Photocatalytic oxidation plays an important role in organic synthesis. This research systematically studied the effect of reactive oxidation species (ROSs) such as surface-bounded hydroxyl radicals ((OHb)-O-center dot), free hydroxyl radicals ((OHf)-O-center dot), and hole (h(+)) on the photocatalytic selective oxidation of phenol in the TiO2/UV system and its corresponding important chemical intermediates, dihydroxybenzenes. Experimental results showed that (1) the oxidation of phenol by hydroxyl radicals, whether in free ((OHf)-O-center dot) or bounded states ((OHb)-O-center dot), led mainly to the ortho- (catechol) and para- oriented hydroxy derivatives (hydroquinone), whereas the meta-oriented hydroxy derivative (resorcinol) became the main product when holes were used as the active species; (2) in naked TiO2 suspensions, where (OHb)-O-center dot was the main ROSs, the selectivity of the catechol detected in the solution was much lower than that on the surface of the fluorinated TiO2 system (TiO2-F), where (OHf)-O-center dot served as the main ROSs. This finding can be attributed to the very strong catechol adsorption on the surface of naked TiO2. However, this adsorption was severely inhibited in the presence of fluorine because of the competitive adsorption-between catechol and fluoride ions over TiO2 photocatalyst; and (3) the hole oxidation of phenol provided a slower oxidation rate but a higher yield of dihydroxybenzenes compared with hydroxyl radical-mediated oxidation. (C) 2016 Elsevier B.V. All rights reserved.