Electrochemica Co-generation of Ozone and Hydrogen Peroxidel

Abstract

Both ozone and hydrogen peroxide are powerful green oxidants. Ozone found applications in oxidation of organic and inorganic compounds, disinfection, sterilization, deodorization and decoloration processes1-2. Hydrogen peroxide has been applied to the organic synthesis, wastewater treatment, bleaching of paper pulp and textiles3 . Furthermore, ozone can react with hydrogen peroxide and generate more powerful oxidant hydroxyl radicals via the peroxone process as formula (1) shows H2O2+2O3→2OH· + 3O2 (1) Hydroxyl radical with oxidation potential of 2.8 V can oxidize some chemicals in wastewater even ozone and hydrogen peroxide individually can not4 . In-situ cogeneration of ozone and hydrogen peroxide in electrochemical flow cell can eliminate transportation costs. It is a safe way to electro-chemically generate ozone and hydrogen peroxide on-site, so its application will be largely simplified5 . The current efficiency for electrochemical ozone generation of 36.3% could be obtained on the antimony- and nickel- doped tin oxide electrode6-7. There were efforts to co-generate ozone and hydrogen peroxide in electrochemical cell8-9, but the current efficiency for ozone generation was lower than 20% and the current efficiency for hydrogen peroxide generation was less than 4%. We reported here that cogeneration of ozone at doped tin oxide anode and hydrogen peroxide at reticulated vitreous carbon (RVC) cathode in a proton-exchange-membrane electrochemical micro flow cell. The current efficiency for ozone and hydrogen peroxide co-generation was largely improved. References 1. U.V. Gunten, Water res., 37, 1469(2003) 2. L.M. Da Silva, L. A. De Faria and J. F. C Boodts, Pure Appl. Chem., 73, 1871(2001) 3. A. D. Pozzo, L. D. Palma, C. Merli and E. Petrucci, J. Appl. Electrochem.,35, 413(2005) 4. C. D. Adams, P. A. Scanlan and N. D. Secrist, Environ. Sci. Technol., 28, 1812 (1994) 5. Z. Qiang, J. H. Chang and C. P. Huang, Water Res., 36, 85(2002) 6. Y. H. Wang, S.A. Cheng, K.Y. Chan and X.Y. Li, J. Electrochem. Soc., 152, D197 (2005) 7. Y. H. Wang, S.A. Cheng, K.Y. Chan, Green Chem., 8,568(2006) 8. P. Tatapudi and J.M. Fenton, J. Electrochem. Soc., 141, 1174(1994) 9. O.J. Murphy and G. D. Hitchens, US005972196A, (1999) Fig. 2 SEM image of freshly prepared doped tin oxide electrode Fig. 1 Illustration of the co-generation of ozone and hydrogen peroxide in electrochemical cell Nafion 324 Doped tin oxide electrode O2 +2H+ +2e- H2O2 E0 = 0.682 V 3 H2O O3 + 6 H+ +6eE0 =1.51 V Cathodic compartment H2O2 Anodic compartment O3 Ag/AgCl electrode RVC 215th ECS Meeting, Abstract #1021, © The Electrochemical Society Downloaded on 2016-03-31 to IP 147.8