Fabrication and visible-light photocatalytic performance of two-dimensional ZnO/Bi3.9Zn0.4V1.7O10.5 nanoscale heterostructures

Abstract:

Surface engineering is an effective means to improve photocatalytic activity of semiconductors. In this work, two-dimensional (2D) ZnO/Bi3.9Zn0.4V1.7O10.5 nanosheets were successfully prepared using Zn5(CO3)2(OH)6 nanosheets as substrate to anchor BiVO4 followed by calcination. As-prepared samples were characterized by X-ray diffraction and transmission electron microscopy with elemental mapping attachment. Results show that with the increasing Zn/Bi molar ratio, the surface composition of ZnO porous nanosheets evolves into Bi3.9Zn0.4V1.7O10.5 step by step. When the Zn/Bi molar ratio is above 1:0.02, additional BiVO4 begins to form and grow into particles in the Bi3.9Zn0.4V1.7O10.5 region. Diffuse reflectance spectra of as-prepared samples reveal that nanoscale heterostructures harvest visible light of 400 ~ 600 nm dependent on the varying Zn/Bi molar ratio. The experiment for photocatalytic degradation of rhodamine B under visible light (λ ≥ 420 nm) illumination shows that this 2D heterostructure with the Zn/Bi molar ratio of 1:0.0133 performs the best photocatalytic activity in spite of no remarkable visible-light absorption. Photoluminescence and photoelectrochemical tests indicate that the enhancement in catalytic activity is attributable to an effective separation and transfer of photoinduced carriers caused by the ZnO/Bi3.9Zn0.4V1.7O10.5 heterostucture. This 2D surface heterogenization can promote the photocatalytic process, being applicable to a wide range of 2D nanostructures.