阅读说明：本技术 原子级助剂修饰的CuO复合介晶催化剂及其制备方法 (Atomic-grade auxiliary-modified CuO composite mesomorphic catalyst and preparation method thereof ) 是由 纪永军 陈晓丽 纪建军 张煜 诸葛骏豪 赵晨 于 2021-06-21 设计创作，主要内容包括：本发明公开了一种原子级助剂修饰的CuO复合介晶催化剂,其包括主催化剂CuO介晶和单原子助剂M1或双单原子助剂M1、M2,且M1、M2均以单原子分散的状态存在,其中,所述M1选自Zn、Zr、Ti、Mn、Fe、Co、Ni、Sn、In、Ce、Ru、Pd、Au、Pt、Rh中的任意一种,所述M2选自Ni,Au,Pt或Pd中的任意一种。本发明原子级助剂修饰的CuO复合介晶催化剂,具有优异的催化性能,用于硅粉与HCl为原料的硅氢氯化反应,能够实现对三氯氢硅和四氯化硅的选择性调控合成,同时降低了反应温度和能耗,并提高了产物收率和硅粉转化率。(The invention discloses an atomic-level auxiliary agent modified CuO composite mesomorphic catalyst, which comprises a main catalyst CuO mesomorphic and a monoatomic auxiliary agent M1 or double monoatomic auxiliary agents M1 and M2, wherein both M1 and M2 exist In a monoatomic dispersion state, wherein M1 is selected from any one of Zn, Zr, Ti, Mn, Fe, Co, Ni, Sn, In, Ce, Ru, Pd, Au, Pt and Rh, and M2 is selected from any one of Ni, Au, Pt and Pd. The CuO composite mesomorphic catalyst modified by the atomic-level auxiliary agent has excellent catalytic performance, is used for the silicon-hydrogen chlorination reaction taking silicon powder and HCl as raw materials, can realize the selective regulation and control synthesis of trichlorosilane and silicon tetrachloride, simultaneously reduces the reaction temperature and energy consumption, and improves the product yield and the silicon powder conversion rate.)

1. An atomic-scale assistant modified CuO composite mesomorphic catalyst is characterized in that the catalyst comprises a main catalyst CuO mesomorphic and a single atom assistant M1 or double single atom assistants M1 and M2, wherein both M1 and M2 exist in a monoatomic dispersion state, wherein,

the M1 is selected from any one of Zn, Zr, Ti, Mn, Fe, Co, Ni, Sn, In, Ce, Ru, Pd, Au, Pt and Rh, and the M2 is selected from any one of Ni, Au, Pt and Pd.

2. The atomic-scale assistant-modified CuO composite mesomorphic catalyst as claimed in claim 1, wherein the catalyst is concave and has a particle size of 1-15 μm.

3. The atomic-scale assistant-modified CuO composite mesogenic catalyst as claimed in claim 1, wherein the mass ratio of CuO mesogenic is 99.98-99.99% and the mass ratio of M1 is 0.01-0.02% in the case of single-atom assistant.

4. The atomic-scale assistant-modified CuO composite mesogenic catalyst as claimed in claim 1, wherein in the case of a diatomic assistant, the mass ratio of CuO mesogens is 99.98-99.99%, and the mass ratios of M1 and M2 are 0.005-0.01%, respectively.

5. A method for preparing the atomic-scale assistant-modified CuO composite mesomorphic catalyst as claimed in any one of claims 1 to 4, which comprises:

a. dissolving a Cu salt precursor and a metal salt precursor containing an auxiliary agent M1 or M1 or M2, and adding into an acetic acid, ethanol or acetone solution to obtain a mixed solution;

b. carrying out solvothermal reaction on the mixed solution obtained in the step a, cooling and separating to obtain a solid product;

c. and c, roasting the solid product obtained in the step b to obtain the aid-modified CuO composite mesomorphic catalyst with atomic-level dispersion.

6. The method for preparing the atomic-scale assistant-modified CuO composite mesomorphic catalyst as claimed in claim 5, wherein in the step a, if the catalyst is a monoatomic assistant, the molar ratio of M1 ions to Cu ions in a metal salt precursor containing an assistant M1 to the Cu salt precursor is 1: 3000-6000; if the metal salt precursor is a double-monoatomic auxiliary agent, the molar ratios of M1 ions, M2 ions and Cu ions in the metal salt precursor containing the auxiliary agents M1 and M2 and the Cu salt precursor are respectively 1: 6000-12000.

7. The preparation method of the atomic-scale assistant-modified CuO composite mesomorphic catalyst according to claim 6, wherein the molar ratio of M2 ions to Cu ions is 1: 7200-9600.

8. The preparation method of the atomic-scale assistant-modified CuO composite mesomorphic catalyst as claimed in claim 5, wherein in the step a, the Cu salt precursor, the M1 or the M2 metal salt precursor are respectively selected from at least one of chloride, nitrate, acetate, acetylacetone salt or methyl chloride, the Cu salt precursor and the metal salt precursor containing the assistant M1 or M1 or M2 are added into a mixed solvent of N, N-dimethylformamide and water for dissolution, the volume ratio of the water to the N, N-dimethylformamide is 1: 7-14, the molar volume ratio of the acetic acid, the ethanol or the acetone to the N, N-dimethylformamide is not less than 0.14mol/L, and the concentration of the Cu salt precursor in the obtained mixed solution is 0.035-0.07 mol/L; in the step b, the reaction temperature is 100-200 ℃, and the reaction time is 2-12 h; in the step c, the roasting is carried out in an oxygen atmosphere, the roasting temperature is 300-600 ℃, the roasting time is 0.5-12h, the roasting mode adopts temperature programming, and the temperature rising rate is 1-5 ℃/min.

9. The application of the atomic-scale assistant-modified CuO composite mesomorphic catalyst as claimed in any one of claims 1 to 4, wherein the catalyst is used for the hydrosilylation reaction using silicon powder and HCl as raw materials to selectively catalyze and synthesize trichlorosilane and silicon tetrachloride.

10. The application of the atomic-scale assistant modified CuO composite mesomorphic catalyst as claimed in claim 9, wherein the reaction temperature is 250-350 ℃.

Technical Field

The invention belongs to the technical field of catalysts, and particularly relates to an atomic-scale assistant modified CuO composite mesomorphic catalyst, and particularly relates to a preparation method of the atomic-scale assistant modified CuO composite mesomorphic catalyst.

Background

The Cu-based oxide composite catalyst is widely applied to a plurality of industrial catalytic reactions, such as methanol synthesis, furfuryl alcohol preparation by furfural hydrogenation, methanol steam reforming, organosilicon monomer synthesis reaction and the like, due to low price and good catalytic performance. At present, the industrial Cu-based oxide composite catalyst is often a polycrystalline structure containing various auxiliary agents and is composed of a main catalyst (Cu)₂O, CuO) and auxiliary agent (including Na, K, etc. alkali metals and transition metal Mn, Fe, Ti, Zn, Ni, Zr, etc. simple substance or oxide nano-particles). However, due to the complexity and diversity of the structure of the industrial Cu-based oxide composite catalyst, the action mechanism of the promoter in the Cu-based catalyst is often unclear, which restricts the further improvement of the performance of the industrial Cu-based oxide composite catalyst.

Mesocrystals are nanoparticle superstructures formed by self-assembling nanoparticles in a crystallographically ordered manner, and have wide application prospects in the aspects of catalysis, sensing, photoelectric devices, biomedicine, energy conversion and the like due to the characteristics of high porosity, large specific surface area, high crystallinity and nanoparticle orientation arrangement, and become a research hotspot in the fields of material science and technology. At present, research on the synthesis, performance and application of metal oxide mesogens is very active and has been demonstrated in many fields to have far superior properties to single crystal and polycrystalline materials.

Trichlorosilane (TCS) is an important component of the silicon industry chain and is the most basic key raw material for producing high-purity polysilicon. Silicon Tetrachloride (STC) is also an important ring in the silicon industry chain, wherein low-purity STC is used to prepare organic silicon products, and high-purity STC is a main raw material for producing optical fiber communication material preforms, and the demand is increasing year by year. The industrial production is mainly to prepare TCS by non-catalytic reaction (silicohydrochlorination method) of metallurgical-grade silicon powder and dry hydrogen chloride gas in a fluidized bed synthesis furnace and simultaneously produce STC as a byproduct. The silicon-hydrogen chlorination method is a normal-pressure reaction, and the reaction temperature is 300-350 ℃. Because the reaction system does not contain a catalytic system, the reaction temperature is high, the energy consumption is high, the yield is low, and the product is difficult to regulate and control. Therefore, if the selective regulation and synthesis of TCS and STC can be realized, and the reaction temperature and energy consumption can be reduced, the method has important significance for the continuous development of various industries such as photovoltaic industry, optical fiber industry, organic silicon industry and the like, but has great challenge.

Disclosure of Invention

The present invention is based on the discovery and recognition by the inventors of the following facts and problems: the Cu-based oxide composite catalyst is low in price and good in catalytic performance, and is widely applied to a plurality of industrial catalytic reactions, but due to the complexity and diversity of the structure of the industrial Cu-based oxide composite catalyst, the action mechanism of the auxiliary agent in the Cu-based catalyst is not clear, and the further improvement of the performance of the industrial Cu-based oxide composite catalyst is restricted. When the silicon powder and the hydrogen chloride gas are used for preparing the trichlorosilane, silicon tetrachloride is a byproduct, which is a main raw material for producing the optical fiber communication material preform, and the conventional silicon hydrochlorination method cannot realize regulation and control of the trichlorosilane and the silicon tetrachloride, and has the problems of high reaction temperature, high energy consumption, low yield and the like.

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, the embodiment of the invention provides an atomic-grade auxiliary agent modified CuO composite mesomorphic catalyst, and the formed ordered atomic interface is helpful for clarifying the action mechanism of multiple auxiliary agents, promoting the electron transfer of the auxiliary agents and a catalytic active component Cu-based oxide, enhancing the interaction of the auxiliary agents and the catalytic active component Cu-based oxide, optimizing the adsorption and activation capacities of reaction substrates and specific intermediates, and improving the activity of the catalyst and regulating and controlling the selectivity of products; the method is used for the silicon hydrochlorination reaction, can realize the selective regulation and control synthesis of trichlorosilane and silicon tetrachloride, simultaneously reduces the reaction temperature and energy consumption, and improves the yield.

The CuO composite mesogenic catalyst modified by the atomic-scale auxiliary agent comprises a main catalyst CuO mesogenic and a single-atom auxiliary agent M1 or double-single-atom auxiliary agents M1 and M2, wherein both M1 and M2 exist in a single-atom dispersed state, wherein,

the M1 is selected from any one of Zn, Zr, Ti, Mn, Fe, Co, Ni, Sn, In, Ce, Ru, Pd, Au, Pt and Rh, and the M2 is selected from any one of Ni, Au, Pt and Pd.

The CuO composite mesomorphic catalyst modified by the atomic-level auxiliary agent provided by the embodiment of the invention has the following advantages and technical effects:

1. according to the catalyst provided by the embodiment of the invention, a Cu-based oxide mesogen and a single/double-monoatomic auxiliary agent are integrated for the first time to form the atomically dispersed auxiliary agent modified Cu-based oxide composite mesogen catalyst, the monoatomic auxiliary agent M1 is uniformly loaded on the surface or bulk phase of the catalyst through a lattice confinement effect, and the M2 is uniformly loaded on the surface of the catalyst through a vacancy anchoring effect; 2. according to the catalyst disclosed by the embodiment of the invention, the formed ordered atomic interface is beneficial to promoting the electron transfer of the auxiliary agent and the catalytic active component Cu-based oxide, enhancing the interaction of the auxiliary agent and the catalytic active component Cu-based oxide, optimizing the adsorption and activation capacities of a reaction substrate and a specific intermediate, and improving the activity of the catalyst and regulating and controlling the selectivity of a product; for the CuO composite mesomorphic catalyst modified by the single-atom auxiliary agent M1, the formed ordered atom interface can promote the electron transfer of the auxiliary agent and the CuO mesomorphic of the catalytic active component, so that the CuO composite mesomorphic shows a more unique electron structure, thereby further enhancing the adsorption and desorption capacity of HCl molecules, realizing the reduction of reaction temperature and simultaneously improving the selectivity and yield of TCS; on the basis, another monatomic auxiliary agent M2 with a dehydrogenation function is introduced, so that the dehydrogenation capacity of TCS and the binding capacity of a dehydrogenation product and Cl can be improved, and the aims of reducing the reaction temperature and regulating and controlling the synthesis of STC are fulfilled; 3. according to the catalyst provided by the embodiment of the invention, the utilization rate of the monatomic assistant is greatly improved due to the special porous structure of the mesomorphic crystal, and the ordered structure and the exposed high-energy crystal face of the mesomorphic crystal provide space for improving the catalytic performance; 4. when the catalyst provided by the embodiment of the invention is used in a silicon-hydrogen chlorination reaction, the effective regulation and control synthesis of the selectivity of trichlorosilane and silicon tetrachloride is realized, the reaction temperature and energy consumption are reduced, and the yield of the product and the conversion rate of silicon powder are improved.

According to the atomic-level assistant modified CuO composite mesomorphic catalyst provided by the embodiment of the invention, the catalyst is concave, and the particle size is 1-15 microns.

According to the atomic-scale assistant modified CuO composite mesomorphic catalyst provided by the embodiment of the invention, if the catalyst is a single-atom assistant, the mass ratio of CuO mesomorphic is 99.98-99.99%, and the mass ratio of M1 is 0.01-0.02%.

According to the CuO composite mesomorphic catalyst modified by the atomic-scale auxiliary agent, provided by the embodiment of the invention, if the catalyst is a diatomic auxiliary agent, the mass ratio of M1 to M2 is 0.005-0.01 percent respectively.

The invention also provides a preparation method of the atomic-scale auxiliary agent modified CuO composite mesomorphic catalyst, which comprises the following steps:

a. dissolving a Cu salt precursor and a metal salt precursor containing an auxiliary agent M1 or M1 or M2, and adding into an acetic acid, ethanol or acetone solution to obtain a mixed solution;

b. carrying out solvothermal reaction on the mixed solution obtained in the step a, cooling and separating to obtain a solid product;

c. and c, roasting the solid product obtained in the step b to obtain the aid-modified CuO composite mesomorphic catalyst with atomic-level dispersion.

The preparation method of the atomic-level assistant-modified CuO composite mesomorphic catalyst provided by the embodiment of the invention has the following advantages and technical effects: 1. according to the method disclosed by the embodiment of the invention, the prepared catalyst is an atomically dispersed auxiliary agent modified Cu-based oxide composite mesomorphic catalyst, and the formed ordered atomic interface is beneficial to promoting the electron transfer of the auxiliary agent and a catalytic active component Cu-based oxide, enhancing the interaction of the auxiliary agent and the catalytic active component Cu-based oxide, optimizing the adsorption and activation capacities of a reaction substrate and a specific intermediate, and promoting the activity of the catalyst and regulating and controlling the selectivity of a product; 2. according to the method disclosed by the embodiment of the invention, the utilization rate of the monatomic auxiliary agent is greatly improved due to the special porous structure of the mesomorphic crystal in the prepared catalyst, and the ordered structure and the exposed high-energy crystal face of the mesomorphic crystal provide space for improving the catalytic performance; 3. according to the method disclosed by the embodiment of the invention, when the prepared catalyst is used for a silicon-hydrogen chlorination reaction, the effective regulation and synthesis of the selectivity of trichlorosilane and silicon tetrachloride are realized, the reaction temperature and the energy consumption are reduced, and the yield of the product and the conversion rate of silicon powder are improved; 4. the method provided by the embodiment of the invention has the advantages of easily available raw materials, simple operation and easy industrial application.

According to the preparation method of the atomic-scale assistant modified CuO composite mesomorphic catalyst, provided by the embodiment of the invention, in the step a, if the atomic-scale assistant is a single-atom assistant, the molar ratio of M1 ions to Cu ions in a metal salt precursor containing an assistant M1 and the Cu salt precursor is 1: 3000-6000; if the metal salt precursor is a double-monoatomic auxiliary agent, the molar ratios of M1 ions, M2 ions and Cu ions in the metal salt precursor containing the auxiliary agents M1 and M2 and the Cu salt precursor are respectively 1: 6000-12000.

According to the preparation method of the atomic-scale assistant modified CuO composite mesomorphic catalyst, disclosed by the embodiment of the invention, the molar ratio of M2 ions to Cu ions is 1: 7200-9600.

According to the preparation method of the CuO composite mesomorphic catalyst modified by the atomic-scale auxiliary agent, wherein, in the step a, the Cu salt precursor, the M1 or the M2 metal salt precursor are respectively selected from at least one of chloride, nitrate, acetate, acetylacetone salt or methyl chloride, the Cu salt precursor and the metal salt precursor containing the assistants M1 or M1 and M2 are added into a mixed solvent of N, N-dimethylformamide and water for dissolving, the volume ratio of the water to the N, N-dimethylformamide is 1: 7-14, the N, N-dimethylformamide plays a role of a reducing agent and a ligand besides the role of a solvent, the molar volume ratio of the acetic acid, the ethanol or the acetone to the N, N-dimethylformamide is more than or equal to 0.14mol/L, the concentration of a Cu salt precursor in the obtained mixed solution is 0.035-0.07 mol/L; in the step b, the reaction temperature is 100-200 ℃, and the reaction time is 2-12 h; in the step c, the roasting is carried out in an oxygen atmosphere, the roasting temperature is 300-600 ℃, the roasting time is 0.5-12h, the roasting mode adopts temperature programming, and the temperature rising rate is 1-5 ℃/min.

The invention also provides an application of the CuO composite mesomorphic catalyst modified by the atomic-scale auxiliary agent, wherein the catalyst is used for the silicon-hydrogen chlorination reaction of silicon powder and HCl which are used as raw materials, and the trichlorosilane and the silicon tetrachloride are selectively synthesized through catalysis.

The application of the CuO composite mesomorphic catalyst modified by the atomic-level auxiliary agent according to the embodiment of the invention brings advantages and technical effects: the CuO composite mesomorphic catalyst modified by the atomic-level auxiliary agent is used as a catalyst in a silicon-hydrogen chlorination reaction, can realize effective regulation and control synthesis of trichlorosilane and silicon tetrachloride selectivity, simultaneously reduces reaction temperature and energy consumption, and improves product yield and silicon powder conversion rate.

The application of the atomic-scale assistant modified CuO composite mesomorphic catalyst provided by the embodiment of the invention is that the reaction temperature is 250-350 ℃.

Drawings

FIG. 1 is an XRD pattern of a composite mesomorphic catalyst of CuO modified by a single atom auxiliary Sn obtained in example 1 of the present invention;

FIG. 2 is a structural representation diagram of a single atom assistant Sn modified CuO composite mesomorphic catalyst obtained in example 1 of the present invention;

FIG. 3 is a HAADF-STEM diagram of a sliced sample of the single atom assistant Sn-modified CuO composite mesogenic catalyst obtained in example 1 of the present invention;

FIG. 4 is a HAADF-STEM diagram and an element plane scan diagram of the CuO composite mesomorphic catalyst modified by Sn and Ni as the diatomic auxiliary agents obtained in example 5 of the present invention;

FIG. 5 is an SEM image and a TEM image of the catalyst obtained in comparative example 1 of the present invention;

FIG. 6 is an HRTEM image of the catalyst obtained in comparative example 1 of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

The CuO composite mesogenic catalyst modified by the atomic-scale auxiliary agent comprises a main catalyst CuO mesogenic and a single-atom auxiliary agent M1 or double-single-atom auxiliary agents M1 and M2, wherein both M1 and M2 exist in a single-atom dispersed state, wherein,

the M1 is selected from any one of Zn, Zr, Ti, Mn, Fe, Co, Ni, Sn, In, Ce, Ru, Pd, Au, Pt and Rh, the M2 is selected from any one of Ni, Au, Pt and Pd, the catalyst is preferably concave, and the particle size is 1-15 μ M, such as 1 μ M, 2 μ M, 5 μ M, 8 μ M, 10 μ M, 12 μ M or 15 μ M.

According to the atomic-level assistant modified CuO composite mesomorphic catalyst provided by the embodiment of the invention, a Cu-based oxide mesomorphic material and a single/double-monoatomic assistant are integrated for the first time to form the atomically dispersed assistant modified Cu-based oxide composite mesomorphic catalyst, the monoatomic assistant M1 is uniformly loaded on the surface or bulk phase of the catalyst through a lattice confinement effect, and the M2 is uniformly loaded on the surface of the catalyst through a vacancy anchoring effect; according to the catalyst disclosed by the embodiment of the invention, the formed ordered atomic interface is beneficial to promoting the electron transfer of the auxiliary agent and the catalytic active component Cu-based oxide, enhancing the interaction of the auxiliary agent and the catalytic active component Cu-based oxide, optimizing the adsorption and activation capacities of a reaction substrate and a specific intermediate, and improving the activity of the catalyst and regulating and controlling the selectivity of a product; for the CuO composite mesomorphic catalyst modified by the single-atom auxiliary agent M1, the formed ordered atom interface can promote the electron transfer of the auxiliary agent and the CuO mesomorphic of the catalytic active component, so that the CuO composite mesomorphic shows a more unique electron structure, thereby further enhancing the adsorption and desorption capacity of HCl molecules, realizing the reduction of reaction temperature and simultaneously improving the selectivity and yield of TCS; on the basis, another monatomic auxiliary agent M2 with a dehydrogenation function is introduced, so that the dehydrogenation capacity of TCS and the binding capacity of a dehydrogenation product and Cl can be improved, and the aims of reducing the reaction temperature and regulating and controlling the synthesis of STC are fulfilled; according to the catalyst provided by the embodiment of the invention, the utilization rate of the monatomic assistant is greatly improved due to the special porous structure of the mesomorphic crystal, and the ordered structure and the exposed high-energy crystal face of the mesomorphic crystal provide space for improving the catalytic performance; when the catalyst provided by the embodiment of the invention is used in a silicon-hydrogen chlorination reaction, the effective regulation and control synthesis of the selectivity of trichlorosilane and silicon tetrachloride is realized, the reaction temperature and energy consumption are reduced, and the yield of the product and the conversion rate of silicon powder are improved.

According to the embodiment of the invention, in the case of the single-atom assistant, the mass ratio of the CuO mesogen in the catalyst is 99.98-99.99%, such as 99.98%, 99.982%, 99.985%, or 99.99%, etc., and the mass ratio of M1 is 0.01-0.02%, such as: 0.01%, 0.012%, 0.015%, 0.018%, or 0.02% or the like; if the CuO is a double-monoatomic assistant, the mass percentage of the CuO mesomorphism is 99.98-99.99 percent, and the mass percentage of M1 and M2 is 0.005-0.01 percent respectively. In the embodiment of the invention, the proportion of the CuO mesogen and the monatomic assistant in the catalyst is optimized, so that the monatomic assistants M1 and M2 can be uniformly loaded on the catalyst in an atomic-level dispersion manner, and the activity of the catalyst is effectively improved.

The invention also provides a preparation method of the atomic-scale auxiliary agent modified CuO composite mesomorphic catalyst, which comprises the following steps:

a. dissolving a Cu salt precursor and a metal salt precursor containing an auxiliary agent M1 or M1 or M2, and adding into an acetic acid, ethanol or acetone solution to obtain a mixed solution; wherein the content of the first and second substances,

preferably, in the case of a monoatomic assistant, the molar ratio of M1 ions to Cu ions in the metal salt precursor containing the assistant M1 to the Cu salt precursor is 1:3000 to 6000, for example, 1:3000, 1:3500, 1:4000, 1:4500, 1:5000, 1:5500, or 1: 6000; if the metal salt precursor containing the assistants M1 and M2 and the Cu salt precursor are diatomic single-atom assistants, the molar ratio of M1 ions and M2 ions to Cu ions in the metal salt precursor and the Cu salt precursor is 1:6000 to 12000, such as 1:6000, 1:6500, 1:7000, 1:8000, 1:9000, 1:10000, 1:11000 or 1:12000, preferably the molar ratio of M2 ions to Cu ions is 1:7200 to 9600;

preferably, the Cu salt precursor, the M1 or the M2 metal salt precursor are respectively selected from at least one of chloride, nitrate, acetate, acetylacetonate or methyl chloride;

preferably, the Cu salt precursor and the metal salt precursor containing the assistants M1 or M1 and M2 are added into a mixed solvent of N, N-dimethylformamide and water for dissolution, the volume ratio of the water to the N, N-dimethylformamide is preferably 1:7 to 14, such as 1:7, 1:8, 1:10, 1:11, 1:12, 1:13 or 1:14, and the like, and the molar volume ratio of the acetic acid, the ethanol or the acetone to the N, N-dimethylformamide is more than or equal to 0.14mol/L, such as 0.14mol/L, 0.15mol/L, 0.18mol/L, 0.2mol/L, 0.5mol/L, 1mol/L or 2 mol/L;

preferably, the concentration of the Cu salt precursor in the obtained mixed solution is 0.035-0.07 mol/L, such as 0.035mol/L, 0.04mol/L, 0.05mol/L, 0.06mol/L or 0.07 mol/L;

b. b, carrying out a solvothermal reaction on the mixed solution obtained in the step a, preferably, the reaction temperature is 100-200 ℃, the reaction time is 2-12h, cooling and separating to obtain a solid product;

c. and c, roasting the solid product obtained in the step b to obtain the aid-modified CuO composite mesomorphic catalyst with atomic-scale dispersion, wherein preferably, the roasting treatment is carried out in an oxygen atmosphere, the roasting temperature is 300-600 ℃, such as 300 ℃, 320 ℃, 350 ℃, 400 ℃, 420 ℃, 450 ℃, 500 ℃, 550 ℃ or 600 ℃, and the like, and the roasting time is 0.5-12h, such as: 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h or 12h, etc., the temperature can be directly raised by the roasting method or can be raised by a program, preferably, the temperature raising rate of the program temperature raising is 1-5 ℃/min, such as 1 ℃/min, 1.5 ℃/min, 2 ℃/min, 2.5 ℃/min, 3 ℃/min, 3.5 ℃/min, 4 ℃/min, 4.5 ℃/min or 5 ℃/min, etc.

According to the preparation method of the atomic-scale auxiliary agent modified CuO composite mesomorphic catalyst provided by the embodiment of the invention, the prepared catalyst is an atomically dispersed auxiliary agent modified Cu-based oxide composite mesomorphic catalyst, and the formed ordered atomic interface is favorable for promoting the electron transfer of the auxiliary agent and a catalytic active component Cu-based oxide, enhancing the interaction of the auxiliary agent and the catalytic active component Cu-based oxide, optimizing the adsorption and activation capacities of a reaction substrate and a specific intermediate, and improving the activity of the catalyst and regulating and controlling the selectivity of a product; according to the method disclosed by the embodiment of the invention, the utilization rate of the monatomic auxiliary agent is greatly improved due to the special porous structure of the mesomorphic crystal in the prepared catalyst, and the ordered structure and the exposed high-energy crystal face of the mesomorphic crystal provide space for improving the catalytic performance; according to the method disclosed by the embodiment of the invention, when the prepared catalyst is used for a silicon-hydrogen chlorination reaction, the effective regulation and synthesis of the selectivity of trichlorosilane and silicon tetrachloride are realized, the reaction temperature and the energy consumption are reduced, and the yield of the product and the conversion rate of silicon powder are improved; the method provided by the embodiment of the invention has the advantages of easily available raw materials, simple operation and easy industrial application.

The invention also provides application of the atomic-grade auxiliary agent modified CuO composite mesomorphic catalyst, wherein the catalyst is used for silicon hydrochlorination reaction taking silicon powder and HCl as raw materials to selectively catalyze and synthesize trichlorosilane and silicon tetrachloride, and preferably, the reaction temperature is 250-350 ℃, such as 250 ℃, 280 ℃, 300 ℃, 320 ℃, 330 ℃ or 350 ℃ and the like.

According to the application of the atomic-level assistant modified CuO composite mesomorphic catalyst provided by the embodiment of the invention, the atomic-level assistant modified CuO composite mesomorphic catalyst provided by the embodiment of the invention is used as a catalyst in a silicon-hydrogen chlorination reaction, so that the selectivity of trichlorosilane and silicon tetrachloride can be effectively regulated and synthesized, the reaction temperature and energy consumption are reduced, the reaction temperature can be reduced to 250 ℃, and the yield of products and the conversion rate of silicon powder are improved.

The present invention is described in detail below with reference to the drawings and examples.

Example 1

(1) Weighing 0.000076gSnCl₂And 0.605000gCu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and roasting the obtained sample for 3 hours at 400 ℃ in an aerobic atmosphere to obtain the single-atom auxiliary Sn modified CuO composite mesomorphic catalyst.

The XRD pattern of the monatomic assistant Sn-modified CuO composite mesomorphic catalyst prepared in this example is shown in fig. 1, and is measured on an X' Pert PRO MPD type multifunctional X-ray diffractometer manufactured by Panalytical corporation, the netherlands show that the observed diffraction peak corresponds to the characteristic diffraction peak of CuO, and no diffraction peak of Sn species is observed, indicating that Sn species exist in a highly dispersed form.

The structural representation diagram of the single-atom assistant Sn-modified CuO composite mesomorphic catalyst prepared in this example is shown in fig. 2, and it can be known from the diagram that the catalyst is concave, has a particle size of about 15 μm, is well dispersed, and is composed of ordered-arranged nanoparticles; the elements Cu, Sn and O are uniformly distributed in the catalyst.

The HAADF-STEM pattern of the sliced sample of the monatomic assistant Sn-modified CuO composite mesogenic catalyst prepared in this example is shown in fig. 3, and is obtained by testing on a JEM ARM200F type spherical aberration correction transmission electron microscope manufactured by JEOL corporation of japan, and as can be seen from the pattern, many observed small bright spots can be attributed to Sn according to the difference in element contrast.

The ICP test of the single atom assistant Sn modified CuO composite mesomorphic catalyst prepared in this example was performed in a Pekin-Elmer inductively coupled plasma atomic emission spectrometer, and the ICP test results show that the obtained catalyst has the following composition: the mass ratio of CuO is 99.99%, and the mass ratio of Sn is 0.01%.

It can be seen that the catalyst synthesized by the method of the present example consists of CuO mesocrystals and Sn, and Sn exists in a form of monoatomic dispersion.

Example 2

(1) 0.000114g of SnCl were weighed out₂And 0.605000g Cu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and roasting the obtained sample for 3 hours at 400 ℃ in an aerobic atmosphere to obtain the single-atom auxiliary Sn modified CuO composite mesomorphic catalyst.

The ICP test results show that the catalyst prepared in this example had the following composition: the mass ratio of CuO is 99.985%, and the mass ratio of Sn is 0.015%.

Example 3

(1) 0.000152g of SnCl were weighed out₂And 0.605000g Cu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and roasting the obtained sample for 3 hours at 400 ℃ in an aerobic atmosphere to obtain the single-atom auxiliary Sn modified CuO composite mesomorphic catalyst.

The ICP test results show that the catalyst prepared in this example had the following composition: the mass ratio of CuO is 99.98%, and the mass ratio of Sn is 0.02%.

Example 4

(1) 0.000088g of InCl were weighed out₃And 0.605000g Cu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and roasting the obtained sample for 3 hours at 400 ℃ In an aerobic atmosphere to obtain the In-modified CuO composite mesomorphic catalyst serving as the monatomic auxiliary agent.

The ICP test results show that the catalyst prepared in this example had the following composition: the mass ratio of CuO is 99.99%, and the mass ratio of In is 0.01%.

Example 5

(1) 0.000038g of SnCl were weighed out₂、0.000026g NiCl₂And 0.605000g Cu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and roasting the obtained sample for 3 hours at 400 ℃ in an aerobic atmosphere to obtain the CuO composite mesomorphic catalyst modified by the double monoatomic auxiliary Sn and Ni.

The HAADF-STEM diagram and the element surface scan diagram of the double monatomic assistant Sn and Ni modified CuO composite mesomorphic catalyst prepared in this example are shown in fig. 4, the element distribution is obtained by testing on an INCAX-MAX type energy spectrometer manufactured by oxford, england, and as can be seen from fig. 4, the Cu, Sn, Ni and O elements are uniformly distributed in the catalyst.

The ICP test results show that the catalyst prepared in this example had the following composition: the mass ratio of CuO was 99.99%, the mass ratio of Sn was 0.005%, and the mass ratio of Ni was 0.005%.

Example 6

(1) 0.000076g of SnCl were weighed out₂、0.000052g NiCl₂And 0.605000g Cu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and roasting the obtained sample for 3 hours at 400 ℃ in an aerobic atmosphere to obtain the CuO composite mesomorphic catalyst modified by the double monoatomic auxiliary Sn and Ni.

The ICP test results show that the catalyst prepared in this example had the following composition: the mass ratio of CuO is 99.98%, the mass ratio of Sn is 0.01%, and the mass ratio of Ni is 0.01%.

Example 7

(1) 0.000038g of SnCl were weighed out₂、0.000036g PdCl₂And 0.605000g Cu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and roasting the obtained sample at 400 ℃ for 3h to obtain the double-monoatomic auxiliary Sn and Ni modified CuO composite mesomorphic catalyst.

The ICP test results show that the catalyst prepared in this example had the following composition: the mass ratio of CuO is 99.99%, the mass ratio of Sn is 0.005%, and the mass ratio of Pd is 0.005%.

Example 8

(1) 0.000076g of SnCl were weighed out₂And 0.605000g Cu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.460000g of ethanol is added dropwise, and the mixture is continuously stirred for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 100 ℃ for 12 hours. Cooling to room temperature, filtering, washing, and drying at 50 deg.C overnight;

(3) and roasting the obtained sample at 400 ℃ for 3h to obtain the single-atom auxiliary Sn modified CuO composite mesomorphic catalyst.

The ICP test results show that the catalyst prepared in this example had the following composition: the mass ratio of CuO is 99.99%, and the mass ratio of Sn is 0.01%.

Example 9

(1) Weighing 0.000076gSnCl₂And 1.210000gCu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 10mL of H were added₂O, after the sample is completely dissolved, 0.580000g of acetone is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 200 ℃ for 2 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and (3) carrying out temperature programming on the obtained sample from room temperature to 300 ℃ at the heating rate of 1 ℃/min, and roasting for 12h at the temperature of 300 ℃ in an aerobic atmosphere to obtain the single-atom auxiliary agent Sn modified CuO composite mesomorphic catalyst.

The ICP test results show that the catalyst prepared in this example had the following composition: the mass ratio of CuO is 99.99%, and the mass ratio of Sn is 0.01%.

Example 10

(1) Weighing 0.000076gSnCl₂And 0.605000gCu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and (3) carrying out temperature programming on the obtained sample from room temperature to 600 ℃ at the heating rate of 5 ℃/min, and roasting for 0.5h at 600 ℃ in an aerobic atmosphere to obtain the single-atom auxiliary agent Sn modified CuO composite mesomorphic catalyst.

From the ICP test results, the resulting catalyst composition was as follows: the mass ratio of CuO is 99.99%, and the mass ratio of Sn is 0.01%.

Comparative example 1

(1) Weighing 0.000228gSnCl₂And 0.605000gCu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and roasting the obtained sample for 3 hours at 400 ℃ in an aerobic atmosphere to obtain the comparative catalyst.

The SEM image and TEM image of the catalyst prepared in comparative example 1 are shown in fig. 5, and the obtained catalyst is convex, uniformly dispersed, and composed of nanoparticles.

Of the catalyst prepared in comparative example 1HRTEM image is shown in FIG. 6, in which CuO and SnO appear₂Indicating that SnO was formed₂Nanoparticles. Thus, in the catalyst prepared in comparative example 1, Sn is not present in the form of a single atom, but is SnO₂The nanoparticles are present.

The catalyst prepared in comparative example 1 had the following composition, as seen from the ICP test results, using the same test method as in example 1: the mass ratio of CuO is 99.97%, and SnO₂The mass ratio of (A) to (B) is 0.03%.

Comparative example 2

(1) Weighing 0.00006g SnCl₂And 0.605000gCu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and roasting the obtained sample for 3 hours at 400 ℃ in an aerobic atmosphere to obtain the single-atom auxiliary Sn modified CuO composite mesomorphic catalyst.

The catalyst prepared in comparative example 2 was composed as follows from the ICP test results using the same test method as in example 1: the mass ratio of CuO was 99.992%, and the mass ratio of Sn was 0.008%.

Comparative example 3

(1) 0.000095g of SnCl were weighed out₂、0.000065g NiCl₂And 0.605000g Cu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) roasting the obtained sample for 3h at 400 ℃ in an aerobic atmosphere to obtain SnO₂And a CuO composite mesomorphic catalyst modified by NiO nano particles.

The catalyst prepared in comparative example 3 was composed as follows from the ICP test results using the same test method as in example 1: the mass ratio of CuO is 99.975 percent, and SnO₂The mass ratio of NiO is 0.0125 percent and the mass ratio of NiO is 0.0125 percent.

Comparative example 4

(1) 0.000030g of SnCl were weighed out₂、0.000020g NiCl₂And 0.605000g Cu (NO)₃)₂·3H₂O was placed in a beaker, then 70mL of N, N dimethylformamide and 5mL of H were added₂O, after the sample is completely dissolved, 0.600000g of acetic acid is added dropwise, and stirring is continued for 15min to obtain a mixed solution;

(2) the mixed solution was transferred to a stainless steel autoclave equipped with a 100mL polytetrafluoroethylene liner and reacted at 140 ℃ for 6 h. Cooling to room temperature, filtering, washing, and drying at 60 deg.C overnight;

(3) and roasting the obtained sample at 400 ℃ for 3h to obtain the double-monoatomic auxiliary Sn and Ni modified CuO composite mesomorphic catalyst.

From the ICP test results, the resulting catalyst composition was as follows: the mass ratio of CuO was 99.992%, that of Sn was 0.004%, and that of Ni was 0.004%.

Evaluation of catalyst Performance:

the catalysts obtained in examples 1 to 10 and comparative examples 1 to 4 were subjected to a catalytic activity test in a micro fixed bed reactor (quartz tube inner diameter of 20mm) apparatus: weighing 10g of silicon powder and 0.2g of the obtained catalyst, grinding and mixing uniformly to form a contact body, and filling the contact body into a reactor; during the reaction, N is firstly introduced₂Purging the reaction system for 1h, then switching to HCl gas at the flow rate of 25mL/min, preheating, and reacting with the contact body at the temperature of 250-350 ℃ for 4 h; the product after reaction flows out from the lower end of the reactor, is condensed by a condenser pipe and then is collected by toluene, and the redundant tail gas is absorbed by alkaline liquor and then is discharged; the collected mixture was subjected to constant volume and then subjected to capillary gas chromatography (Agilent 7890B, KB-210 column,FID detector) for quantitative analysis. The reaction results are shown in table 1, wherein the product selectivity is calculated by the corrected area normalization method, and the Si powder conversion is calculated according to the following formula:

si powder conversion rate (mass of Si powder before reaction-mass of Si powder after reaction)/mass of Si powder before reaction X100%

Comparative example 5

No catalyst was added during the catalyst performance test, and the reaction temperature was 250 ℃.

Comparative example 6

No catalyst is added in the catalyst performance test process, and the reaction temperature is 350 ℃.

Comparative example 7

Commercial CuO catalysts were used during the catalyst performance test at a reaction temperature of 250 ℃.

Comparative example 8

Commercial CuO catalyst was used during the catalyst performance test at a reaction temperature of 350 ℃.

Comparative example 9

In the catalyst performance test process, a single CuO mesomorphic catalyst is used, and the reaction temperature is 300 ℃.

TABLE 1

Note: -means no reaction occurred

As can be seen from Table 1, when the catalysts prepared in examples 1 to 10 were used in the hydrosilylation reaction, wherein the single-atom promoter modified CuO composite mesomorphic catalysts prepared in examples 1 to 4 and examples 8 to 10 mainly generated TCS, the reaction temperature could be reduced to 250 ℃; the CuO mesocrystal modified by the diatomic auxiliary agent prepared in the examples 5-7 mainly generates STC at 300 ℃, and the STC is synthesized under the mild condition (300 ℃) through the silicon-hydrogen chlorination reaction.

In comparative example 1, the mass percentage of the auxiliary agent M1 reaches 0.03%, and at the moment, M1 is not modified at the atomic level, as shown in figure 5, the performance of the prepared catalyst is reduced, so that the TCS selectivity, the yield and the silicon powder conversion rate are all reduced; in comparative example 2, the mass ratio of the assistant M1 is less than 0.01%, and the performance of the catalyst is reduced due to the low content of M1, so that the selectivity, yield and conversion rate of silicon powder of TCS are reduced.

In comparative example 3, excessive Sn and Ni salt precursors were added, and instead of forming the Sn and Ni-modified CuO composite mesomorphic catalyst, a diatomic auxiliary, SnO₂Compared with the CuO composite mesomorphic catalyst modified by NiO nano particles, the selectivity and yield of STC and the conversion rate of silicon powder are obviously reduced in the example 6. In comparative example 4, the amount of Sn and Ni salt precursors added was reduced as compared to example 5, and although the bi-monoatomic auxiliary Sn and Ni modified CuO composite mesogenic catalyst was prepared, the selectivity and yield of STC and the conversion rate of silicon powder all showed a downward trend.

In comparative example 5, at 250 ℃, no catalyst was added and the reaction could not proceed; in comparative example 7, although commercial CuO catalyst was added, reaction did not occur at a low temperature of 250 ℃; in comparative examples 6 and 8, the reaction temperature is increased to 350 ℃, the trichlorosilane can be generated through reaction, but the product yield and the silicon powder conversion rate are very low; in the comparative example 9, a single CuO mesomorphic catalyst is adopted, although the selectivity of trichlorosilane can reach more than 90%, the product yield and the silicon powder conversion rate are both very low and are less than 20%.

The CuO composite mesomorphic catalyst modified by the aid dispersed in atomic level provided by the embodiment of the invention has excellent catalytic performance, and mainly because for the CuO composite mesomorphic catalyst modified by the monoatomic aid, the formed ordered atomic interface can promote the electron transfer of the aid and CuO mesomorphic as a catalytic active component, so that CuO composite mesomorphic shows a more unique electronic structure, the adsorption and desorption capacity of HCl molecules is further enhanced, the reaction temperature is reduced, and the selectivity and the yield of TCS are improved; on the basis, another monatomic auxiliary agent with the dehydrogenation function is introduced, so that the dehydrogenation capacity of TCS and the binding capacity of a dehydrogenation product and Cl can be improved, and the aims of reducing the reaction temperature and regulating and controlling the synthesis of STC are fulfilled.

In the present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" and the like mean that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.