The use of heterogeneous prolonged-photocatalytic oxidation for wastewater treatment has been the subject of a wide range of investigations. Much attention has been paid to the preparation of new kinds of photocatalysts that respond to visible light.
Flowers, discs, tubes and plates
Using a simple hydrothermal method and without adding any template, additive or surfactant, scientists at Huazhong Normal University have created BiVO4 nanostructures with different morphologies such as flower-like, disc-like, tube-like and plate-like shapes by controlling the solvent, pH value, concentration of precursors and reaction temperature.
The group has found that the nanostructures have much better photocatalytic activity than bulk materials and the 2D (disc-like and plate-like) nanostructures demonstrate better activity than the 3D (flower-like and tube-like) versions of the material under visible light. Additionally, the different microstructure leads to a different degradation route for organic compounds.
The relationship between the microstructure and the photocatalytic activity will provide clues for the future preparation of photocatalysts with high activity based on the material morphology design.
The image shows the first reported 3D hexagonal BiVO4 nanotubes. They are composed of nanoplates, which are firstly formed by aggregation of primary nanocrystallites and then self-assembled into hexagonal-prismatic nanotubes via an oriented attachment mechanism.
To make the material system easier to implement, the team is now investigating the mobilization of these nanostructures onto different substrates.
The researchers presented their results in Nanotechnology.