title: The effect of operational parameters on the photocatalytic degradation of Congo red organic dye using ZnO-CdS core-shell nano-structure coated on glass by Doctor Blade method.
abstract: Photocatalytic degradation of Congo red was investigated using ZnO-CdS core-shell nano-structure coated on glass by Doctor Blade method in aqueous solution under irradiation. Field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques were used for the morphological and structural characterization of ZnO-CdS core-shell nanostructures. XRD results showed diffractions of wurtzite zinc oxide core and wurtzite cadmium sulfide shell. FESEM results showed that nanoparticles are nearly hexagonal with an average diameter of about 50 nm. The effect of catalyst loading, UV-light irradiation time and solution pH on photocatalytic degradation of Congo red was studied and optimized values were obtained. Results showed that the employment of efficient photocatalyst and selection of optimal operational parameters may lead to complete decolorization of dye solutions. It was found that ZnO-CdS core-shell nano-structure is more favorable for the degradation of Congo red compare to pure ZnO or pure CdS due to lower electron hole recombination. The results showed that the photocatalytic degradation rate of Congo red is enhanced with increasing the content of ZnO up to ZnO(0.2 M)/CdS(0.075 M) which is reached 88.0% within 100 min irradiation.
authors.affiliation: Nanotechnology Laboratory, Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Islamic Republic of Iran. Electronic address: habibi@chem.ui.ac.ir.
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Habibi
authors.affiliation: Nanotechnology Laboratory, Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Islamic Republic of Iran.
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Rahmati
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D002384:Catalysis / Q000528:radiation effects; D004396:Coloring Agents / Q000737:chemistry*; D003224:Congo Red / Q000737:chemistry / Q000528:radiation effects*; D005898:Glass / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008027:Light; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry / Q000528:radiation effects; D010782:Photolysis; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D013440:Sulfides / Q000737:chemistry*; D014961:X-Ray Diffraction; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D004396:Coloring Agents; D009930:Organic Chemicals; D012996:Solutions; D013440:Sulfides; C034939:cadmium sulfide; D003224:Congo Red; D015034:Zinc Oxide
keywords: Degradation; Doctor Blade; Nanostructure; Photocatalytic; ZnO–CdS