A facile route for the formation of shape-selective ZnO nanoarchitectures with superior photo-catalytic activity

A facile route for the formation of shape-selective ZnO nanoarchitectures has been demonstrated. ZnO nanostructures with variable sizes and shapes have been successfully synthesized using microwave (MW) heating for 5 min in an aqueous solution containing Zn(II) salt, CTAB, 2,7-DHN, and NaOH. The size and shape of the nanomaterials can be controlled by tuning the molar ratio of Zn(II) salt to CTAB and by controlling other reaction parameters. This process exclusively generates different shapes, e.g., ‘bacteria-like’, ‘larva-like’, ‘flake-like’ and ‘flower-like’, on a shorter time scale. The incorporation of alkaline 2,7-DHN plays a dual role; it controls the solution pH, and it directly affects the growth process of various ZnO crystal facets. Shape-selective ZnO nanostructures have been utilized as an excellent photo-catalyst for the degradation of methyl red (MeR) under UV illumination. Among the various shapes examined, the ‘flower-like’ nanostructure exhibited superior photo-catalyst activity due to its special structural features. Furthermore, the synthesized shape-selective ZnO nanostructures could be useful in large-scale heterogeneous photo-catalysis reactions to target wastewater contamination and environmental pollution. Moreover, they could also be useful as novel gas sensors and as suitable templates for the synthesis of other nanomaterials with uniform morphologies.