In this work, we consider two different quinonemediated electrochemical CO 2 capture mechanisms, known as "EEC" and "EECC" (Figure ). In these mechanisms, two electron transfer (E) steps occur before any chemical (C) CO 2 capturing step, which has been supported in previous CV analysis of EWG-substituted quinones at low CO 2 concentration. Since our goal is to mitigate side-reactions of reduced quinones with O 2 , our main interest is to add EWGs to stabilise the reduced quinones, increasing the likelihood of both electrochemical reduction steps being required prior to any CO 2 capture. The electrochemical reduction occurs as: