Nickel oxide nanoparticles (NiO NPs) were synthesized using Ananas comosus leaf extract, and were characterized by UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, high resolution transmission electron microscopy (HRTEM), Energy dispersive X-ray (EDX) and X-ray diffraction (XRD) techniques. The FTIR analysis confirms the formation of the NiO with appearance of NiAO band at 468 cm(-1). The HRTEM analysis reveals that the NiO NPs size was in the range of 0.63-5.75 nm, with an average particle size of 1.42 +/- 1.76 nm. The EDX analysis shows clear peaks of Ni (2.7%) and O (5.74%) in the spectrum. The peaks of XRD analysis at (2 theta) 30 degrees, 43.89 degrees, 60.16 degrees, 77.95 degrees and 82.94 degrees were assigned to (1 1 1), (2 0 0), (2 2 0), (3 1 1) and (2 2 2) planes of the face-centered cubic (fcc) lattice of NiO. The photocatalytic properties of the NiO NPs were studied through the solid phase degradation of low-density polyethylene (LDPE) film. We observed that polymeric nanocomposites (NCs) showed a significant weight loss of 33 +/- 1.6% compared with the pure LDPE (8.6 +/- 0.7%) after exposure to solar light irradiation for 240 h, while the nanocomposites under the dark condition gave a weight reduction of 1.90 +/- 0.05 at the end of 240 h. The FTIR analysis also confirms the presence of carbonyl group, a degradation product of LDPE, with carbonyl index of 0.4. All these important factors showed that NiO is an effective photocatalyst. The study therefore suggests the incorporation of NiO NPs into the polymer matrix so as to enhance its photodegradation. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.