Controlled Synthesis of TT Phase Niobium Pentoxide Nanowires Showing Enhanced Photocatalytic Properties

Abstract The controlled synthesis of niobia nanowires with TT (tief–tief) phase (TT-Nb2O5-NW) that is the stable phase at low temperature was accomplished through calcination of niobium-based amorphous nanowires (Nb2O5-NW) composed of closely packed primary particles, obtained by the reaction of water-soluble niobium oxo-oxalate complex (NH4)3[NbO(Ox)3]·H2O (Ox = oxalate) with trioctylamine (TOA) employed as a structure-directing agent. TT-Nb2O5-NW gave a sharp absorption edge, which agreed well with that of the same crystalline phase of bulk niobia (TT-Nb2O5-B), suggesting no influence on the band gap energies by the shape transformation. An aqueous suspension containing TT-Nb2O5-NW and a sacrificial reagent was irradiated with white light (λ > 300 nm) from a Xe lamp to afford the enhanced photocatalytic activities for H2 or O2 evolution compared with that of conventional TT-Nb2O5-B.