In situ sum-frequency vibrational spectroscopy of electrochemical interfaces with surface plasmon resonance.
Electrochemical (EC) reactions are crucial in many applications, yet most EC analytical tools lack the sensitivity to access molecular-level information of reactants and products. By combining sum-frequency vibrational spectroscopy and surface plasmon resonance at EC interfaces, we demonstrate the feasibility of measuring in situ and real-time vibrational spectra during EC reactions at noble metal electrodes. Application of the technique to EC reactions at a gold surface helps in understanding how the surface in a basic solution is oxidized and reduced during a cyclic voltammetry cycle. Study of desorption of a thiol self-assembled monolayer from gold through EC reactions in a basic solution shows that the desorbed thiols by reductive reaction remain as an ordered layer near the gold interface, but do diffuse away if they are desorbed oxidatively from gold.
Physics Department, State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, Shanghai 200433, China.
Wei-Tao
WT
Liu
Y Ron
YR
Shen
buried interface; field enhancement; spectroelectrochemistry