GREEN SYNTHESIS AND CHARACTERIZATION OF NICKEL OXIDE NANOPARTICLES USING SALVIA OFFICINALIS LEAF EXTRACT AND EVALUATION OF THEIR CATALYTIC ACTIVITY IN HYDROGEN PEROXIDE DECOMPOSITION

This study aims to synthesize nickel oxide nanoparticles (NiO NPs) via a green method using aqueous Salvia officinalis (sage) leaf extract as a natural reducing and capping agent without the addition of any toxic chemicals. The synthesized nanoparticles were characterized using Fourier Transform Infrared Spectroscopy (FTIR) to identify the functional groups involved in the reduction and stabilization processes. The FTIR spectra showed characteristic peaks at 450.3 cm-1 and 418.5 cm-1, which are attributed to Ni-O bond vibrations, confirming the successful formation of NiO nanoparticles capped with plant phytochemicals. Furthermore, the catalytic activity of the prepared nanoparticles was evaluated in the decomposition of hydrogen peroxide (H2O2). The results showed that the green NiO NPs exhibited outstanding catalytic performance, with the decomposition efficiency progressively increasing over time to reach a maximum of 61.11% after 60 minutes. Kinetic modeling revealed that the catalytic degradation strictly followed pseudo-first-order kinetics, with a calculated reaction rate constant (k) of 0.014 min-1 and a strong coefficient of determination (R2 = 0.953). The findings indicate that sage extract provides an effective, low-cost, and sustainable route for the synthesis of NiO nanoparticles with excellent catalytic activity, making them promising candidates for future environmental and catalytic applications.