... Common targets include ethanol and ethylene—C2 compounds. Sargent explains that his group works on these molecules because ethanol is widely used in automobile fuel. Plus, companies already have methods for turning the alcohol into sustainable aviation fuel. And ethylene, which normally has a large carbon footprint, can be converted to many products, including aviation fuel and polymers. Brian Seger, a physics professor at the Technical University of Denmark, says that SelectCO2, a European Union–based consortium he coordinates, focuses on the same products for the same reasons. The group includes partners from academia and national laboratories, as well as from large companies such as De Nora, an Italian supplier of equipment and materials for industrial electrochemistry...