1. Department of Inorganic Technology, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, 81237 Bratislava, Slovakia, Fax: +421‐2‐59325560, http://www.fchpt.stuba.sk
2. Department of Chemistry, Naresuan University, 65000 Phitsanulok, Thailand
3. J. Heyrovský Institute of Physical Chemistry of ASCR, v.v.i., Dolejškova 3, 18223 Prague 8, Czech Republic
4. Electrochemical Nanoscience Group, Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland