COMPARISON OF ELECTROCATALYTIC ACTIVITY OF SMOOTH AND PLATINIZED PLATINUM-ELECTRODES - THE SIZE-EFFECT APPROACH

Electrochemical behavior of S2O82- anion in alkaline media on smooth a nd platinized Pt electrodes with a roughness factor R(f) less-than-or- equal-to 590 was studied. The S2O82- anion was shown not to form a pro duct strongly chemisorbed on platinum in the studied solutions. With i ncreasing R(f), the specific rate of S2O82- reduction decreased by alm ost two orders. We analysed the R(f)-dependence of the specific rate o f electrode processes for the case, in which the process on small (and imperfect) particles is slower than on large particles and compact pl atinum. To do this we used two simple models of platinum deposit that provide for the occurrence of particles with particular properties, in cluding particles of different size. Experimental data on S2O82- reduc tion on the Pt/Pt-electrode does not contradict the hypothesis of a si ze effect.