RuO2 electrodes consist of a ruthenium substrate covered with an oxide coating and are applied as dimensionally stable anodes in several important electrolytic processes, such as oxygen and chlorine evolution or the electrochemical oxidation of organic pollutants in wastewaters. As a result, RuO2 electrodes have been widely used due to their good catalytic activity, even for the oxygen evolution reaction (OER). However, for applications such as electrochemical oxidation of organic compounds, the electrode material requires minimal catalytic activity toward the OER.
Water resources are increasingly under threat due to human industrial activities. This has become a major issue, which countries at all stages of development are now treating with great importance. However, many organic contaminants which are not biodegradable are found at low concentrations in rivers and even groundwater. They have become a focus of concern among the public and leaders, as any long-term pollutant discharge into water is an environmental threat to the use of this water in, for example, agriculture. It is therefore necessary to minimize emissions of pollutants in effluents and to address the treatment of these pollutants.
In this work, we are interested in O-cresol, used in the textile industry and as an intermediate of several products: deodorants, pharmaceuticals, perfumes, antioxidants, dyes, pesticides and resins, as well as additives in phenolic resins.
This work proposes the study of electrochemical oxidation of a synthetic o-cresol solution using a RuO2 electrode at pH = 0. Cyclic voltammetry and in situ UV–visible spectrophotometry are combined to analyze the degradation products obtained. Cyclic voltammetry confirmed the formation of a polymer on the surface of the RuO2 electrode, where the oxidation of cresol is progressively prevented until a stable voltammogram is obtained blocking the surface of the electrode. Also, its combined use with in situ UV–visible spectrophotometry identified the products of the degradation of o-cresol to methylbenzoquinone.
