Photocatalytic Studies of La,Ce Co-Doped ZnO Nanoparticles
Syed Irtiqa, Atikur Rahman
Abstract
Abstract Zinc oxide nanoparticles were co-doped with varying concentrations of lanthanum (La) and cerium (Ce) ions using co-precipitation method. The resulting powders were calcined in a muffle furnace for 1 h at a temperature of 500°C to produce La,Ce-doped ZnO nanoparticles of varying stoichiometry viz. (Zn0.98La0.01Ce0.01O, Zn0.96La0.02Ce0.02O, Zn0.94La0.03Ce0.03O, and Zn0.92La0.04Ce0.04O). This method of co-doping is cost effective and does not require any complex procedure, equipment or inert gases. The synthesized samples were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) to study the size, phases and grain morphology. XRD patterns revealed the hexagonal wurtzite phase of the synthesized samples. The average size of the undoped and La,Ce co-doped ZnO nanoparticles, as calculated from XRD pattern, was found to be 25 nm. Further, the size of co-doped nanoparticles decreased significantly with increasing dopant concentration. Optical properties were studied through UV-Visible spectrophotometry. The photocatalytic activities of undoped and La,Ce co-doped ZnO nanoparticles were examined by observing the decomposition of Rhodamine B dye under UV lamp within 0–80 min. The Rhodamine B (RB) dye solution was efficiently photo-degraded within 35 min when using Zn0.92La0.04Ce0.04O as catalyst, mechanism of which has been thoroughly discussed below. Further, photoluminescence (PL) studies revealed the narrowing of band gap with increase in concentration of dopant ions as indicated by the red shift in the PL emission spectrum of co-doped nanoparticles.