In-Situ Probing of the Surface Properties of Droplets in the Air and Electrochemical Reduction of CO2

 

In-Situ Probing of the Surface Properties of Droplets in the Air and Electrochemical Reduction of CO₂

 

Date: 11^th May, 2026 (Monday)

Time: 10:30 - 11:30 am (HKT)

 

Venue: Lecture Theatre P1, Chong Yuet Ming Chemistry Building

 

 

Department of Chemistry and Biochemistry

Utah State University

 

Dr. Yi Rao is a Full Professor in the Department of Chemistry and Biochemistry at Utah State University. He earned his PhD from the Institute of Chemistry, Chinese Academy of Sciences, in 2003. Following his doctoral studies, he served as a postdoctoral fellow in Dr. Kenneth Eisenthal’s group at Columbia University, specializing in experimental nonlinear interfacial spectroscopy. He continued at Columbia as a Research Associate, collaborating with Drs. Nicholas Turro and Kenneth Eisenthal, before moving to Temple University as a Research Associate Professor in 2014. In 2017, Dr. Rao started his independent career in Utah State University. Dr. Rao was promoted to Associate Professor with tenure in 2023. In 2026, he was promoted to Full Professor.

 

Since 2017, Dr. Rao has established a research program focused on interfacial physical chemistry, solar energy conversion, and catalysis. His team has developed several state-of-the-art interface-specific nonlinear optical spectroscopies to probe structure and dynamics at various interfaces. His work has been featured in premier journals, including Science, Nature Chemistry, PNAS, and JACS. Dr. Rao is a recipient of the NSF CAREER Award (2021), the ACS Utah Outstanding Educator Award (2024), and the USU College of Science Researcher of the Year (2023).

 

This presentation details recent advancements in second-order nonlinear optical scattering techniques for the in situ analysis of complex interfaces. The first section outlines the development of Second Harmonic Scattering (SHS), electronic Sum-Frequency Scattering (ESFS), and vibrational Sum-Frequency Scattering (VSFS) as applied to aerosol droplets in ambient air. These techniques provide fundamental insights into unique droplet surface properties, bridging a knowledge gap for audiences unfamiliar with the recent progress in nonlinear scattering applicability. The second section focuses on the in situ probing of electrochemical CO₂ reduction at gold (Au) electrode surfaces. By coupling ultrafast sum-frequency generation (SFG) spectroscopy with electrochemistry, we successfully quantified the orientation angle of the *CO intermediate for the first time. This high-sensitivity approach further enabled the observation of generation and diffusion kinetics, revealing the coverage density and surface binding free energy of the intermediate. Collectively, these works demonstrate the power of surface-specific SFG in uncovering molecular mechanisms across diverse environmental and electrochemical systems.