POS6-0637
Enhancing Selectivity of Electrochemical CO2 reduction in Highly Acidic Media via Local Environment Modulation Using Block Copolymer-Templated Carbons with Abundant Inner Cavities
When and Where
Nov 30, -0001
12:00am - 12:00am
Presenter(s)
Jaeyoung Choi (KAIST)
Co-Author(s)
Abstract
Performing the electrochemical CO2 reduction reaction (CO2RR) under basic or neutral conditions triggers carbonate generation, thereby restricting the overall carbon conversion efficiency. Operating the reaction in an acidic medium resolves this specific drawback; however, it encounters severe competition from the prevalent hydrogen evolution reaction (HER). In this study, we introduce Au catalysts deposited on cavitated carbon particles (CCPs) with an average cavity diameter of 130 nm. These carbon particles exhibit abundant inner cavities designed to maintain a high pH microenvironment. Such cavity structures were successfully generated by inducing interfacial instability within block copolymer particles. For comparison, a solid carbon particle (SCP)-supported Au catalyst lacking inner cavities was additionally prepared. CO2RR performance was evaluated with 5 wt% Au/CCP and Au/SCP within an electrolyte at pH 2. CO2RR performance and multi-physics simulation results demonstrated that an inner cavity geometry could increase the local pH of the cavity structure, thus suppressing HER and increasing CO2RR selectivity. Moreover, we systematically adjusted the microenvironment via modifications to the binder type, alkali metal ions, and their concentrations. This work establishes that the confinement effect derived from the cavity structure acts as a powerful strategy for the formation of a local alkaline microenvironment and enables higher CO2RR selectivity under acidic media, offering a practical approach for efficient CO2 electrolysis.
