Role of oxygen vacancies in the O2 photoreduction at the (100) TiO2 (anatase) surface

Photooxidation of molecules involves both surface and electronic properties of a semiconducting catalyst. Here, we investigate the photoreduction of O$_2$ molecules on the perfect and defective (i.e., with oxygen vacancies) (100) anatase surface by treating molecules on the surface like defects. Our results give a novel evidence of the acceptor behavior of the O$_2$ molecule and reveal a central role of the vacancies in the photoreduction process.