Synthesis of L-Cysteine capped ZnSe QDs and their photocatalytic activity

Radhika N, Sharmila Lydia I

Photocatalysis is one of the most powerful tool for the degradation of dyes and textile waste water. Heterogeneous photocatalyst like TiO₂, ZnO, CdS, and CdSe are mostly used semiconductor Quantum dots (QD’s).  Biocompatible ZnSe QD’s with the direct band gap 2.7eV were synthesised by hydrothermal route with amino acid namely L-cysteine. The as-synthesised biomolecules capped ZnSe QDs were characterized by UV-visible, FT-IR and PL for their optical and structural properties. The size of ZnSe QD’s was calculated by XRD analysis using Scherer’s formula.  The morphology analysis was confirmed by SEM. The photocatalytic degradation of Red 2G in aqueous solution was monitored at 556nm using UV-vis spectrometer. The degradation kinetics was found to follow pseudo-first order kinetics as seen from Langmuir- Hinshel wood model. Biomolecules capped ZnSe QDs were found to be effective sunlight responsive photocatalysts. Hence this study paves a way to use these biocompatible photocatalysts for the treatment of textile dye industry wastewater under solar light irradiation.