The integration of CO<sub>2</sub> capture and electrochemical conversion introduces a complex landscape of reaction pathways and optimization parameters that, despite recent attention, may make fast-paced progress challenging. Many integration efforts have focused on amines as the sorbent-electrolyte due to their ubiquity in commercial capture systems. However, a more complete understanding of the transport and interfacial processes in these systems, as well as the characteristics and speciation of the sorbent-electrolyte, will be necessary before engineered prototypes can be developed. For these amine-mediated systems, the selection of the amine is a critical, performance-governing component. Amines well-suited as capture sorbents may prove suboptimal for electrochemical reactions, and their performance depends on their physicochemical properties. Here, we present measurements of several exemplar primary alkylamines (e.g., ethanolamine, 2-ethoxyelthylamine, 2-amino-2-(hydroxymethyl)propane-1,3-diol, n-butylamine), selected for their varied steric hindrance, pKa, and N-C bond strength. The electrochemical performance of each amine was evaluated on the basis of Faradaic efficiency, partial current density to reduced products, and the dynamics of production (species evolution over time) to elucidate trends dependent on the above-listed parameters for Ag-based electrocatalysts at several temperatures between room temperature and 80°C. These results are integrated to provide early guidelines for amine selection and support future development of sorbent-electrolytes for integrated capture-conversion systems.

Linking amine physicochemical properties and electrochemical activity for aqueous reduction of captured-state CO<sub>2</sub>

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Linking amine physicochemical properties and electrochemical activity for aqueous reduction of captured-state CO2

Linking amine physicochemical properties and electrochemical activity for aqueous reduction of captured-state CO₂