热解炭中原位熔盐催化SiC纳米线的合成及表征(英文)

Synthesis and characterization of silicon carbide nanowires from lignin-phenolic resin and silicon powder with an in-situ formed molten salt as catalyst

不加金属催化剂,以碱木素酚醛树脂（LPF）和硅粉作为原料在低温条件下合成SiC纳米线。利用SEM、TEM、XRD表征样品的形貌及显微结构,用热力学方法分析反应条件对SiC纳米线生长的影响。结果表明,SiC纳米线在1100℃左右开始生长,其由气-液-固生长机理控制,同时其生成温度比用商业酚醛树脂作为原料低。生成的SiC纳米线的直径为30~100nm并沿晶面的[1 1 1]方向生长。碱木素酚醛树脂中的无机盐在热解炭化过程中原位形成熔盐并起着液相催化剂球滴的作用,促进SiC纳米线的生长,并提出合成SiC纳米线的生长机理模型。

Silicon carbide （ SiC） nanowires were synthesized using lignin-phenolic resin （ LPR） and silicon powder as raw materi-als. The morphology and structures of the nanowires were characterized by scanning electron microscopy, transmission electron mi-croscopy and X-ray diffraction. The influence of reaction conditions on the growth of the nanowires was investigated by thermody-namic analysis. It was revealed that the growth of the nanowires starts at around 1 100℃ by a vapor-liquid-solid （ VLS） mechanism and the growth temperature is lower than that for the formation of SiC nanowires from commercial phenolic resin and silicon powder. The nanowires have diameters of 30-100 nm and lengths of several microns. It was revealed that the inorganic salts are formed in-si-tu from LPR in the lignin segment as liquid catalyst droplets during pyrolysis. These dissolve SiC and become supersaturated, from which SiC nanowires grow along the [1 1 1] direction by the stacking of （1 1 1） planes.