(124c) Operando Attenuated Total Reflection Surface Enhanced Infrared Spectroscopy of the Electrochemical CO2 Reduction Reaction on Gold Thin Films Under Mass Transport Control
AIChE Annual Meeting
2021
2021 Annual Meeting
Catalysis and Reaction Engineering Division
Electrochemical CO2 Conversion II
Monday, November 8, 2021 - 1:06pm to 1:24pm
A platform was developed to enable operando SEIRAS with product collection and quantification with on-line gas chromatography. An electrochemical flow reactor was designed for compatibility with ATR-IR spectroscopy, and hydrodynamic control. Gold thin films were synthesized with electron beam physical vapor deposition (EBPVD) on ATR silicon crystals; the films are electrochemically activated to produce the surface enhanced infrared absorption (SEIRA) effect. This process yields gold thin films that are reproducibly SEIRA active and stable under ECO2RR conditions.
Operando spectroscopy is demonstrated at various potentials, as negative as -1V vs RHE, and electrolyte flowrates; the local concentration of CO2 and the interfacial water structure are all investigated as a function of potential or flowrate. Electrochemical ferricyanide reduction is used to calculate the boundary layer thickness as a function of electrolyte flowrate, demonstrating the capacity to control hydrodynamics near the catalyst-electrolyte interface.
This platform allows control of the microenvironment at the catalyst-electrolyte interface to investigate their effect on the ECO2RR. The platform can be further applied to other catalysts and electrolytes to elucidate on the reaction pathways of the ECO2RR reaction, as well as other electrochemical reactions of interest sensitive to mass transport conditions.