阅读说明：本技术 一种不含氨气气流合成硼碳氮材料的制备方法及其应用 (Preparation method and application of ammonia-free airflow synthesis boron-carbon-nitrogen material ) 是由 张明文 沈宏敏 刘雯婧 陈炜灏 孙文静 陈益宾 于 2021-02-03 设计创作，主要内容包括：本发明涉及一种不含氨气气流合成硼碳氮材料的制备方法,具体步骤如下：步骤S1、按重量份数计,将1份碳源固体有机物、3～20份硼源固体原料和6～200份氮源固体有机物进行均匀混合；步骤S2、将均匀混合得到的混合粉末移至带盖的弧底刚玉舟,而后将带盖的弧底刚玉舟置于高温管式炉中部位置,在惰性气体下进行高温热聚合反应,即得硼碳氮材料；本发明所涉及的硼碳氮材料合成方法具有工艺流程简单,耗时短,原材料廉价易得,无需通入氨气、不产生大量含氨废气,所得产品具有光解水产氢性能等优点。(The invention relates to a preparation method for synthesizing a boron-carbon-nitrogen material by ammonia-free airflow, which comprises the following specific steps: step S1, uniformly mixing 1 part of carbon source solid organic matter, 3-20 parts of boron source solid raw material and 6-200 parts of nitrogen source solid organic matter in parts by weight; step S2, transferring the uniformly mixed powder to a covered arc-bottom corundum boat, then placing the covered arc-bottom corundum boat in the middle of a high-temperature tube furnace, and carrying out high-temperature thermal polymerization reaction under inert gas to obtain a boron-carbon-nitrogen material; the method for synthesizing the boron-carbon-nitrogen material has the advantages of simple process flow, short time consumption, cheap and easily-obtained raw materials, no need of introducing ammonia gas, no generation of a large amount of ammonia-containing waste gas, capability of photolyzing water to produce hydrogen and the like.)

1. The preparation method for synthesizing the boron-carbon-nitrogen material by using the ammonia-free gas flow is characterized by comprising the following specific steps of: step S1, uniformly mixing 1 part of carbon source solid organic matter, 3-20 parts of boron source solid raw material and 6-200 parts of nitrogen source solid organic matter in parts by weight;

and step S2, transferring the uniformly mixed powder to a covered arc-bottom corundum boat, then placing the covered arc-bottom corundum boat in the middle of a high-temperature tube furnace, and carrying out high-temperature thermal polymerization reaction under inert gas to obtain the boron-carbon-nitrogen material.

2. The method for preparing the boron-carbon-nitrogen material synthesized by the airflow without ammonia gas as claimed in claim 1, wherein the method comprises the following steps: the reaction conditions of the high-temperature thermal polymerization reaction are as follows: the heating rate is 2-10 ℃/min; the heat preservation time is 2-8 h; the constant temperature is 900-1500 ℃.

3. The method for preparing the boron-carbon-nitrogen material synthesized by the airflow without ammonia gas as claimed in claim 1, wherein the method comprises the following steps: the uniform mixing method is one of mechanical grinding mixing, water dissolving dispersion and heating drying mixing or water dissolving dispersion and freezing drying mixing.

4. The method for preparing the boron-carbon-nitrogen material synthesized by the airflow without ammonia gas as claimed in claim 1, wherein the method comprises the following steps: the carbon source solid organic matter is one of glucose, fructose or citric acid.

5. The method for preparing the boron-carbon-nitrogen material synthesized by the airflow without ammonia gas as claimed in claim 1, wherein the method comprises the following steps: the boron source solid raw material is one of boron oxide, boric acid or sodium tetraphenylborate.

6. The method for preparing the boron-carbon-nitrogen material synthesized by the airflow without ammonia gas as claimed in claim 1, wherein the method comprises the following steps: the nitrogen source solid organic matter is one of biuret, urea and dicyandiamide.

7. The method for preparing the boron-carbon-nitrogen material synthesized by the airflow without ammonia gas as claimed in claim 1, wherein the method comprises the following steps: the inert gas is one of nitrogen, argon and helium; the gas flow rate is 50-500 mL/min.

8. Use of the ammonia-free gas stream synthesized boron carbon nitride material according to any one of claims 1 to 7, characterized in that: the boron carbon nitrogen material has the half-reaction performance of hydrogen production by photolysis of water, and is applied to the field of photolysis of water but not limited thereto.

Technical Field

The invention relates to the technical field of preparation of boron-carbon-nitrogen materials, in particular to a preparation method and application of a boron-carbon-nitrogen material synthesized by ammonia-free airflow.

Background

Semiconductor photocatalysis technology can convert low-density solar energy into high-density chemical energy (such as H)₂、CH₄Etc.) or solar energy to drive degradation, mineralization and pollutants, and is a new technology which is expected to solve the problems of energy shortage, environmental pollution and the like. The core direction of the technology is to develop a photocatalyst which is cheap and easy to obtain, strong in stability and high in solar energy conversion rate. The hexagonal phase boron carbon nitride is a novel non-metal photocatalyst material, and has the advantages of good thermal stability and chemical stability, wide raw material source, low toxicity and the like. In 2015, the Wangxinchen subject group firstly adopted the material for reactions such as hydrogen production by photolysis of water, oxygen production, carbon dioxide reduction and the like (nat. Commun.2015,6,7698; Sci. China mater, 2015,58, 867). After that, researchers also find that the boron carbon nitrogen material can be applied to organic matter redox reactions such as photocatalysis phenol synthesis (Catal. today,324,73), benzyl alcohol oxidation (ACS Catal.2018,8,4928), N-heterocyclic dehydrogenation (CN107353245A, CN108546233A) and the like, and the boron carbon nitrogen material has wide application prospects.

There are many methods for synthesizing boron-carbon-nitrogen materials, such as CVD method, high-temperature and high-pressure method, mechanical grinding method, solvothermal method, high-temperature pyrolysis polymerization method, etc. (ACS appl. Most of the methods have harsh synthesis process, precise equipment and low yield, and are not suitable for large-scale synthesis; in addition, the boron-carbon-nitrogen material synthesized by the method has no report on the photocatalytic activity of a semiconductor, and is only suitable for the fields of semiconductor circuits, gas adsorption, fluorescent display, lithium ion batteries, electrochemistry and the like. The boron-carbon-nitrogen material with photocatalytic performance is usually prepared by adopting a high-temperature solid-phase method, and ammonia gas (CN103787289A, CN106430128A and CN108341404A) with a certain flow rate is continuously introduced in the synthesis process. The ammonia gas is used as a reducing atmosphere to reduce a boron source and a carbon source, is a nitrogen source, and is one of essential raw materials in the synthesis of the boron-carbon-nitrogen material. Therefore, in the conventional method, it is indispensable to introduce ammonia gas into the reaction. However, ammonia gas is a toxic gas with pungent odor, and if ammonia gas is continuously introduced in the whole high-temperature polymerization process, a large amount of ammonia-containing waste gas is generated, and the environment is greatly damaged.

Disclosure of Invention

Technical problem to be solved

In order to solve the problems in the prior art, the invention provides a preparation method for synthesizing a boron-carbon-nitrogen material by using a gas flow without ammonia gas and application thereof, expensive instruments and raw materials are not needed, and the process flow is simple; the boron-carbon-nitrogen material can be synthesized in batch without continuously introducing toxic ammonia gas with serious environmental pollution. Therefore, the invention can better overcome the defects of the prior art displayed by the background part and has wide application prospect. Meanwhile, the boron carbon nitride material prepared by the invention is a semiconductor photocatalytic material, has proper band gap width and energy band structure position, has the semi-reaction performance of hydrogen production by photolysis of water, and is a photocatalyst material with great potential.

(II) technical scheme

In order to achieve the purpose, the invention adopts the main technical scheme that:

a preparation method for synthesizing a boron-carbon-nitrogen material by ammonia-free airflow comprises the following specific steps: step S1, uniformly mixing 1 part of carbon source solid organic matter, 3-20 parts of boron source solid raw material and 6-200 parts of nitrogen source solid organic matter in parts by weight;

and step S2, transferring the uniformly mixed powder to a covered arc-bottom corundum boat, then placing the covered arc-bottom corundum boat in the middle of a high-temperature tube furnace, and carrying out high-temperature thermal polymerization reaction under inert gas to obtain the boron-carbon-nitrogen material.

Further, the reaction conditions of the high-temperature thermal polymerization reaction are as follows: the heating rate is 2-10 ℃/min; the heat preservation time is 2-8 h; the constant temperature is 900-1500 ℃.

Further, the method for uniformly mixing is one of mechanical grinding mixing, water dissolving dispersion and heating and drying mixing or water dissolving dispersion and freezing and drying mixing.

Further, the carbon source solid organic matter is one of glucose, fructose or citric acid.

Further, the boron source solid raw material is one of boron oxide, boric acid or sodium tetraphenylborate.

Further, the nitrogen source solid organic matter is one of biuret, urea and dicyandiamide.

Further, the inert gas is one of nitrogen, argon and helium; the gas flow rate is 50-500 mL/min.

The application of the boron-carbon-nitrogen material synthesized by the gas flow without ammonia gas is characterized in that the boron-carbon-nitrogen material has the half-reaction performance of hydrogen production by photolysis of water and is applied to the field of photolysis of water but not limited thereto.

(III) advantageous effects

The invention has the beneficial effects that: the present invention introduces common nitrogen source solid organics which decompose at elevated temperatures to release nitrogen-containing species such as ammonia and the like. The nitrogen-containing species generated in situ can not only create a good reducing atmosphere to reduce a boron source and a carbon source, but also serve as a nitrogen source to improve the proportion of nitrogen in the product, thereby obtaining the boron-carbon-nitrogen material with semiconductor photocatalytic performance in one step. Therefore, the method for synthesizing the boron-carbon-nitrogen material has the advantages of simple process flow, short time consumption, cheap and easily-obtained raw materials, no need of introducing ammonia gas, no generation of a large amount of ammonia-containing waste gas, capability of photolyzing water to produce hydrogen and the like.

Drawings

FIG. 1 is an XRD pattern of a boron carbon nitride material in accordance with one embodiment of the present invention;

FIG. 2 is an FT-IR plot of a boron carbon nitride material in accordance with one embodiment of the present invention;

FIG. 3 is a DRS map of a boron carbon nitride material in accordance with one embodiment of the present invention;

FIG. 4 is an SEM image of a boron carbon nitride material in accordance with one embodiment of the invention;

FIG. 5 is a graph showing the half-reaction performance of the boron carbon nitride material in hydrogen production by photolysis of water according to an embodiment of the present invention.

Detailed Description

For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.

The preparation method for synthesizing the boron-carbon-nitrogen material by the ammonia-free airflow, provided by the embodiment of the invention, comprises the following specific steps of: step S1, uniformly mixing 1 part of carbon source solid organic matter, 3-20 parts of boron source solid raw material and 6-200 parts of nitrogen source solid organic matter in parts by weight;

and step S2, transferring the uniformly mixed powder to a covered arc-bottom corundum boat, then placing the covered arc-bottom corundum boat in the middle of a high-temperature tube furnace, and carrying out high-temperature thermal polymerization reaction under inert gas to obtain the boron-carbon-nitrogen material.

Further, the reaction conditions of the high-temperature thermal polymerization reaction are as follows: the heating rate is 2-10 ℃/min; the heat preservation time is 2-8 h; the constant temperature is 900-1500 ℃.

Further, the method for uniformly mixing is one of mechanical grinding mixing, water dissolving dispersion and heating and drying mixing or water dissolving dispersion and freezing and drying mixing.

Further, the carbon source solid organic matter is one of glucose, fructose or citric acid.

Further, the boron source solid raw material is one of boron oxide, boric acid or sodium tetraphenylborate.

Further, the nitrogen source solid organic matter is one of biuret, urea and dicyandiamide.

Further, the inert gas is one of nitrogen, argon and helium; the gas flow rate is 50-500 mL/min.

The application of the boron-carbon-nitrogen material synthesized by the gas flow without ammonia gas is characterized in that the boron-carbon-nitrogen material has the half-reaction performance of hydrogen production by photolysis of water and is applied to the field of photolysis of water but not limited thereto.

The invention adopts a strategy of high-temperature solid-phase polymerization, reasonably adjusts the input proportion of solid organic matters such as a boron source, a carbon source, a nitrogen source and the like, and carries out thermal polymerization reaction on the mixture under the conditions of inert atmosphere and high temperature. During the heating process, a higher proportion of the nitrogen source can decompose a certain amount of nitrogen-containing species (such as ammonia gas, etc.) in situ. At the moment, the method not only can create a good reducing atmosphere to reduce a boron source and a carbon source, but also can be used as a nitrogen source to improve the proportion of nitrogen in the product, and is beneficial to producing the boron-carbon-nitrogen material with semiconductor photocatalytic performance. In the invention, expensive instruments and raw materials are not needed, and the process flow is simple; the boron-carbon-nitrogen material can be synthesized in batch without continuously introducing toxic ammonia gas with serious environmental pollution; meanwhile, the boron carbon nitride material prepared by the invention is a semiconductor photocatalytic material, has proper band gap width and energy band structure position, has the semi-reaction performance of hydrogen production by photolysis of water, and is a photocatalyst material with great potential.

As shown in fig. 1, the XRD pattern of the boron carbon nitride material shows two diffraction peaks: (002) interlaminar stacking diffraction peaks with a low angle of 26.4 degrees attributed to the graphite phase characteristics; the high angle of 42.3 ° is attributed to the in-plane six-membered ring repeat unit (100) diffraction peak, and the data indicates that the resulting boron carbon nitride material is a hexagonal phase crystal structure.

As shown in FIG. 2, the FT-IR chart of the boron carbon nitride material shows two characteristic infrared absorption peaks: at 1380cm^-1The wider peaks correspond to stretching vibrations in the B-N, C-N and C-C bond planes in the transverse direction; at 780cm^-1The peak at (a) corresponds to bending vibration out of the B-N-B bonding plane. In addition, a larger infrared absorption is obtained within the range of 3000-3600 cm < -1 >, and the results correspond to the stretching vibration peaks of N-H with unpolymerized tail ends and O-H of adsorbed water, and all the results accord with the chemical structure characteristics of hexagonal repeating units of the boron-carbon-nitrogen material.

As shown in fig. 3, the DRS graph of the boron carbon nitride material indicates that the synthesized boron carbon nitride material can absorb a certain range of visible light and has the semiconductor performance of a multi-level energy band structure.

As shown in FIG. 4, the SEM image of the B-C-N material shows that the synthesized B-C-N material is irregular bulk material with the size of 10-20 μm.

Example 1

The preparation method for synthesizing the boron-carbon-nitrogen material by the ammonia-free airflow, provided by the embodiment of the invention, comprises the following specific steps of: step S1, uniformly mixing 1 part of glucose, 7 parts of boron oxide and 20 parts of urea in parts by weight;

and step S2, transferring the uniformly mixed powder to a covered arc-bottom corundum boat, then placing the covered arc-bottom corundum boat in the middle of a high-temperature tube furnace, and carrying out high-temperature thermal polymerization reaction under inert gas to obtain the boron-carbon-nitrogen material.

Further, the reaction conditions of the high-temperature thermal polymerization reaction are as follows: nitrogen is taken as carrier gas, and the gas flow is 100 mL/min; the heating rate is 5 ℃/min; keeping the temperature for 5 hours; the constant temperature is 1250 ℃.

Further, the method for uniformly mixing is mechanical grinding and mixing. Dispersing 30mg of boron carbon nitrogen material in 100mL of triethanolamine aqueous solution containing 10 vol.% and adding an amount of chloroplatinic acid solution (such that the loading of Pt atoms is 1 wt.% of the mass of the photocatalyst); transferring the mixed solution into an up-illuminated photolysis water reactor, and reacting by using a xenon lamp (300W) as a light source; from fig. 5, it can be seen that the prepared product has certain photolytic water hydrogen production activity under visible light irradiation (the lambda of the filter at the light source is greater than 420nm) and full-band irradiation (no filter is placed).

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.