen. Preferably, hydrogen accounts for 5-30% by volume of the total gas volume. The heat treatment can be carried out in any apparatus that provides the above-described heat treatment conditions, for example, in a tube furnace. The temperature of the heat treatment can be 80-200°C, preferably 100-180°C, and the duration of the heat treatment is 1-4 hours, preferably 2-3 hours. Furthermore, the heating rate of the heat treatment can be 4-15°C / min, typically 5-10°C / min.

[0075] A third aspect of the present invention provides a platinum-carbon catalyst, which is prepared by the preparation method of the second aspect of the present invention described above.

[0076] The fourth aspect of the present invention provides the application of the platinum-carbon catalyst described in the first or third aspect of the present invention in the dehydrogenation of low-carbon alkanes to olefins.

[0077] According to the present invention, the low-carbon alkane is selected from one or more C2-C8 alkane compounds. Examples of C2-C8 alkane compounds include ethane, propane, n-butane, isobutane, hexane, pentane, heptane, or octane.

[0078] Preferably, the dehydrogenation reaction conditions include: a temperature of 400-650℃, more preferably 400-550℃, a reaction space velocity of 1000-6000 mL of reaction gas / (h·g catalyst), and a pressure of 0.01-0.5 MPa.

[0079] Preferably, the content of the low-carbon alkanes in the reaction gas is 1-5% by volume, more preferably 1.5-3% by volume, and even more preferably, the molar ratio of low-carbon alkanes to hydrogen in the reaction gas is 1:(0.5-5), more preferably 1:(0.8-2).

[0080] A fifth aspect of the present invention provides a method for the dehydrogenation of alkane to olefins, the method comprising: contacting a reaction gas containing low-carbon alkanes and hydrogen with a platinum-carbon catalyst under dehydrogenation reaction conditions; wherein the platinum-carbon catalyst comprises sulfur-containing conductive carbon black and platinum metal supported thereon, the sulfur-containing conductive carbon black comprising conductive carbon black and sulfur element incorporated therein, the total sulfur content in the sulfur-containing conductive carbon black being greater than or equal to the surface sulfur content, preferably the total sulfur content being more than 1.2 times the surface sulfur content, more preferably more than 1.5 times; the platinum content in the platinum-carbon catalyst being 0.1-5% by mass, preferably 0.2-1% by mass.

[0081] In the method of the fifth aspect of the present invention, the same reaction gas, platinum-carbon catalyst and conditions as in the fourth aspect may be used.

[0082] A sixth aspect of the present invention provides a platinum-carbon catalyst comprising sulfur-containing conductive carbon black and platinum metal supported thereon, wherein the sulfur-containing conductive carbon black comprises conductive carbon black and sulfur element incorporated therein, and the total sulfur content in the platinum-carbon catalyst is greater than or equal to the surface sulfur content, preferably more than 1.2 times the surface sulfur content, more preferably more than 1.5 times; the platinum content in the platinum-carbon catalyst is 0.1-5% by mass, preferably 0.2-1% by mass.

[0083] The platinum-carbon catalyst of the fifth aspect of the present invention has the same properties and preparation methods as the platinum-carbon catalyst of the first aspect, and can also be used in the applications of the fourth aspect and the methods of the fifth aspect.

[0084] The present invention will be described in detail below through embodiments. The instruments and testing methods used in the embodiments and comparative examples of the present invention are as follows:

[0085] The high-resolution transmission electron microscope (HRTEM) model is JEM-2100 (HRTEM) (Nippon Electron Ltd.), and the test conditions are: accelerating voltage 200kV.

[0086] The aberration-corrected transmission electron microscope (AC-STEM) is a JEOL ARM200F model.

[0087] Instruments, methods and conditions for XRD analysis: X-ray diffraction (XRD) analysis was performed on a Shimadzu XRD-6000 X-ray diffractometer from Japan. The test conditions included: tube voltage 40 kV, tube current 40 mA, Cu target Kα radiation, and 2θ scan range of 10° to 70°.

[0088] The X-ray photoelectron spectroscopy (XPS) analyzer was a VG Scientific ESCALab220i-XL model equipped with Avantage V5.926 software. The XPS analysis conditions were as follows: monochromatic AlKα X-ray excitation source at 330 W power, and a base vacuum of 3 × 10⁻⁹ mbar. The electron binding energy was corrected using the C1s peak (284.3 eV) of elemental carbon, and XPSPEAK software was used for post-analysis peak setting.

[0089] The specific method for detecting surface sulfur content using XPS analysis is as follows: Full-spectrum scanning has a scan range of 0-1200 eV, a bandpass energy of 100 eV, an analysis energy step of 1.0 eV, 1211 channels, and 1 scan cycle. Narrow-spectrum scanning has a bandpass energy of 30.0 eV, an analysis energy step of 0.05 eV, 401 channels, and 16 scan cycles.

[0090] The sulfur and carbon analyzer is a CS-844 model from LECO Corporation of the United States.

[0091] Synchrotron radiation refers to the Beijing Electron-Positron Collider 4B7A-Medium Energy X-ray Experiment Station.

[0092] Instruments, methods, and conditions for testing the platinum mass fraction in platinum-carbon catalysts: Take 30 mg of the prepared Pt / C catalyst, add 30 mL of aqua regia, reflux at 120 °C for 12 h, cool to room temperature, take the supernatant, dilute it, and test the Pt content using ICP-AES.

[0093] Ketjenblack ECP600JD (manufactured by Lion Corporation of Japan) was tested using the aforementioned instrumental methods, and the results showed a specific surface area of ​​1362 m². 2 / g, pore volume 2.29mL / g, I D / I G It is 1.25.

[0094] Preparation Example 1

[0095] 0.55 g of sulfur was dissolved in 70 mL of cyclohexane to form a homogeneous solution. 9.45 g of KetjenblackECP600JD was dispersed in the solution, stirred until homogeneous, impregnated for 5 h, and then vacuum dried at 50 °C to obtain a sulfur-modified carbon support, designated as carbon support A.

[0096] Preparation Example 2

[0097] 0.85 g of sulfur was dissolved in 70 mL of cyclohexane to form a homogeneous solution. 9.15 g of KetjenblackECP600JD was dispersed in the solution, stirred until homogeneous, impregnated for 5 h, and then vacuum dried at 50 °C to obtain a sulfur-modified carbon support, designated as carbon support B.

[0098] Preparation Example 3

[0099] 1.20 g of sulfur was dissolved in 70 mL of cyclohexane to form a homogeneous solution. 8.8 g of Ketjenblack ECP600JD was dispersed in the solution, stirred until homogeneous, impregnated for 5 h, and then vacuum dried at 50 °C to obtain a sulfur-modified carbon support, designated as carbon support C.

[0100] Example 1

[0101] This embodiment illustrates the preparation of the platinum-carbon catalyst of the present invention.

[0102] 0.003 g of chloroplatinic acid (calculated as platinum) was dissolved in 20 mL of a water:ethanol solution with a volume ratio of 10:1. 1.0 g of carbon support A was dispersed in the chloroplatinic acid solution, stirred until uniformly dispersed, and allowed to stand for 24 h. The precursor was then dried in a vacuum drying oven to obtain the precursor. The dried precursor was placed in a tube furnace and heated to 140 °C at a rate of 5 °C / min. It was reduced for 2 h in an atmosphere of N2:H2 = 5:1, and then cooled in an N2 atmosphere to obtain a platinum-carbon catalyst A-0.3 with a loading of 0.3% by mass.

[0103] Example 2

[0104] This embodiment illustrates the preparation of the platinum-carbon catalyst of the present invention.

[0105] The platinum-carbon catalyst was prepared according to the method of Example 1, except that the carbon support B prepared in Preparation Example 2 was used to obtain a platinum-carbon catalyst B-0.3 with a loading of 0.3% by mass.

[0106] Example 3

[0107] This embodiment illustrates the preparation of the platinum-carbon catalyst of the present invention.

[0108] The platinum-carbon catalyst was prepared according to the method of Example 1, except that the carbon support C prepared in Preparation Example 3 was used to obtain a platinum-carbon catalyst C-0.3 with a loading of 0.3% by mass.

[0109] Example 4

[0110] This embodiment illustrates the preparation of the platinum-carbon catalyst of the present invention.

[0111] The platinum-carbon catalyst was prepared according to the method of Example 1, except that 0.01 g of chloroplatinic acid (calculated as platinum) was added per gram of carbon support to obtain a platinum-carbon catalyst A-1 with a loading of 1% by mass.

[0112] Comparative Example 1

[0113] The platinum-carbon catalyst KT-0.3 was prepared according to the method of Example 1, except that the carbon support used was not treated with composite sulfur.

[0114] Test Example 1

[0115] The surface sulfur content and total sulfur content of the sulfur-modified carbon supports prepared in Examples 1-3 above were determined, and the results are shown in Table 1.

[0116] Table 1

[0117] serial number Surface sulfur content Total sulfur content Total sulfur content / Surface sulfur content Carbon support A 3.49％ 5.5％ 1.6 Carbon support B 5.36％ 8.5％ 1.6 carbon support C 9.66％ 12％ 1.2

[0118] In Table 1, the surface sulfur content represents the sulfur mass fraction measured by XPS analysis, and the total sulfur content represents the sulfur mass fraction measured by a sulfur-carbon analyzer.

[0119] Furthermore, the XPS spectra of the platinum-carbon catalysts of Example 1 and Comparative Example 1 were measured, and the results are as follows: Figure 1 and Figure 2 As shown. From Figure 1 and Figure 2 As can be seen, the characteristic peak of the platinum-carbon catalyst Pt 4f 7 / 2 in Example 1 is located at 71.9 eV, while the characteristic peak of the platinum-carbon catalyst Pt 4f 7 / 2 in Comparative Example 1 is located at 71.5 eV.

[0120] Similarly, the characteristic peaks of the platinum-carbon catalyst Pt 4f 7 / 2 in Examples 2-4 were all found to be above 71.9 eV.

[0121] Test Example 2

[0122] This test example illustrates the propane dehydrogenation reaction catalyzed by catalyst A-0.3 from Example 1.

[0123] 0.2 g of catalyst was placed in a continuous flow fixed bed reactor. The reaction gas composition was 2.0% propane and 2.0% hydrogen by volume, with nitrogen as the balance gas. The flow rate of the reaction gas was 15 mL / min, and the reaction temperature was 500 °C. The evaluation results are shown in Table 2.

[0124] Table 2

[0125]

[0126] Test Example 3

[0127] This test example illustrates the propane dehydrogenation reaction catalyzed by catalyst B-0.3 from Example 2.

[0128] 0.2 g of catalyst was placed in a continuous flow fixed bed reactor. The reaction gas composition was 2.0% propane and 2.0% hydrogen by volume, with nitrogen as the balance gas. The flow rate of the reaction gas was 15 mL / min, and the reaction temperature was 500 °C. The evaluation results are shown in Table 3.

[0129] Table 3

[0130]

[0131] Test Example 4

[0132] This test example illustrates the propane dehydrogenation reaction catalyzed by catalyst C-0.3 of Example 3.

[0133] 0.2 g of catalyst was placed in a continuous flow fixed bed reactor. The reaction gas composition was 2.0% propane and 2.0% hydrogen by volume, with nitrogen as the balance gas. The flow rate of the reaction gas was 15 mL / min, and the reaction temperature was 500 °C. The evaluation results are shown in Table 4.

[0134] Table 4

[0135]

[0136] Test Example 5

[0137] This test example illustrates the reaction of propane dehydrogenation catalyzed by catalyst A-1 in Example 4.

[0138] 0.2 g of catalyst was placed in a continuous flow fixed bed reactor. The reaction gas composition was 2.0% propane and 2.0% hydrogen by volume, with nitrogen as the balance gas. The flow rate of the reaction gas was 15 mL / min, and the reaction temperature was 500 °C. The evaluation results are shown in Table 5.

[0139] Table 5

[0140]

[0141] Test Example 6

[0142] This test example illustrates the propane dehydrogenation reaction catalyzed by catalyst KT-0.3 of Comparative Example 1.

[0143] 0.2 g of catalyst was placed in a continuous flow fixed bed reactor. The reaction gas composition was 2.0% propane and 2.0% hydrogen by volume, with nitrogen as the balance gas. The flow rate of the reaction gas was 15 mL / min, and the reaction temperature was 500 °C. The evaluation results are shown in Table 6.

[0144] Table 6

[0145]

[0146] In existing technologies, the reaction temperature for propane dehydrogenation catalyzed by platinum-based catalysts is typically between 550 and 650 °C. As shown in Tables 2-6, when the carbon support is modified using the method of this invention, the catalyst's activity and stability are significantly improved. It can efficiently catalyze the dehydrogenation of low-carbon alkanes to olefins under relatively low temperature and platinum loading conditions, reducing catalyst cost, reaction temperature, and energy consumption. This provides a new reference direction for improving the performance of platinum-based catalysts.

[0147] Furthermore, as can be seen from the results in Table 2-4, by making the total sulfur content of the sulfur-modified carbon support 6-12% by mass and the surface sulfur content 5-10% by mass, the prepared platinum-carbon catalyst can have higher olefin selectivity.

[0148] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A platinum carbon catalyst characterized in that, The platinum-carbon catalyst comprises sulfur-containing conductive carbon black and platinum metal supported thereon. The sulfur-containing conductive carbon black comprises conductive carbon black and sulfur elements therein. The total sulfur content in the sulfur-containing conductive carbon black is greater than or equal to the surface sulfur content. The surface sulfur content represents the sulfur mass fraction measured by XPS analysis, and the total sulfur content represents the sulfur mass fraction measured by a sulfur-carbon analyzer. The platinum content in the platinum-carbon catalyst is 0.1-5% by mass.

2. The platinum carbon catalyst of claim 1, wherein, The total sulfur content is more than 1.2 times that of the surface sulfur content.

3. The platinum carbon catalyst of claim 1, wherein, The total sulfur content is more than 1.5 times that of the surface sulfur content.

4. The platinum carbon catalyst of claim 1, wherein, The platinum content in the platinum-carbon catalyst is 0.2-1% by mass.

5. The platinum carbon catalyst according to any one of claims 1 to 4, wherein, The total sulfur content in the sulfur-containing conductive carbon black is 3% by mass or more.

6. The platinum carbon catalyst according to any one of claims 1 to 4, wherein, The total sulfur content in the sulfur-containing conductive carbon black is 5-15% by mass.

7. The platinum carbon catalyst according to any one of claims 1 to 4, wherein, The surface sulfur content in the sulfur-containing conductive carbon black is 2-15% by mass.

8. The platinum carbon catalyst according to any one of claims 1 to 4, wherein, The surface sulfur content in the sulfur-containing conductive carbon black is 3-14% by mass.

9. The platinum carbon catalyst of claim 1, wherein, The characteristic peak of Pt 4f 7 / 2 in the XPS spectrum of the platinum-carbon catalyst is above 71.9 eV.

10. The platinum-carbon catalyst according to any one of claims 1-4 and 9, wherein, The conductive carbon black is one or more of EC-300J, EC-600JD, ECP600JD, VXC72, VXC72R, Black Pearls 2000, PRINTEX XE2-B, PRINTEX L6, and HIBLAXK 40B2.

11. The platinum-carbon catalyst according to claim 10, wherein, The oxygen content in the conductive carbon black, as determined by XPS analysis, is greater than 4% by mass.

12. The platinum carbon catalyst of claim 10, wherein, The specific surface area of ​​the conductive carbon black is 200-2000 m². 2 / g.

13. A method for producing a platinum carbon catalyst, characterized by, The preparation method includes: (1) Impregnate conductive carbon black with a sulfur-containing solution at 10-80℃ for 1-5 hours, and then dry the impregnated product to obtain sulfur-containing conductive carbon black; (2) Remove the solvent from the homogeneous mixture containing sulfur-containing conductive carbon black, platinum source and solvent obtained in step (1) to obtain the precursor material; (3) In a reducing atmosphere, the precursor material obtained in step (2) is heat-treated at 80-200℃ for 1-4 hours to obtain a platinum-carbon catalyst; In step (2), the amount of platinum source used is 0.001-0.055g relative to 1g of sulfur-containing conductive carbon black.

14. The production method according to claim 13, wherein In step (2), the amount of platinum source used is 0.001-0.011g relative to 1g of sulfur-containing conductive carbon black.

15. The preparation method according to claim 13, wherein, In step (1), the conductive carbon black is one or more of EC-300J, EC-600JD, ECP600JD, VXC72, VXC72R, Black Pearls 2000, PRINTEX XE2-B, PRINTEX L6 and HIBLAXK 40B2.

16. The method of making according to claim 15, wherein, The oxygen content in the conductive carbon black, as determined by XPS analysis, is greater than 4% by mass.

17. The method of manufacturing according to claim 15 or 16, wherein, The specific surface area of the conductive carbon black is 200-2000 m 2 / g.

18. The method of making according to claim 13, wherein, In step (1), the solvent in the sulfur-containing solution is one or more of CCl4, CS2, cyclohexane, and n-hexane.

19. The preparation method according to claim 13 or 18, wherein, The concentration of sulfur in the sulfur-containing solution is 0.0004-0.02 g / mL.

20. The method of manufacturing according to claim 13 or 18, wherein, The amount of sulfur used is 0.005-0.15g relative to 1g of conductive carbon black.

21. The method of making according to claim 13 or 18, wherein, The drying conditions include a temperature of 20-100℃ and a time of 5-10 hours.

22. The method of manufacturing according to claim 13, wherein, In step (2), the platinum source is one or more of chloroplatinic acid, chloroplatinate, tetraammineplatinum acetate, and platinum acetylacetonate.

23. The method of manufacturing according to claim 13 or 22, wherein, The solvent is one or more of water, alcohols, or ketones.

24. The method of manufacturing according to claim 13 or 22, wherein, The solvent is water and / or ethanol.

25. The method of manufacturing according to claim 13 or 22, wherein, The solvent is a mixture of water and ethanol.

26. The method of making according to claim 13 or 22, wherein, In step (2), the uniform mixture is allowed to stand for more than 10 hours before the solvent is removed.

27. The method of manufacturing according to claim 26, wherein, The settling time is 15-24 hours.

28. The method of making according to claim 13 or 22, wherein, In step (2), the drying temperature during solvent removal is below 100°C.

29. The method of manufacturing according to claim 13, wherein, In step (3), the reducing atmosphere includes hydrogen.

30. The preparation method according to claim 29, wherein, In step (3), the reducing atmosphere is a mixture of hydrogen and inert gas.

31. The preparation method according to claim 30, wherein, In step (3), the reducing atmosphere is a mixture of hydrogen and nitrogen.

32. The method of making according to any one of claims 29-31, wherein, Hydrogen accounts for 5-30% of the total gas volume.

33. A platinum carbon catalyst characterized by, The platinum-carbon catalyst is prepared by the method described in any one of claims 13-32.

34. The use of the platinum-carbon catalyst according to any one of claims 1-12 and 33 in the dehydrogenation of low-carbon alkanes to olefins.

35. The use of claim 34, wherein, The low-carbon alkane is selected from one or more C2-C8 alkane compounds.

36. The use according to claim 34 or 35, wherein The reaction conditions for the dehydrogenation of low-carbon alkanes include: a temperature of 400-650℃, a reaction space velocity of 1000-6000 mL of reaction gas / (h•g catalyst), and a pressure of 0.01-0.5 MPa.

37. The use of claim 36, wherein, The temperature is 400-550℃.

38. The application according to claim 34 or 35, wherein, The content of the low-carbon alkanes in the reaction gas is 1-5% by volume.

39. The use according to claim 34 or 35, wherein, The molar ratio of low-carbon alkanes to hydrogen in the reaction gas is 1:(0.5-5).

40. A method for dehydrogenating alkanes to olefins, characterized in that, The method includes: contacting a reaction gas containing low-carbon alkanes and hydrogen with a platinum-carbon catalyst under dehydrogenation reaction conditions; The platinum-carbon catalyst comprises sulfur-containing conductive carbon black and platinum metal supported thereon. The sulfur-containing conductive carbon black comprises conductive carbon black and sulfur element incorporated therein. The total sulfur content in the sulfur-containing conductive carbon black is greater than or equal to the surface sulfur content. The surface sulfur content represents the sulfur mass fraction measured by XPS analysis, and the total sulfur content represents the sulfur mass fraction measured by a sulfur-carbon analyzer. The platinum content in the platinum-carbon catalyst is 0.1-5% by mass.

41. The method of claim 40, wherein, The total sulfur content is more than 1.2 times that of the surface sulfur content.

42. The method of claim 40, wherein, The total sulfur content is more than 1.5 times that of the surface sulfur content.

43. The method of claim 40, wherein, The platinum content in the platinum-carbon catalyst is 0.2-1% by mass.

44. The method of claim 40, wherein, The low-carbon alkane is selected from one or more of the C2-C8 alkane compounds.

45. The method according to any one of claims 40-44, wherein, The conditions for the dehydrogenation reaction include: a temperature of 400-650℃, a reaction space velocity of 1000-6000 mL of reaction gas / (h•g catalyst), and a pressure of 0.01-0.5 MPa.

46. The method of claim 45, wherein, The temperature is 400-550℃.

47. The method of any one of claims 40-44, wherein, The content of the low-carbon alkanes in the reaction gas is 1-5% by volume.

48. The method of any one of claims 40-44, wherein, The molar ratio of low-carbon alkanes to hydrogen in the reaction gas is 1:(0.5-5).

49. A platinum carbon catalyst characterized by, The platinum-carbon catalyst comprises sulfur-containing conductive carbon black and platinum metal supported thereon. The sulfur-containing conductive carbon black comprises conductive carbon black and sulfur element incorporated therein, and the total sulfur content in the platinum-carbon catalyst is greater than or equal to the surface sulfur content, wherein the surface sulfur content represents the sulfur mass fraction measured by XPS analysis, and the total sulfur content represents the sulfur mass fraction measured by a sulfur-carbon analyzer. The platinum content in the platinum-carbon catalyst is 0.1-5% by mass.

50. The platinum-carbon catalyst according to claim 49, wherein, The total sulfur content is more than 1.2 times that of the surface sulfur content.

51. The platinum carbon catalyst of claim 49, wherein, The total sulfur content is more than 1.5 times that of the surface sulfur content.

52. The platinum-carbon catalyst according to any one of claims 49-51, wherein, The platinum content in the platinum-carbon catalyst is 0.2-1% by mass.

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