VOLTAMMETRY OF AZOBENZENE MICROCRYSTALS

Azobenzene solid particles have been mechanically attached to a graphi te electrode and measured by cyclic staircase voltammetry. Well-develo ped and widely separated cathodic and anodic peaks were observed. Redo x reaction is controlled by both the heterogeneous charge transfer kin etics and the mass transfer. Its mechanism is explained by the surface diffusion model. Reaction starts at the three-phase boundary, where e lectrons are transferred from the electrode surface to the attached az obenzene molecules. The electrons are then propagated over the surface of microcrystals by a series of exchange reactions between hydrazoben zene and azobenzene molecules, with the participation of proton donors from the solution. The apparent mass transfer occurs in this way. In the crystal lattice the transmission of protons is not possible, and c onsequently there is no propagation of electrons.