Alkynes Electrooxidation to ,-Dichloroketones in Seawater with Natural Chlorine Participation via Competitive Reaction Inhibition and Tip-Enhanced Reagent Concentration

The traditional synthesis of a,a-dichloroketones usually requires corrosive chlorine, harsh reaction conditions, or excessive electrolytes. Here, we report an electrooxidation strategy of ethynylbenzenes to a,a-dichloroketones by directly utilizing seawater as the chlorine source and electrolyte solution without an additional supporting electrolyte. High-curvature NiCo2O4 nanocones are designed to inhibit competitive O-2 and Cl-2 evolution reactions and concentrate Cl- and OH- ions, accelerating a, a-dichloroketone electrosynthesis. NiCo2O4 nanocones produce 81% yield, 61% Faradaic efficiency, and 44.2 mmol gcat.-1 h-1 yield rate of a,a-dichloroketones, outperforming NiCo2O4 nanosheets. A Cl- radical triggered Cl- and OH- radical addition mechanism is revealed by a variety of radicaltrapping and control experiments. The feasibility of a solar-powered electrosynthesis system, methodological universality, and extended synthesis of a,a-dichloroketone-drug blocks confirm its practical potential. This work may provide a sustainable solution to the electrocatalytic synthesis of a,a-dichloroketones via the utilization of seawater resources.