BACKGROUNDDue to urbanization, the release of coloured wastewaters from textile industries into various environmental components has increased and is posing a threat to water bodies, so that their eradication from water bodies is necessary. To this end, semiconductor heterogeneous photocatalysis has emerged as a promising tool. However, as is well known, photocatalysis is a surface phenomenon; therefore it is strongly influenced by the fabrication technique employed for its synthesis. To address this issue, the present work demonstrates the dependence of synthetic methodology on photocatalytic efficacy of ZnO catalyst. RESULTSCatalytically active nanostructured ZnO particles were fabricated by five different facile methodologies. The fabricated nanostructures were critically analysed using techniques such as, X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller (BET) and photoluminescence (PL) spectrophotometer. The photocatalytic activity of different ZnO catalysts was compared by using safranin O dye as probe molecule. CONCLUSIONSZnO nanopowders fabricated by different methodologies were found to display different catalytic efficiencies, which was ascribed to large variations in specific surface area and rate of recombination of electrons and holes. Therefore, it is perceived that ZnO catalyst with best catalytic activity can be utilized to streamline the treatment of dye wastewater and is an ideal catalyst for a practical approach. (c) 2015 Society of Chemical Industry