Ag-induced anatase-rutile TiO2−x heterojunction facilitating the photogenerated carrier separation in visible-light irradiation

Abstract

Nanocomposites Ag-TiO2−x have been fabricated simply by Ag+ ion exchange of H2Ti3O7 nanowires. Ag NPs, appearing on the catalyst surface, exhibit strong visible-light absorption and generate hot electrons due to their localized surface plasmon resonance. Moreover, Ag introduction leads to the generation of anatase-rutile biphase heterojunction with Ti3+ defect energy level, narrowing the bandgap to 2.85 eV and inhibiting the recombination of electron-hole pairs, thus facilitating photocatalytic reduction of Cr (VI) under visible light. A possible photocatalytic reduction mechanism, i. e., the synergistic effect of the Ti3+ defect energy level, anatase-rutile heterojunction and SPR effect of Ag nanoparticles, has also been proposed.