pH swing cycle for CO₂capture electrochemically driven through proton-coupled electron transfer

Abstract

This study analyzes the energetic cost of CO2 separation using a pH swing created by electrochemical redox reactions of organic molecules involving PCET in aqueous electrolyte, and compares the experimental energetic cost to other methods.

Biomimetic Amino Acid Functionalized Phenazine Flow Batteries with Long Lifetime at Near‐Neutral pH

“…As the proton‐coupled electron transfer reaction of phenazines in water influences the pH, the reduction potential of 1,6‐DPAP exhibits a pH‐dependent behavior (Supporting Information, Figure S31). The pH of the negolyte increased to 14 when the cell was fully charged, and went back to 8 when the cell was fully discharged, which was also observed in the previous literature [9d, 28] . The cell was cycled at a constant current density of 20 mA cm −2 for approximately 5.3 days and there was no obvious capacity fade observed.…”

Perspective and challenges in electrochemical approaches for reactive CO2 separations

“…Quinone chemistry has been typically used for CO 2 capture by PCET reactions ( Watkins et al., 2015 ). In 2020, sodium 3,3′-(phenazine-2,3-diylbis(oxy))bis(propane-1-sulfonate) (DSPZ) was studied as a redox-active organic proton carrier ( Jin et al., 2020 ). By utilizing the redox activity of 3,3'-(phenazine-2,3-diylbis(oxy))bis(propane-1-sulfonate) as a pH mediator, it was possible to capture CO 2 by forming an alkaline solution via the reduction of the redox molecule and to release CO 2 through acidification by re-oxidation.…”

Spiers Memorial Lecture: CO2 utilization: why, why now, and how?

“…148 Continued efforts will develop enhanced sorbents and processes that will capture more CO 2 per specic amount of sorbent, that are more stable, and that require less energy for desorption. [149][150][151][152][153][154][155] The present amount of captured CO 2 is on the order of 77 million tons a year, and only a small fraction of that is used in CDU processes. This is a far cry from where the activity level needs to be, based on climate models and business opportunities, as shown in Fig.…”