VOLTAMMETRY UNDER HIGH-MASS TRANSPORT CONDITIONS - THE HIGH-SPEED CHANNEL ELECTRODE AND HETEROGENEOUS KINETICS

The application of the high-speed microband channel electrode to the s tudy of fast heterogeneous electron transfer kinetics is described. Th e necessary theory relating the voltammetric wave shape to the standar d electrochemical rate constant, k(0), the cell geometry, and the solu tion flow rate is given. Experiments utilizing the one-electron reduct ion of benzoquinone in acetonitrile solution, containing 0.1 M tetrabu tylammonium perchlorate (TBAP) as supporting electrolyte, at a 5 mu m platinum microband electrode gave a value of k(0) equal to 0.30 (+/-0. 04) cm s(-1), in excellent agreement with independent measurements rep orted for the same system. The results of further experiments on the p reviously unstudied electrode kinetics associated with the reduction o f 3,3'-dibromobenzophenone in 0.1 M TBAP/dimethylformamide solution ar e presented.