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چکیده
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Ozone is a strong oxidant with the oxidation-reduction potential (ORP) about 2.07 V, which is higher than that of hydrogen peroxides (1.77V) and chlorine (1.36V). Ozone is an environmentally- friendly oxidant that is widely used for industrial applications, such as water disinfection, air purification, and medical use. Electrochemical ozone production (EOP) can provide very high concentrations of the reagent in both the gas phase and solution[1]. The electrolysis of water is generally believed to generate ozone by a six-electron reaction (Eq. 1): (1) Whiles, E0 for the four-electron process of water oxidation to produce oxygen is somewhat lower(Eq.2) (2) Thus, the producing-oxygen from water always take place with ozone generation, therefore the current efficiency for ozone generation is the percentage of the observed current[2]. Accordingly, minimizing oxygen evolution reaction )OER( is a key requirement for EOP with an appropriate current efficiency. Under electrolysis condition, effective approaches should be developed to substantially increase the overpotential of the OER, to prohibit the competitive oxygen generation[3]. This approach can be achieved by suitable choice of the anode material to have a high overpotential for OER. In addition to, the material electrode in anode should have good conductance, high durability under drastic operating conditions, and particularly good electrocatalytic activity for ozone production. Different electrodes contain β-PbO2, Pt, Pt composites, boron-doped diamond, TiO2 thin films on Si/TiOx/Pt substrate, and Ti/Ni-Sb-SnO2 catalysts are among the materials that have been used for EOP.[1-5] In this work, a high-performance porous titanium oxide electrode (Ti/TiO2/ Ni-Sb-SnO2) has been developed for electrochemical production of ozone(Fig. 1 a). The Ti/TiO2 electrode was prepared using anodizing method at high voltage for forming a layer of porous TiO2 on the surface of Ti mesh, then followed by depositing a layer of Ni-Sb-SnO2 under deep eutectic solvent on the Ti/TiO2 surface The deep eutectic solvent was used for electrodepositing, because its great effect on electrode performance. The conventional electrodes prepared by electrodepositing in aqueous solvent has poor electrochemical activity and short service life. The enhance properties can be related due to increase electrochemically active surface area of electrode which has a higher roughness, multilayer and uniform surface with pack structure of nanoparticles. Moreover, this electrode has good optical activity(Fig. 1 b) Ozone was electrogenerated from HClO4 solutions on Ti/TiO2/ Ni-Sb-SnO2 electrodes at different operating conditions. Higher efficiency of O3 generation was obtained at 2.8 V in 1 M HClO4 (Fig. 1 c). Finally, The result of electrochemically and morphologically characterization of prepared electrodes by linear sweep voltammetry and scanning electron microscopy(SEM) showed that the electrodes were efficient for EOP.
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