At present,the most common preparation method of amorphous boron powder is magnesium thermal reduction method,but the amorphous boron powder obtained by this method mostly contains impurities such as magnesium and oxy...At present,the most common preparation method of amorphous boron powder is magnesium thermal reduction method,but the amorphous boron powder obtained by this method mostly contains impurities such as magnesium and oxygen which are difficult to remove,and these impurities will seriously affect the application of amorphous boron powder and need to be strictly removed.In this research,the acid-insoluble impurities were modified through sintering and quenching,while the magnesium impurities were optimized via ultrasonic acid leaching.We observed that the quenching temperature played a crucial role in determining the efficiency of magnesium impurity removal.The results show that the magnesium content in amorphous boron powder can be reduced from 5.67%to 2.40%by quenching the amorphous boron powder at 800°C and using ultrasonic assisted acid leaching.Furthermore,the oxidation reaction of boron is influenced by the powder's particle size and specific surface area,with the effective activation energy being intimately tied to both these factors.Post-quenching and acid leaching,we observed an increase in the specific surface area of the boron powder samples,leading to enhanced activity.In conclusion,our study presents an effective strategy to mitigate magnesium impurities and elevate the performance of amorphous boron powder,offering promising avenues for advancing its utilization across diverse industries.展开更多
Lowering the synthesis temperature of boron nitride nanotubes(BNNTs)is crucial for their development.The primary reason for adopting a high temperature is to enable the effective activation of highmelting-point solid ...Lowering the synthesis temperature of boron nitride nanotubes(BNNTs)is crucial for their development.The primary reason for adopting a high temperature is to enable the effective activation of highmelting-point solid boron.In this study,we developed a novel approach for efficiently activating boron by introducing alkali metal compounds into the conventional MgO–B system.This approach can be adopted to form various low-melting-point AM–Mg–B–O growth systems.These growth systems have improved catalytic capability and reactivity even under low-temperature conditions,facilitating the synthesis of BNNTs at temperatures as low as 850℃.In addition,molecular dynamics simulations based on density functional theory theoretically demonstrate that the systems maintain a liquid state at low temperatures and interact with N atoms to form BN chains.These findings offer novel insights into the design of boron activation and are expected to facilitate research on the low-temperature synthesis of BNNTs.展开更多
基金support on this research from the Talent Training Program of Yunnan of China(Grant Nos.202005AC160041 and KKXY202252002)the"Xingdian Talent"Industry Innovation Talent Program in Yunnan Province(Grant No.XDYC-CYCX-2022-0042)。
文摘At present,the most common preparation method of amorphous boron powder is magnesium thermal reduction method,but the amorphous boron powder obtained by this method mostly contains impurities such as magnesium and oxygen which are difficult to remove,and these impurities will seriously affect the application of amorphous boron powder and need to be strictly removed.In this research,the acid-insoluble impurities were modified through sintering and quenching,while the magnesium impurities were optimized via ultrasonic acid leaching.We observed that the quenching temperature played a crucial role in determining the efficiency of magnesium impurity removal.The results show that the magnesium content in amorphous boron powder can be reduced from 5.67%to 2.40%by quenching the amorphous boron powder at 800°C and using ultrasonic assisted acid leaching.Furthermore,the oxidation reaction of boron is influenced by the powder's particle size and specific surface area,with the effective activation energy being intimately tied to both these factors.Post-quenching and acid leaching,we observed an increase in the specific surface area of the boron powder samples,leading to enhanced activity.In conclusion,our study presents an effective strategy to mitigate magnesium impurities and elevate the performance of amorphous boron powder,offering promising avenues for advancing its utilization across diverse industries.
基金supported by the National Natural Science Foundation of China(No.51972162)the Fundamental Research Funds for the Central Universities(No.2024300440).
文摘Lowering the synthesis temperature of boron nitride nanotubes(BNNTs)is crucial for their development.The primary reason for adopting a high temperature is to enable the effective activation of highmelting-point solid boron.In this study,we developed a novel approach for efficiently activating boron by introducing alkali metal compounds into the conventional MgO–B system.This approach can be adopted to form various low-melting-point AM–Mg–B–O growth systems.These growth systems have improved catalytic capability and reactivity even under low-temperature conditions,facilitating the synthesis of BNNTs at temperatures as low as 850℃.In addition,molecular dynamics simulations based on density functional theory theoretically demonstrate that the systems maintain a liquid state at low temperatures and interact with N atoms to form BN chains.These findings offer novel insights into the design of boron activation and are expected to facilitate research on the low-temperature synthesis of BNNTs.
