Synthesis of SnO-Sb2O5 ceramic anodes coated with cadmium and calcium ferrites for the depletion of emerging contaminants

This manuscript studies cadmium and calcium ferrite coatings on a ceramic electrode, based on tin oxide doped with antimony, to be used as photoanodes in the degradation of atenolol, as a model emerging contaminant. Solution combustion synthesis and thermal treatment were used to generate and fix ferrite precursors over the electrode surface, respectively. Firstly, the physical and photoelectrochemical characterization of these ceramic ferrites was carried out. Photoluminescence measurements indicated an emission band between the orange-red zone of the visible spectrum and the near infrared, which the basic ceramic electrode did not show. Furthermore, an improvement in the photocatalytic activity of ferrites was observed by linear sweep voltammetry and light pulsed chronoamperometry tests. The band gap energies obtained were 1.3 and 2.64 eV for cadmium and calcium ferrites, respectively. Subsequently, both ferrites were tested in photoelectrooxidation assays using atenolol. The degradation of the contaminant was greater under light irradiation conditions than in the darkness for both anodes. Increasing the applied current density enhanced both atenolol degradation and mineralization but worsened the mineralization current efficiency and energy consumed per gram of total organic carbon removed. Comparing the type of electrode, cadmium ferrite showed better results as a photoanode than calcium ferrite in terms of degradation and mineralization of the atenolol. • Sb-doped SnO 2 ceramic anodes coated with ferrite of Cd and Ca were studied. • Both ferrites are photoactive electrodes. • Cadmium ferrite presented a lower band gap energy value than calcium ferrite. • Higher oxidation degree was obtained in the presence of light for both ferrites. • Cadmium ferrite showed better results as a photoanode than calcium ferrite.