Facile synthesis of carbon-supported silver nanoparticles as an efficient reduction catalyst for aqueous 2-methyl-p-nitrophenol

A facile technique for preparing the stable Ag nanoparticles (NPs) of 5–19 nm average size, anchored onto the heat-treated melamine-oxalic acid supramolecular complex is demonstrated. The synthesized material is tested for its catalytic efficiency towards reduction of aqueous 2-CH₃-p-nitrophenol to aminophenol using NaBH₄ as reducing agent at 28 °C. The reaction followed the pseudo first-order kinetics with respect to the nitrophenol concentrations, and the reaction rate constant was determined to be greater than the reported literature values. The superior catalytic activity of the catalyst was attributed to the combined roles of the Ag NPs and carbon substrate enriched with nitrogen functional groups. Notably, the prepared catalyst sustained its reactivity even after eight consecutive test runs without leaching of the metal NPs in the reaction mixture. The results clearly indicate the organic complex precursor-based carbon supported Ag NPs to be an efficient catalyst for removal of recalcitrant organic compounds from wastewater by reduction.