China's scientific research-grade high-purity black phosphorus crystal powder manufacturer 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. In 2014, black phosphorus became a “dark horse” in the field of 2D materials, and its emergence quickly attracted attention. From transistors, optoelectronic devices, to catalysis, energy, biomedicine and other fields, black phosphorus shows broad application prospects.
Recently, Dr. Jiahong Wang, the R&D team of China's scientific research-grade high-purity black phosphorous crystal powder manufacturer SZZK, told Hay Think that under the leadership of researcher Yu Xuefeng, the team achieved a four-order increase in the output of black phosphorous crystals in a single tube. The "killer" application laid the foundation.
Large-scale preparation achieves a breakthrough in magnitude
If black phosphorus is to replace traditional phosphorus resources and become the "protagonist" in the industry, large-scale production is the most basic and critical step. 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.
"The pressure is too large, and the feeding amount is too large. It is easy to burst the tube." Wang Jiahong introduced that the large-scale preparation of black phosphorus has three main difficulties: one is the high temperature, the maximum growth temperature exceeds 600 degrees; the other is the pressure, when the raw materials are fully volatilized The pressure generated at the time exceeds ten megapascals or even more; third, it is highly corrosive, and the steam generated during the reaction can easily cause damage to the vessel wall.
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.
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. 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."
Hold the restless "phosphorus atom"
Two-dimensional black phosphorus has the advantages of large specific surface area and band gap adjustment. However, the lone pair of electrons and defects on black phosphorus make it prone to decomposition and performance degradation under water and oxygen conditions, which greatly limits the development and application of black phosphorus.
"We found that two-dimensional black phosphorus has more edge defects and is easily oxidized. Once oxidized, it will further aggravate its instability." Wang Jiahong said.
In response to this problem, Wang Jiahong adopted the method of constructing a "heterojunction" to "repair" the damaged edge of black phosphorus. Specifically, the reducibility of phosphorous atoms at edges or defects is used to convert them into a more stable metal phosphide in situ. 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.
"After filling the damaged edges and defects, the electrochemical stability and electrochemical activity of the material have been greatly improved, effectively expanding the application of black phosphorus in energy chemical conversion related fields." The result was published in the top journal in the field of materials chemistry. "German Applied Chemistry".
"Not only on the shelves, but also on the shelves"
In addition to continuously adjusting the material structure and improving the material performance, Wang Jiahong also started from the application side to explore new applications of black phosphorus in photoelectric catalysis and optoelectronic devices. 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 light bulb can release the energy of the power source.
The application of black phosphorus in new energy is one of his main research directions. Taking the important chemical raw material "ammonia" in industrial and agricultural production as an example, the traditional Haber process not only consumes high energy, but also emits a large amount of greenhouse gas. Using black phosphorus as a catalyst, an inorganic bionic nitrogenase is artificially constructed to directly convert nitrogen and water into ammonia. 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.