A ternary metal nanocatalyst, a preparation method and application thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHONGQING UNIV
- Filing Date
- 2026-03-05
- Publication Date
- 2026-06-09
Smart Images
Figure CN122164445A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a ternary metal nanocatalyst, its preparation method, and its application. Background Technology
[0002] While Pd nanocatalysts can catalyze the hydrogenation of alkynes (such as phenylacetylene) and furfural, the strong adsorption of Pd nanocatalysts for alkenes formed by hydrogenation of alkynes and furfuryl alcohol formed by hydrogenation of furfural can easily lead to over-hydrogenation during the catalytic hydrogenation reaction. For example, alkynes may be converted into alkanes, resulting in low conversion rates and poor selectivity for either alkenes or furfuryl alcohol. Summary of the Invention
[0003] In view of this, the present invention provides a ternary metal nanocatalyst, its preparation method, and its application. This ternary metal nanocatalyst comprises a ternary metal-bonded compound formed by the combination of Pd, a metal element or metal-like element from Group VA, and a metal element or metal-like element from Group VIA. The simultaneous action of the metal element or metal-like element from Group VA and the metal element or metal-like element from Group VIA on Pd significantly broadens the tunable range of Pd's 4d orbital energy, moving Pd energy away from the critical point and reducing the adsorption of olefins or furfuryl alcohol, thereby preventing excessive H addition to olefins or furfuryl alcohol. Furthermore, the metal element or metal-like element from Group VA and the metal element or metal-like element from Group VIA can isolate the active sites of Pd, preventing the continuity of Pd active sites and altering the electron density and energy density of Pd. This results in the ternary metal-bonded compound exhibiting superior activity and selectivity, as well as a milder catalytic temperature.
[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a ternary metal nanocatalyst, comprising: Pd, a metal element or metalloid element from Group VA and a metal element or metalloid element from Group VIA; Pd, metals or metalloids in Group VA, and metals or metalloids in Group VIA form ternary metallic compounds.
[0005] Optionally, the ternary metal-bonded compound has a long-range ordered crystal structure.
[0006] Optionally, the atomic ratio of the ternary metallic compound is Pd: metal element or metalloid element in Group VA: metal element or metalloid element in Group VIA = 1:1:1.
[0007] Optionally, the ternary metal-bonded compound is composed of Pd, Bi and Te.
[0008] Optionally, the ternary metal-bonded compound includes: a PdBi3Te3 octahedral structure with one Pd atom bonded to three equivalent Bi atoms and three equivalent Te atoms; a TeBiPd3 trigonal pyramidal structure with one Bi atom bonded to three equivalent Pd atoms and one Te atom; and a BiTePd3 trigonal pyramidal structure with one Te atom bonded to three equivalent Pd atoms and one Bi atom.
[0009] Optionally, each vertex of the PdBi3Te3 octahedral structure is connected to 12 equivalent PdBi3Te3 octahedrons, 3 equivalent BiTePd3 triangular pyramids, and 3 equivalent TeBiPd3 triangular pyramids; each vertex of the TeBiPd3 triangular pyramid structure is connected to 3 equivalent PdBi3Te3 octahedrons, 6 equivalent TeBiPd3 triangular pyramids, and 9 equivalent BiTePd3 triangular pyramids; and each vertex of the BiTePd3 triangular pyramid structure is connected to 3 equivalent PdBi3Te3 octahedrons, 6 equivalent BiTePd3 triangular pyramids, and 9 equivalent TeBiPd3 triangular pyramids.
[0010] Optionally, the Pd-Bi bond length is 2.80 Å, the Pd-Te bond length is 2.76 Å, and the Bi-Te bond length is 2.99 Å.
[0011] Optionally, the particle size of the ternary metal nanocatalyst is 100 nm to 300 nm.
[0012] Optionally, the ternary metal nanocatalyst further includes a support for loading and dispersing the ternary metal bonded compound.
[0013] Optionally, the carrier is selected from one or more of activated carbon, graphene, carbon nanotubes, oxides, and molecular sieves.
[0014] Secondly, embodiments of the present invention provide a method for preparing a ternary metal nanocatalyst, comprising: Step 1: Mix a certain molar ratio of a first metal precursor containing Pd, a second metal precursor containing a metal element or metalloid element from Group VA, and a third metal precursor containing a metal element or metalloid element from Group VIA into a certain amount of oleylamine, stir to dissolve, and heat to react. Step 2: Add a certain amount of alkyl thiol to the oleylamine mixed with the first metal precursor, the second metal precursor and the third metal precursor, and further heat the reaction.
[0015] Optionally, the first metal precursor is palladium halide.
[0016] Optionally, the first metal precursor is PdBr2.
[0017] Optionally, the second metal precursor is one or more of bismuth citrate, bismuth octate, bismuth nitrate, and bismuth acetate.
[0018] Optionally, the second metal precursor is bismuth acetate.
[0019] Optionally, the third metal precursor is Ph2Te2.
[0020] Optionally, the preparation method further includes: step 3, dispersing the ternary metal bond compound and the support obtained in step 2 in a solvent, and stirring and drying at high speed.
[0021] Optionally, the molar ratio of the first metal precursor, the second metal precursor, and the third metal precursor is 2:2:1.
[0022] Optionally, the molar ratio of the alkyl thiol to the first metal precursor is (2~5):1.
[0023] Optionally, the molar ratio of the oleylamine to the first metal precursor is (15~45):1.
[0024] Optionally, the temperature for heating the reaction in step 1 is 60℃~80℃.
[0025] Optionally, the temperature for heating the reaction in step 2 is 150℃~180℃.
[0026] Optionally, the heating reaction time in step 2 is 30 min to 70 min.
[0027] Optionally, the ternary metal nanocatalyst is used for selective hydrogenation reactions of alkynes or furfural.
[0028] Optionally, the ternary metal nanocatalyst can be applied to the selective hydrogenation reaction of alkynes. The ternary metal nanocatalyst and alkyne are dissolved in a solvent in a certain mass ratio, and H2 is introduced to maintain the reaction space under a certain pressure to catalyze the reaction.
[0029] Optionally, the mass ratio of the ternary metal nanocatalyst to the alkyne is 1:(0.5~2.5).
[0030] Optionally, the pressure in the reaction space is maintained at 0.5 MPa to 2 MPa after H2 is introduced.
[0031] Optionally, the catalytic reaction temperature is 25℃~50℃, and preferably, the catalytic reaction temperature is 25℃~30℃.
[0032] The technical solution of the first aspect of the above invention has the following advantages or beneficial effects: The ternary metal nanocatalyst provided in this invention comprises a ternary metal-bonded compound formed by the combination of Pd, a metal element or metal-like element from Group VA, and a metal element or metal-like element from Group VIA. The simultaneous action of the metal element or metal-like element from Group VA and the metal element or metal-like element from Group VIA on Pd significantly broadens the tunable range of Pd's 4d orbital energy, moving Pd energy away from the critical point and reducing the adsorption of olefins or furfuryl alcohol, thereby preventing excessive H addition to olefins or furfuryl alcohol. Furthermore, the metal element or metal-like element from Group VA and the metal element or metal-like element from Group VIA can isolate Pd active sites, preventing the continuity of Pd active sites and altering the electron density and energy density of Pd. This results in the ternary metal-bonded compound exhibiting superior activity and selectivity, as well as a milder catalytic temperature. Attached Figure Description
[0033] Figure 1 This is a schematic diagram of the three-dimensional structure of a ternary metal nanocatalyst containing Te, Bi and Pd provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the three-dimensional structure of a single package of a ternary metal nanocatalyst containing Te, Bi and Pd provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the main process of preparing ternary metal nanocatalysts according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the reaction process for the preparation method of ternary metal nanocatalysts provided in the embodiments of the present invention; Figure 5 This is a flow chart of the reaction of phenylacetylene hydrogenation catalyzed by a ternary metal nanocatalyst according to an embodiment of the present invention; Figure 6 This is the X-ray powder diffraction pattern of the ternary metal nanocatalyst in Example 1; Figure 7 This is a scanning electron microscope image of the ternary metal nanocatalyst from Example 1; Figure 8 The graphs show the conversion rates of phenylacetylene and the selectivity of phenylacetylene to styrene in each embodiment and Comparative Example 1. Figure 9 This is a comparison graph showing the conversion rate of phenylacetylene and the selectivity of phenylacetylene to styrene after 6 hours of catalytic reaction in Examples 1, 2, 3 and 4. Figure 10 This is a comparison chart of the conversion rate and selectivity of the ternary metal nanocatalyst in Example 1 during its eight cycles of use; Figure 11This is the X-ray powder diffraction pattern of the ternary metal nanocatalyst of Example 1 after 8 cycles. Detailed Implementation
[0034] Catalytic hydrogenation is a core chemical process in which hydrogen reacts with unsaturated compounds (or compounds containing heteroatoms) in the presence of a catalyst in an addition / reduction reaction. It is widely used in organic synthesis, petroleum refining, and fine chemicals. For alkynes or furfural-like unsaturated compounds, selective catalytic hydrogenation is generally required to obtain the desired product. In particular, styrene, a raw material for producing polystyrene (PS), ABS resin, and styrene-butadiene rubber, can be directly obtained through the selective hydrogenation of phenylacetylene. However, the core bottleneck for the industrialization of selective catalytic hydrogenation lies in the need for a catalyst with high selectivity to suppress side reactions. For example, while hydrogenating phenylacetylene (C≡C triple bond) to styrene (C=C double bond), it is necessary to prevent further hydrogenation of styrene to ethylbenzene (CC single bond).
[0035] Currently, catalysts used for the catalytic hydrogenation of alkynes or furfural-like unsaturated compounds are mainly based on the noble metal palladium (Pd). However, research has found that conventional Pd nanocatalysts, due to their strong adsorption of C=C double bonds, are prone to over-hydrogenation during the reaction, generating byproducts (e.g., unwanted ethylbenzene is generated in phenylacetylene). Furthermore, conventional Pd nanocatalysts are easily deactivated during the reaction due to carbon deposition or sintering. Although there are studies on adding another metal (such as Ag or Cu) to partially improve the selectivity of Pd-based materials, this often comes at the cost of sacrificing Pd activity, and the catalyst preparation process is complex and has poor stability. In addition, existing Pd nanocatalysts generally require high catalytic reaction temperatures (usually not lower than 50°C), which is detrimental to the stability and efficiency of Pd nanocatalysts and increases process energy consumption and operating costs. In addition, during long-term or cyclic reactions, isolated Pd sites in existing Pd nanocatalysts are prone to migration and aggregation; some existing intermetallic compounds (such as Pd and Se-containing systems) may experience component leaching or surface reconstruction, leading to a gradual decrease in activity and selectivity and a limited lifespan.
[0036] Furthermore, existing Pd nanocatalyst preparation processes require multi-step, meticulous synthesis, which is cumbersome and subject to stringent conditions (such as high-temperature hydrothermal treatment and high-temperature annealing), making large-scale production difficult. Moreover, achieving atomic-level dispersion currently requires the use of special supports (such as ZSM-5 molecular sieves or nanodiamond-graphene) or noble metal precursors, and the synthesis often necessitates template agents and organic protecting agents, resulting in persistently high material and manufacturing costs.
[0037] To address the aforementioned problems in the existing technology, this invention provides a ternary metal nanocatalyst, its preparation method, and its application.
[0038] It should be noted that the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," and "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0039] The ternary metal-bonded compounds involved in the embodiments of the present invention, often referred to as ternary intermetallic compounds, are crystalline compounds formed by three different metal elements bonded together through metallic bonds, covalent bonds, or ionic bonds. They differ from simple alloy solid solutions (which are generally random mixtures of atoms). These ternary metal-bonded compounds have definite stoichiometric ratios and unique crystal structures.
[0040] Specifically, this invention provides a ternary metal nanocatalyst. The ternary metal nanocatalyst may include: Pd, a metal element or metal-like element from Group VA, and a metal element or metal-like element from Group VIA; wherein Pd, the metal element or metal-like element from Group VA, and the metal element or metal-like element from Group VIA constitute a ternary metal-bonded compound.
[0041] In Group VA, the metal element or metalloid is one of As (arsenic), Sb (antimony), and Bi (bismuth), while in Group VIA, the metal element or metalloid is one of Se (selenium), Te (tellurium), and Po (polonium). For example, the ternary metal nanocatalyst can be one of PdAsSe, PdSbSe, PdBiSe, PdAsTe, PdSbTe, PdBiTe, PdAsPo, PdSbPo, and PdBiPo.
[0042] The ternary metal nanocatalyst provided in this invention comprises a ternary metal-bonded compound formed by the combination of Pd, a metal element or metal-like element from Group VA, and a metal element or metal-like element from Group VIA. The simultaneous action of the metal element or metal-like element from Group VA and the metal element or metal-like element from Group VIA on Pd significantly broadens the tunable range of Pd's 4d orbital energy, moving Pd energy away from the critical point and reducing the adsorption of olefins or furfuryl alcohol, thereby preventing excessive H addition to olefins or furfuryl alcohol. Furthermore, the metal element or metal-like element from Group VA and the metal element or metal-like element from Group VIA can isolate Pd active sites, preventing the continuity of Pd active sites and altering the electron density and energy density of Pd. This results in the ternary metal-bonded compound exhibiting superior activity and selectivity, as well as a milder catalytic temperature.
[0043] More specifically, the aforementioned ternary metal-bonded compounds generally possess a long-range ordered crystal structure. This long-range ordered crystal structure enables the ternary metal-bonded compounds to form active sites with consistent geometry and identical electronic environments, which is beneficial for improving catalytic selectivity. Furthermore, this long-range ordered crystal structure allows the ternary metal-bonded compounds to achieve the optimal region of the volcano-shaped adsorption curve for reactants and products.
[0044] In addition, the long-range ordered crystal structure of ternary metal-bonded compounds makes atomic migration difficult and can effectively suppress catalyst sintering and particle growth, thereby significantly improving catalyst lifetime.
[0045] Furthermore, regarding the ternary metal nanocatalyst provided in this embodiment of the invention, the atomic ratio of the ternary metal-bonded compounds is Pd: a metal element or metalloid from Group VA: a metal element or metalloid from Group VIA = 1:1:1. By controlling the atomic ratio of the ternary metal nanocatalyst to 1:1:1, the discontinuous Pd active sites can be ensured, effectively controlling the Pd electron density and energy density, making it easier for the long-range ordered crystal structure to expose the 100 interface, and giving the ternary metal nanocatalyst superior activity and selectivity.
[0046] More preferably, the ternary metallic compound is composed of Pd, Bi and Te.
[0047] More specifically, the ternary metal-bonded compounds include: a PdBi3Te3 octahedral structure with one Pd atom bonded to three equivalent Bi atoms and three equivalent Te atoms; a TeBiPd3 trigonal pyramidal structure with one Bi atom bonded to three equivalent Pd atoms and one Te atom; and a BiTePd3 trigonal pyramidal structure with one Te atom bonded to three equivalent Pd atoms and one Bi atom. These structures in the ternary metal-bonded compounds can achieve atomically dispersed Pd active sites, enabling interactions between Bi and Te atoms and Pd atoms, as well as interactions between Bi atoms and Te atoms. This not only achieves geometric isolation of Pd active sites but also alters the electron density and energy density of Pd atoms, making the long-range ordered crystal structure more easily exposed at the 100 interface. Therefore, the ternary metal nanocatalysts exhibit superior activity and selectivity, and remain highly efficient even under milder reaction conditions.
[0048] Furthermore, in an embodiment of the present invention, a more preferred structure of the ternary metal nanocatalyst includes at least: each vertex of the PdBi3Te3 octahedral structure is connected to 12 equivalent PdBi3Te3 octahedra, 3 equivalent BiTePd3 trigonal pyramids, and 3 equivalent TeBiPd3 trigonal pyramids. This structure allows for a better match between the electron density and energy density of Pd atoms and the selectivity of the ternary metal nanocatalyst.
[0049] In addition, in an embodiment of the present invention, a more preferred structure of the ternary metal nanocatalyst includes at least the following: each vertex of the TeBiPd3 triangular pyramidal structure is connected to 3 equivalent PdBi3Te3 octahedra, 6 equivalent TeBiPd3 triangular pyramids and 9 equivalent BiTePd3 triangular pyramids.
[0050] Furthermore, in an embodiment of the present invention, a more preferred structure of the ternary metal nanocatalyst includes at least the following: each vertex of the BiTePd3 triangular pyramidal structure is connected to 3 equivalent PdBi3Te3 octahedra, 6 equivalent BiTePd3 triangular pyramids, and 9 equivalent TeBiPd3 triangular pyramids.
[0051] The aforementioned structure can effectively reduce the risk of Pd atom migration and aggregation during long-term reactions, thereby improving the lifetime of ternary metal nanocatalysts. Furthermore, this structure also possesses potential advantages such as strong electronic tunability, high thermodynamic stability, and significant atomic synergistic effects.
[0052] Based on the structure of the ternary metal nanocatalyst containing Bi, Te and Pd, the Pd-Bi bond length is 2.80 Å, the Pd-Te bond length is 2.76 Å, and the Bi-Te bond length is 2.99 Å. This can ensure the stability of the ternary metal nanocatalyst structure, further reduce the risk of Pd atom site migration and aggregation during long-term reactions, and improve the lifetime of the ternary metal nanocatalyst.
[0053] Regarding the aforementioned ternary metal nanocatalysts, Figure 1 This diagram illustrates the three-dimensional structure of a ternary metal nanocatalyst comprising Te, Bi, and Pd provided in an embodiment of the present invention. Figure 2 A schematic diagram of the three-dimensional structure of a single package of ternary metal nanocatalysts containing Te, Bi, and Pd is shown.
[0054] Furthermore, based on any of the structures of the ternary metal nanocatalysts provided in any of the above embodiments, the particle size of the ternary metal nanocatalyst is generally 100 nm to 300 nm. For example, the particle size of the ternary metal nanocatalyst can be 100 nm, 150 nm, 200 nm, 250 nm, or 300 nm, etc. Ternary metal nanocatalysts with too small a particle size have poor selectivity, while ternary metal nanocatalysts with too large a particle size have poor activity.
[0055] Based on the structure of the ternary metal nanocatalyst provided in any of the above embodiments, the ternary metal nanocatalyst may further include: a support for loading and dispersing the ternary metal bond compound; optionally, the support is selected from one or more of activated carbon, graphene, carbon nanotubes, oxides, and molecular sieves. The ternary metal bond compound can be further dispersed through the support.
[0056] In summary, the novel catalyst provided by the embodiments of the present invention has high efficiency, stability and environmental friendliness.
[0057] Furthermore, embodiments of the present invention provide a method for preparing a ternary metal nanocatalyst. Specifically, this preparation method is used to prepare the ternary metal nanocatalyst provided in any of the above embodiments. Specifically, as... Figure 3 As shown, the preparation method may include the following steps: Step S301: A certain molar ratio of a first metal precursor containing Pd, a second metal precursor containing a metal element or metalloid element from Group VA, and a third metal precursor containing a metal element or metalloid element from Group VIA are mixed into a certain amount of oleylamine, stirred and dissolved, and then heated to react.
[0058] Oleylamine typically reduces Pd at temperatures exceeding 80°C. Furthermore, oleylamine exhibits poor reducing power for metals or metalloids in Group VA. Therefore, the heating temperature in step S301 is generally not higher than 80°C, effectively slowing down or preventing the reduction of Pd by oleylamine in this step S301.
[0059] For step S301, the heating reaction temperature is generally 60℃~80℃; for example, the heating reaction temperature can be 60℃, 70℃ or 80℃, etc., preferably, the heating reaction temperature is 70℃.
[0060] Step S302: Add a certain amount of alkyl thiol to oleylamine mixed with the first metal precursor, the second metal precursor and the third metal precursor, and further heat the reaction.
[0061] For example, alkyl thiols can be n-octathiols, n-dodecylthiols, or n-hexadecylthiols.
[0062] The heating temperature in step S302 is generally the temperature at which the alkyl thiol can reduce the second and third metal precursors. More specifically, the heating temperature in step S302 is 150°C to 180°C, for example, 150°C, 160°C, 170°C, or 180°C.
[0063] Furthermore, the heating reaction time in step S302 can be 30 min to 70 min, for example, the heating reaction time can be 30 min, 40 min, 50 min, 60 min or 70 min, etc.
[0064] Both oleylamine and alkyl thiols act as reducing agents. Through the coordination of steps S301 and S302 and the execution order of steps S301 and S302, oleylamine can form a coordination structure with alkyl thiols, enabling Pd, metal elements or metalloids in Group VA and Group VIA to be reduced relatively synchronously, ensuring that Pd, metal elements or metalloids in Group VA and Group VIA form ternary metal-bonded compounds.
[0065] The preparation method for ternary metal nanocatalysts provided in this invention is simple, requires few controllable parameters, and offers mild and controllable reaction conditions, which is conducive to industrialization. Furthermore, the materials used in the above preparation method are readily available and have low cost. Moreover, the entire reaction process avoids the use of toxic or potentially harmful elements such as lead and selenium, aligning with the trend of green chemistry and contributing to environmental safety.
[0066] Preferably, the first metal precursor is palladium halide, and more preferably, the first metal precursor is PdBr2.
[0067] Further, the second metal precursor is one or more of bismuth citrate, bismuth octate, bismuth nitrate, and bismuth acetate. Preferably, the second metal precursor is bismuth acetate.
[0068] The third metal precursor is Ph2Te2. The combination of PdBr2, bismuth acetate and Ph2Te2 enables Pd, Te and Bi in the ternary metal nanocatalyst to completely form ternary metal bond compounds, without the presence of binary metal bond compounds or alloys.
[0069] Furthermore, the above preparation method may further include: Step S303: Dispersing the ternary metal-bonded compound and the support obtained in step S302 in a solvent, and stirring and drying at high speed. The stirring rate is generally not less than 10 rpm. The drying temperature is generally not lower than the evaporation temperature of the solvent, which is generally the temperature range within which the solvent significantly / completely evaporates under normal pressure within a certain time.
[0070] As can be seen from the above, the present invention provides two methods for preparing ternary metal nanocatalysts. The first method includes steps S301 and S302 as described above, forming a ternary metal nanocatalyst composed of a ternary metal-bonded compound. Taking the preparation of a ternary metal-bonded compound using PdBr2, bismuth acetate (Bi(AC)3), and Ph2Te2 as an example, the reaction process is as follows: Figure 4 As shown. The second preparation method includes steps S301 to S303 above, forming a ternary metal nanocatalyst composed of a ternary metal bond compound and a support (the support is used to support and disperse the ternary metal bond compound).
[0071] It is worth noting that, for the first and second preparation methods mentioned above, after the ternary metal nanocatalyst is prepared in step S302, the solvent (such as excess oleylamine, excess alkyl thiols, etc.) liquid phase can be removed by centrifugation to obtain a dry ternary metal nanocatalyst.
[0072] The molar ratio of the first metal precursor, the second metal precursor, and the third metal precursor is 2:2:1; preferably, the molar ratio of PdBr2:bismuth acetate:Ph2Te2 is 2:2:1.
[0073] Furthermore, the molar ratio of alkyl thiol to the first metal precursor is (2~5):1; for example, the molar ratio of alkyl thiol to the first metal precursor can be 2:1, 3:1, 4:1 or 5:1, etc.
[0074] Furthermore, the molar ratio of oleylamine to the first metal precursor is (15~45):1; for example, the molar ratio of oleylamine to the first metal precursor can be 15:1, 20:1, 25:1, 30:1, 35:1, 40:1 or 45:1, etc.
[0075] By controlling the molar ratio of the above components, the yield of ternary metal-bonded compounds can be increased.
[0076] Furthermore, this invention also provides an application of the ternary metal nanocatalyst provided in any of the above embodiments. Specifically, the ternary metal nanocatalyst is used for the selective hydrogenation reaction of alkynes or furfural. This ternary metal nanocatalyst, in catalyzing the selective hydrogenation reaction of alkynes or furfural, can achieve high reactivity, conversion rate, and selectivity under relatively mild conditions.
[0077] More specifically, regarding the application of ternary metal nanocatalysts in the selective hydrogenation reaction of alkynes, the specific catalytic process is as follows: a certain mass ratio of ternary metal nanocatalyst and alkynes are dissolved in a solvent, and H2 is introduced to maintain the reaction space under a certain pressure for catalytic reaction.
[0078] The mass ratio between the ternary metal nanocatalyst and the alkyne is 1:(0.5~2.5); for example, this mass ratio can be 1:0.5, 1:1, 1:1.5, 1:2 or 1:2.5, etc.
[0079] Optionally, the pressure maintained in the reaction space after H2 is introduced is 0.5 MPa to 2 MPa; for example, the pressure maintained in the reaction space after H2 is introduced can be 0.5 MPa, 1 MPa, 1.5 MPa or 2 MPa, etc.
[0080] Optionally, the catalytic reaction temperature is 25℃~50℃, preferably 25℃~30℃. For example, the catalytic reaction temperature can be 25℃, 20℃, 40℃, 45℃, or 50℃, etc. That is, the ternary metal nanocatalyst provided in this embodiment of the invention can selectively catalytically reduce alkynes to olefins at room temperature or lower temperatures. Furthermore, the alkyne conversion rate can reach 100%, and the selectivity for olefins exceeds 90%. The alkyne conversion rate and olefin selectivity are obtained by gas chromatography detection.
[0081] For example, such as Figure 5 The diagram shows the reaction flow of the hydrogenation of phenylacetylene catalyzed by the above-mentioned ternary metal nanocatalyst. The main product is styrene, with a selectivity exceeding 90% at catalytic temperatures not exceeding 50°C. The byproduct is phenylethane, with a selectivity less than 10%.
[0082] The following describes in detail the ternary metal nanocatalysts provided in the embodiments of the present invention and their applications, using multiple examples and comparative examples.
[0083] Example 1
[0084] Step A: PdBr2, Bi(AC)3 and Ph2Te2 are mixed into oleylamine (OAM) in a molar ratio of 1:1:0.5, wherein the molar ratio of PdBr2 to oleylamine is 1:30.4, and the solution is stirred and heated to 70°C.
[0085] Step B: Add n-dodecyl mercaptan to the solution in step A and mix. Heat the mixture to 180°C and react for 60 minutes. The molar ratio of PdBr2 to n-dodecyl mercaptan is 1:4.17.
[0086] Step C: Centrifuge the solution after the reaction in step B to remove the liquid phase and retain the solid ternary metal nanocatalyst.
[0087] Step D: Dissolve the ternary metal nanocatalyst from Step C, the substrate phenylacetylene, and the test standard n-dodecane in ethanol in the reaction vessel at a molar ratio of 1:1. Introduce hydrogen gas into the reaction vessel and pressurize it to 2 MPa. Then place the reaction vessel in a magnetically stirred high-pressure reactor and carry out a catalytic hydrogenation reaction at 50°C with a stirring rate of 500 rpm.
[0088] Step E: Use gas chromatography to periodically detect the conversion rate of phenylacetylene catalyzed in step D and the selectivity of phenylacetylene to styrene.
[0089] Example 2
[0090] The difference from Example 1 is that step D involves a catalytic hydrogenation reaction at 40°C.
[0091] Example 3
[0092] The difference from Example 1 is that step D involves a catalytic hydrogenation reaction at 50°C.
[0093] Comparative Example 1
[0094] The difference from Example 1 is that step D involves a catalytic hydrogenation reaction at 60°C.
[0095] Comparative Example 2
[0096] The difference from Example 1 is that Ph2Te2 was omitted in step A, and the binary metal nanocatalyst PdBi was obtained in step C.
[0097] Comparative Example 3
[0098] The difference from Example 1 is that Bi(AC)3 was omitted in step A, and the binary metal nanocatalyst PdTe was obtained in step C.
[0099] Comparative Example 4
[0100] Pd is loaded onto activated carbon using existing technologies.
[0101] The conversion rate of phenylacetylene refers to the percentage of the amount of phenylacetylene that has been converted to the amount of phenylacetylene added. The amount of phenylacetylene that has been converted is equal to the amount of phenylacetylene added and the amount of phenylacetylene remaining as detected by gas chromatography. Similar to existing detection methods, the amount of phenylacetylene remaining as detected by gas chromatography is determined based on the test standard n-dodecane, which will not be elaborated further here.
[0102] X-ray diffraction analysis was performed on the solid ternary metal nanocatalyst prepared in Example 1, and the X-ray powder diffraction pattern is shown below. Figure 6 As shown, from Figure 6 It can be seen that the ternary metal nanocatalyst (PdBiTe Exp) prepared in Example 1 is completely consistent with the standard PdBiTe PDF#25-0092 card, proving that the ternary metal nanocatalyst prepared in Example 1 is a crystalline pure-phase PdBiTe ternary metal bond compound. Furthermore, the morphology of the solid ternary metal nanocatalyst prepared in Example 1, as scanned by scanning electron microscopy, is shown below. Figure 7 As shown. Among them, Figure 7 The morphology of the ternary metal nanocatalyst was photographed using a 1 μm scale. Figure 7 It can be seen that ternary metal nanocatalysts can form nanoscale (about 200 nm) particles with relatively uniform size.
[0103] Regarding the conversion rate of phenylacetylene and the selectivity of phenylacetylene to styrene in the above embodiments and Comparative Example 1, as shown below... Figure 8 As shown, where, Figure 8In the figures, (a) shows the conversion rate of phenylacetylene and the selectivity for its conversion to styrene in Example 1 over time; (b) shows the conversion rate of phenylacetylene and the selectivity for its conversion to styrene in Example 2 over time; (c) shows the conversion rate of phenylacetylene and the selectivity for its conversion to styrene in Example 3 over time; and (d) shows the conversion rate of phenylacetylene and the selectivity for its conversion to styrene in Comparative Example 1 over time. (Comparison) Figure 8 Figures (a), (b), (c), and (d) show that, at temperatures not exceeding 50°C, the conversion rate of phenylacetylene can reach 100% within 1 hour. However, the selectivity decreases with increasing temperature. At a catalytic temperature of 30°C, the selectivity can reach over 90%, and it remains relatively stable above 90% with increasing reaction time. At a catalytic temperature of 40°C, the selectivity can reach over 85% with increasing reaction time. At a catalytic temperature of 50°C, the selectivity can reach over 77% with increasing reaction time, while the selectivity of the comparative example is below 75%.
[0104] Regarding Examples 1, 2, 3, and 4 above, after 6 hours of catalytic reaction, the conversion rate of phenylacetylene and the selectivity for its conversion to styrene are as follows: Figure 9 As shown, from Figure 9 It can be seen that the phenylacetylene conversion rate in Example 1 reached 100%, and the selectivity reached 92%; the phenylacetylene conversion rate in Comparative Example 2 reached 94%, and the selectivity reached 79%; the phenylacetylene conversion rate in Comparative Example 3 reached 93%, and the selectivity reached 81%; and the phenylacetylene conversion rate in Comparative Example 4 reached 100%, and the selectivity reached 31%. Figure 9 As can be seen, compared with the comparative examples, the ternary metal nanocatalyst provided in the embodiments of the present invention can maintain a high conversion rate and selectivity at lower temperatures and longer reaction temperatures.
[0105] Furthermore, the conversion rate and selectivity of the ternary metal nanocatalyst from Example 1 were tested after eight cycles, and the results were as follows: Figure 10 As shown, from Figure 10 It can be seen that after eight cycles, there is no significant decrease in activity and selectivity. Here, N cycles refers to the ternary metal nanocatalyst being used N times. For example, eight cycles means that after obtaining the solid ternary metal nanocatalyst in step C of Example 1, the catalytic reaction is continued for 6 hours in step D, the product is removed, and the ternary metal nanocatalyst is retained, completing one cycle; then, the substrate phenylacetylene is added back to the ternary metal nanocatalyst that has completed one cycle, and the catalytic reaction is continued for another 6 hours, the product is removed, and the ternary metal nanocatalyst is retained, thus completing the second cycle, and so on.
[0106] Furthermore, X-ray diffraction analysis was performed on the ternary metal nanocatalyst after 8 cycles, and the X-ray powder diffraction pattern is shown below. Figure 11 As shown, from Figure 11 It can be seen that the ternary metal nanocatalyst (PdBiTe Exp) after 8 cycles is completely consistent with the standard PdBiTe PDF#25-0092 card, proving that the structure and phase of the ternary metal nanocatalyst prepared in Example 1 did not change after multiple catalytic cycles.
[0107] In summary, the ternary metal nanocatalysts provided in the embodiments of the present invention have structural stability, mild catalytic reaction conditions, and can achieve 100% conversion and more than 90% selectivity at room temperature and lower temperatures. Furthermore, the ternary metal nanocatalysts have a long service life, stable activity, and stable selectivity.
[0108] The above steps are provided only to help understand the method, structure, and core ideas of this invention. Those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims.
Claims
1. A ternary metal nanocatalyst, characterized in that, include: Pd, metallic elements or metalloids in Group VA and metallic elements or metalloids in Group VIA; Pd, metals or metalloids in Group VA, and metals or metalloids in Group VIA form ternary metallic compounds.
2. The ternary metal nanocatalyst according to claim 1, characterized in that, The ternary metallic compound has a long-range ordered crystal structure; Preferably, the atomic ratio of the ternary metallic compound is Pd: metal element or metalloid element in Group VA: metal element or metalloid element in Group VIA = 1:1:
1.
3. The ternary metal nanocatalyst according to claim 1 or 2, characterized in that, The ternary metallic compound is composed of Pd, Bi and Te.
4. The ternary metal nanocatalyst according to claim 2, characterized in that, The ternary metal-bonded compounds include: a PdBi3Te3 octahedral structure with one Pd atom bonded to three equivalent Bi atoms and three equivalent Te atoms; a TeBiPd3 trigonal pyramidal structure with one Bi atom bonded to three equivalent Pd atoms and one Te atom; and a BiTePd3 trigonal pyramidal structure with one Te atom bonded to three equivalent Pd atoms and one Bi atom. Preferably, each vertex of the PdBi3Te3 octahedral structure is connected to 12 equivalent PdBi3Te3 octahedrons, 3 equivalent BiTePd3 triangular pyramids, and 3 equivalent TeBiPd3 triangular pyramids; each vertex of the TeBiPd3 triangular pyramid structure is connected to 3 equivalent PdBi3Te3 octahedrons, 6 equivalent TeBiPd3 triangular pyramids, and 9 equivalent BiTePd3 triangular pyramids; each vertex of the BiTePd3 triangular pyramid structure is connected to 3 equivalent PdBi3Te3 octahedrons, 6 equivalent BiTePd3 triangular pyramids, and 9 equivalent TeBiPd3 triangular pyramids. Preferably, the Pd-Bi bond length is 2.80 Å, the Pd-Te bond length is 2.76 Å, and the Bi-Te bond length is 2.99 Å.
5. The ternary metal nanocatalyst according to any one of claims 1, 2, and 4, characterized in that, The particle size of the ternary metal nanocatalyst is 100nm~300nm; And / or, The ternary metal nanocatalyst further includes a support for loading and dispersing the ternary metal bonded compound; optionally, the support is selected from one or more of activated carbon, graphene, carbon nanotubes, oxides and molecular sieves.
6. A method for preparing the ternary metal nanocatalyst according to any one of claims 1 to 5, characterized in that, include: Step 1: Mix a certain molar ratio of a first metal precursor containing Pd, a second metal precursor containing a metal element or metalloid element from Group VA, and a third metal precursor containing a metal element or metalloid element from Group VIA into a certain amount of oleylamine, stir to dissolve, and heat to react. Step 2: Add a certain amount of alkyl thiol to the oleylamine mixed with the first metal precursor, the second metal precursor and the third metal precursor, and further heat the reaction.
7. The preparation method according to claim 6, characterized in that, The first metal precursor is palladium halide, preferably, the first metal precursor is PdBr2; The second metal precursor is one or more of bismuth citrate, bismuth octate, bismuth nitrate and bismuth acetate, preferably, the second metal precursor is bismuth acetate; The third metal precursor is Ph2Te2; Optionally, the preparation method further includes: step 3, dispersing the ternary metal bond compound and the support obtained in step 2 in a solvent, and stirring and drying at high speed.
8. The preparation method according to claim 7, characterized in that, The molar ratio of the first metal precursor, the second metal precursor, and the third metal precursor is 2:2:1; And / or, The molar ratio of the alkyl thiol to the first metal precursor is (2~5):1; And / or, The molar ratio of oleylamine to the first metal precursor is (15~45):1; And / or, The temperature for the heating reaction in step 1 is 60℃~80℃; And / or, The temperature for heating the reaction in step 2 is 150℃~180℃; And / or, The heating reaction time in step 2 is 30 min to 70 min.
9. The application of the ternary metal nanocatalyst according to any one of claims 1 to 5, characterized in that, The ternary metal nanocatalyst is used for selective hydrogenation reactions of alkynes or furfural.
10. The application of the ternary metal nanocatalyst according to claim 9, characterized in that, The ternary metal nanocatalyst is intended for use in the selective hydrogenation reaction of alkynes. A certain mass ratio of the ternary metal nanocatalyst and alkyne is dissolved in a solvent, and H2 is introduced to maintain the reaction space under a certain pressure to catalyze the reaction. Optionally, the mass ratio of the ternary metal nanocatalyst to the alkyne is 1:(0.5~2.5); Optionally, the pressure in the reaction space is maintained at 0.5 MPa to 2 MPa after H2 is introduced; Optionally, the catalytic reaction temperature is 25℃~50℃, and preferably, the catalytic reaction temperature is 25℃~30℃.