Efficient catalytic activity of NiO and CeO films in benzoic acid removal using ozone.

This research focuses on the synthesis of NiO and CeO thin films using spray pyrolysis for the removal of benzoic acid using ozone as an oxidant. The results indicate that the addition of CeO films significantly enhances the mineralization of benzoic acid, achieving a rate of over 80% as the CeO films react with ozone to produce strong oxidant species, such as hydroxyl radicals, superoxide radicals, and singlet oxygen as demonstrated by the presence of quenchers in the reaction system. The difference in catalytic activity between NiO and CeO films was analyzed XPS technique; specifically, hydroxyl oxygen groups in the CeO film were greater in number than those in the NiO film, thus benefitting catalytic oxidation as these species are considered active oxidation sites.