1. Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, 165 02 Prague, Czech Republic, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Prague 8, Czech Republic, Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic 250 68 Řež near Prague, Czech Republic, and National Institute of Materials and Chemical Research, AIST, MITI, Tsukuba, Ibaraki 305, Japan