高氮含量氮化碳微粉的制备

Preparation of Carbon Nitride Powder with High Nitrogen/Carbon Ratio

利用常压脉冲电弧等离子体在氮气氛下裂解二氰二胺有机晶体制备含C-N键的碳氮前驱物,然后将该前驱物置于微波氮等离子体中处理,研究了具有高氮含量氮化碳微粉的合成。采用扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶红外光谱(FTIR)和X射线光电子能谱(XPS)分析了样品的形貌、成分和结构。研究结果表明:在电弧等离子体的作用下二氰二胺分子发生断键,得到碳氮直接相连的分子碎片吸附在微晶二氰二胺上。样品经脉冲电弧等离子体多次处理,其中的二氰二胺有机晶体结构被破坏,主要产物为含sp3C-N单键的非晶态碳氮化合物。非晶态的碳氮化合物在微波氮等离子体的作用下重组结晶,XPS分析表明样品表面主要由非晶碳和含有大量sp3C-N单键的高氮含量的碳氮结构组成,XRD分析表明碳氮微粉中有β-C3N4晶体相的存在。

Carbonitride precursor with C-N bond was prepared from dieyandiamide using pulsed are discharge under nitrogen atmospheric pressure. The synthesis of carbon nitride powder with high N/C ratio and large amount of sp^3C-N single bond was performed on a microwave plasma CVD system using the precursor. The morphology, composition and structure of the samples were characterized by scanning electron microscopy （SEM）, X-ray diffraction（XRD）, Fourier transform infrared （FTIR） and X-ray photoelectron spectroscopy （XPS）. The results show that the dieyandiamide molecule is broken into carbon nitride fragments and absorbed on the surface of the micro-dicyandiamide under the effect of pulsed arc plasma. The crystal structure of dicyandiamide is destroyed and turned into amorphous carbonitride compound mainly with sp^3C-N single bond through a number of treatments by the pulsed are plasma. Amorphous earbonitride compound is reeombined under the effect of the microwave nitrogen plasma. XPS result suggests that the surface of the product is mainly made of amorphous carbon and earbonitride with high N/C ratio and large amount of sp^3C-N single bond. XRD result suggests that the earbonitride powder is with a crystalline structure of β-C3N4.