Plasmonic O 2 dissociation and spillover expedite selective oxidation of primary C-H bonds.

Manipulating O 2 activation via nanosynthetic chemistry is critical in many oxidation reactions central to environmental remediation and chemical synthesis. Based on a carefully designed plasmonic Ru/TiO 2- x catalyst, we first report a room-temperature O 2 dissociation and spillover mechanism that expedites the "dream reaction" of selective primary C-H bond activation. Under visible light, surface plasmons excited in the negatively charged Ru nanoparticles decay into hot electrons, triggering spontaneous O 2 dissociation to reactive atomic ˙O. Acceptor-like oxygen vacancies confined at the Ru-TiO 2 interface free Ru from oxygen-poisoning by kinetically boosting the spillover of ˙O from Ru to TiO 2 . Evidenced by an exclusive isotopic O-transfer from 18 O 2 to oxygenated products, ˙O displays a synergistic action with native ˙O 2 - on TiO 2 that oxidizes toluene and related alkyl aromatics to aromatic acids with extremely high selectivity. We believe the intelligent catalyst design for desirable O 2 activation will contribute viable routes for synthesizing industrially important organic compounds.