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对碳毡表面HNO_3化学改性引起电极性能的变化进行较详细研究。物理分析数据表明,由于HNO_3氧化处理,碳毡表面亲水性含氧官能团含量增加及HNO_3分子易嵌入并吸引高温碳毡石墨层状结构中的电子使空穴增多,电极表面浸润性和导电性明显提高。碳毡比表面也因HNO_3腐蚀作用有所增加。另外,循环伏安分析结果指出,在表面改性电极上Cr~(3+)/Cr~(2+)及Fe~(3+)/Fe~(2+)反应电化学活性增强,不仅峰值电流I_(pa)、I_(pa)随HNO_3氧化时间增长明显加大,而且峰电位差△Ep(=E_(pa)-E_(pc))变小,反应更趋可逆。还因为催化剂Pb沉积量增加而提高了其催化活性,经HNO_3氧化处理后的碳毡表面更利于Cr~(3+)/Cr_(2+)反应进行,其I_(pa)、I_(pc)值的增加明显高于Fe~(3+)/Fe~(2+)反应。
The change of electrode properties caused by the chemical modification of HNO_3 on the carbon felt surface was studied in more detail. Physical analysis of the data shows that due to the HNO_3 oxidation, the content of hydrophilic oxygen-containing functional groups on the surface of the carbon felt is increased and the HNO_3 molecules are easy to intercalate and attract electrons in the high-temperature carbon felt graphite layered structure to increase the holes, the surface wettability and the conductivity Significantly improved. Carbon felt than the surface due to HNO_3 corrosion has increased. In addition, the results of cyclic voltammetry showed that the electrochemical activity of Cr ~ (3 +) / Cr ~ (2+) and Fe ~ (3 +) / Fe ~ The current I_ (pa) and I_ (pa) increased with the increase of HNO_3 oxidation time, and the peak potential difference ΔEp (= E_ (pa) -E_ (pc)) became smaller and the reaction became more reversible. The catalytic activity was also increased because of the increase of the deposition amount of catalyst Pb. The surface of the carbon felt treated with HNO_3 was more favorable for Cr 3+ / Cr 2 + reaction. The I pa, I pc, The increase of the value was obviously higher than that of Fe ~ (3 +) / Fe ~ (2+) reaction.