Photocatalytic oxidation of NO over TiO2-Graphene catalyst by UV/H2O2 process and enhanced mechanism analysis

This study aimed at investigating the photocatalytic oxidation (PCO) of NO under the UV/H2O2 system over a series of TiO2-Graphene (TiO2-GR) catalysts, which was able to dramatically improve the PCO efficiency of NO compared with pure TiO2, and the NO oxidative product was the stable nitrate. The electronic interfacial interaction between GR and TiO2 resulted in a negative shift of the CB of TiO2 evidenced by MS. The excellent conductivity of GR suppressed e(-)/h(+) pairs recombination effectively, and GR as a kind of dispersant reduced the size of TiO2, increased the active sites. These advantages offered e(-) and h(+) more opportunities to participate in PCO of NO, resulting in significant improvement of the PCO efficiency. The effects of the active species involved in the photocatalytic process were also examined. Moreover, different tests were designed to further confirm the improved mechanism. Further investigations showed that their could oxidize NO directly. (C) 2016 Elsevier B.V. All rights reserved.