Raman under water - advanced spectroscopies for electrochemistry
For a manifold of electrochemical systems like fuel cells or sensitized solar cells, lack of molecular-level understanding of the interfacial chemistry hinders efficient development of novel improved systems. Advanced Raman spectroscopies can provide unique pieces of information otherwise inaccessible to help build a solid knowledge base of electrochemical processes that occur at interfaces or in confinement. Correlating known macroscopic device behaviour to molecular-level processes under in situ working conditions will enable performance evaluation in an unprecedented detailed manner and pave the way for rational device design.
Water management in fuel cell membranes
Proper water management in fuel cell membranes is critical for the design of efficient fuel cells, because the level of membrane humidity strongly affects the cell performance. To ensure high power density, long-term operation and an increased fuel cell robustness by careful control of the water content in the membrane, the water behaviour inside thin-film membranes needs to be clarified.
With help of coherent anti-Stokes Raman spectroscopy (CARS), we want to quantify the water content inside the membrane and visualize its distribution in 3D with (sub)micrometer resolution. The high sensitivity of CARS provides millisecond temporal resolution and thus allows us to directly monitor how membrane flooding and dehydration processes proceed. Furthermore, the effect of temperature and applied voltage on the water behaviour in the membrane will be studied to mimic realistic working conditions.
- in collaboration with Dr. S. Parekh, MPIP -
Electrochemical growth of metal-organic frameworks (MOFs)
Metal-organic frameworks (MOFs) constitute an important class of complex functional materials relevant, amongst others, for sensing, catalysis, optoelectronics and energy storage and conversion applications. The manifold of chemical and structural options provided through metallic and organic building blocks provides an enticing playground to fabricate MOFs with specifically tailored properties. However, the growth process, particularly the nucleation phase and the early growth stages that govern the final material properties, are not fully understood yet. Such knowledge is crucial for the design pf tailored bottom-up MOF fabrication protocols.
We want to characterize the initial stages of potential-controlled MOF growth as a function of applied substrate potential, e;ectrolyte composition, substrate morphology and functional ligans in situ with unprecedented molecular topographic and chemical resolution. Based on the detailed mechanistic insight into the molecular interactions underlying (early stage) MOF growth thus gained, we can rationally design improved preparation protocols for MOFs with desired properties.
- in collaboration with Prof. M.A. Van der Veen, TU Delft -