The Electrochemical Generation of Ozone: A Review

Abstract

This paper reviews work on the electrochemical generation of ozone from the original studies by Schönbein in the early 1800's to the present day, and is intended for specialists and non-specialists in the field of electrochemistry. The experimental techniques employed to study the mechanism of electrochemical ozone generation are described, as is the most commonly quoted mechanism and the experimental evidence for the mechanism is summarised and discussed. The types of electrochemical cells employed are described, and the effect of: temperature, anode type and composition, current density and electrolyte composition & pH are discussed.

Electrode characteristics for ozone production: a case study using undoped and doped PbO2 on porous platinised titanium substrates

“…therein]. Indeed, this is not a trivial task and one cannot but agree with Christensen et al [15] that it is difficult to get insights into the mechanism of O 3 formation at high anodic potentials where intense O 2 evolution takes place. Additional complications are introduced by the porous nature of the anodes employed.…”

“…The use of polymer-electrolyte-membrane cells seems to offer ideal operative conditions for high ozone yields while, at the same time, guaranteeing electrode stability. Very good and informative reviews have appeared recently, covering a period of more than 30 years of research in this field [15] or focusing particularly on developments in the studies of electrode materials [16].…”

Carbon Electrodes in Electrochemical Technology

“…The electro-generation of ozone has recently been reviewed [20,21]. Ozone is electro-generated by the anodic oxidation of water:…”

“…Doped diamond is the alternative carbon material to glassy carbon for ozone generation [20,21], but the technology is much less developed. Boron-doped diamond is prepared by chemical vapor deposition and has been used as an anode when (i) deposited as a thin film on substrates such as silicon, titanium, or niobium or (ii) fabricated as a bulk plate -for example, Element Six supplies Diafilm EP as a free-standing polycrystalline plate capable of supporting current densities of >1 A cm −2 [25].…”

“…The direct mechanisms involve electron transfer and oxidation via weakly adsorbed OH • radicals, while the indirect mechanisms have seen a role for solution-free OH • radicals, ozone, sulfate radicals, or chlorine compounds if suitable anions are present or added. Indirect routes via ozone [20,21] and sulfate radicals [40,74,[76][77][78] can, of course, become dominant with appropriate selection of the conditions. This literature has been extensively reviewed and the interested reader is referred to these reviews [26,38,39,[71][72][73][74][75].…”