STUDIES OF 3-DIMENSIONAL ELECTRODES IN THE FM01-LC LABORATORY ELECTROLYZER

A FM01-LC parallel plate, laboratory electrochemical reactor has been modified by the incorporation of stationary, flow-by, three-dimensiona l electrodes which fill an electrolyte compartment. The performance of several electrode configurations including stacked nets, stacked expa nded metal grids and a metal foam (all nickel) is compared by (i) dete rmining the limiting currents for a mass transport controlled reaction , the reduction of ferricyanide in 1 M KOH and (ii) measuring the limi ting currents for a kinetically controlled reaction, the oxidation of alcohols in aqueous base. It is shown that the combination of the data may be used to estimate the mass transfer coefficient, k(L), and the specific electrode area, A(e), separately. It is also confirmed that t he use of three dimensional electrodes leads to an increase in cell cu rrent by a factor up to one hundred. Finally, it is also shown that th e FM01-LC reactor fitted with a nickel foam anode allows a convenient laboratory conversion of alcohols to carboxylic acids; these reactions are of synthetic interest but their application has previously been r estricted by the low rate of conversion at planar nickel anodes.