Stearic acid-coated plasmonic Ag nanoparticles as a dual catalyst for enhanced NiO chemo and photo catalysis

Abstract

The phenomenon of Localized Surface Plasmon Resonance (LSPR) in plasmonic metal nanoparticles causes a strong absorption of visible light and leads to the generation of hot electrons on the surface and the creation of localized electromagnetic fields near the surface. This characteristic enhances the catalytic performance of a plasmonic metal Ag–NiO nanocomposite (NiO-SNP) when exposed to low-flux visible light irradiation. The NiO-SNP was synthesized using a simple and cost-effective ultrasonication method. Its structural, morphological, and optical properties were analyzed, confirming the formation of nanocomposites. The proximity of stearic acid-coated Ag nanoparticles (SNP) acts as visible light-harvesting antennas, promoting NiO's activity for effectively reducing paracetamol (PM) drugs. The improved catalytic property is attributed to an electron relay effect, while the strong electromagnetic fields generated by irradiated Ag nanoparticles facilitate the concentration of PM molecules at active sites, leading to accelerated reaction rates. NiO-SNP2 demonstrates remarkable PM degradation: 97 % in tap water and 82.6 % in deionized water within 10 min, demonstrating its catalytic effectiveness. The plasmonic SNP mechanism in NiO-SNP1 nanocomposites enhances photocatalytic efficiency by up to 90 %, owing to efficient charge separation and transfer, resulting in a notable 1.5-fold increase in PM degradation. The degradation kinetics follow a pseudo-first-order model, with rate constants (k) ranging from approximately 0.059 to 0.6104 min⁻1, underscoring the crucial role of Ag nanoparticles in enhancing photocatalytic activity and degradation efficiency. Catalysis and visible light photocatalysis are significantly improved with increasing concentrations of NiO and SNP, respectively. This research could inspire a new approach to transforming traditional metal catalysis into plasmonic-metal catalysis.