One-Pot Synthesis, Characterization and Photocatalytic Activity of ZnTe/ZnSe Common Cation Nanocomposites

Abstract

Today, the environmental and energy problems at the global level are considered as the most important matters of discussion in the scientific community. Now, it has become essential to develop clean and renewable energy sources to overcome these problems. Apart from the energy crisis, the major environmental issue that arises is the contamination of ground and surface water due to industrial discharges, usage of excessive pesticides as well as by domestic wastes. Hence, there is a need of such a system that can blow away the effects of these problems while using the green technologies i.e. using renewable energy. This work provoked the development of semiconductor-based photocatalysts including zinc telluride (ZnTe), zinc selenide (ZnSe) and the heterostructure ZnTe/ZnSe for the wide range of energy and environmental applications i.e. simultaneous hydrogen production by water splitting and organic pollutant degradation in water while using the sunlight. The photocatalysts were synthesized successfully via hydrothermal technique. The phase, morphology and composition of as-prepared products were studied by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) spectroscopy, respectively. The alignment of energy levels of the common-cation heterostructure was also plotted based on optical properties from the UV-Vis diffuse reflectance spectroscopy (DRS) as well as from the X-ray photoelectron spectroscopy (XPS) analysis. These as-synthesized photocatalysts were then employed for the degradation studies of the Congo red dye under UV light. The composite with equimolar ratio of ZnTe and ZnSe expressed the best results with overall degradation efficiency of 94 %, which was due to the minimum recombination of produced electron-hole pairs in this sample.