Monitoring potential-dependent adsorbate behaviour at solid/liquid interfaces with EC-TERS

One crucial parameter that determines surface reactivity or device functionality in a large variety of applications, such as heterogeneous catalysis, electrochemical energy conversion schemes, biotechnology or molecular electronics, is the adsorption geometry of the (re)active molecules. Accessing adsorbate orientation in relation to specific surface sites in situ or in operando is a first crucial step toward controlling interfacial geometries for improved device architecture. However, suitable in-situ techniques to study molecular orientation at well- defined adsorption sites are still scarce. In my talk, I will present a novel electrochemical nearfield Raman spectroscopy (EC-TERS) tool that enables to access the vibrational fingerprint of less than 100 small, non-resonant molecules adsorbed at a potential-controlled Au surface. From the spectral changes observed as a function of potential, the conformational and chemical changes of showcase DNA base adenine in terms of adsorption and reorientation following molecular (de)protonation can be deduced by combining experimental and theoretical simulation data. This unique addition to nanoscale spectroscopy of electrified solid/liquid interfaces holds great potential to access molecular-scale chemistry in situ, for example to unravel electrocatalytic conversion mechanisms or biophysical processes on the single-protein level.

Bio: Katrin F. Domke studied chemistry at the Universities of Bonn, Alicante and CSIC/Sevilla and received her PhD in 2006 from the Free University Berlin / Fritz Haber Institute of the Max Planck Society for her seminal TERS work. After postdoctoral studies as a Feodor Lynen Fellow at Bern University and FOM Institute AMOLF in Amsterdam, in 2012 she set up an independent Emmy Noether Group at the Max Planck Institute for Polymer Research in Mainz. Katrin’s research interests evolve around ad- vanced molecular spectroscopy of electrified solid/liquid interfaces important for energy and catalytic conversion processes.