Activation of Carbon Materials by Plasma Processing and Industrial Application

研究了直流辉光放电低温氧等离子体对改性乙炔黑(AB)的表面电导率、润湿性、表面官能团和H_2O_2分解速率常数等表面性质的影响。本文还研究了氧等离子体处理AB气体扩散电极的表面性质与其在KOH水溶液中的电化学行为的关系。结果表明：AB的电导率随处理时间的延长而降低，AB表面由疏水向亲水转变，处理提高了AB分解H_2O_2的能力，这可以用AB表面的芳香族-OH、&GT；C=O、-COOH等氧官能团的增加来解释。通过等离子体处理，AB氧电极的极化和放电行为得到了很大的改善。这是由于AB电极具有足够的润湿性、较高的H_2O_2分解能力和较细的气孔，形成了稳定的三相区。用旋转圆环电极进行的实验表明，氧电极在AB表面的反应是一个以H_2O_2为中间体的双电子反应。

We have investigated the surface properties which are electric conductivity, wettability, surface functional groups, and rate constant of H_2O_2 decomposition of surface modified acetylene black (AB) by low temperature oxygen plasma of dc glow discharge. This work also describes the relations between the surface properties and the electrochemical behavior in an aqueous KOH solution of the gas diffusion electrodes with oxygen plasma processed AB.The results are as follows ; the conductivity of AB decreases with processing time, the AB surface changes from hydrophobic to hydrophilic, and the processing enhances the H_2O_2 decomposition ability of AB.These facts would be explained by the increase of oxygen functionalities such as aromatic -OH,>C=O,-COOH etc.of AB surface. The polarization and discharge behavior of oxygen electrode with AB have been much improved by the plasma processing. These can be regarded as forming the stable three phase zone owing to adequate wettability, high H_2O_2 decomposition ability, and developed fine pore of the AB electrode. From experiments using a rotating ring disk electrode, it can be concluded that oxygen electrode reaction on AB surface is a two electron reaction forming H_2O_2 as an intermediate.