Abstract: The electrocatalytic activity of Ti/PbO₂, graphite and platinum electrodes for the electrooxidation of p-methylphenol was studied by linear sweeping voltammetry and galvanostatic electrolysis in an electrolytic cell without diaphragm. The conversion, degradation rate, reaction mechanism and rate determining steps of p-methylphenol at the three kinds of electrodes were explored by determinations of p-methylphenol and intermediates in the electrolyte before and after electrolysis. The experimental results indicate that Ti/PbO₂ electrode with a high activity can effectively oxidize and remove p-methylphenol; graphite electrode can also oxidize p-methylphenol, but its removal ability was poor; platinum electrode can only oxidize p-methylphenol to hydroquinone in the electrolytic time of 3 h; p-methylphenol can not be oxidized completely. The mechanism of the electrooxidation degradation of p-methylphenol may be p-methylphenol→p-hydroxy-benmethanol→p-hydroxybenzaldehyde→p-hydroxybenzoic acid→hydroquinone→benzoquinone→maleic acid→oxalic acid, and the final product is CO₂. The electrooxidation reactions of hydroquinone and maleic acid are the rate determining steps for Ti/PbO₂ electrode, while the electrooxidation reaction of hydroquinone is a rate determining step for graphite electrode.

Key words: p-Methylphenol, Electrooxidation, Electrocatalysis, Reaction mechanism