La 3+ ,Gd 3+ -codoped BiVO 4 nanorods with superior visible-light-driven photocatalytic performance for simultaneous removing aqueous Cr(VI) and azo dye

Approximately 300 nm La3+,Gd3+-codoped BiVO4 nanorods were synthesized via a facile hydrothermal method. Different physicochemical techniques were used to characterize the nanorods. The photocatalytic performance test in orange II oxidation and Cr(VI) reduction showed that La3+,Gd3+-BiVO4 composite nanorods exhibited superior performance for removal of orange II and Cr(VI). Doping of La3+ and/or Gd3+ obviously decreased the crystallite size of BiVO4 and increased its surface area. Moreover, codoping of La3+ and Gd3+ significantly promoted the separation efficiency of photo-generated charges. The improvement in texture property and the separation and transfer of electron/hole pairs mainly accounted for the high photocatalytic performance of La3+,Gd3+-BiVO4 composite nanorods. When Cr(VI) and orange II were coexistent, this synergistic reaction further efficiently suppressed the electron–hole recombination, leading to a large increase in photocatalytic performance with respect to single system. These studies suggest that La3+,Gd3+-BiVO4 nanorods are promising visible-light-driven photocatalysts for environmental remediation. Graphical abstract