This study examined processes of decomposing phenol and its derivatives (resorcin, pyrocatechol and hydroquinone) in aqueous solutions under the action of an atmospheric pressure oxygen dielectric barrier discharge in the presence or absence of catalysts in the plasma zone. Two types of catalysts were tested, NiO and TiO2. It was found that both materials exhibited catalytic properties. The action of NiO accelerated the step of phenol destruction while the action of TiO2 catalyst resulted in a more preferable composition of decomposition products and provided a higher degree of carboxylic acid conversion into carbon dioxide than the NiO catalyst.