二维ZnO/ Bi3.9Zn0.4V1.7O10.5纳米异质结构的制备及其可见光催化活性

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

摘要:

表面建造是提高半导体光催化活性的一种有效方法。本文利用Zn5(CO3)2(OH)6纳米片为基底沉积了BiVO4再通过煅烧成功制备了二维ZnO/Bi3.9Zn0.4V1.7O10.5复合纳米片。通过X射线衍射，透射电镜和元素映像技术表征了所制样品。结果显示随着锌与铋的原子比的上升，ZnO多孔片状的表面逐渐变成Bi3.9Zn0.4V1.7O10.5物质。但其比例高于1:0.02时，在片状Bi3.9Zn0.4V1.7O10.5的区域表面又生长出BiVO4纳米颗粒。漫反射光谱测试显示出ZnO/Bi3.9Zn0.4V1.7O10.5复合物随着锌与铋的原子比的上升其在400~600 nm可见光区的吸收逐渐增强。所制样品在可见光（波长大于420 nm）进行了光催化降解罗丹明B的测试，结果表明在所制样品中，锌与铋的原子比为1:0.0133的ZnO/Bi3.9Zn0.4V1.7O10.5纳米片虽然其可见光的吸收并没有明显增强但却表现出最佳的光催化活性。荧光与电化学测试得出了低含量BZVO的ZnO纳米片可见光催化活性的提高主要是因为表面ZnO/Bi3.9Zn0.4V1.7O10.5异质结构提高了光生载流子的分离与传送。这种二维材料的表面建造有利于光催化的进行。因此，此法可应用于其它二维纳米材料的建造以提高光催化活性。

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.