炭化聚苯胺/四氧化三铁复合物制备介孔炭性能研究

Study on property of mesoporous carbon from carbonization polyaniline and ferroferric oxide composite

以油酸表面处理后的纳米四氧化三铁为添加剂,制备了聚苯胺/四氧化三铁复合物。将该复合物在氮气气氛下于500℃炭化、800~1300℃进行石墨化处理,得到介孔炭材料。使用扫描电子显微镜、透射电子显微镜、X射线衍射仪、傅里叶变换红外光谱仪和等温吸脱附仪等对介孔炭材料进行表征,探讨了石墨化温度对材料形貌和结构的影响规律。研究表明:石墨化温度从800℃到1000℃,复合物转变为不规则颗粒状的多孔炭,具有不规则局部石墨化的碳层结构;石墨化温度为1200℃时,材料中存在碳化铁(Fe3C),出现大量开口的球状物,大小约600nm,壁为石墨化的碳层,壁厚约为50nm;石墨化温度为1300℃时,则得到空心炭球,直径1~2μm,球壁厚约为20nm。另外,通过改变石墨化温度可以调控介孔炭材料的孔结构和比表面积,平均孔径为5.9~19.9nm,比表面积为62.6~677.8m^(2)/g。循环伏安法测试表明,经过800℃石墨化处理的介孔炭材料比容量最高,以0.5mol/L硫酸为电解液,扫描速率为5mV/s时,介孔炭材料比容量为161F/g。

Mesoporous carbon has extensive application in many fields,such as second-batteries,supercapacitors,fuel cells,etc.It is the hottest project to obtain mesoporous carbon with certain morphology or components in order to meet particular needs for a long time.The composite of polyaniline and ferroferric oxide was manufactured through polymerization of aniline in suspension of ferroferric oxide with its surface modified by oleic acid.A series of mesoporous carbon was obtained after the composite being carbonized at 500℃,graphitized at the temperature from 800℃to 1300℃under nitrogen atmosphere in a tube oven.SEM,TEM,XRD,FT-IR and isothermal desorption apparatus were adopted to characterize as-prepared carbon.Effect of graphitic temperature on morphology and components of the carbon was explored in detail.The research results shown that graphitic temperature of the composite was the key factor to structure and properties of as-obtained carbon.For example,it shown particles possessing irregular shapes,which was with partly graphitic carbon layers,when graphitic temperature was from 800℃to 1000℃.Some spheres with open mouths,liked bows,were found in samples when the composite being treated at1200℃.Diameter of the bows was about 600 nm.The wall of bows was conformed by graphitic carbon layers,with about 50 nm in thickness.Fe 3C component was also found in these samples.However,when the graphitic temperature was at 1300℃,only some hollow spheres were found in as-obtained carbon.Diameter of these hollow spheres was about from 1μm to 2μm.Wall of the hollow spheres was about 20 nm in thickness,which was formed by highly graphitic carbonlayers.By changing graphitic temperature of the composite,BJH adsorption average pore diameter and BET specific surface area of the mesoporous carbon can be easily adjusted in the range from 5.9 nm to 19.9 nm,and from 62.6 m^(2)/g to 677.8 m^(2)/g,respectively.Among all these as-prepared mesoporous carbon,the sample from being graphitized at 800℃had the best electrochemical performance,whose specific capacitance was 161 F/g in 0.5 mol/L sulfuric acid aqueous solution,at the scan rate of 5 mV/s,tested by cyclic voltammetry technics.