Hydrothermally synthesized nano-carrots ZnO with CeO2 heterojunctions and their photocatalytic activity towards different organic pollutants

In current study, ZnO, CeO2, and a series of ZnO/CeO2 nano-composites with different Zn/Ce molar ratios (2:1, 4:1, 6:1, 8:1 and 10:1) are synthesized using a low-temperature hydrothermal method by varying synthesis processing time. X-ray diffraction pattern confirms the presence of hexagonal wurtzite ZnO and cubic CeO2 in synthesized ZnO/CeO2 nano-composites. The shape and morphology of ZnO/CeO2 nanostructures are uncovered by using field emission scanning electron microscope which shows the dispersion of CeO2 nanoparticles on the surface of ZnO nano-carrots. UV-Visible absorption spectra show a slight red shift in the absorption edge of binary oxides relative to pure oxide. X-ray photoelectron spectroscopy is examined to evident the formation of binary nano-composites and to predict the elemental states present in synthesized materials. All samples are employed for photocatalytic degradation of organic dye; rhodamine B (RhB) and a pesticide; triclopyr (TC) under UV light irradiation. The ZC-8 (Zn/Ce = 8:1) nano-composite possesses the highest photodegradation activity for the removal of RhB and TC among all the synthesized nano-composites. The photocatalytic removal of RhB and TC by varying the synthesis conditions such as time duration, pH, and molar ratio is also demonstrated. Furthermore, the role of active species in degradation process is also studied by performing radical scavenging assay. These photodegradation characteristics of ZnO/CeO2 nanostructures are valuable for environmental purification in various fields.