Effect of contact interface type in charge transfer mechanism and visible-light photocatalytic activity of ZnO-g-C3N4 heterostructures

Abstract

The dimension of semiconductor nanostructures is an effective parameter in their applications as photocatalysts, catalysts, sensors, etc. This effect of semiconductor nanostructures is more significant in heterostructures with different applications. In detail, we investigate the dimensional effect of ZnO nanostructures on the contact interface type of heterostructures and the number of created electron transfer channels at the contact place. In this work, heterostructures were designed and prepared by merging one component with fixed dimension (2D g-C3N4) and one component with variable dimension (0D ZnO, 1D ZnO, 2D ZnO, and 3D ZnO). Then, the accuracy of their structure was confirmed by various analyzes such as SEM, TEM, XRD, XPS, and Raman. Also, the charge transfer efficiency and photocatalytic properties were explored via electrochemical study, optical analysis, and photocatalytic tests for the degradation of organic pollutants. Examining the effect of dimension parameters on the interface area and charge transfer properties of carbon-based heterostructures showed that the heterostructures with more interface area create higher transfer channels for electron transfer to the surface and provide greater charge transfer efficiency. Among the prepared heterostructures with different dimensions, the 2D-2D heterostructure with more interface area between the two components has more electron transfer channels on all over of contact interface (surface-to-surface contact) and trapped more charge on the surface; thus, it shows a higher charge transfer efficiency and photocatalytic properties.