Growth mechanism and photocatalytic properties of flower-like Bi_2WO_6 powders synthesized by a microwave hydrothermal method

摘要

Pure orthorhombic phase Bi_2WO_6 powders were synthesized by a microwave hydrothermal method in the absence of surfactants and templates, using Bi(NO_3)_3?5H_2O and Na_2WO_4?2H_2O as raw materials. Photocatalytic properties of the samples prepared at different reaction temperatures were also studied with Rhodamine B (RhB) solution as the target catabolite under visible light. The results indicate that flower-like Bi_2WO_6 powders can be obtained by controlling the microwave reaction temperatures in the absence of any additives. The growth of flower-like Bi_2WO)6 powders is a multistage layer assembly process, in which the flower-like Bi_2WO_6 self-assembling with the uniform size about 2 μm is synthesized at 180 ℃. At the same time, the photocatalytic reaction rate constant (k) gets up to 0.04167/min and the degradation rate of RhB solution is more than 96 % after being irradiated under visible light for 70 min.