Determining the speciation on Cu surfaces via operando characterizations is critical to understanding the reaction mechanism and impact of experimental variables of Cu-catalyzed electrochemical CO/CO2 reduction reactions. Surface-enhanced Raman spectroscopy (SERS) is a powerful technique with high sensitivity and surface selectivity ideally suited for monitoring interfacial catalytic transformations. In this work, we employ shell-isolated nanoparticle enhanced Raman spectroscopy (SHINERS) to understand species available on a polycrystalline Cu (Cu foil) surface at conditions typically used in the electrochemical CO reduction. SiO2 coated Au nanoparticles (Au@SiO2) are synthesized to enable the detection of surface species on the flat (non-surface enhancing) Cu surface without the interference from the Au surface in the core. Strong potential dependent Raman features attributable to CuOx and Cu(OH)x are observed on the Cu foil with Au@SiO2, while no detectable spectral feature is present without Au@SiO2. Importantly, the surface speciation is highly dependent on the atmosphere in which experiments were conducted. Our results suggest that mechanistic interpretations of Cu-catalyzed electrochemical CO reduction must take the available surface species under reaction conditions into account.

SHINERS detection of electrochemical CO/CO2 reduction reactions on Cu metal

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.