This interdisciplinary activity focuses on the evaluation of multiphase microstructures
for a novel smart catalyst concept in the anode compartment of a fuel cell system.
The drawback of currently used state-of-the-art nickel cermet catalysts is the general
lack of microstructural stability against high temperature, humidity, varying oxygen
partial pressures. In addition, sulphur, which is present in fossil but also in renewable
fuels as addressed in the joint project, immediately harm the Ni-catalyst and cause an
irreversible degradation, if exposed to sulphur for longer times.
Microstructural and catalytic degradation becomes obvious by aggregation, particle
growth and loss of active surface area and results in an increase of the polarisation
resistance and lowers the electrochemical activity. Furthermore, percolation of the
catalytic active nickel phase is limited and the electron pathways are interrupted by
particle growth, what again affects the ohmic resistance of the fuel cell.
To overcome these major degradation effects a new material-based strategy is applied.
An anode material with an innovative “smart” effect is applied, where activity and
performance will be recovered by the material intrinsic functionality to regenerate itself
under an externally triggered stimulus. A commonly harmful redox cycle with transient
pO2 operating conditions is actively used to self regenerate the anode catalyst. For this
a fundamental understanding of the complex reaction mechanism and the
relationships between performance and topological parameters on micro- and
nanoscales is needed. Sophisticated microstructure analysis (nanotomography, TEM,
image analysis) and numerical modelling and simulation will be combined with
detailed electrochemical investigations.