Green synthesis of a recyclable Ag/rGO@LS nanocomposite: utilizing Piper chaba stem extract for the one-pot immobilization of Ag/rGO onto luffa sponge scaffolds.

This study details the green and environmentally benign one-pot aqueous-phase synthesis of a silver nanoparticle/reduced graphene oxide immobilized luffa sponge (Ag/rGO@LS) ternary nanohybrid, utilizing Piper chaba stem extract. UV-vis, FTIR, Raman, and EDX confirmed the successful synthesis of the Ag/rGO binary nanocomposite. Spectra exhibited characteristic rGO (255 nm) and AgNP (407 nm) peaks. XRD validated the crystalline nature of the AgNPs, while SEM and TEM confirmed spherical particles (5-20 nm) anchored to exfoliated rGO sheets. Finally, XRD and SEM analyses verified the successful immobilization of the Ag/rGO binary system onto the LS framework and the formation of the Ag/rGO@LS ternary nanohybrid. The synthesized Ag/rGO nanocomposite demonstrated significant catalytic activity for the rapid reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4. This reduction was completed in 9 min, which is substantially faster than that achieved by AgNPs (24 min) or (AgNPs and rGO) the mixture (13 min). The enhanced catalytic performance is attributed to the synergistic properties facilitating electron transport. However, the Ag/rGO nanocomposite showed poor reusability (49% of reduction after 4th cycle). In contrast, the ternary Ag/rGO@LS hybrid showed excellent reusability (∼100% at 5th cycle) and retained its structural integrity as observed by SEM analysis. This work supports a sustainable route for producing functional nanomaterials for environmental remediation applications.