Role of Electrolyte-Adsorbates Interaction in Determining CO2 Reduction Reaction Pathways

Abstract

Electrochemical CO2 reduction reaction (CO2RR) is a promising strategy to convert atmospheric CO2 into valuable fuels and chemicals. Although the optimization of the catalyst-adsorbates interaction via tuning the binding energies of electrocatalysts has been extensively studied, activity and product selectivity remain a challenge. Recently, there has been a growing recognition that cations in electrolytes influence the activity of surface electrocatalytic reactions.1 A recent density functional theory study suggested that partially desolvated metal cations stabilize CO2RR intermediates via electrostatic interactions.2 Therefore, an experimental understanding of how the cations (and surrounding water molecules) control the intermediates present on the surface and govern the reaction pathway is critical to establish further insights into the design of electrolytes for CO2RR.In this talk, the role of alkali metal cations and water molecules on the CO2RR is revealed by tracking the surface-bound intermediates using operando attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS). We will also integrate the operando surface analysis with final product selectivity, further strengthening the understanding of the reaction mechanism. It will also be demonstrated that the holistic information about the electrolyte-adsorbates interaction can provide additional knobs to tune the energetics of key reaction intermediates, leading to further improvements in electrocatalytic activity for the CO2RR.[Reference]1 Ringe, S. et al., Energy Environ. Sci. 2019, 12, 3001–3014.2 Monteiro, MCO. et al., Nat. Catal. 2021, 4, 654–662.