In-Situ Environmental TEM Studies of Electro- and Photo-Electrochemical Systems for Water Splitting
by Emanuel Ronge
Date of Examination:2020-12-18
Date of issue:2021-02-22
Advisor:Prof. Dr. Christian Jooß
Referee:Prof. Dr. Christian Jooß
Referee:Prof. Dr. Michael Seibt
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Abstract
English
This thesis presents studies on the structure and stability of materials for electrochemical water splitting and the changes in the active state. The stability of a TiO2 protection layer on a silicon multi-junction is analyzed and a degradation mechanism is suggested. To replace the expensive and not-abundant platinum as a HER catalyst, MoS2+δ electrodes are studied and a structure model is suggested to advance the understanding of possible active sites in this partially disordered system, and to further improve the catalytic activity. And last, for the OER catalyst, the changes and dynamics under reactive conditions of the layered calcium manganese oxide Birnessite are analyzed by post-operando and in-situ TEM studies to obtain a better understanding of the stability and the active state of the catalyst.
Keywords: water splitting; oxygen evolution; hydrogen evolution; manganese oxide; photo-cathode; electrochemical corrosion; TiO2 protection layer; molybdenum sulfides; catalysis; ion-exchange; in-situ microscopy; surface dynamics