Hexagonal ZnO nanorods assembled flowers for photocatalytic dye degradation: Growth, structural and optical properties

A facile hydrothermal method was used to synthesize highly crystalline hexagonal ZnO nanorods assembled flowers by the reaction of zinc acetate and hexamethylenetetraamine (HMTA) at 105 degrees C. The morphological characterizations revealed that well defined ZnO nanorods were assembled into flowers morphology. X-rays diffraction patterns showed the highly crystalline nature of ZnO with hexagonal wurtzite structure. The structural and optical properties of hexagonal ZnO nanorods assembled flowers were measured by Fourier transform infra-red (FT-IR) and ultraviolet-visible (UV-Vis) measurements. The as-synthesized hexagonal ZnO nanorods assembled flowers were applied as an efficient photocatalyst for the photodegradation of organic dyes under UV-light irradiation. The methylene blue (MB) and rhodamine B (RhB) over the surface of hexagonal ZnO nanorods assembled flowers considerably degraded by similar to 91% and similar to 80% within 140 min respectively. The degradation rate constants were found to be k(app) (0.01313 mint(-1)) and k(app)(0.0104 mint(-1)) for MB and RhB dye respectively. The enhanced dye degradation might be attributed to the efficient charge separation and the large number of oxyradicals generation on the surface of the hexagonal ZnO nanorods assembled flowers. (C) 2013 Elsevier Ltd. All rights reserved.