In situ laser activation of glassy carbon electrodes

Abstract

Laser pulses of short duration (10 ns) and high intensity (20 MW cm/sup -2/) can increase the rate of heterogeneous electron transfer at a glassy carbon electrode by 1-3 orders of magnitude. The laser pulse may be delivered in situ, directly in the solution of interest, repeatedly if desired. The heterogeneous electron transfer rate constant, k/sup 0/, for the ferri-/ferrocyanide redox system increases from 0.004 to 0.20 cm s/sup -1/ with laser activation, resulting in the highest k/sup 0/ yet observed for this system on glassy carbon. Laser activation results in minor morphological changes to the surface, as observed by scanning electron microscopy, mainly removal of an apparent layer of carbon microparticles. The technique holds promise as a means to repeatedly activate glassy carbon electrodes in situ, thus circumventing the need for renewal or reactivation by polishing or other ex situ treatments.