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碳毡电极材料经高温热氧化改性后,表面结构和性质发生明显变化。随热氧化温度上升,碳毡石墨结构更趋有序定向排列,石墨化程度提高。这不仅明显提高了其导电性能,同时也使表面含氧官能团的含量或O/C原子比下降。由于碳毡金属杂质含量减少以及表面担载的催化剂颗粒变大且分布更为不均匀,高温热氧化碳毡表面对析氢副反应具有较高的过电位,放氢电流大幅度降低,但提高热氧化温度使碳毡电极的电化学反应活性有所下降。为使碳毡电极上放氢电流降低的同时又保证电极具有较高的Fe~(3+)/Fe~(2+)及Cr~(3+)/Cr~(2+)反应的电化学活性,热氧化温度1700℃为宜。
Carbon felt electrode material after high temperature thermal oxidation modified surface structure and properties of significant changes. With the increase of thermal oxidation temperature, the graphite structure of carbon felt is more orderly oriented and the degree of graphitization is improved. This not only significantly improves its electrical conductivity, but also reduces the content of oxygen-containing functional groups on the surface or the O / C atomic ratio. Due to the decrease of the metal impurity content of the carbon felt and the larger and more uneven distribution of the catalyst particles on the surface, the surface of the high-temperature thermal oxidized carbon felt has a higher overpotential for the hydrogen evolution side reaction and the hydrogen desorption current is greatly reduced. However, The oxidation temperature decreased the electrochemical reaction of carbon felt electrode. In order to reduce the discharge current of the carbon felt electrode and ensure the high electrochemical reaction of Fe ~ (3 +) / Fe ~ (2+) and Cr ~ (3 +) / Cr ~ (2+) Activity, thermal oxidation temperature of 1700 ℃ is appropriate.