(Invited) Platinum Electrochemial Dissolution and Its Consequences for Platinum Electrocatalysis

While the fact that platinum dissolves has been known for more than a century, its nature is still obscure. Platinum dissolution as a result of an anodic treatment of a platinum electrode was documented as early as at the beginning of the twentieth century in the works of the founder of electrochemical kinetics, Julius Tafel.^{1, 2} In the second half of the twentieth century several groups reported on the quantification of platinum dissolved from platinum electrodes during potentio- or galvano-static or potentiodynamic conditions.^3-5 Later, platinum dissolution was mainly discussed in relation to  platinum catalyst degradation in proton exchange membrane fuel cell (PEMFC) cathodes.⁶ Recently, we applied a novel setup composed of a scanning flow cell and inductively coupled plasma mass-spectrometer (SFC-ICP-MS) for precise time- and potential-resolved investigation of platinum dissolution under acidic conditions.⁷ In the current work we are going to show and discuss these and new results obtained using SFC-ICP-MS. Inter alia an effect of pH, potential, temperature, presence of chloride ions or reactive gases on the process of platinum dissolution will be communicated. Besides dissolution of polycrystalline platinum electrode new data on the stability of nanoparticulated carbon-supported platinum catalysts will be shown and a comparison with the bulk material will be made. Based on the obtained experimental results consequences of platinum dissolution on the application of platinum in electrocatalysis of oxygen reduction and other important reaction of platinum electrocatalysis will be discussed.     

References

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2.         G. T. Burstein, Corros. Sci., 47, 2858 (2005).

3.         A. N. Chemodanov, Ya. M. Kolotyrkin, M. A. Dem'rovskii and T. V. Kudryavina, Doklady. Akad. Nauk. SSSR, 171, 1384 (1966).

4.         D. A. J. Rand and R. Woods, J. Electroanal. Chem., 35, 209 (1972).

5.         D. C. Johnson, D. T. Napp and S. Bruckenstein, Electrochim. Acta, 15, 1493 (1970).

6.         R. M. Darling and J. P. Meyers, J. Electrochem. Soc., 150, A1523 (2003).

7.         A. A. Topalov, S. Cherevko, A. Zeradjanin, J. Meier, I. Katsounaros and K. J. J. Mayrhofer, Chemical Science, 5, 631 (2014).