Comprehensive Characterization of <scp>NiO</scp> / <scp>PMMA</scp> Polymeric Nanocomposite Films: Physicochemical, Thermal, Optical, and Photocatalytic Properties

ABSTRACT This research employs the solution casting method to produce NiO/PMMA polymeric nanocomposite films, which are subsequently used to fabricate flexible photocatalytic membranes with varying nickel oxide nanoparticle (NiO NP) concentrations (0.25–3 wt%). XRD analysis confirmed the cubic structure of NiO, with the most intense (200) peak indicating a crystallite size of 19.42 nm. The Williamson–Hall method estimated the crystallite size to be 48.65 nm with a strain of 2.85 × 10 −3 . XPS results confirmed the presence of Ni +2 with characteristic Ni 2p 3/2 and Ni 2p 1/2 peaks at 856.55 and 874.94 eV, respectively. TGA revealed enhanced thermal stability, with 3 wt% NiO showing a decomposition temperature of 360.45°C. Optical studies revealed a redshift in the absorption edge and a decrease in the bandgap from 5.08 to 4.88 eV (direct) and from 4.77 to 4.46 eV (indirect). The lower band gap and higher optical constants of NiO/PMMA nanocomposites are correlated with the PL enhancement and redshift. Under UVC light, 3 wt% NiO/PMMA exhibited the highest MB dye degradation efficiency of 99.6% within 90 min. These nanocomposites demonstrate high potential for photocatalytic water purification.