Enhanced photocatalytic activity of Cu-doped ZnO nanorods

• Published in: Solid state communications Vol. 152; no. 5; pp. 375 - 380
• Main Authors: Mohan, Rajneesh, Krishnamoorthy, Karthikeyan, Kim, Sang-Jae
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2012; Elsevier
• Subjects: A. ZnO nanorods; Catalysis; Catalytic reactions; Chemistry; D. Optical properties; D. Photocatalytic activity; E. Vapor transport method; Exact sciences and technology; General and physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; D. Photocatalytic activity; A. ZnO nanorods; D. Optical properties; E. Vapor transport method; Copper addition; A ZnO nanorods; Impurity density; Photocatalysis; Doping; Crystal growth from vapors; X ray diffraction; Spectral line shift; Reaction mechanism; Zinc oxide; Ultraviolet visible spectrum; Microstructure; Nanorod; Photochemical degradation
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2011.12.008

Cu-doped ZnO nanorods with different Cu concentrations were synthesized through the vapor transport method. The synthesized nanorods were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and UV–vis spectroscopy. The XRD results revealed that Cu was successfully doped into ZnO lattice. The FE-SEM images showed that the undoped ZnO has needle like morphology whereas Cu-doped ZnO samples have rod like morphology with an average diameter and length of 60–90 nm and 1.5–3 μm respectively. The red shift in band edge absorption peak in UV-vis absorbance spectrum with increasing Cu content also confirm the doping of Cu in ZnO nanorods. The photocatalytic activity of pure and Cu-doped ZnO samples was studied by the photodegradation of resazurin (Rz) dye. Both pure ZnO and the Cu-doped ZnO nanorods effectively removed the Rz in a short time. This photodegradation of Rz followed the pseudo-first-order reaction kinetics. ZnO nanorods with increasing Cu doping exhibit enhanced photocatalytic activity. The pseudo-first-order reaction rate constant for 15 % Cu-doped ZnO is equal to 10.17×10−2min−1 about double of that with pure ZnO. The increased photocatalytic activity of Cu-doped ZnO is attributed to intrinsic oxygen vacancies due to high surface to volume ratio in nanorods and extrinsic defect due to Cu doping. ► Cu-doped ZnO nanorods with different Cu concentrations were synthesized through vapor transport method.► The photocatalytic activity of these synthesized Cu-doped nanorods was studied by the photodegradation of resazurin dye.► Cu-doped ZnO nanorods effectively decomposed the resazurin in a short time compared to undoped ZnO.► The increased photocatalytic activity of Cu-doped ZnO is due to large intrinsic oxygen vacancies and extrinsic defects.