Clay was modified by pillaring, which was performed by combinations of pillaring cations: Al3+ and Fe3+ or Al3+, Fe3+ and Ni2+. The synthesized materials were used to obtain glassy carbon electrode (GCE) coatings. Electrochemical oxidation of phenol from acidic solution was investigated on clay-modified electrodes by method of cyclic voltammetry. As a consequence of electrode fouling the peak current registered in the tenth cycle droped in the comparison to the current obtained in the first cycle. The first-order derivative linear sweep voltammetry was used in the analytical procedure. Hydroquinone/catechol current ratio increased in the opposite manner to the phenol oxidation current drop
