Green and sustainable methods of syntheses of photocatalytic materials for efficient application in dye degradation

Recently, researchers have focused their attention on exploring the technique for removal of organic pollutants, such as dyes in wastewater, by using semiconductor based nanomaterials. However, most of the presently available semiconductor nanomaterials act as a harmful UV light driven photocatalyst and also in many reports toxic chemicals have been used during their syntheses. In this concern, development of biocompatible photocatalyst by using green approach is very much essential. In this chapter, we have discussed the limitations of traditional syntheses methods and also highlighted the need for green synthesis of such photocatalyst materials. As a model photocatalyst system which works under visible light excitations, we discuss the green approach for synthesis of ZnO and it's composite with various two dimensional (2D) carbon nanostructures, such as graphene, reduced graphene oxide, graphitic carbon-nitride, etc. The effect of band-gap engineering in ZnO-anchored 2D-layered material in their visible light driven photocatalytic performance is discussed in this chapter. We expect that this chapter could provide some recipes for green and sustainable synthesis of visible-light-driven photocatalytic materials for efficient application in degradation of organic pollutants.