Fabrication of several SnO2-based anodes for electrochemical ozone generation: comparison, characterization and application

In this study, several titanium-based electrodes (e.g., Ti, Ti/SnO2-Sb-Ni, Ti/SnO2-Sb-Ni-MWCNTs, Ti/TiHx/SnO2-Sb-Ni and Ti/TiHx/SnO2-Sb-Ni-MWCNTs) were fabricated by spin-coating and pyrolysis methods for electrochemical ozone generation. The modified electrodes were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) techniques. These electrodes are used as an anode for electrochemical ozone generation. The ozone generation at the surface of the electrodes was investigated. The optimum molar ratio of metal salts and multi-walled carbon nanotubes (MWCNTs) (Sn/ Sb/ Ni/ MWCNTs) was obtained 500:8:1:15. The repetition coating time, electrolysis time, electrolysis current density and kind of electrolytes (H3PO4, HClO4 and H2SO4) at different concentrations (0.1, 0.05, 0.1, 0.2, 0.5 and 1 M) were investigated and, respectively, were determined (i.e., 22 times, 120 s, 20 mA cm(-2), HClO4 and 0.1 M). As the results showed, in 4 mL HClO4 (0.1 M) after 25 min electrolysis under a constant current of 12.8 mA, at the surface of the Ti/TiHx/SnO2-Sb-Ni-MWCNTs electrode (A = 0.64 cm(2)) could produce 19.9 mg L-1 of ozone, which is triple the amount produced by the electrodes not modified with MWCNTs. Also, the best-modified electrode (Ti/TiHx/SnO2-Sb-Ni-MWCNTs) was used for electrooxidation of three types of disperse dyes. The results showed that Ti/TiHx/SnO2-Sb-Ni-MWCNTs electrode can remove the dye (100 mg L-1) molecules up to 97%, 90% and 86% for C.I. Disperse yellow 54 (DY 54), C.I. Disperse blue 198 (DB 198) and C.I. Disperse red 167 (DR 167), respectively. [GRAPHICS]

Automated summary

In this study, several titanium-based electrodes were fabricated for electrochemical ozone generation and characterized by various techniques. The use of MWCNTs modification significantly increased the ozone production, and the modified electrode showed a high efficiency in removing disperse dyes.