用钌钛氧化膜电极电解食盐水时pH对放氧速率的影响及其机理的探讨

On the Influence of pH on Kinetics and Rate of Oxygen Evolution at Ti Electrode Covered with Film of RuO_(2) and TiO_(2)

用气体吸收法测定了电解食盐水时阳极气体中氯与氧的含量,得到含氧率随阳极液pH值(pH^(s))变化的规律.讨论了电解过程中H^(+)和HClO的扩散行为及其对放氧速率的影响,得到放氧速率、电极表面附近pH值(pH^(e))对pH^(s)的依赖关系,与实验结果相符.

The chlorine and oxygen content in anode gas has been determined by gsa absorption method. The result shows that the oxygen evolution rale changes with pH^(s) (the pH value of anode chamber electrolyte): when pH^(s)<2, the rale of oxygen evolution increascs rapidly with increasing pH^(s);between 2-4.2, the rate of it changed slowly, and, when pH^(s)>4.2 it increases again quite rapidly. The rule stated above are independent of the density of current and the constitution of the oxide film of the electrodes within the current density range 150-550mA/cm^(2).The diffusion processes of H^(+) and HC1O in electrolysis, which controll the pH^(e) ( the pH value of electrode surface region) and oxygen evolution rate, has been discussed according to Fick’s first law and i_(o2) = nFk(a_(H^(+)))^(-1)·[S^(z)] exp(βFη_(a)/ RT). The result of analysis is in agreement with the experiment data.