Surface Engineering of CdS Quantum Dots for Photocatalytic Applications under Direct Sunlight

摘要

The photocatalytic ability of materials is globally studied and has many applications in the field of water purification, water splitting to produce hydrogen fuel and decomposition of toxic chemicals. Herein, we present CdS quantum dots (QDs) based efficient photocatalyst for potential photocatalytic applications by modifying its surface with different capping ligands or thin ZnO shell. For this purpose, we have prepared CdS quantum dots by passivating its surface with 3-mercaptopropionic acid (MPA), diphenylamine (DPA) and sodium succinate (SS) as capping agents. Additionally, Zn~(2+) doping or thin ZnO shell was grown in-situ on CdS cores with varied molar concentrations to observe its effect on photocatalytic activity. The study includes both the synthesis and characterization of the products along with their photocatalytic activity under direct sunlight (75000-90000 Lux). The effect of surface passivation of CdS QDs on their photocatalytic activity is discussed in detail. We also propose the possible mechanism for degradation of methylene blue using surface engineered CdS QDs.