表面氧化改性对碳气凝胶的分散性和导电性的影响

Effect of Surface Modification on Dispersion and Electric Conductivity of Carbon Aerogels

为了得到具有优良的分散性和导电性的碳气凝胶,研究了碳气凝胶的硝酸氧化改性温度对碳气凝胶的结构和性能的影响。通过FTIR、XPS、Zeta电位、XRD和N2等温吸附-脱附等技术对样品进行表征,结果表明:硝酸氧化改善分散性的机理在于对碳气凝胶表面的含氧官能团数量的改变,而且氧化温度越高,含氧官能团的数量就越多,碳气凝胶的分散性就越好;与此相反,较低温度的氧化处理有利于保持碳气凝胶的导电性(40℃,87.7%),而高温氧化由于易使碳气凝胶的微孔迅速增多从而导致其电导率急剧下降(100℃,2.5%)。

The temperature of oxidation modification of carbon aerogels by using nitric acid and the influence of the oxidation temperature on its structure and property was studied in order to obtain the carbon aerogels with good dispersion and electric conductivity.Carbon aerogels before and after oxidation treatment were characterized by the FTIR,XPS,Zeta potential,XRD and N2 isothermal adsorption-desorption techniques.It was found that the dispersion stability of the carbon aerogels was closely associated with the oxygen-containing functional groups on the surface.For comparison,conductivity of carbon aerogels was well kept after oxidation treatment by HNO3 at low temperature rather than that at high temperature（40℃,87.7% vs.100℃,2.5%）,which was attributed to the higher number of micropores formed at high temperature.