Efficient non-noble metal Ni3ZnN selective hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention discloses a preparation method and application of an efficient non-noble metal Ni3ZnN selective hydrogenation catalyst, and belongs to the technical field of supported metal catalysts. The method comprises the following steps: loading a nickel salt and a zinc salt on a nano-carrier by an impregnation method, and then heating in an ammonia-containing atmosphere to successfully prepare the Ni3ZnN catalyst. Performance test results show that the catalyst shows excellent catalytic performance in a 1, 3-butadiene hydrogenation reaction, and the selectivity of the catalyst is improved from 30% of Ni to 93%. In addition, the activity of the Ni3ZnN (0.079 s <-1 >) catalyst is obviously higher than that of a Ni3Zn (0.009 s <-1 >) alloy catalyst and is slightly higher than that of a single-metal Ni (0.067 s <-1 >) catalyst.

Description

Technical Field

[0001] The invention relates to the technical field of supported metal catalysts, and in particular to a method for preparing a highly efficient non-precious metal selective hydrogenation catalyst and an application thereof in a selective hydrogenation reaction. Background Art

[0002] Short-chain unsaturated hydrocarbons are one of the important industrial raw materials in the field of petrochemicals, mainly produced by thermal cracking of naphtha. However, in the process of catalytic cracking to prepare monoolefins, a small amount of alkyne and diene impurities will inevitably be produced, which will poison the downstream catalyst in the subsequent polymerization process. Therefore, these impurities must be reduced to below 3 to 5 ppm before producing polymerization-grade olefins. Selective hydrogenation reaction is an effective means to solve this problem. At present, highly active precious metal palladium catalysts are usually used in industry to remove impurities in raw gas, but their high cost and low selectivity limit their wide application. Therefore, the design and development of non-precious metal catalysts with high activity and high selectivity is a hot spot in selective hydrogenation reactions. Among them, non-precious metal nickel has a low cost and exhibits excellent catalytic performance in hydrogenation reactions, and has the potential to replace industrial palladium-based catalysts. However, nickel-based catalysts still face the problem of poor selectivity in selective hydrogenation reactions, and are prone to over-hydrogenation and polymerization reactions, thereby reducing the selectivity of the target product. In addition, the oligomers produced by the polymerization reaction will cover the catalyst surface, resulting in the loss of active sites and deactivation of the catalyst. Previous studies have used a variety of strategies to improve the selectivity of catalysts, but often at the expense of activity. Therefore, developing non-precious metal selective hydrogenation catalysts with both high activity and high selectivity is the focus and difficulty of research in the field of heterogeneous catalysis. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing an efficient non-precious metal selective hydrogenation catalyst and its application in a selective hydrogenation reaction. The present invention uses non-precious metals to prepare a supported Ni3ZnN catalyst, which effectively replaces the precious metal catalyst, not only reduces the catalyst cost, but also effectively regulates the geometric and electronic structure of the active metal Ni. It exhibits excellent catalytic performance in the hydrogenation reaction of 1,3-butadiene, and its activity and selectivity are significantly improved.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A highly efficient non-precious metal selective hydrogenation catalyst, wherein the active component nickel is loaded on the carrier surface in a bimetallic nitride structure, wherein the bimetallic nitride is Ni3ZnN, and the loading amount of nickel is 0.1-50wt.% (preferably 5-15wt.%). The atomic ratio of the active components Ni and Zn in the bimetallic nitride is 1:10 to 10:1 (preferably 2-5:1); the atomic ratio of Ni to N is 3:0.1-1.2; preferably, in the bimetallic nitride Ni3ZnN, the atomic ratio of Ni to N is 3:1.

[0006] The method for preparing the highly efficient non-precious metal selective hydrogenation catalyst comprises first loading nickel salt and zinc salt onto a nano-carrier by an impregnation method, and then performing a nitridation treatment in an atmosphere containing ammonia to obtain a bimetallic nitride structure, namely the highly efficient non-precious metal selective hydrogenation catalyst. The method comprises the following steps:

[0007] (1) dissolving nickel salt and zinc salt in an appropriate amount of solvent, then adding the nanocarrier, stirring by ultrasonic for 0.5 to 3 hours to ensure uniform dispersion, and removing the solvent by rotary evaporator to obtain a catalyst precursor loaded with nickel salt and zinc salt;

[0008] (2) placing the catalyst precursor loaded with nickel salt and zinc salt obtained in step (1) in an oven for drying at a temperature of 50 to 300° C. for a drying time of 1 to 24 hours;

[0009] (3) The catalyst precursor loaded with nickel salt and zinc salt treated in step (2) is subjected to nitridation treatment in an atmosphere containing ammonia, and the ammonia drives the formation of Ni3ZnN structure to obtain a Ni3ZnN supported catalyst.

[0010] In the above step (1), the nano-carrier material is one or more of boron nitride, aluminum oxide, carbon nanotubes, activated carbon, nano-carbon fibers, silicon oxide, diatomaceous earth, graphene or zinc oxide, etc. The particle size ranges from 10 nanometers to 20 micrometers.

[0011] In the above step (1), the nickel salt is selected from one or more of nickel acetate, nickel chloride, nickel nitrate, nickel carbonate, nickel sulfate and nickel acetylacetonate; the zinc salt is one or more of zinc chloride, zinc acetate, zinc nitrate, zinc sulfate, zinc carbonate and zinc acetylacetonate; the solvent is one or more of water, ethanol or methanol;

[0012] In the above step (3), the nitriding treatment is one or more of the following treatment conditions:

[0013] The catalyst precursor loaded with nickel salt and zinc salt is first reduced in a mixed atmosphere of hydrogen and inert gas to obtain a Ni3Zn catalyst, and then nitrided in a mixed atmosphere of ammonia and inert gas;

[0014] Or, the catalyst precursor loaded with nickel salt and zinc salt is directly subjected to nitridation treatment in a mixed atmosphere of ammonia and inert gas;

[0015] Alternatively, the catalyst precursor loaded with nickel salt and zinc salt is directly nitrided in a mixed atmosphere of ammonia, hydrogen and a mixture of an inert gas or a mixture of an inert gas, and the ammonia drives the formation of the Ni3ZnN catalyst.

[0016] The inert gas is one or more of nitrogen, helium or argon.

[0017] When a mixed atmosphere of hydrogen and inert gas is used in the above step (3), the mixed gas flow rate is 1 to 1000 mL / min, the volume ratio of hydrogen in the mixed atmosphere is 0.1 to 99.9 vol.%, the treatment temperature is 200 to 1000° C., and the treatment time is 1 to 24 hours;

[0018] When a mixed atmosphere of ammonia and inert gas is used for treatment, the mixed gas flow rate is 1 to 1000 mL / min, the volume ratio of ammonia in the mixed atmosphere is 0.1 to 99.9 vol.%, the treatment temperature is 300 to 1000° C., and the treatment time is 1 to 24 hours;

[0019] When using ammonia, hydrogen, and a mixed atmosphere containing or without inert gas for treatment, the mixed gas flow rate is 1 to 1000 mL / min, the volume proportion of ammonia in the mixed atmosphere is 0.1 to 99.9 vol.%, the volume proportion of hydrogen is 0.1 to 99.9 vol.%, the treatment temperature is 300 to 1000°C, and the treatment time is 1 to 24 hours.

[0020] The catalyst of the present invention is applied to the selective hydrogenation reaction of 1,3-butadiene, and the application conditions are as follows: the gas components of the selective hydrogenation reaction of 1,3-butadiene are: 1.0-99.0 vol.% H2, 0.1-99.0 vol.% 1,3-butadiene, and no or inert gas as the balance gas;

[0021] The inert gas is one or more of nitrogen, helium or argon.

[0022] Pretreatment of catalyst before application:

[0023] A mixed gas of ammonia and an inert gas (ammonia 0.1-100 vol.%, preferably 40-60 vol.%) is introduced into a reaction tube containing a supported Ni3ZnN catalyst, and the catalyst is nitrided at a treatment temperature of 300-1000° C. (preferably 400-600° C.) for 1-24 hours (preferably 1-6 hours);

[0024] The present invention has the following advantages and beneficial effects:

[0025] 1. The present invention prepares the supported Ni3ZnN catalyst by a simple impregnation method and an ammonia gas driving strategy, uses a non-precious metal as an active phase, effectively reduces the catalyst cost, and the preparation strategy is simple and easy to industrialize and mass produce.

[0026] 2. The present invention prepares Ni3ZnN catalyst, and the activity and selectivity are significantly improved in the 1,3-butadiene hydrogenation reaction performance test. When the conversion rate is 95.8%, the butene selectivity is increased from 30.0% of the Ni catalyst to 92.9%, and the activity is increased from 0.067s -1 Improved to 0.079s -1 In addition, after long-term stability testing, the activity and selectivity of the Ni3ZnN catalyst remained basically unchanged, indicating that the catalyst has excellent stability in the hydrogenation reaction of 1,3-butadiene and has broad application prospects in the field of heterogeneous catalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 TEM images and particle size distribution diagrams of Ni / ZnO, Ni3Zn / ZnO and Ni3ZnN / ZnO catalysts in Example 1 and Comparative Examples 1-2; wherein: (a) and (d) are TEM images and particle size distribution diagrams of Ni / ZnO catalysts, respectively; (b) and (e) are TEM images and particle size distribution diagrams of Ni3Zn / ZnO catalysts, respectively; (c) and (f) are TEM images and particle size distribution diagrams of Ni3ZnN / ZnO catalysts, respectively.

[0028] Figure 2 (a) and (b) the transmission electron microscope image of the Ni3ZnN / BN catalyst in Example 1. Figure 3 The XRD spectra of Ni / ZnO, Ni3Zn / ZnO and Ni3ZnN / ZnO catalysts in Example 1 and Comparative Examples 1-2 are shown.

[0029] Figure 4 These are high-resolution transmission electron micrographs of Ni / ZnO, Ni3Zn / ZnO and Ni3ZnN / ZnO catalysts in Example 1 and Comparative Examples 1-2; wherein: (ae) are high-resolution images of single metal Ni, Ni3Zn and Ni3ZnN, respectively; and the illustrations are fast Fourier transform images of the corresponding structures, respectively.

[0030] Figure 5 2. High-resolution transmission electron microscopy image ( ) of the Ni3ZnN / BN catalyst in Example 1 and fast Fourier transform image ( b ) of the corresponding structure.

[0031] Figure 6The selective hydrogenation performance of 1,3-butadiene over Ni / ZnO, Ni3Zn / ZnO and Ni3ZnN / ZnO catalysts in Example 1 and Comparative Examples 1-2 at 100°C.

[0032] Figure 7 is the conversion frequency of Ni / ZnO, Ni3Zn / ZnO and Ni3ZnN / ZnO catalysts in the selective hydrogenation reaction of 1,3-butadiene in Example 1 and Comparative Examples 1-2.

[0033] Figure 8 This is a long-term stability test of the Ni / ZnO, Ni3Zn / ZnO and Ni3ZnN / ZnO catalysts in Example 1 and Comparative Examples 1-2 in the selective hydrogenation reaction of 1,3-butadiene. DETAILED DESCRIPTION

[0034] The present invention uses non-precious metal to replace the precious metal catalyst, and prepares the supported Ni3ZnN catalyst by impregnation and ammonia treatment. The present invention is further described below in conjunction with the examples and drawings.

[0035] Embodiment 1:

[0036] The process of preparing the supported Ni3ZnN catalyst in this embodiment is as follows:

[0037] 1. Dipping method:

[0038] When zinc oxide is used as a carrier, first, 24.78 mg of nickel nitrate hexahydrate is dissolved in 40 mL of ethanol, and then 95 mg of zinc oxide carrier (particle size range 10 nanometers-20 microns) is added, and ultrasonic stirring is performed for about 1 hour to ensure uniform dispersion, and then the solvent ethanol is removed by a rotary evaporator (temperature is 40°C), and the mixture is kept warm in an oven at 100°C for 2 hours to obtain a catalyst precursor loaded with nickel salt.

[0039] When boron nitride is selected as a carrier, first, 24.78 mg of nickel nitrate hexahydrate and 8.45 mg of zinc nitrate hexahydrate are dissolved in 40 mL of ethanol, and then 88.14 mg of a boron nitride carrier (particle size range 10 nanometers-20 microns) is added, and ultrasonic stirring is performed for about 1 hour to ensure uniform dispersion, and then the solvent ethanol is removed by a rotary evaporator (temperature is 40°C), and the mixture is kept warm in an oven at 100°C for 2 hours to obtain a catalyst precursor loaded with nickel salt and zinc salt.

[0040] 2. The samples treated in step 1 were subjected to reduction treatment in a mixed atmosphere of hydrogen and argon, with a mixed gas flow rate of 100 mL / min and a hydrogen volume ratio of 50 vol.% in the mixed gas; during the reduction treatment, the temperature was increased to 500°C at a heating rate of 5°C / min and kept at a constant temperature for 2 hours, and then cooled to room temperature to obtain a supported Ni3Zn catalyst.

[0041] 3. After switching to helium purging for 30 minutes, switch to a mixed gas of ammonia and helium with a mixed gas flow rate of 100 mL / min, in which the ammonia ratio is 50 vol.%; heat up to 500°C at a heating rate of 5°C / min and keep the temperature constant for 2 hours. After cooling to room temperature, supported Ni3ZnN catalysts (Ni3ZnN / ZnO and Ni3ZnN / BN catalysts, respectively) are obtained.

[0042] In the supported Ni3ZnN catalyst prepared in this example, the Ni loading amount is 10.0 wt.%.

[0043] Comparative Example 1:

[0044] The process and conditions are the same as those of Example 1, except that step 3 is omitted, the addition of zinc nitrate hexahydrate in step 1 is omitted, the amount of boron nitride carrier is adjusted to 95 mg, and then the reduction temperature in step 2 is adjusted to 350° C. After constant temperature treatment for 2 hours, the temperature is cooled to room temperature to obtain a supported Ni / ZnO or Ni / BN catalyst with a Ni loading of 10.0 wt.%.

[0045] Comparative Example 2:

[0046] The process and conditions are the same as those of Example 1, except that step 3 is omitted to obtain a supported Ni3Zn / ZnO or Ni3Zn / BN catalyst with a Ni loading of 10.0 wt.%.

[0047] The transmission electron microscope images and particle size distribution of the Ni / ZnO, Ni3Zn / ZnO and Ni3ZnN / ZnO catalysts prepared in Example 1 and Comparative Examples 1-2 are shown in FIG. Figure 1 , TEM images and particle size distribution of Ni3ZnN / BN catalysts are shown in Figure 2 The XRD spectra of Ni / ZnO, Ni3Zn / ZnO and Ni3ZnN / ZnO catalysts are shown in Figure 3 , high-resolution transmission electron microscopy images of Ni / ZnO, Ni3Zn / ZnO and Ni3ZnN / ZnO catalysts are shown in Figure 2. Figure 4 , high-resolution transmission electron microscopy images of Ni3ZnN / BN catalysts are shown in Figure 5 .

[0048] Embodiment 2:

[0049] The Ni / ZnO, Ni3Zn / ZnO and Ni3ZnN / ZnO catalysts prepared in Example 1 and Comparative Examples 1-2 were respectively applied to the selective hydrogenation reaction of 1,3-butadiene. The application process is as follows:

[0050] Take 2.5 mg of the above-obtained 10 wt.% loading Ni / ZnO, Ni3Zn / ZnO and Ni3ZnN / ZnO catalysts respectively and add them into a quartz reaction tube, and fix the catalyst in the middle constant temperature area of ​​the fixed bed reactor by quartz wool.

[0051] First, preprocess:

[0052] A mixture of hydrogen and helium (hydrogen 50 vol.%) was introduced into a reaction tube containing a supported Ni / ZnO catalyst, and the catalyst was reduced at 350° C. for 2 hours. The gas flow rate was controlled at 20 mL / min by a mass flow meter.

[0053] A mixture of hydrogen and helium (hydrogen 50 vol.%) was introduced into a reaction tube containing a supported Ni3Zn / ZnO catalyst, and the catalyst was reduced at 500°C for 2 hours. The gas flow rate was controlled at 20 mL / min by a mass flow meter.

[0054] A mixture of ammonia and helium (ammonia 50 vol.%) was introduced into a reaction tube containing a supported Ni3ZnN / ZnO catalyst, and the catalyst was nitrided at 500°C for 2 hours. The gas flow rate was controlled at 20 mL / min by a mass flow meter.

[0055] After pretreatment, the temperature was lowered to 100°C, and then the catalyst performance was tested. Specifically, the gas composition of 1,3-butadiene hydrogenation reaction was 5.0 vol.% H2, 1.0 vol.% 1,3-butadiene, and the rest was helium as a balance gas; the above gases were introduced into the reaction tube at a gas flow rate of 50 mL / min.

[0056] 1,3-Butadiene hydrogenation reaction performance test results (reference Figure 6-8 ):

[0057] When the Ni3ZnN / ZnO catalyst prepared in Example 1 was used in the selective hydrogenation reaction of 1,3-butadiene, the selectivity of butene was significantly improved to about 93%. In addition, the Ni3ZnN / ZnO catalyst had the highest catalytic activity, with a TOF of 0.079s -1 , slightly higher than the single metal Ni / ZnO catalyst (0.067s -1 ). Compared with Ni3Zn / ZnO catalyst (0.009s -1 ), and its TOF increased by about 9 times. In addition, after a 10-hour long-term stability test, the conversion rate and selectivity of the Ni3ZnN / ZnO catalyst remained basically unchanged, indicating that the catalyst has excellent stability in the 1,3-butadiene hydrogenation reaction.

[0058] The Ni / ZnO catalyst prepared in Comparative Example 1 has a butene selectivity of about 30%, and its conversion rate decreases significantly after a long-term anti-stability test.

[0059] The Ni3Zn / ZnO catalyst prepared in Comparative Example 2 has a butene selectivity of about 54%, and its conversion rate decreases significantly after a long-term stability test.

[0060] The above description is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A highly efficient non-precious metal selective hydrogenation catalyst, characterized in that: The active component of the catalyst is a bimetallic nitride, which is loaded on the surface of the carrier. The bimetallic nitride is preferably a Ni3ZnN structure, and the loading amount of the active component nickel is 0.1-50wt.% (preferably 5-15wt.%).

2. The high-efficiency non-precious metal selective hydrogenation catalyst according to claim 1, characterized in that: The atomic ratio of the active components Ni and Zn in the bimetallic nitride is 1:10 to 10:1 (preferably 2-5:1); the atomic ratio of Ni and N is 3:0.1-1.2, and preferably in the bimetallic nitride Ni3ZnN, the atomic ratio of Ni and N is 3:0.8-1.

2.

3. The high-efficiency non-precious metal selective hydrogenation catalyst according to claim 1 or 2, characterized in that: The catalyst carrier is one or more of boron nitride, aluminum oxide, carbon nanotubes, activated carbon, nanocarbon fibers, silicon oxide, diatomaceous earth, graphene or zinc oxide, etc.; the particle size range is 10 nanometers to 20 microns.

4. A method for preparing a high-efficiency non-precious metal selective hydrogenation catalyst according to claim 1, 2 or 3, characterized in that: Firstly, nickel salt and zinc salt are loaded onto a nano-carrier by an impregnation method, and then nitridation treatment is performed in an atmosphere containing ammonia to obtain a Ni3ZnN bimetallic nitride structure, which is the highly efficient non-precious metal selective hydrogenation catalyst.

5. The method for preparing a highly efficient non-precious metal selective hydrogenation catalyst according to claim 4, characterized in that: The method comprises the following steps: (1) dissolving nickel salt and zinc salt in a solvent, then adding a nanocarrier, and stirring by ultrasonic for 0.5 to 3 hours to ensure uniform dispersion, and removing the solvent to obtain a catalyst precursor loaded with nickel salt and zinc salt; (2) placing the catalyst precursor loaded with nickel salt and zinc salt obtained in step (1) in an oven for drying at a temperature of 50 to 300° C. for a drying time of 1 to 24 hours; (3) The catalyst precursor loaded with nickel salt and zinc salt treated in step (2) is subjected to nitridation treatment in an atmosphere containing ammonia, and the ammonia drives the formation of Ni3ZnN structure to obtain a Ni3ZnN supported catalyst.

6. The method for preparing a highly efficient non-precious metal selective hydrogenation catalyst according to claim 4 or 5, characterized in that: In step (1), the nickel salt is selected from one or more of nickel acetate, nickel chloride, nickel nitrate, nickel carbonate, nickel sulfate and nickel acetylacetonate; the zinc salt is one or more of zinc chloride, zinc acetate, zinc nitrate, zinc sulfate, zinc carbonate and zinc acetylacetonate; the solvent is one or more of water, ethanol or methanol; The solvent was removed by rotary evaporation at a temperature of 30-60 °C.

7. The method for preparing a highly efficient non-precious metal selective hydrogenation catalyst according to claim 5, characterized in that: In step (3), the nitriding treatment is one or more of the following treatment conditions: The catalyst precursor loaded with nickel salt and zinc salt is first reduced in a mixed atmosphere of hydrogen and inert gas to obtain a Ni3Zn catalyst, and then nitrided in a mixed atmosphere of ammonia and inert gas; Alternatively, the catalyst precursor loaded with nickel salt and zinc salt is directly subjected to nitridation treatment in a mixed atmosphere of ammonia and inert gas; Alternatively, the catalyst precursor loaded with nickel salt and zinc salt is directly subjected to nitridation treatment in a mixed atmosphere of ammonia, hydrogen, and a mixture of no or containing inert gas, and the ammonia drives the formation of Ni3ZnN catalyst; The inert gas is one or more of nitrogen, helium or argon.

8. The method for preparing a highly efficient non-precious metal selective hydrogenation catalyst according to claim 7, characterized in that: Nitriding treatment conditions: When the catalyst with a mass of 0.1 mg to 100 g is treated in a mixed atmosphere of hydrogen and inert gas, the mixed gas flow rate is 1 to 1000 mL / min; the volume ratio of hydrogen in the mixed atmosphere is 0.1 to 99.9 vol.% (preferably 40 to 60 vol.%), the treatment temperature is 200 to 1000° C. (preferably 300 to 600° C.), and the treatment time is 1 to 24 hours (preferably 2 to 4 hours); When the catalyst with a mass of 0.01 mg to 100 g is treated with a mixed atmosphere of ammonia and inert gas, the mixed gas flow rate is 1 to 1000 mL / min; the volume ratio of ammonia in the mixed atmosphere is 0.1 to 99.9 vol.% (preferably 40 to 60 vol.%), the treatment temperature is 300 to 1000° C. (preferably 400 to 600° C.), and the treatment time is 1 to 24 hours (preferably 2 to 4 hours); When a catalyst with a mass of 0.01 mg to 100 g is treated with ammonia, hydrogen, and a mixed atmosphere containing or without an inert gas, the flow rate of the mixed gas is 1 to 1000 mL / min; the volume proportion of ammonia in the mixed atmosphere is 0.1 to 99.9 vol.% (preferably 40 to 60 vol.%), the volume proportion of hydrogen is 0.1 to 99.9 vol.% (preferably 40 to 60 vol.%), the treatment temperature is 300 to 1000°C (preferably 400 to 600°C), and the treatment time is 1 to 24 hours (preferably 2 to 4 hours).

9. Use of a high-efficiency non-precious metal selective hydrogenation catalyst according to claim 1, 2 or 3, characterized in that: The catalyst is used in the selective hydrogenation reaction of 1,3-butadiene.

10. Use of the high-efficiency non-precious metal selective hydrogenation catalyst according to claim 9, characterized in that: The catalyst is applied to the selective hydrogenation reaction of 1,3-butadiene, and the application conditions are as follows: the gas components of the selective hydrogenation reaction of 1,3-butadiene are: 1.0-99.0 vol.% H2 (preferably 75-95 vol.%), 0.1-99.0 vol.% (preferably 5-25 vol.%) 1,3-butadiene, and no or inert gas as balance gas; The inert gas is one or more of nitrogen, helium or argon. When the mass of the catalyst is 0.01 mg to 100 g, the gas flow rate is 1 to 1000 mL / min; the reaction temperature is 10 to 300° C. (preferably 80 to 200° C.).

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