High-performance visible light photocatalytic activity of cobalt (Co) doped CdS nanoparticles by wet chemical route

The role of cobalt (Co) dopant on structural, morphological, optical and photocatalytic properties of CdS nanoparticles were methodically reported. XRD analysis confirms that both pure and Co-doped CdS samples have cubic structure with no impurity phases detected and the results are good in agreement with the standard JCPDS value (Card No. 80-0019). TEM images reveal the spherical morphology with an average diameter of around 15-35 nm. A noticeable red-shift of absorption edge and bandgap narrowing can be attributed to the inclusion of cobalt ions and creation of defect levels in the bandgap, which is confirmed by UV analysis. Photoluminescence spectra show defects-free nature of synthesized nanoparticles. The functional groups and chemical interaction were determined by FTIR spectra. The photodegradation of MB dye with Co-doped CdS is more efficient under visible light compared to pure CdS. The 15 mol% Co-doped CdS acts as an efficient photocatalyst. The presence of Co2+ generated electron and holes and prolonged the recombination rate by introducing the temporary trapping sites, which essentially causes to improve the photocatalytic efficiency of the synthesized samples. The possible photocatalytic mechanism by Co doping is also discussed in detail.