Hydrothermal synthesis of Nb5+-doped SrTiO3 mesoporous nanospheres with greater photocatalytic efficiency for Cr(VI) reduction

Abstract

The Nb 5+ -doping strategy was adopted to enhance the photocatalytic efficiency of SrTiO 3 to overcome the limitation for its practical photocatalytic applications. Different amounts of Nb 5+ doped SrTiO 3 (Nb-SrTiO 3 ) mesoporous nanospheres were synthesized via a convenient hydrothermal approach. The photocatalytic reduction of aqueous Cr(VI) using the Nb-SrTiO 3 products under xenon lamp irradiation was investigated. Results indicated that 3% Nb-SrTiO 3 was the optimum product, which exhibited a photocatalytic efficiency 3 times as much as that of SrTiO 3 and a fair reuse stability. Moreover, 3% Nb-SrTiO 3 also demonstrated higher photocatalytic efficiency than many other metal cations doped SrTiO 3 synthesized via the same process and a number of previously reported photocatalysts. The best photocatalytic activity of 3% Nb-SrTiO 3 was found to be predominantly due to its most efficient separation and transfer of photogenerated holes and electrons. This study suggests that Nb-SrTiO 3 is a potential efficient photocatalyst for the remediation of Cr(VI)-contaminated water. • Nb 5+ -doped SrTiO 3 mesoporous nanospheres were synthesized by a hydrothermal method. • 3% Nb-SrTiO 3 has far higher photocatalytic activity than SrTiO 3 in Cr(VI) reduction. • It outperforms many other metal ions doped SrTiO 3 and many reported photocatalysts. • It has good photocatalytic stability. • Its higher activity mainly results from enhanced separation and transfer of e − and h + .