论文部分内容阅读
以放于冰晶石熔体中的CO_2/C为参此电极,测量了铝电解中碳素阳极上的过电压。首先研究了参此电极对铝阴极的行为。此原电池给出稳定的电位1.15伏特。它与铝电解中的电解槽反应的可逆电位完全一致。类似的测量还用CO/C与在CO,CO_2/C电极作过。CO/C电极的电位与更大可能的电解槽反应的可逆电位很一致。采用CO_2—CO混合气体所得到的电位,是在这些纯气体的电位之间,并随着CO_2含量的增加而增加。对CO_2,CO/C电极的行为作了解释。阳极过电压仅在有限程度上与碳同氧的化学反应能力有关。石墨阳极比其他所有碳素阳极的过电压都高。向碳中加入触媒剂与抑止剂对于过电压有小的但意义重大的影响。得到了塔菲尔直线图(Tafel plots),其斜率介于0.26与0.27之间。这些结果表明,过电压可能是由于氧离子经过双电层传输的迟缓或化学吸附的氧与碳的反应迟缓所致。
Taking the CO 2 / C placed in the cryolite melt as the reference electrode, the overvoltage on the carbon anode in aluminum electrolysis was measured. The behavior of the electrode on the aluminum cathode was first studied. This galvanic cell gives a stable potential of 1.15 volts. It is exactly the same as the reversible potential of the cell in aluminum electrolysis. Similar measurements were also made with CO / C and CO, CO2 / C electrodes. The potential of the CO / C electrode is consistent with the more likely reversible potential of the cell reaction. The potential obtained with the CO 2 -CO mixed gas is between the potentials of these pure gases and increases with the CO 2 content. The behavior of CO_2, CO / C electrodes is explained. The anodic overvoltage is only to a limited extent related to the ability of the carbon to chemically react with oxygen. The graphite anode is overvoltage above all other carbon anodes. The addition of catalyst and inhibitor to carbon has a small, but significant, effect on overvoltages. Tafel plots were obtained with slopes between 0.26 and 0.27. These results indicate that overvoltages may be due to sluggish or chemically adsorbed oxygen and slow reaction of carbon with oxygen ions passing through the electric double layer.