Membrane-Free Electrosynthesis of Epichlorohydrins Mediated by Bromine Radicals over Nanotips.

The industrial manufacture of epichlorohydrin (ECH) often suffers from excessive corrosive chlorine and multistep processes. Here, we report a one-pot membrane-free Br radical-mediated ECH electrosynthesis. Bromine radicals electro-oxidized from Br - ions initiate the reaction and then eliminate HBr from bromohydrin to give ECH and release Br - ions for reuse. A high energy barrier for *OH oxidation and isolated Br adsorption sites enables NiCo 2 O 4 to suppress the competitive oxygen and bromine evolution reactions. The high-curvature nanotips with an increased electric field concentrate Br - and OH - ions to accelerate ECH electrosynthesis. This strategy delivers ECH with a Faradaic efficiency of 47% and a reaction rate of 1.4 mol h -1 g cat -1 at a high current density of 100 mA cm -2 , exceeding the profitable target from the techno-economic analysis. Economically profitable electrosynthesis, methodological universality, and the extended synthesis of epoxide-drug blocks highlight their promising potential.