Contribution to the Study of Ir Electrodes in Aqueous Solution of KNO₃/HNO₃ and KNO₃/HNO₃/Hg₂(NO₃)₂

E. Milaré, E. Y. Ionashiro, A. V. Benedetti*, F. L. Fertonani

Instituto de Química, Universidade Estadual Paulista, Araraquara, São Paulo, C.P. 355, CEP 14.801-970, Brazil

Received 9 October 2002; accepted in revised form 21 February 2003

Abstrac

Cyclic voltammetry and surface analysis techniques (EDX microanalysis, mapping of elements and SEM images) have been used to study the solid state reactions of Ir in blank solution or Hg(I)-containing solution. The studies in KNO₃/HNO₃ solution permit to suggest the formation of a thin oxide layer film deposited in the substrate. The RCV process exhibits the decrease of capacitive current associated to the substrate surface restructuring. The electro deposition of Hg occurs initially in UPD condition from Hg(I)-containing solution, C_Hg(I) = 3.51x10^-7 mol L^-1. The electro deposition of bulk mercury occurs from Hg(I)-containing solution, C_Hg(I) = 3.51x10^-5 mol L^-1. It was observed the deposition of Hg in the substrate in open circuit for all employed conditions.

Keywords: iridium, mercury, cyclic voltammetry, UPD.

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Referências

1. I.C. Hwang and S.I. Woo, Zeolites and Related Micropor 84 (1994) 757.        [ Links ]

2. P. Albers, B. Engler, J. Leyner, E. Lox, G. Prescher and K.Seibold, Chem. Eng. Technol. 17 (1994) 161.        [ Links ]

3. G.E. Poirier, B.K. Hance and J.M. White, J. Phys.-Chem. 97 (1993) 5965        [ Links ]

4. A. Talo, J. Lahtinen, P. Hautojarvi, Appl. Catal. B-Environ. 5 (1995) 221.        [ Links ]

5. A. Aramata and M. Masuda, J. Electrochem. Soc. 138 (1991) 1949.        [ Links ]

6. R.W. Joyner and E.S. Shpiro, Catalysis Letter 9 (1991) 239.        [ Links ]

7. E. Xue, K. Seshan, J.G. Vanommem and J.R.H. Ross, Appl. Caltal. B-Environ. 2 (1993) 183.        [ Links ]

8. J.L.G. Fierro, J.M. Palacios and F.Tomas, J. Mater. Sci. 27 (1992) 685.        [ Links ]

9. K.G. Kreider, M.J. Tarlov and J.P. Cline, Sensor Actuator B-Chem. 289 (1995) 165.        [ Links ]

10. E. Bolzán, M.I. Florit and A.J. Arvia, J. Electroanal. Chem. 461 (1999) 40.        [ Links ]

11. E. Martins, R.C. Salvarezza and A.J. Arvia, Electrochem. Acta 43 (1998) 549.        [ Links ]

12. E. Martins, R.C. Salvarezza and A.J. Arvia, Electrochem. Acta 41 (1996) 2441.        [ Links ]

13. C. Chialvo, W.E. Triaca and A.J. Arvia, J. Electroanal. Chem. 146 (1983) 93.        [ Links ]

14. F.L. Fertonani, E. Milaré, M. Ionashiro, A.V. Benedetti, J. Thermal Analysisand Calorimetry 67 (2002) 403.        [ Links ]

15. F.L. Fertonani, A.V. Benedetti, M. Ionashiro, Thermochim. Acta 265 (1995) 151.        [ Links ]

16. F.L. Fertonani, M. Yonashiro, P. Melnikov, F. Sanz and A.V. Benedetti. - XII Congreso Iberoamericano, IX Encuentro Venezolano de Electroquimica - Livro de Resúmenes - 1996 (416).        [ Links ]

17. F.L. Fertonani, Preparo e caracterização de eletrodos de mercúrio com substratos de platina, platina-irídio e platina-ródio (Tese de Doutoramento), 196 (1996).        [ Links ]

18. E. Milaré, F.L. Fertonani, M. Ionashiro, A.V. Benedetti, P. Melnikov, XIII Congreso de la Sociedad Iberoamericana de Electroquimica - SIBAE 98, libro de resumenes. (1998) 140.        [ Links ]

19. E. Milaré, F.L. Fertonani, M. Ionashiro, A.V. Benedetti, XI Simpósio Brasileiro de Eletroquímica e Eletroanalítica, Livro de Resumos - (1999) 419.        [ Links ]

20. E. Milaré, F.L. Fertonani, M. Ionashiro, A.V. Benedetti, J. Thermal Anal. 59 (2000) 617.        [ Links ]

21. E. Milaré, F.L. Fertonani, M. Ionashiro, A.V. Benedetti, 51ª Reunião Anual da SBPC, VI JNIC (Jornada Nacional de Iniciação Científica) (1999).        [ Links ]

22. F.L. Fertonani, A.V. Benedetti, J. Servat, J. Portillo, F. Sanz, Thin Solid Films 341 (1999) 1.        [ Links ]

23. M.C. Santos, S.A.S. Machado, L.A. Avaca, L.H. Mascaro, Química Nova 23 (2000) 392.        [ Links ]

*Corresponding author. E-mail address: benedeti@iq.unesp.br. Communication presented at XV Ibero-American Meeting of Electrochemistry.