Ti/SnO2-Sb-Ni electrodes with various Ni- and Sb-doping levels have been prepared by dip-coating thermal pyrolysis procedure, and their simultaneous electrochemical ozone production (EOP) and oxygen evolution reaction (OER) were investigated. The effects of electrode composition on the nanostructure, morphology, electrochemical behavior, kinetic parameters, and lifetime of the electrodes were systematically studied using X-ray diffraction, scanning electron microscopy, cyclic voltammetry, linear sweep voltammetry, and chronopotentiometry. Dissolved ozone was produced in a quartz cell and its concentration was monitored by in situ UV spectrophotometry. The presence of small amounts of Ni (Ni？:？Sn atomic ratio of 0.2？:？100) gives valuable characteristics to the electrodes such as increasing EOP activity and service life. Higher Ni concentrations increase the electrode film resistance and decrease its capacitance, roughness factor, and service life, while increasing Sb level up to 12 atom% improves the electrode performance with respect to these parameters. Nevertheless, the Sb/Sn atomic ratio of more than 2% reduces the EOP current efficiency in favor of OER. The optimum composition of the electrode for EOP was determined to be Sb/Sn and Ni/Sn atomic ratios of 2% and 0.2%, respectively. The highest current efficiency was 48.3% in 0.1？M H2SO4 solution at room temperature. 1. Introduction Ozone (O3), as an environmentally friendly reagent with high oxidizing power, has found a broad range of applications in various fields such as water and wastewater treatment, sterilization of surgical equipments, bleaching processes, cleaning of semiconductor materials, and chemical synthesis [1–5]. There are two main methods for preparation of dissolved ozone: corona discharge followed by dissolving ozone into solution and electrolysis . The latter method has the advantages of being a simple process which produces relatively high concentrations of ozone directly into solution without producing harmful nitrogen oxides and without need for a high voltage power source as compared to corona discharge. The OER (1) is thermodynamically more favorable and severely competes with EOP (2) on the anode of an electrochemical ozone generator. Consequently, minimizing OER is a key requirement for EOP with a reasonable current efficiency. This can be achieved by suitable choice of the anode material to have a high overpotential for OER. In addition, the anode should have good conductance, high durability under drastic operating conditions, and particularly good electrocatalytic
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