Novel nano-flowers of Nb₂O₅ by template free synthesis and enhanced photocatalytic response under visible light

Niobium pentoxide (Nb₂O₅) has attracted considerable interest owing to its potential applications. A facile surfactant and template free hydrothermal method has been adopted to synthesize novel nanoflowers of Nb₂O₅. The incomplete oxidation process was completed by annealing in air at 400°C for 1 h. The initial band gap value varied from 3.1 eV to 2.9 eV with a red shift of 27.5 nm. Time dependent experiments were performed to understand growth mechanism. RhB under visible light was degraded by using Nb₂O₅ nanoflowers before and after annealing. The photdegradation constant k: 0.89 h_-1 and 2.62 h_-1 were calculated, respectively. The rate constant of Nb₂O₅ nanoflowers after annealing was found larger than commercial Nb₂O₅, Commercial TiO₂ Degussa P25, HTiNbO₅, N-TiO₂, SnNb₂O₆ nanosheets, Bi₃NbO₇ nanocomposites and C, N-codoped InOOH microspheres.