College of LAS Events

Attaching molecular catalysts on (photo-) electrodes offers a promising approach for modular and rational design of hybrid catalysts for (photo-) electrochemical transformations. The design and improvement of such hybrid catalysts require fundamental understanding of the structure and microenvironment of catalysts, interfacial field, and adsorbate-electrode interaction as well as their effects on adsorbate/catalysts excited state dynamics. To probe these electrode-adsorbate interactions at the molecular level, we have been developing and applying time-resolved vibrational sum frequency generation (VSFG) spectroscopy and surface enhanced Raman spectroscopy (SERS) as in situ interface specific/sensitive vibrational spectroscopic tools. 

In this talk, I will discuss two recent studies in this area. 1) We have observed surprisingly large electrochemical-Stark effect of adsorbed molecules and molecular CO₂ reduction catalysts. We demonstrated that the Stark-effect is dominated by through bond interaction of the electrode on the adsorbates (i.e. the electrode induction effect), and this result suggests a potential new approach for design and control of catalysts. 2) Using time-resolved SERS, we directly observe plasmon-driven mode-selective adsorbate vibrational excitation caused by strong adsorbate-metal interaction (i.e. the dynamic electrode induction effect). This finding suggests possible electrochemical control of photocatalysis on plasmonic metal surface and/or light-enhanced electrocatalysis.