PEG-assisted morphological transformation of 3D flower-like ZnO to 1D micro-/nanorods and nanoparticles for enhanced photocatalytic activity

A simple, non-toxic, cost-effective and environmentally benign hydrothermal method has been used to synthesize ZnO with different morphologies. The effects of polyethylene glycol (PEG) addition on the structural, morphological, optical properties and photocatalytic performance of the ZnO nano-/microstructures were studied. The synthesized ZnO products were of highly crystalline hexagonal phase. The reorientation of crystal planes took place without any alteration of the crystalline phase with the addition of PEG. The morphology of the ZnO products could be controlled using appropriate amounts of PEG in the reaction precursor. Compositional analyses revealed that the obtained products were phase pure with a 1:1 atomic ratio of Zn versus O. The band gap of ZnO without PEG additive was determined to be 3.36 eV and changed slightly with the addition of PEG. The photoluminescence (PL) study revealed defect-related emissions and the enhancement or decreases in PL intensity depended significantly on the amount of the PEG addition. The photocatalytic activity of the ZnO catalyst was evaluated for methylene blue dye, which shows 98% degradation within 60 min.