Figure 1From: Environmentally persistent free radicals amplify ultrafine particle mediated cellular oxidative stress and cytotoxicity Mechanism of formation of a phenoxyl-type PFR from a substituted aromatic on a metal oxide surface. PFR formation proceeds through a mechanism of: 1) physisorption, 2) chemisorption by elimination of HX, and electron transfer to form the surface-associated PFR and a reduced metal. The resulting radical may be primarily oxygen-centered or carbon-centered based on the properties of the PFR-metal complex.Back to article page