Electrolytic Generation of Ozone on an Antimony-Doped Tin Dioxide Coated Electrode

Abstract

Dissolved ozone up to 34 mg/L was generated by direct electrolysis of water using a titanium electrode coated with an antimonydoped tin dioxide film. The electrode was prepared by spray pyrolysis at 520°C. The current efficiency of ozone generation was 15% in a 0.1 M HClO 4 aqueous solution at room temperature. The electrolytic generation of ozone depends critically on the composition and morphology of the coating and a good generation was observed with Sb:Sn atomic ratio of 1:7 and a smooth and compact surface with connected particles of 3-5 nm diameter.The generation of ozone by the direct electrolysis of water is attractive for applications of disinfection and oxidation in aqueous media. Ideally, the electrochemical route can generate a high concentration of dissolved ozone with a high current efficiency, and without the high voltages needed in conventional ozone generators. The scalable and flexible generation can lead to devices suitable for on-site utilization. 1-4 In addition to green oxidation of pollutants, ozone has other applications such as chemical syntheses. 5,6 While dissolved ozone is generated at the anode, the possibility of cogeneration of hydrogen peroxide, another green oxidant, at the cathode gives additional attractive options. 7 An electrochemical ozone generator has an anode and a cathode separated by a liquid or solid electrolyte. Ozone is formed by electrolytic decomposition of water at the anode by either of two equationsThese reactions are normally not observed because the dioxygen evolution reaction, thermodynamically more favorable, occurs at a much lower potential according to the equation

High-efficiency ozone generation via electrochemical oxidation of water using Ti anode coated with Ni–Sb–SnO2

“…The electrodes were prepared by thermal coating of NiSb-SnO 2 on a titanium mesh (Ti) substrate with an absolute ethanol solution containing SnCl 4 ·5H 2 O (98%, Sigma Aldrich), SbCl 3 (99.5%, Merck), and NiCl 2 ·6H 2 O (98%, Merck) precursors followed by pyrolysis at 520°C. The preparation procedure is near the same as described in Cheng and Chan [19] and Wang et al [10]. For making an electrode, 2.5×2.5 cm titanium screen spot-welded with a 1 mm diameter Ti wire was treated in 10% boiling oxalic acid for 1 h for two times, washed with distilled water, and dried naturally.…”

“…For making an electrode, 2.5×2.5 cm titanium screen spot-welded with a 1 mm diameter Ti wire was treated in 10% boiling oxalic acid for 1 h for two times, washed with distilled water, and dried naturally. The pyrolysis solution was prepared as consists of Ni-Sb-SnO 2 in the molar ratio of 500:8:1 [10,19]. Each mesh electrode is dipped into the coating solution for 30 s, stirred around for 30 s (1 min), and then transferred to an oven at 105°C for 15 min, and in continuance, the electrodes were annealed in furnace to 520°C for 25 min.…”

Electrochemical Ozone Water Production with External Gas–Liquid Mixer

“…Electrochemical ozone dissolved water production (EOP) systems using a polymer electrolyte membrane have shown significant progress, because they enable the realization of a compact apparatus and low-voltage operation suitable for home use (Stucki et al, 1985;Feng et al, 1994;Marselli et al, 2003;Cheng and Chan, 2004;Santana et al, 2004;Wang et al, 2005;Arihara et al, 2006;Awad et al, 2006;Kraft et al, 2006;Honda et al, 2013). We have developed a new EOP system using mesh electrodes which provide a microchannel waterway so that a greater amount of the formed O 3 can dissolve in the anolyte (Okada and Naya, 2009).…”

Deposition efficiency in the preparation of ozone-producing nickel and antimony doped tin oxide anodes

“…In 2004 a research group at The University of Hong Kong presented a new electrode coating for electrochemical ozone formation [8]. The ceramic coating was an antimony doped tin oxide (ATO) deposited on a titanium substrate showing very promising results for the formation of ozone (15 % current efficiency).…”

“…Some studies have however reported measured compositions of their oxide coatings: Cheng et al [8] determined the Sn:Sb ratio of their coating to 7:1 using ICP-MS (inductively coupled plasma -mass spectrometry), far from the composition in the prepared precursor solution of 65:1. This was later discussed to be a consequence of surface enrichment of Sb [9,14].…”