Visible-light-driven deep oxidation of NO over Fe doped TiO2 catalyst: Synergic effect of Fe and oxygen vacancies

A Fe doped TiO2 catalyst (Fe-TiO2) was evaluated for NO oxidation reaction under visible light irradiation. The Fe-TiO2 not only exhibited better catalytic activity and stability, but also suppressed the production of nitrogen dioxide (NO2) than the undoped TiO2. The results of in situ DRIFTS indicated that visible light benefited the adsorption and activation of NO at Fe sites (Fe-(NO)2) and Ti sites (Ti3+-NO) as well as the formation of active intermediates (e.g. Fe3+-NO3− and Ti4+-NO−). After EPR, DRS, PL and XPS testing, it was proposed that incorporating Fe ions into TiO2 induced the formation of more oxygen vacancies (OVs), while visible light further facilitated this process, resulting in an enhanced adsorption & activation of NO and also a promoted formation of reactive oxygen species (ROS). Thus, a strengthened photo-driven effect for oxidizing NO into NO2− and NO3− occurred on Fe-TiO2.