Dr. Svetlana Korneychuk (Karlsruhe Institute of Technology, Institute of Nanotechnology, Germany)

Abstract :

Hydrogen is one of the new energy sources which can take up a leading role in the transfer to the green economy. In this seminar I will demonstrate the application of in-situ TEM to the two major topics in the field of hydrogen technology.
In the first part, I will speak about solid oxide cells which play a key role in the energy transition. They use the chemical energy of the fuel, for instance, hydrogen to produce electricity in a clean way generating only heat and water in the process. Increasing the durability of solid oxide fuel cells is one of the main goals for achieving wider industrial application. The quality of the electrode plays a major role in the performance and durability of a fuel cell. Upon exposure to hydrogen and heat inside in-situ TEM, the reduction mechanism of NiO, a part of NiO/YSZ template for a fuel electrode, can be studied. Using in situ TEM atmosphere system from Protochips the electrode reduction at the H2 pressures up to 1 atmosphere and temperatures up to 850 °C are analyzed. In-situ results go in a good agreement with ex situ results obtained from a bulk cell reduced in a test bench.
Secondly, I am going to address the mechanism of the hydrogen absorption in the nanoscale systems on the example of Pd nanoparticles. Compared to bulk, nanoscale systems interact with hydrogen faster making them more attractive for hydrogen storage, hydrogen detection and catalysis. However, they reveal significant thermodynamic deviations from the bulk due to higher surface to volume ratio, absence of grain boundaries and mechanical stress. Pd is ideal model system to study hydrogen delivery in metals due to its high affinity to hydrogen. In this part I will show the behavior of Pd nanoparticles, in real time with in-situ H2-gas loading in TEM. Initial stages of hydrogen absorption in Pd nanoparticles, local formation of PdHx at different temperatures and pressures can be analyzed by measuring the shift of Pd bulk plasmon with STEM-EELS during in-situ hydrogen loading and unloading in TEM.

Contact : Florian Banhart (florian.banhart@ipcms.unistra.fr)