A facile green synthesis of silver nanoparticle-decorated hydroxyapatite for efficient catalytic activity towards 4-nitrophenol reduction

Abstract: Silver nanoparticles (AgNPs) were gradually grown on a hydroxyapatite surface via a green self-reducing approach. Hydroxyapatite (HAP) was functionalized by dopamine and subsequently self-polymerized onto the HAP surface. Surface-adhered polydopamine acted as a self-reducing agent for the Ag⁺ ion; thus the process is considered to be green. The nanoparticles were evaluated by UV–visible spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The characterization data revealed that the AgNPs were spherical and crystalline, with an average size of 14.79 nm. The AgNP-decorated HAP was applied as a heterogeneous catalyst for the reduction of 4-nitrophenol (4-NP), which obeyed first-order reduction kinetics. Our reported catalyst can thus be used as an eco-friendly, efficient, cost-effective, and easy-to-fabricate heterogeneous catalyst system with potential use in industrial applications. Graphical Abstract: [Figure not available: see fulltext.].