Thiourea and Triton X-100 as shape manipulating tools or more for Bi2WO6 photocatalysts?

In the present work Bi2WO6 hierarchical flowers were obtained by hydrothermal crystallization and characterized by SEM, DRS, IR and XPS. The crystallization time and the influence of the crystal-shaping agents (Triton-X 100 and thiourea) was investigated on the UV and visible light degradation of Rhodamine - B and methyl orange (MO). It was found that after 15 h of hydrothermal crystallization an interesting structure appeared in the middle of the microflowers. The appearance of this morphological feature coincides with the appearance of Bi5+ and with the highest UV and Visible light activity. However, this material showed an outstanding activity when no thiourea was used. The latter contributed to the formation of surface anchored organics, which was proven to be detrimental for the sample obtained at longer crystallization times. These organic deposits can be removed partially, but it was not decisive concerning the photocatalytic activity.