Disclosure of Invention
In view of the above, the present invention provides a boron phosphide material and a method for preparing the same, wherein a boron source and a phosphorus source are grown in a high temperature solution by using a metal as a flux, so as to obtain a boron phosphide material with a hierarchical structure, the method has the advantages of simple process, low production cost and high production safety, and the obtained boron phosphide material has different structural appearances, indirect wide band gaps and high electron mobility, thereby solving the technical problem that no effective method for preparing the boron phosphide material with the hierarchical structure exists in the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme:
a preparation method of a boron phosphide material comprises the following steps:
mixing a boron source material and a phosphorus source material to prepare uniform first powder;
adding a metal fluxing agent into the first powder and uniformly mixing to prepare second powder;
and carrying out high-temperature reaction on the second powder under a vacuum condition, and then sequentially carrying out acid washing, water washing and drying to obtain the boron phosphide material.
Further, the boron source material is selected from amorphous boron powder, single crystal boron particles or boron iodide.
Further, the phosphorus source material is selected from amorphous red phosphorus powder, elemental phosphorus with the crystallinity of more than 95%, zinc phosphide, nickel phosphide or copper phosphide.
Further, the metal flux includes nickel, tin, copper, magnesium, silver, indium, or antimony.
Further, in the first powder, the boron source material and the phosphorus source material are mixed in such a manner that the molar ratio of boron element to phosphorus element is 1: (1-5) mixing;
in the second powder, the molar ratio of boron element to metal element in the metal flux is 1: (1-4).
Further, the vacuum condition is that the vacuum degree is between 1.0 and 10-3~9.0×10-3Pa。
Further, the high-temperature reaction comprises the following specific steps: firstly heating to 500-900 ℃ at the speed of 2-10 ℃/min, then heating to 1000-1200 ℃ at the speed of 0.08-10 ℃/min, preserving heat for 0.5-6 days, then cooling to 500-900 ℃ at the cooling speed of 1-10 ℃/h, and finally naturally cooling.
Furthermore, a washing liquid adopted by the acid washing is aqua regia, and the specific step of the acid washing is to soak a sample subjected to high-temperature reaction in the aqua regia.
Another object of the present invention is to provide a boron phosphide material prepared by the preparation method described in any one of the above schemes.
Compared with the prior art, the invention has the following beneficial effects:
according to the invention, the boron source material and the phosphorus source material are subjected to high-temperature solution growth and acid pickling treatment under the action of the metal fluxing agent, so that the prepared boron phosphide material has a hierarchical structure, the preparation method is simple in process, and the use of dangerous gases such as phosphine, boron bromide and the like is avoided, so that the production safety is greatly improved, and the pollution to the environment is reduced; the used fluxing agent is cheap metal fluxing agent, and the production cost is low.
According to the preparation method disclosed by the invention, boron phosphide materials with different structural morphologies can be prepared by regulating the proportion of the boron source, the phosphorus source material and the metal fluxing agent and the high-temperature reaction control program, and the boron phosphide materials have indirect wide band gaps and high electron mobility and have good application prospects when used as photocatalysts and electrocatalysts.
Detailed Description
In order that the invention may be more fully understood, reference will now be made to the specific embodiments illustrated. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
The first aspect of the invention discloses a preparation method of a boron phosphide material, which comprises the following steps:
mixing a boron source material and a phosphorus source material to prepare uniform first powder;
adding a metal fluxing agent into the first powder and uniformly mixing to prepare second powder;
and carrying out high-temperature reaction on the second powder under a vacuum condition, and then sequentially carrying out acid washing, water washing and drying to obtain the boron phosphide material.
According to the invention, metal is used as a fluxing agent, the metal is mixed with a boron source material and a phosphorus source material and then reacts at a high temperature, and then the boron phosphide material with a hierarchical structure is prepared through acid washing, water washing and drying in sequence, wherein the metal fluxing agent has the function of reducing the melting point of a reactant, and is beneficial to reducing the crystallization temperature of boron phosphide crystals. In addition, the uniform powder made from the boron source material and the phosphorus source material is not limited to visible lumps, and the powder making method is not limited to a specific method as long as the uniformly mixed powder can be made.
Further, the boron source material and the phosphorus source material employed in the present invention may be conventionally selected in the art, but in view of the influence of impurities, byproducts, etc., in some specific embodiments of the present invention, it is preferable that the boron source material is selected from amorphous boron powder, single crystal boron particles, or boron iodide; the phosphorus source material is selected from amorphous red phosphorus powder, elemental phosphorus with the crystallinity of more than 95%, zinc phosphide, nickel phosphide or copper phosphide, so that the generation of impurities difficult to remove is greatly avoided. Furthermore, the use of high quality phosphorus source materials or flux-carrying phosphorus source materials (such as zinc phosphide, copper phosphide or nickel phosphide) can avoid the formation of boron phosphide crystal secondary product B2P 12.
Further, the metal flux in the present invention may be a metal flux such as nickel or copper which is conventional in the art, and in addition, a part of low melting point metal is also preferred as the metal flux in the present invention, which is advantageous for lowering the reaction temperature, and mentioned examples include, but are not limited to, tin, magnesium, silver, indium or antimony.
The addition amounts of the boron source material, the phosphorus source material and the metal flux in the present invention are not specifically limited, and the boron phosphide material in the present invention can be prepared by mixing the boron source material, the phosphorus source material and the metal flux in any ratio, except that the ratio of the boron source material to the phosphorus source material to the metal flux is different, and the hierarchical structure of the obtained boron phosphide material is also different, and preferably, in some specific embodiments of the present invention, the molar ratio of the boron source material to the phosphorus source material in the first powder is 1: (1-5) mixing; in the second powder, the molar ratio of boron element to metal element in the metal flux is 1: (1-4).
Further, the single crystal growth is generally carried out under vacuum, and the high temperature reaction of the present invention is preferably carried out under high vacuum, on one hand, to avoid the formation of oxide with oxygen during the reaction and on the other hand, to provide space for the vapor pressure released by phosphorus, and preferably, the vacuum degree is between 1.0 × 10-3~9.0×10-3Pa. Further, in some embodiments of the present invention, the high temperature reaction is preferably carried out in a horizontal tube furnace by: and putting the second powder into a quartz tube, sealing the quartz tube by flame under a high vacuum condition, putting the sealed quartz tube into a corundum magnetic boat, and putting the quartz tube and the corundum magnetic boat together into a horizontal tube furnace for high-temperature reaction. It is to be understood that the specific steps of the foregoing high temperature reaction are only for example and not limited to the foregoing steps, as long as the high temperature reaction performed under vacuum conditions can be used in the present invention.
Further, the high-temperature reaction in the present invention is preferably performed in stages at different temperature rise rates, and specifically, the high-temperature reaction specifically comprises the following steps: firstly heating to 500-900 ℃ at the speed of 2-10 ℃/min, then heating to 1000-1200 ℃ at the speed of 0.08-10 ℃/min, preserving heat for 0.5-6 days, then cooling to 500-900 ℃ at the cooling speed of 1-10 ℃/h, and finally naturally cooling. The higher heating rate (2-10 ℃/min) is adopted firstly because reactants can not be melted and can not react within 500-900 ℃, so that the time can be saved by increasing the heating rate, the reaction starts to occur at about 900 ℃, the full reaction can be ensured by reducing the heating rate at the moment, the crystal quality is improved, and the same reason is also realized during the cooling.
Further, since unreacted metal flux and some byproducts may remain in the sample after the reaction, the metal flux and other byproducts must be washed away with an acid solution, preferably, the washing solution used in the acid washing is aqua regia, since the aqua regia can sufficiently remove the unreacted metal flux and byproducts, specifically, the sample after the high temperature reaction is only soaked in aqua regia, and it can be understood that the treatment time is not specifically limited, and the acid washing time can be appropriately prolonged or shortened according to specific conditions.
In a second aspect of the invention, there is disclosed a boron phosphide material produced by the production method according to the first aspect of the invention.
The boron phosphide material has a micro-nano assembly hierarchical structure, has brief introduction and wide band gap and high electron mobility, and has good application prospect when being used as a photocatalyst and an electrocatalyst.
The technical solution of the present invention will be more clearly and completely described below with reference to specific embodiments.
Example 1
According to the molar ratio of boron element to phosphorus element of 1: weighing amorphous boron powder and amorphous phosphorus powder as raw materials, mixing and grinding the raw materials into uniform first powder;
adding high-purity tin powder (with the purity of more than 98%) of the metal fluxing agent into the first powder, and uniformly mixing to prepare second powder, wherein the molar ratio of boron to tin in the metal fluxing agent is 1: 1;
placing the second powder into a quartz tube, and placing the quartz tube under high vacuum (1.0 × 10)-3 Pa), putting the quartz tube in corundum magnetic boat, putting the quartz tube in horizontal tube furnaceAnd (3) performing high-temperature reaction, namely heating to 500 ℃ at the speed of 10 ℃/min, heating to 1000 ℃ at the speed of 3 ℃/min, keeping the temperature for 0.5 day, cooling to 900 ℃ at the speed of 3 ℃/h, and finally naturally cooling to room temperature.
And (3) preparing 20mL of aqua regia in a fume hood, placing the aqua regia in a beaker, taking out a sample after high-temperature reaction, placing the sample in the beaker for treatment for 2h, centrifugally washing the sample with deionized water until the solution is neutral, and placing the obtained precipitate in a drying box for drying at 80 ℃ to obtain the hollow boron phosphide powder with the hierarchical structure.
The boron phosphide powder in the present example was characterized by XRD and SEM respectively, and the results are shown in fig. 1 (a) and fig. 2 (a), where XRD characteristic peaks of the boron phosphide powder in fig. 1 (a) correspond to standard cards one-to-one, and the SEM image in fig. 2 (a) confirms that the boron phosphide powder in the present example has a hollow and hierarchical structure composed of nanoparticles; furthermore, XPS and N were applied to the boron phosphide powder in this example2Absorption-desorption characterization, as shown in FIGS. 3 and 4, it can be seen that the 188.2eV peak in the B1 s region and the 188.97 eV peak in the P2 s region, and the 130.4eV and 131.2eV peaks in the P2P region are respectively assigned to B and P species of boron phosphide through N2The absorption-desorption characteristics show that the specific surface area of the boron phosphide powder is 1.65m2The result of the above shows that boron phosphide powder having both hollow and hierarchical structure was successfully prepared in this example.
Example 2
According to the molar ratio of boron element to phosphorus element of 1: weighing boron iodide and massive phosphorus as raw materials, mixing and grinding the raw materials into uniform first powder;
adding indium powder of a metal fluxing agent into the first powder, and uniformly mixing to prepare second powder, wherein the molar ratio of boron to indium in the metal fluxing agent is 1: 1;
the second powder was placed in a quartz tube under high vacuum (3.0X 10)-3 Pa), placing the vacuum-sealed quartz tube in a corundum magnet boat, and placing the corundum magnet boat together in a horizontal tube furnace for high-temperature reaction, wherein the high-temperature reaction is specifically heating to 500 ℃ at the speed of 10 ℃/min, and then heating to 0.08 ℃/minHeating to 1100 deg.C, maintaining for 6 days, cooling to 900 deg.C at a rate of 1 deg.C/h, 3 deg.C/h or 10 deg.C/h, and naturally cooling to room temperature.
And (3) preparing 20mL of aqua regia in a fume hood, placing the aqua regia in a beaker, taking out a sample subjected to high-temperature reaction, placing the sample in the beaker for treatment for 2h, performing centrifugal washing by using deionized water until the solution is neutral, and placing the obtained precipitate in a drying box for drying at 80 ℃ to obtain boron phosphide powder with cluster and hierarchical structure.
As a result of performing XRD and SEM characterization on the boron phosphide powder in this example, as shown in fig. 1 (b) and fig. 2 (b), it can be seen that the XRD characteristic peak of the boron phosphide powder in fig. 1 (b) completely corresponds to the standard card, which indicates that the boron phosphide powder was successfully prepared in this example, whereas the SEM image confirms that the boron phosphide powder has a cluster with a micron rod-like crystal composition and a graded flower-like structure.
Example 3
According to the molar ratio of boron element to phosphorus element of 1: 3, weighing boron single crystal (with the purity of more than 93%) and phosphorus powder as raw materials, mixing and grinding the raw materials into uniform first powder;
adding high-purity nickel (with the purity of more than 99%) in the metal fluxing agent into the first powder, and uniformly mixing to prepare second powder, wherein the molar ratio of boron to nickel in the metal fluxing agent is 1: 1;
the second powder was placed in a quartz tube under high vacuum (6.0X 10)-3 Pa), placing the quartz tube after vacuum sealing in a corundum magnet boat, and placing the quartz tube in a horizontal tube furnace for high-temperature reaction, wherein the high-temperature reaction is to heat up to 500 ℃ at the speed of 10 ℃/min, heat up to 1200 ℃ at the speed of 0.8 or 3 ℃/min, keep the temperature for 0.5 or 3 days, then cool down to 900 ℃ at the speed of 3 ℃/h, and finally naturally cool down to room temperature.
And (3) preparing 20mL of aqua regia in a fume hood, placing the aqua regia in a beaker, taking out a sample after high-temperature reaction, placing the sample in the beaker for treatment for 2h, centrifugally washing the sample with deionized water until the solution is neutral, and placing the obtained precipitate in a drying box for drying at 80 ℃ to obtain the boron phosphide material with the bead-type hierarchical structure.
The boron phosphide powder in the example was characterized by XRD and SEM respectively, and the results are shown in fig. 1 (c) and fig. 2 (c), wherein the XRD characteristic peak of the boron phosphide powder in fig. 1 (c) completely corresponds to the standard card, which indicates that the boron phosphide powder was successfully prepared in the example, and the SEM image confirms that the boron phosphide powder has a beaded hierarchical structure consisting of fibers and particles.
Example 4
According to the molar ratio of boron element to phosphorus element of 1: 3, weighing amorphous boron powder and a massive red phosphorus source as raw materials, mixing and grinding the raw materials into uniform first powder;
adding a metal fluxing agent nickel net into the first powder, and uniformly mixing to prepare second powder, wherein the molar ratio of boron to nickel in the metal fluxing agent is 1: 2;
the second powder was placed in a quartz tube under high vacuum (6.0X 10)-3 Pa), placing the quartz tube after vacuum sealing in a corundum magnet boat, and placing the quartz tube in a horizontal tube furnace for high-temperature reaction, wherein the high-temperature reaction is to heat up to 500 ℃ at the speed of 10 ℃/min, heat up to 1100 ℃ at the speed of 0.08 ℃/min, keep the temperature for 3 days, then reduce the temperature to 900 ℃ at the speed of 1 ℃/h, and finally naturally cool the temperature to room temperature.
And (3) preparing 20mL of aqua regia in a fume hood, placing the aqua regia in a beaker, taking out a sample subjected to high-temperature reaction, placing the sample in the beaker for treatment for 2h, performing centrifugal washing by using deionized water until the solution is neutral, and placing the obtained precipitate in a drying box for drying at 80 ℃ to obtain the boron phosphide material with the fibrous structure.
The boron phosphide material in the example was characterized by XRD and SEM, respectively, and the results are shown in fig. 1 (d) and fig. 2 (d), wherein the characteristic peaks of XRD of the boron phosphide powder in fig. 1 (d) completely correspond to those of the standard card, which indicates that the boron phosphide material was successfully prepared in the example, and the SEM image confirms that the boron phosphide powder has a fibrous structure.
Example 5
According to the molar ratio of boron element to phosphorus element of 1: weighing boron single crystals and massive phosphorus as raw materials, mixing and grinding the raw materials into uniform first powder;
adding high-purity antimony (with the purity of more than 99%) in the metal fluxing agent into the first powder, and uniformly mixing to prepare second powder, wherein the molar ratio of boron to antimony in the metal fluxing agent is 1: 4;
the second powder was placed in a quartz tube under high vacuum (9.0X 10)-3 Pa), placing the quartz tube after vacuum sealing in a corundum magnet boat, and placing the quartz tube in a horizontal tube furnace for high-temperature reaction, wherein the high-temperature reaction is to heat up to 500 ℃ at the speed of 10 ℃/min, heat up to 1100 ℃ at the speed of 0.08 ℃/min, keep the temperature for 3 days, then reduce the temperature to 900 ℃ at the speed of 1 ℃/h, and finally naturally cool the temperature to room temperature.
And (3) preparing 20mL of aqua regia in a fume hood, placing the aqua regia in a beaker, taking out a sample after high-temperature reaction, placing the sample in the beaker for treatment for 2h, centrifugally washing the sample with deionized water until the solution is neutral, and placing the obtained precipitate in a drying box for drying at 80 ℃ to obtain the hollow boron phosphide powder with the hierarchical structure.
Example 6
According to the molar ratio of boron element to phosphorus element of 1: 5, weighing amorphous boron powder and amorphous phosphorus powder as raw materials, mixing and grinding the raw materials into uniform first powder;
adding magnesium powder (with the purity of more than 98%) of a metal fluxing agent into the first powder, and uniformly mixing to prepare second powder, wherein the molar ratio of boron to magnesium in the metal fluxing agent is 1: 1;
the second powder was placed in a quartz tube under high vacuum (6.0X 10)-3 Pa), placing the quartz tube after vacuum sealing in a corundum magnet boat, and placing the quartz tube in a horizontal tube furnace for high-temperature reaction, wherein the high-temperature reaction is to heat up to 500 ℃ at the speed of 10 ℃/min, heat up to 1100 ℃ at the speed of 3 ℃/min, preserve heat for 14 days, reduce to 900 ℃ at the speed of 3 ℃/h, and finally naturally cool to room temperature.
And (3) preparing 20mL of aqua regia in a fume hood, placing the aqua regia in a beaker, taking out a sample after high-temperature reaction, placing the sample in the beaker for treatment for 2h, centrifugally washing the sample with deionized water until the solution is neutral, and placing the obtained precipitate in a drying box for drying at 80 ℃ to obtain the hollow boron phosphide powder with the hierarchical structure.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.