3. Results and discussion
Silver chloride precipitated and immobilized on a graphite electrode
according to Fig. 1 is electrochemically active. Fig. 2 shows cyclic
voltammograms exhibiting three signals: I is due to the reduction of
solid AgCl to Ag metal accompanied by the release of Cl− to the solution.
Due to the micrometer size of the AgCl crystals, the reduction leads to
the formation of a closed silver shell (8–10 nm thickness), which of
course terminates the reduction (the AgCl crystal is silverized). This
scenario has been elucidated in a previous in situ AFM electrochemistry
study of immobilized silver halide crystals [18]. The formed silver layer
is oxidized in the anodic scan (peak II) releasing a “cloud” of silver ions