Cyclic carbon energy systems have to involve the utilization of emitted fossil CO2 i.e. its capture and subsequent electrosynthetic reduction with water to hydrocarbons (e-fuels). However, this renders a multi-step process, where in particular electrocatalysis is kinetically limited by the low solubility of CO2.
CarboRed develops alternative, carbonate-selective electrocatalysts based on recently discovered biopolymers. These are designed for selective carbonate reduction enabling a significant breakthrough in the kinetic limitations. Carbonates possess a 250-fold increased solubility in water compared to CO2. Furthermore, by use of carbonate, capture- and electrosynthetic reactions occur in parallel forming a quasi-one-step aqueous carbonate to e-fuels process. This will ultimately facilitate the installation of large-scale industrial zero-emission carbon energy cycles. The required carbonate-selective biopolymer electrocatalysts rely on recently presented polydopamines - systems that are able to incorporate high amounts of carbonate directly. This is the unique innovation in CarboRed, as the carbonates are tightly bind to the electrocatalytic centers and hence easily reduced to hydrocarbons in aqueous solutions. As such a simple e-fuel production at quantitative turnover rates can be established. This is urgently required to reduce atmospheric CO2-emissions directly from exhaust gases and to install a sustainable anthropogenic carbon cycle.