Oxy-reductive C-N bond formation via pulsed electrolysis

Co-electrolysis of CO2 with simple N-species is an appealing route to sustainable fabrication of C-N bond containing products. A prominent challenge in, the area is to promote the C-N coupling step in place of the established CO2 reduction pathways. This can be particularly difficult when relying on solution-based species (e.g., NH3) to intercept intermediates that are continually being reduced on heterogeneous catalyst surfaces. In light of this, we introduce pulsed electrocatalysis as a tool for C-N bond formation. The reaction routes opened through this method involve both partial reduction and partial oxidation of separate reactants on the same catalyst surface in parallel to co-adsorb their activated intermediates proximal to one another. Using the CO2 and NH3 as model reactants, the end result is an enhancement of selectivity and formation rates for C-N bond containing products (urea, formamide, acetamide, methylamine) by factors of 3-20 as compared to static electrolysis in otherwise identical conditions. An array of operando measurements and computational modelling was carried out to pinpoint the key factors behind this performance enhancement. Finally, the oxy-reductive coupling strategy was extended to additional carbon and nitrogen reactants as well as applied to boost electrochemical C-S coupling.