碳酸钠催化制备纳米碳纤维

Preparation of carbon nanofibers catalyzed by sodium carbonate

碳纳米材料中残留的金属催化剂会影响其本征性能的发挥,通常需要采用强酸酸洗除去,但酸洗成本较高且破坏碳纳米材料的表面结构,甚至带来环境问题。本文以乙炔为碳源,碳酸钠为催化剂,采用化学气相沉积法裂解制备纳米碳纤维(CNFs),考察制备温度对CNFs形貌的影响。通过场发射扫描电子显微镜、透射电子显微镜和能谱仪表征CNFs的微观结构和元素组成,通过X射线衍射、拉曼光谱和傅里叶红外光谱表征CNFs的晶体结构和表面官能团。结果表明,500℃制备的CNFs直径约为50nm,产品直径均匀,通过简单的水洗后能除掉CNFs表面的碳酸钠催化剂,乙炔转化率为31.0%,CNFs产率为1396.7%;CNFs表面的碳原子呈无序排列,石墨化度低,主要由C—H、C==C官能团组成。

The residual metal catalysts in carbon nanomaterials will affect the performance of their intrinsic properties and usually need to be removed by strong acid pickling.However,the cost of acid pickling is high and the surface structure of carbon nanomaterials is destroyed,even causing environmental problems.Carbon nanofibers(CNFs)were prepared by chemical vapor deposition using acetylene as carbon source and sodium carbonate as catalyst.The effect of preparation temperature on the morphology of CNFs was investigated.The microstructure and elemental composition of CNFs were characterized by field emission scanning electron microscopy,transmission electron microscopy and energy dispersive spectroscopy.The crystal structure and surface functional groups of CNFs were characterized by X-ray diffraction,Raman spectroscopy and Fourier transform infrared spectroscopy.The results showed that the diameter of CNFs prepared at 500℃was about 50nm and the diameter of the product was uniform.The sodium carbonate catalyst on the surface of CNFs can be removed by simple water washing.The acetylene conversion rate was 31.0%and the yield of CNFs was 1396.7%.The carbon atoms on the surface of CNFs were disorderly arranged and the degree of graphitization was low,which was mainly composed of C—H and C==C functional groups.