Shenzhen Advanced Institute achieves four orders of magnitude growth in black phosphorus crystal output

Two-dimensional materials represented by graphene are known as the super materials of the 21st century and are expected to develop into the next trillion-level industry
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In 2014, black phosphorus became a "dark horse" in the field of two-dimensional materials, and its emergence quickly attracted attention
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From transistors, optoelectronic devices, to catalysis, energy, biomedicine and other fields, black phosphorus shows broad application prospects
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? Recently, Dr.
Wang Jiahong of the Shenzhen Advanced Institute of Chinese Academy of Sciences told reporters that under the leadership of researcher Yu Xuefeng, the team achieved a four-order increase in the output of black phosphorous crystals per tube, laying the foundation for the development of more "killer" applications
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? Large-scale production achieves a breakthrough of magnitude? To replace traditional phosphorus resources with black phosphorus to become the "protagonist" in the industry, large-scale production is the most basic and critical step
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According to Wang Jiahong's recollection, the single-time yield was less than 0.
5 grams by repeating the previous preparation methods in the early days
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? "The air pressure is too high, and the feeding amount is large, and the tube will burst easily
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" Wang Jiahong introduced that the large-scale preparation of black phosphorus has three main difficulties: first, the temperature is high, and the maximum growth temperature exceeds 600 degrees; the second is the pressure, when the raw materials are sufficient The pressure generated during volatilization exceeds ten MPa or more; the third is that it is highly corrosive, and the steam generated during the reaction can easily cause damage to the vessel wall
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Beginning in 2016, Wang Jiahong led the team to analyze the chemical vapor transmission mechanism, explore new reaction mechanisms, continuously optimize process parameters, and successfully solve a series of scientific and engineering problems.
The output of a single tube has achieved four orders of magnitude growth
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? It is reported that the current technological process basically goes through, which means that the laboratory part of the large-scale preparation of black phosphorus crystals will come to an end, and the next step will enter the pilot stage of closer integration with the industry
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However, Wang Jiahong is not satisfied with such results.
"We still look forward to a more ideal process.
For example, after the phosphate rock is reduced to phosphorus vapor, we can directly convert the phosphorus vapor into black phosphorus
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"? Restless "phosphorus atoms"? Two-dimensional black phosphorus has the advantages of large specific surface area and band gap control, but the lone pair of electrons and defects on the black phosphorus make it prone to decomposition and performance degradation under water and oxygen conditions, which greatly limits Development and application of black phosphorus
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? "We found that two-dimensional black phosphorus has more edge defects and is easily oxidized.
Once oxidized, it will further aggravate its instability
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" Wang Jiahong said
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? In response to this problem, Wang Jiahong adopted the method of constructing a "heterojunction" to "repair" the damaged edge of the black phosphorus
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Specifically, the reducibility of phosphorous atoms at edges or defects is used to convert them into a more stable metal phosphide in situ
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After experimenting with a series of elements and reaction conditions, Wang Jiahong found that cobalt and phosphorus have a strong effect, and the heterojunction also has a good electrocatalytic total water splitting performance
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? "After repairing the damaged edges and defects, the electrochemical stability and electrochemical activity of the material are greatly improved, effectively expanding the application of black phosphorus in the field of energy chemical conversion
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" The result was published at the top of the field of materials chemistry.
The publication "German Applied Chemistry"
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? "Not only on the bookshelf, but also on the shelves"? In addition to continuously adjusting the material structure and improving material performance, Wang Jiahong also started from the application side to explore new applications of black phosphorous in photoelectric catalysis and optoelectronic devices
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He described material development as a power source, and functional applications as a light bulb.
In his view, the power source is the foundation, and the light and heat of the bulb can release the energy of the power source
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? The application of black phosphorus in new energy is one of his main research directions
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Taking the important chemical raw material "ammonia" in industrial and agricultural production as an example, the traditional Haber method not only consumes high energy, but also emits a large amount of greenhouse gas
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Using black phosphorus as a catalyst, an inorganic bionic nitrogenase is artificially constructed to directly convert nitrogen and water into ammonia
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He is also exploring the application of other black phosphorus-like materials and materials with two-dimensional unit structure in hydrogen energy and environmental governance
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Due to the forward-looking layout in the field of black phosphorous materials, Wang Jiahong's team received 25 million yuan investment from Hubei Xingfa Group in 2016 to cooperate in the development of high-end industrial applications of phosphorous chemicals
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At present, the two parties have entered into the construction of the pilot platform
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(Reporter Yuan Siru, correspondent Yan Sisi)