Fading of rhodamine B using CdS quantum dots under solar light

Plate like cadmium sulfide (CdS) quantum dots were prepared by using β-cyclodextrin as reductant. Photoluminescence and uv-visible diffused reflectance spectroscopic techniques are used to investigate the optical property of CdS. The blue shifted emission of CdS at 469nm than the bulk particle is observed. The calculated band gap of CdS quantum dot is 2.62 eV showed a difference of 0.2 eV energy greater than that of bulk, indicating quantum size effect. The synthesized quantum dot has size in the range of 3.5nm with zinc blende crystallite structure. The plate like nanoclusters of CdS are inferred from SEM images. The photocatalytic efficiency of prepared CdS was tested for the degradation of rhodamine B dye using natural solar light. Effect of weight of catalyst, concentration of dye, pH of solution and reusability of catalyst were investigated. Existence of isosbestic point observation of high intense absorbance peak at 550nm at 300min in different matrix circumstances confirms the formation of leuco Rh B.