Synthesis and characterization of ternary metallic oxide electrodes containing (SnO₂)₉₃Sb₅M₂ (M = Ce, ta, Bi, Gd) using an ionic liquid as the precursor solvent

Abstract

The present study synthesized mixed metal oxide (MMO) anodes composed of (SnO₂)₉₃Sb₅M_{2(M=Ce,Ta,Bi,Gd)} through thermal decomposition calcinated at 500, 550, and 600 °C. The anodes were characterized by linear and cyclic voltammetry, electrochemical impedance spectroscopy, service lifetime tests, and morphology factors. Furthermore, physical characterizations included X-ray diffractometry and scanning electron microscopy to obtain information on their crystallographic structure and surface morphology, respectively. Finally, electrocatalytic activity was tested by electrolysis for 1 h in solutions containing 10 ppm of Diuron® using various electrolytes (Na₂SO₄, Na₂CO₃, NaNO₃, NaCl). The highest superficial area and oxygen evolution onset potential, the longest service lifetime, and considerable Diuron^® degradation rates in all electrolytes were obtained for (SnO₂)₉₃Sb₅Ce₂ (32%). However, it is essential to highlight the outstanding service lifetime presented by (SnO₂)₉₃Sb₅Bi₂ (46.32 h), overcoming the results for (SnO₂)₉₃Sb₅Ce₂ by over 50-fold. This behavior is associated with the peculiar nanoflower star-like surface organization seen in the scanning electron microscopy images.

Keywords:

• 3-(3,4-dichlorophenyl)-1,1-dimethylurea
• Electrolysis
• mixed metal oxide anodes

Additional information

Funding

The present work was done with the financial support of CNPq (grants 304419/2015-0 and 310282/2013-6), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (grant 001), and FAPITEC/SE. We also acknowledge the MSc. Milson dos Santos Barbosa for its contribution in Diuron molecule sketch.