Studies On The Preparation And Properties Of B-C-N Micro-nano Structures By Using Hainan Local Biomass Resources As Carbon Sources

In recent years,carbon nanotubes(CNTs)and boron nitride nanotubes(BNNTs)have attracted considerable attention due to their unique physical and chemical properties,while ternary compound boron,carbon and nitrogen nanotubes(BCNNTs)have very similar structures to CNTs and BNNTs.while BCNNTs are different from CNTs,the properties of BCNNTs mainly depend on their chemical composition rather than their diameter and chirality.In addition,BCNNTs have some properties,such as high hardness,high temperature resistance and adjustable band gap with composition.They are new inorganic non-metallic functional materials with great application prospects.Therefore,BCNNTs have become one of the hot materials in current research.In this paper,coconut shell,cassava and natural latex of Hainan local biomass resources are used as carbon sources.The mixture of amorphous boron powder and ferric chloride hexahydrate with molar mass ratio of 1:0.05 is evenly mixed with different carbon sources.After drying,the reaction precursors are obtained.BCN micro-nanostructures with different morphologies are prepared after high temperature treatment.When natural coconut shell is used as carbon source,the morphology of the product is regulated by controlling the content of coconut shell.We found that when the mass ratio of mixture to coconut shell is 1:1,BCN microwires modified with nano-flakes are obtained,its diameter is about 200-600 nm.When the nass ratio of mixture to coconut shell is 13,the product morphology are uniform micron-scale BCN trumpet-shaped tubes.At the same time,the effects of reaction temperature,reaction time and ammonia flow rate on the two products are studied.The results show that BCN products with good morphology can be prepared when the reaction temperature is 1200?,the reaction time is 2 h and the ammonia flow rate is 50 mL min-1.At the same time,the photoluminescent properties of the two materials are studied.The results show that the microwires with 417.8 nm and 489.4 nm visible light have better luminescent properties,and the trumpet-shaped tubes with 416.8 and 489.2 nm have better luminescent properties.We propose that microwires are mainly formed by vapor-liquid-solid(VLS)and vapor-so lid(VS)mechanisms.The growth mechanism of trumpet tubes are mainly VLS mechanism.When cassava meal is used as carbon source,the effects of carbon source content,reaction temperature,reaction time and almonia flow rate on the product are studied.The results show that the best reaction conditions are the mass ratio of mixture to cassava powder 12,reaction temperature 1200?,reaction time 4 h and ammonia flow rate 50 mL min-1.At this time,a large number of BCN microwires assembled by bamboo-shaped nanotubes coated with nanosheets could be prepared.Similarly,the photoluminescence properties of these microwires have been studied.The results show that the micro wires have good luminescence properties in the visible light range of 417.4 and 489.8 nm.When natural latex is used as carbon source,the morphology of the product can be controlled by controlling the content of natural latex based on the previous work of the research group.The optimum technological route for preparing BCNNTs is obtained.When the reaction temperature is 1200?,the reaction time is 3 h and the latex content is B:NRL=1:40,the BCN bamboo-shaped nanotubes with high purity,high yield and uniform size(diameter:50-150 nm)are prepared.The formation of BCNNTs is mainly through VLS mechanism.The biological safety of purified BCNNTs is investigated by CCK8 method.The results show that BCNNTs have no toxic effect on normal cells and toxic effect on tumor cells,indicating that BCNNTs have potential anti-turnor activity.