Factors affecting the electro-catalytic characteristics of Eu doped SnO₂/Sb electrode

Different compositions of Eu doped electrodes were prepared by a pyrolysis method in order to investigate the effect of Eu on the electro-catalytic behavior of Ti-based SnO₂/Sb electrodes. The electrodes were characterized by SEM, EDS, XRD and their degradation abilities were evaluated using phenol. The electro-catalytic performance of prepared electrodes was strongly influenced by the heat-treatment temperature and Eu doping content. A temperature of 750°C and a Eu content of 2% provided optimal catalytic activity for the SnO₂/Sb electrode. Phenol removal percentage was lowered by 13.2% compared to the control when higher Eu doping (5%) was applied due to the potential concentration of oxygen vacancies and the enrichment of Eu atoms on electrode surface. The unit cell of SnO₂ expanded by about 2% after Eu doping due to the replacement of the smaller Sn⁴⁺ by larger Eu³⁺. The average size of the SnO₂ grains on the electrode surface for the Eu doped samples ranged from 8 to 9nm, which was smaller than that of the control, suggesting catalysis improvement since smaller grain sizes produced more active sites on the electrode surface.