Zn-doped Nb2O5 photocatalysts driven by visible-light: An experimental and theoretical study

Zn-doped Nb2O5 are prospective photocatalysts since they can be activated by visible-light. In this context, undoped and Zn-doped Nb2O5 (0.1 and 0.2% mol of Zn) were synthesized by the oxidant peroxide method with crystallization under hydrothermal conditions. All the synthesized materials presented the diffraction pattern of the Nb2O5 orthorhombic-type phase and part of the structure was amorphous. The doped samples presented better crystallinity, high specific surface area and low band gap values, i.e., low content of zinc were able to considerably improve the photocatalytic activity of Nb2O5 under visible irradiation. Furthermore, the as-synthesized samples were versatile photocatalysts since they presented great photoactivity in rhodamine B and caffeic acid degradation. The materials with 0.1% and 0.2% mol of Zn remained degrading about 80% and 87%, respectively of caffeic acid after three consecutive use cycles, proving that the organic compounds were really degraded not just adsorbed. In addition, the computational calculations showed that the presence of Zn leads to a significant decrease of band gap, decreasing the energy required to activate the photocatalyst.