J. Phys. IV France 7 (1997) C2-887-C2-889
The Catalytic Centre of Transition Metal Chalcogenides vis-à-vis the Oxygen Reduction Reaction : An In Situ Electrochemical EXAFS StudyN. Alonso-Vante1, M. Fieber-Erdmann2, H. Rossner2, E. Holub-Krappe2, Ch. Giorgetti3, A. Tadjeddine3, E. Dartyge3, A. Fontaine3 and R. Frahm4
1 Hahn-Meitner-Institut, Department Solare Energetik CS, Glienicker Str. 100, 14109 Berlin, Germany
2 Hahn-Meitner-Institut, PG Synchrotronstrahlung AS, Glienicker Str. 100, 14109 Berlin, Germany
3 LURE, Bât. 209D, Centre Universitaire Paris-Sud, 91405 Orsay cedex, France
4 HASYLAB at DESY, Notkestrasse 85, 22603 Hamburg, Germany
The Chevrel type chalcogenide with the stoichiometry Mo6-xMxX8 (M=transition metal, e.g., Mx = Ru2 ; X=Chalcogene atom, e.g., S, Se) containing octahedral mixed-metal clusters of transition-metal atoms was investigated with respect to the oxygen reduction process in an in situ electrochemical enviroment via the EXAFS technique. The spectra analysis on Ru and Mo edges as a function of applied electrode potential revealed that ruthenium centers were preferentially modified by the presence of oxygen in the electrolyte. The variation in distance between Ru-(Ru, Mo) was more sensitive in oxygen saturated solution as compared to Mo-(Ru, Mo) and Ru-Se.
© EDP Sciences 1997