PNNL

Abstract

Photo-stimulated reactions on TiO2 have attracted much attention due to the variety of potential applications ranging from a hydrogen production by water splitting to environmental remediation through organic pollutant oxidation.[1,2] In the majority of these processes the oxygen plays a crucial role, serving as a simplest oxidizing reagent and/or as an electron scavenger.[3,4] Hence, the physicochemical properties of O2 adsorbed on rutile TiO2(110) (model oxide surface) has been extensively investigated,[7-13] and, in particular, the chemisorbed O2 molecules have been recently imaged by scanning tunneling microscopy (STM).[14-16] While the O2 desorption from rutile TiO2(110) is the most comprehensively studied photoreaction on TiO2 (by traditional ensemble-averaging techniques), details of its mechanism are still far from being understood. On a basis of extensive research of photostimulated desorption (PSD) of O2 from TiO2(110) by ultraviolet (UV) light, Yates and co-workers have developed a hole-mediated desorption model.