Synthesis and Characterization of Novel Mg(OH)_2/CdS Hetero Nanostructures for Sunlight-Induced Degradation of Phenolic Pollutant

Mg(OH)_2/CdS hetero nanostructures have been successfully synthesized by a novel precipitation method and the synthesis involves three steps. The first step involves the synthesis of Mg(OH)_2 nanoparticles using the homogeneous precipitation method. Then, surface-modifying agent citric acid was used to functionalize Mg (OH)_2. Finally, the cadmium sulfide (CdS) shell was deposited on the surface-modified Mg (OH)_2 by the co-precipitation method. The Mg (OH)_2/CdS hetero nanostructures were characterized using X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), and photoluminescence spectroscopy. DRS results indicated a blue shift of CdS bandgap absorption with respect to the bulk CdS. XPS results showed evidence for the binding energies of Mg(OH)_2, Cd, and S. The Mg (OH)_2/CdS hetero nanostructures were explored as a catalyst for sunlight-induced photocatalytic degradation of β- naphthol pollutant. The 0.2 mg/ mL batch of Mg (OH)_2/ CdS hetero nanostructures maintained at pH 8.5 showed maximum photodegradation efficiency (75 ± 2.1 %). Higher photocatalytic degradation efficiency for Mg(OH)_2/CdS hetero nanostructures could be due to the incorporation of CdS and increased reactive oxygen species (ROS) generation. The reusability of the Mg (OH)_2/CdS hetero nanostructures was also tested, indicating stability for up to three cycles without any loss of efficiency.