Dopant-induced electron localization drives CO2 reduction to C2 hydrocarbons

The electrochemical reduction of CO 2 to multi-carbon products has attracted much attention because it provides an avenue to the synthesis of value-added carbon-based fuels and feedstocks using renewable electricity. Unfortunately, the efficiency of CO 2 conversion to C 2 products remains below that necessary for its implementation at scale. Modifying the local electronic structure of copper with positive valence sites has been predicted to boost conversion to C 2 products. Here, we use boron to tune the ratio of Cu δ+ to Cu 0 active sites and improve both stability and C 2 -product generation. Simulations show that the ability to tune the average oxidation state of copper enables control over CO adsorption and dimerization, and makes it possible to implement a preference for the electrosynthesis of C 2 products. We report experimentally a C 2 Faradaic efficiency of 79 ± 2% on boron-doped copper catalysts and further show that boron doping leads to catalysts that are stable for in excess of ~40 hours while electrochemically reducing CO 2 to multi-carbon hydrocarbons. On copper catalysts, Cu δ+ sites play a key role in the electrochemical reduction of CO 2 to C 2 hydrocarbons, however, they are prone to being reduced (to Cu 0 ) themselves. Now, a Cu δ+ -based catalyst is reported that is stable for in excess of ~40 hours while electrochemically reducing CO 2 to multi-carbon hydrocarbons and that exhibits a Faradaic efficiency for C 2 of ~80%.