Electrochemical CO2 reduction is among the technologies being developed to aid in decarbonizing industrial processes and energy systems. However, commercial application requires a significant enhancement of both catalyst activity and durability, hindered by an incomplete understanding of the reaction mechanism, the complex environment at and near the catalyst-electrolyte interface, and unique degradation mechanisms affecting electrolyzer devices.
We developed two model systems with mass transport control to probe the catalyst-electrolyte interface of metal thin films with operando ATR-SEIRAS, and the evolution of Au nanoparticles (NPs on nearly atomically flat carbon supports (HOPG) with ex situ high-resolution scanning electron microscopy and Pb underpotential deposition. In the former, we demonstrate operando observations of the interface for Au thin films of difference surface morphology and how the reaction selectivity’s dependence on mass transport changes with the catalyst surface structure; in situ experiments on Cu also demonstrate the capabilities to monitor local pH and adsorbates. The evolution of Au NPs on carbon supports is found to have a surprising dependence on the carbon support’s treatment, hinting at the nature of the degradation mechanisms; we will discuss what these degradation pathways are and how they may be experimentally vetted. Overall, our work highlights many unknowns regarding the degradation of CO2 reduction catalysts and the reaction mechanism itself as well as the experimental pathways to elucidate their underlying nature.
Bio: Jaime Aviles Acosta was born in San Germán, Puerto Rico. He began a B.S. in Chemistry in the Interamerican University of Puerto Rico, and finished with a B.S. in Applied Physics in Indiana University. Currently, he is a Materials Science and Engineering Ph.D. candidate at Stanford University, and will graduate in June 2023.