Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)SiO2/ZrO2/C carbon ceramic material with composition (in wt%) SiO2 = 50, ZrO2 = 20, and C = 30 was prepared by the sol-gel-processing method. A high-resolution transmission electron microscopy image showed that ZrO2 and the graphite particles are well dispersed inside the matrix. The electrical conductivity obtained for the pressed disks of the material was 18 S cm(-1), indicating that C particles are also well interconnected inside the solid. An electrode modified with flavin adenine dinucleotide (FAD) prepared by immersing the solid SiO2/ZrO2/C, molded as a pressed disk, inside a FAD solution (1.0 x 10(-3) mol L-1) was used to investigate the electrocatalytic reduction of bromate and iodate. The reduction of both ions occurred at a peak potential of -0.41 V vs. the saturated calomel reference electrode. The linear response range (lrr) and detection limit (dl) were: BrO3-, lrr = 4.98 x 10(-5) - 1.23 x 10(-3) mol L-1 and dl = 2.33 mu mol L-1; IO3-, lrr= 4.98 x 10(-5) up to 2.42 x 10(-3) and dl = 1.46 mu mol L-1 for iodate.133377383Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)LTK [00/11103-5]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [04/00919-5]LTK [00/11103-5]