The current study aims to prepare nickel nanoparticles (NiNPs) using aqueous Sargassum cervicorne (SC) extract and Nickel (II) chloride hexahydrate (NiCl 2 .6H 2 O) as starting materials. The bio-reduction of NiNPs was confirmed using ultra-violet visible (UV–Vis) spectroscopy by observing the loss of the Ni 2+ peak at 394 nm in the UV–vis spectrum of NiNPs. The Fourier transform infrared (FTIR) spectral analysis confirms the formation and capping of NiNPs by functional groups such as hydroxyl group, nitriles, pyridyl moiety, carboxylates, and sulfate ester. The X-ray diffraction (XRD) analysis unveiled that NiNPs exhibited a polycrystalline structure with an average crystalline size of 9.3 nm. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis results have shown that all the nanoparticles formed were spherical in the nano-range. The thermal analysis of SC-based NiNPs was carried out using thermal gravimetric analysis (TGA) and the Brunauer Emmett and Teller (BET) analysis showed a surface area of 3.4198 m²/g. The NiNPs were applied as a catalyst for the degradation of azo dyes like Congo Red (CR), Methyl Orange (MO), and Methyl Red (MR). The NiNPs catalysed the degradation of all three azo-dyes (CR, MO, and MR) in the presence of aqueous NaBH 4, which was monitored by UV–visible spectroscopy. The overall results indicated maximum degradation for Methyl Orange (0.1 mM) of about 94.76% in 30 min at the catalyst load of 200 (µg/µL) with a kₐₚₚ value of 0.10992 min −1 and with a significant reusability up to 4 cycles. Thus, the fabrication of NiNPs using water and water-soluble components of SC extract as reducing agents could be stated as a novel single-pot synthesis approach for catalyst preparation.
Anwar et al. (Tue,) studied this question.