以还原Fe粉和活性炭为原料, 通过热CVD法制备出微米级的空心碳球串珠结构. 利用TEM、EDS和多点氮吸附仪进行形貌、成分、比表面积及孔径分布表征. 串珠结构由f(1~2)μm的空心碳球串联而成, 长度可达十几微米. 碳球的壁厚为3~5nm的石墨球壳结构. 所制备产物的比表面积 S BET 达到306.523m2/g, 其孔径分布在中孔范围, 峰值位于3.761nm. 微米级空心碳球串珠结构的形成机理为含C的Fe微液滴在低温区凝聚并以石墨烯片层的方式析出C, 外延于Fe液滴形成石墨层, 与Fe液滴构成Fe/石墨层核壳结构, 石墨球壳的收缩趋势挤压Fe液滴沿轴向移动. 循环往复上述即形成空心串珠结构. 该结构在节能材料、药物、染料和催化剂等的载体材料、储氢、储能等方面可能具有良好的应用前景.
Usingreduced iron powder and activated carbon as starting materials, micron-levelhollow carbon rosary structures were synthesized by thermal CVD method. Their morphology,composition and specific surface area and pore-size distribution of the productwere characterized by TEM, HRTEM, EDS and N2 adsorption apparatus.With dozens microns in length and 1-2 μm in diameter, the rosarystructures were formed by hollow carbons. The hollow carbon actually wasgraphite shells with 3-5 nm in thickness. Thespecific surface area SBETof the product was up to 306.523 m2/g, and the pore-size was mainlydistributed in the mesoporous range, whose peak mark at 3.761 nm. The mechanismof the product can be described as follows, carbon was precipitated in the formof graphene pieces at lower temperature by iron/C droplet, which epitaxiallygrew on iron/C droplet and formed graphite shells. The graphite shells andiron/C droplet constituted shell/core structures. The contraction trend ofgraphite shells squeezed the iron/C droplet along the axial direction. Theprocesses above repeated and the carbon rosary structures formed. The product may have potential applications in the energy-savingmaterials, supporter materials for drugs/dyes/catalysts, hydrogen/energystorage materials.
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