Preparation of CuO nanopowders and their catalytic activity in photodegradation of Rhodamine-B

•The nano-sized CuO powders were synthesized via co-precipitation and reflux (gel to crystalline) methods respectively.•Optical properties of synthesized CuO nanopowders were studied.•Photocatalytic degradation of Rhodamine-B was investigated based on CuO nanopowders photocatalytic activity.•Flower like CuO showed highest photocatalytic activity than other towards RhB degradation.•Possible mechanism of photocatalytic degradation of Rhodamine-B was suggested.

CuO nanopowders have been successfully synthesized in two different morphologies from same precursor using a facile gel to crystalline (reflux) and co-precipitation synthesis routes. SEM and TEM observations indicate that the morphology of the products depends on preparation technology, while XRD shows the formation of CuO nanocrystals with monoclinic crystal system in both cases. A comparison of morphological characterization of CuO nanopowders showed flower-like and aggregated nanoparticles in the form of clusters using reflux and co-precipitation techniques, respectively. Photocatalytic activity of the products in the aqueous solution of Rhodamine-B has been investigated under UV-light for a given time using UV–visible spectroscopy and the mineralization of organic substance was measured by total organic carbon (TOC) analysis. It was observed that the photocatalytic activity in the presence of flower-like CuO nanopowders was higher than that of observed with aggregated nanoparticles. Also the mechanisms for the formation of CuO nanopowders and the obtained results of photocatalytic degradation of Rhodamine-B are discussed.

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