GO and Co(NO3)(2) were respectively used as rGO and Co3O4 precursors for preparing magnetically separable Co(3)O(4)NPs attached Co(3)O(4)NPs@rGO nanocomposites by a straightforward sol-gel technique. To characterize the nanocomposite materials, FESEM, EDX, elemental mapping, XRD, FTIR, Raman spectroscopy, UV-vis, VSM and BET were employed. When exposed to UV rays, the nanocomposite showed extraordinary photocatalytic degradation of MO dye. According to the measurements of photocatalytic activity, the highly efficient photocatalytic efficiency of the nanocomposite could be attributed to preventing electron-hole recombination by highly effective electron transfer between rGO and semiconductor NPs. The nanocomposite succeeded in the efficient degradation of MO dye, even after five photocatalytic cycles. (c) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.