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.
