Photocatalytic degradation of methyl orange by cadmium oxide nanoparticles synthesized by the sol-gel method

Cadmium oxide (CdO) nanoparticles were synthesized successfully by use of the sol-gel reaction route using ethanol, in order to study their structural, optical, morphological and photocatalytic properties. A variety of techniques were used to characterize the CdO nanoparticles,including, XRD, UV–visible absorption spectroscopy,Scanning Electron Microscope (SEM) with energy dispersive X-ray Analysis (EDAX) and transmission electron microscopy (TEM). The resultant CdO nanoparticles were tested as a photocatalyst for the degradation of methyl orange (MO) under visible light.The results show that cadmium oxide nanoparticles were synthesized using a single phase through sol- gel method, with a crystal structure corresponding to a cubic system as confirmed by the XRD pattern. The surface morphology and chemical composition of the nanoparticles revealed a spherical morphology which lacked impurities. The band gap of the samples was calculated using the Tauc relationship; the energy band gap (Eg) was seen to increase with particle-size reduction. Photocatalytic degradation of methyl orange (MO) dye was tested under visible light exposure, with the best results being seen within 45 min; we conclude therefore that cadmium oxide nanoparticles are more effective photocatalysts at this nanoscale when synthesized by sol- gel method.