Wastewater pollution from industries, has always been a serious environmental problem. In this regard, one of the solutions that has been effectively used is the treatment of contaminated wastewater by advanced oxidation processes. Several studies have been conducted on the use of Sn(Sb)O2 particles for electrocatalytic oxidation applications. However, the optimal percentage of antimony dopant has been reported to be different. In this study, Sn(Sb)O2 particles were produced by a thermal method an‎d the optimal amount of antimony was 1.5 mol%. Next, the effect of the core-shell composite structure of TiO2@Sn(Sb)O2 on the electrocatalytic performance of these particles was investigated compared to pure Sn(Sb)O2 particles. The TiO2@Sn(Sb)O2 core-shell particles were synthesized by chemical co-deposition methods. Also, the electrophoretic deposition method was used to deposit both types of synthesized particles. The successful synthesis of this structure was confirmed by X-ray diffraction, Fourier transform infrared spectroscopy an‎d transmission electron microscopy. After electrophoretic deposition on titanium substrate, field emission scanning electron microscopy an‎d energy dispersive X-ray spectroscopy analyses were used to observe the surface an‎d cross-section of the coatings. In order to create comparable conditions between the two electrodes, their thickness was adjusted to about 15 μm. The electrochemical properties of the electrodes were investigated by cyclic voltammetry, electrochemical impedance spectroscopy an‎d linear sweep voltammetry experiments in a three-electrode cell. The electrochemical impedance spectroscopy results showed that the electrical conductivity of the TiO2@Sn(Sb)O₂ core-shell nanoparticles was significantly reduced compared to Sn(Sb)O₂, which was attributed to the formation of heterojunctions. The oxygen evolution potential of the TiO2@Sn(Sb)O₂ electrode was 2.67 V, which was slightly reduced compared to the Sn(Sb)O₂ electrode (2.87 V). The fabricated coatings were used as anodes for the electrocatalytic degradation of methylene blue, a common model organic pollutant. Electrocatalytic tests were carried out in a two-electrode cell in 0.1 M sodium sulfate an‎d 0.1 M potassium chloride solutions as supporting electrolytes, each containing 5 mg/L methylene blue, as an organic pollutant pigment, an‎d the solutions were eva‎luated by UV-vis spectroscopy. The results showed that the electrocatalytic efficiency of Sn(Sb)O₂ electrode in sodium sulfate electrolytes reached 97.1% within 180 min an‎d 97.3% within 60 min in potassium chloride electrolyte. The TiO2@Sn(Sb)O₂ core-shell electrode showed a degradation efficiency of 95.9% within 120 min in sodium sulfate electrolyte an‎d 97.3% within 40 min in potassium chloride electrolyte, which was a 1.5-fold increase compared to the Sn(Sb)O₂ electrode. Both electrodes maintained their electrocatalytic properties over five cycles without significant degradation. Next, the kinetics of the electrocatalytic degradation of methylene blue in both sodium sulfate an‎d potassium chloride electrolytes were investigated by eva‎luating the electrolyte at specific time intervals. The results show that all electrocatalytic processes follow first-order (linear) kinetics.

كيوان رئيسي

موسي فرهاديان

مهشيد خرازيهاي اصفهاني , علي اشرفي