Photocatalytic activity of Nb2O5/SrNb2O6 heterojunction on the degradation of methyl orange

The pure SrNb2O6 powders were prepared at 1400 °C by a conventional solid-state method and characterized by X-ray powder diffraction and UV-vis diffuse reflection spectrum. The powders of Nb2O5 and SrNb2O6 were ball-milled together and annealed to form the Nb2O5/SrNb2O6 composite. Photocatalytic activities of the composites were investigated on the degradation of methyl orange. The results show that the proportion of Nb2O5 to SrNb2O6 and the annealing temperature greatly influence the photocatalytic activities of the composites. The best photocatalytic activity occurs when the weight proportion of Nb2O5 to SrNb2O6 is 30% and the annealing temperature is 600 °C. The tremendously enhanced photocatalytic activity of the Nb2O5/SrNb2O6 composite compared to Nb2O5 or SrNb2O6 is ascribed to the heterojunction effect taking place at the interface between particles of Nb2O5 and SrNb2O6. The powders also show a higher photocatalytic activity than commercial anatase TiO2.