A triboelectric radical generation route to chlorine disinfectants from brine.

Contact electrification (CE), one of the earliest documented physical phenomena, has traditionally been associated with triboelectric charging but rarely considered as a driver of chemical transformations. Here we show that CE generates radicals at solid-liquid interfaces, establishing contact-electro-chemistry (CE-Chemistry) as a metal-catalyst-free route that uses ambient mechanical energy. Ultrasonically driven contact-separation of fluorinated ethylene propylene (FEP) particulates in brine generates hydroxyl radicals (•OH) and chlorine radicals (•Cl), forming active chlorine [hypochlorous acid (HOCl) and hypochlorite ions (ClO-)], without detectable chlorine gas (Cl2) production. Using natural seawater, this strategy achieves active chlorine production of 208.8 μmol g-1 h-1 and operates for over 700 h without detectable FEP dissolution or toxic intermediates. Cation hydration engineering modulates interfacial electrical double layers, strengthening triboelectric fields and tuning reaction kinetics. This work enables Cl2-free disinfectant production from brine without external bias or illumination, opening avenues for heterogeneous catalysis and CE-driven reaction design.