Enzymes as Blueprints for Power-To-X-Applications
The efficient reduction of protons and CO2 under mild conditions is a current challenge for modern society. Nature utilizes enzymatic machineries that comprise iron- and nickel- containing active sites to perform these transformations. Recently, we reported on the formidable HER activity of bulk Fe4.5Ni4.5S8 electrodes revealing similar structural and functional properties of the enzymes. Specific Fe-Ni as well as metal chalcogen interactions seem to be the key for materials reactivity. Furthermore, due to the resemblance of Fe4.5Ni4.5S8 with CO2 converting enzymes, we likewise investigated the material to perform CO2 reduction. In non-aqueous conditions as well as in supercritical CO2, this material is indeed a potential catalyst affording CO or formic acid, respectively, as main product with high Faradaic yields.
Notably, the reactivity of the pentlandite materials can be further tuned by the reactor environment as well as the electrodes shape and composition. Thus, process engineering was found to be equally important as the catalyst itself.