Μελέτη της ηλεκτροχημικής ενίσχυσης μετάλλων χρησιμοποιώντας θερμοπρογραμματιζόμενη εκρόφηση (TPD), θερμοπρογραμματιζόμενη οξείδωση (TPO ) και πειράματα δυναμικής απόκρισης υπό συνθήκες υψηλού κενού

Abstract

Many studies have been curried out during the last two decades reporting the use of solid electrolytes. Their use in chemical co-generation studies leads to a new phenomenon, the called ‘’Non-faradaic Electrochemical Modification of Catalytic Activity’’ or otherwise NEMCA effect or Electrochemical Promotion, ΕΡ. It has been found that the catalytic activity and selectivity of metal films deposited on solid electrolytes can be altered dramatically and reversible under constant apply of current or potential. Isotope oxygen, 18Ο2, and supported metals on solid electrolyte (YSZ) were used during this study in conjunction with temperature programmed desorption technique in order to study NEMCA effect. The presence of lattice oxygen in the oxygen desorption spectra during the heating proved the participation and the great importance of this non stoichiometric oxygen. Experiments also were curried out using nanodispersed Pt catalyst on YSZ. Comparison was done between the results of supported catalyst and nanodispersed catalyst showing the similarities of these types of catalysts. The above cells (Pt, Pd, Au / YSZ) were used both under open circuit conditions and anodic or cathodic polarization during temperature programmed oxidation of CO by isotope oxygen. Such electrochemical promotion studies were done successfully (non Faradaic behaviour) for first time in this study under high vacuum conditions (P?10-5 mbar).