Anodic chlorate formation on platinized titanium

The mechanism of anodic chlorate formation on platinized titanium was studied under well-controlled forced-convection conditions identical to those of previous experiments with graphite. Experimental results obtained in 4m NaCl and in 0·05m NaCl were compared to those predicted by mass transfer models describing anodic chlorate formation on graphite. In concentrated NaCl solution anodic chlorate formation rates for both electrode materials are smaller than expected for a diffusion controlled process. In dilute NaCl the ratio between measured rates and those predicted for diffusion control is shifted to higher values in qualitative agreement with predictions. Quantitative differences observed between the two electrode materials were attributed to the fact that hypochlorite oxidation on platinized titanium did not proceed at limiting current because of the slowness of the heterogeneous oxidation reaction.