Electro-oxidation of phenol on zeolite/graphite composite electrodes - Part 2. Influence of zeolite type and composition

In this work, the electro-oxidation of phenol was investigated by cyclic voltammetry using composite electrodes built with graphite and different types of zeolites; porous and non-porous silica were also used for comparison purposes. In part 1 of this series it was shown that a NaY/graphite composite electrode has a very good response for phenol oxidation. In this work the influence of the nature and structure of the zeolite component by using different zeolites, such as Y, Beta, ZSM5, X and A, both in their sodium and protonic forms was analysed. Among all the zeolites that were used in this study, NaY with a Si/Al ratio of 2.5 seems to produce the best results for the electrochemical oxidation of phenol, by producing a larger current and a lower oxidation potential. It was also concluded that sodium zeolites consistently show better results than acidic ones and that the increase in hydrophobicity is not advantageous either. (c) 2006 Elsevier B.V. All rights reserved.