Microwave synthesis and photocatalytic activity of Tb3+ doped BiVO4 microcrystals

Tb 3+ doped BiVO 4 has been successfully synthesized by a simple microwave-assisted hydrothermal method at 140   °C for 30   min. The structure, morphology and optical property of the Tb 3+ doped BiVO 4 products have been systematically investigated. This study indicates that the incorporation of Tb 3+ could induce the conversion of structure from monoclinic to tetragonal for BiVO 4 . Furthermore, the as-obtained Tb 3+ doped BiVO 4 samples showed an obvious morphological change: the hollow square rod-like BiVO 4 crystal gradually changed to spindle-like crystal. The Tb 3+ doped BiVO 4 products exhibited extraordinary photocatalytic activity for Methylene Blue (MB) degradation under visible light irradiation. The doped BiVO 4 at a molar ratio of 2   at% (Tb and Bi) with a mixture of monoclinic and tetragonal phases showed and prominent photocatalytic degradation rate, which reached 99.9% in 120   min. The results suggest that the differences in the photocatalytic activity of these BiVO 4 crystals with different Tb 3+ doping concentrations can be attributed to the change of crystalline phases, and the coexistence of the monoclinic/tetragonal phases in BiVO 4 products, which improve the efficient charge separation and transportation.