Catalysis is a core science in the chemical manufacturing sector that plays a key role in our path to sustainability. The development of active, efficient, and selective catalysts relies on our fundamental understanding of the surface chemistry, molecular-level reactivity, and selectivity of catalysts. However, our progress is hindered because of our limited knowledge in this area. By investigating catalysts under actual operating conditions, especially at the single-nanoparticle level, insights into surface adsorbates and rare intermediates dynamically formed during the reaction can be obtained. Simultaneously, probing of catalytic activity at the single-nanoparticle (NP) level can reveal the interparticle heterogeneity in catalytic activity, which is otherwise masked in ensemble-level measurements. By employing surface-sensitive surface enhanced Raman scattering (SERS) in situ, chemical imaging of catalysts in aqueous media is possible. Using nanoscale-SERS, with single-NP-level sensitivity and 100-ms time-resolution, we studied the plasmon-assisted CO2 reduction reaction (CO2RR) on the surface of individual diffraction-limited locations of Ag nanoparticle (NP) catalysts in water. This led to the discovery of a rich profile of C1 and C2+ surface species formed during visible-light-driven CO2RR on Ag NPs in aqueous conditions. These surface species are primarily long chain C–C coupled hydrocarbons and alcohols many of which are valuable liquefiable, energy-dense fuels that are kinetically-challenging-to-produce. Using isotope labeling, the precursor of the observed CO2RR is confirmed to be CO2. Additionally, the comparison of catalytic activity at several individual nanoscale locations revealed a spatial and temporal variability in the profile of species. Thus, this work manifests the potential of single-NP-level operando studies to uncover surface chemistry and nanoscale-level heterogeneities that characterize the complex catalytic processes.

In-situ discovery of surface species in the photochemistry of CO2 on plasmonic silver

ACS Spring Meeting 2021

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