Enhancement strategies for ZnSe based photocatalysts: Application to environmental remediation and energy conversion

In recent times, the increase in the growth of population and industries has become a major issue for environmental resources and energy. The foremost reason behind environmental pollution is the discharging of hazardous pollutants like antibiotics, pesticides, dyes, phenols, and heavy metal ions into the water, which cause the lack to access to pure water. The photocatalysis method, obtained from solar energy can surely be helpful for the improvement of the environment. Recently, Zinc selenide (ZnSe) is a noteworthy and admirable photocatalytic material that belongs to the II-VI group with a direct energy gap of 2.67 eV. Due to ZnSe good photocatalytic properties, it is a useful photocatalytic material in environmental remediation. The present review illustrated the structural and optoelectronic properties of ZnSe with theoretical studies. The density functional theory (DFT) computation was used to validate the structural characteristics and optoelectronic properties. Various modification strategies like doping, conventional heterojunctions, and Z-scheme heterojunctions have been illustrated which enhanced the photocatalytic activity of ZnSe. These strategies lower the recombination rate and enhance the photoinduced charge carrier separation and migration efficacy. Similarly, photocatalytic applications of ZnSe in pollutant degradation, Co2 reduction, H2 evolution, and Cr(VI) reduction have been highlighted with its photocatalytic mechanism. Finally, the review ended with a conclusion and emerging future challenges in the field of ZnSe photocatalysts for water purification.