Momentum Relaxed, Plasmon-Resonant Vibrational Sum Frequency Generation of Electrochemical Interfaces: Direct Observation of Carbon Dioxide Electroreduction on Gold

2020 ◽  
Author(s):  
Spencer Walletine ◽  
Savini Bandaranayake ◽  
Somnath Biswas ◽  
L. Robert Baker
Keyword(s):  
Carbon Dioxide ◽  
High Current Density ◽  
Sum Frequency Generation ◽  
High Current ◽  
Signal To Noise ◽  
Sum Frequency ◽  
Frequency Generation ◽  
Good Signal ◽  
Electrochemical Interfaces

We present a vibrational sum frequency generation method to probe the Au/electrolyte interface with a detection limit of < 1% of a monolayer, and with currents exceeding 1 mA/cm<sup>2</sup> during CO<sub>2</sub> reduction. We couple light to the interface using momentum relaxed surface plasmon resonance. Using this technique we make in-situ measurements of catalytic CO with good signal-to-noise and at high current density.

Momentum Relaxed, Plasmon-Resonant Vibrational Sum Frequency Generation of Electrochemical Interfaces: Direct Observation of Carbon Dioxide Electroreduction on Gold

2020 ◽  
Author(s):  
Spencer Walletine ◽  
Savini Bandaranayake ◽  
Somnath Biswas ◽  
L. Robert Baker
Keyword(s):  
Carbon Dioxide ◽  
High Current Density ◽  
Sum Frequency Generation ◽  
High Current ◽  
Signal To Noise ◽  
Sum Frequency ◽  
Frequency Generation ◽  
Good Signal ◽  
Electrochemical Interfaces

We present a vibrational sum frequency generation method to probe the Au/electrolyte interface with a detection limit of < 1% of a monolayer, and with currents exceeding 1 mA/cm<sup>2</sup> during CO<sub>2</sub> reduction. We couple light to the interface using momentum relaxed surface plasmon resonance. Using this technique we make in-situ measurements of catalytic CO with good signal-to-noise and at high current density.

Study of FeOx/Au inverse model catalysts by in situ sum frequency generation vibrational spectroscopy

2009 ◽  
Vol 96 (2) ◽  
pp. 345-356 ◽  
Author(s):  
Orsolya Hakkel ◽  
Zoltán Pászti ◽  
Tamás Keszthelyi ◽  
Krisztina Frey ◽  
László Guczi
Keyword(s):  
Vibrational Spectroscopy ◽  
Sum Frequency Generation ◽  
Inverse Model ◽  
Model Catalysts ◽  
Sum Frequency ◽  
Frequency Generation

scholarly journals Orientational Analysis of Monolayers at Low Surface Concentrations Due to an Increased Signal-to-Noise Ratio (S/N) Using Broadband Sum Frequency Generation Vibrational Spectroscopy

2019 ◽  
Vol 73 (10) ◽  
pp. 1146-1159 ◽  
Author(s):  
Narendra M. Adhikari ◽  
Uvinduni I. Premadasa ◽  
Zachary J. Rudy ◽  
Katherine Leslee A. Cimatu
Keyword(s):  
Tilt Angle ◽  
Signal To Noise Ratio ◽  
Sum Frequency Generation ◽  
Ambient Conditions ◽  
Signal To Noise ◽  
Sum Frequency ◽  
Low Concentrations ◽  
Assembled Monolayers ◽  
Frequency Generation ◽  
Protonated Molecules

Sum frequency generation (SFG) * Equal contributors. spectroscopy was used to deduce the orientation of the terminal methyl (CH3) group of self-assembled monolayers (SAMs) at the air–solid and air–liquid interfaces at surface concentrations as low as 1% protonated molecules in the presence of 99% deuterated molecules. The SFG spectra of octadecanethiol (ODT) and deuterated octadecanethiol (d37 ODT) SAMs on gold were used for analysis at the air–solid interface. However, the eicosanoic acid (EA) and deuterated EA (d39 EA) SAMs on the water were analyzed at the air–liquid interface. The tilt angle of the terminal CH3 group was estimated to be ∼39 ° for a SAM of 1% ODT : 99% d37 ODT, whereas the tilt angle of the terminal CH3 group of the 1% EA : 99% d39 EA monolayer was estimated to be ∼32 °. The reliability of the orientational analysis at low concentrations was validated by testing the sensitivity of the SFG spectroscopy. A signal-to-noise (S/N) ratio of ∼60 and ∼45 was obtained for the CH3 symmetric stretch (SS) of 1% ODT : 99% d37 ODT and 1% EA : 99% d39 EA, respectively. The estimated increase in S/N ratio values, as a measure of the sensitivity of the SFG spectroscopy, verified the capacity to acquire the SFG spectra at low concentrations of interfacial molecules under ambient conditions. Overall, the orientational analysis of CH3 SS vibrational mode was feasible at low concentrations of protonated molecules due to increased S/N ratio. In support, the improved S/N ratio on varying incident power density of the visible beam was also experimentally demonstrated.

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