Silvered TiO2 for Facet-Dependent Photocatalytic Denitrification

In this paper, the influence of exposed facets of silvered TiO2 photocatalysts for photodenitrification was fundamentally investigated. We found that photodeposition of silver on 001-faceted TiO2 was prone to form Ag/Ag2O/001-TiO2 triple junctions. Comparatively, oxygen vacancies in 101-faceted TiO2 alleviated the oxidation rate, which contributed to the formation of a junctioned interface between TiO2 and metallic Ag-0. Benefiting from the Z-scheme charge transfer pathway mediated by adjacent Ag, the nitrate reduction rate and N2 selectivity for Ag2O/Ag/101-TiO2 reached 99.1 and 81.1%, respectively, which were much higher than those of silvered 001-TiO2 and P25. In this work, we prepared TiO2-based photocatalysts with specific exposed crystal facets and good crystallinity at the heterogeneous interface for denitrification applications.