Rational decoration of porous organic polymers with silver nanoparticles for strategic reduction of hazardous nitroaryl compounds

Porous organic polymers (POPs) have garnered significant attention across various industries due to their promising physicochemical properties. In this study, we employ the classical Friedel-Crafts alkylation strategy to synthesize two types of porous organic polymers, namely Py-CH POP and TPA-CH POP, utilizing chloranil (CH), pyrene (Py), and triphenylamine (TPA) as building blocks. The Py-CH POP exhibits coaxial-like morphologies, uniform micropores, and a moderate surface area of up to 822 m² g⁻¹, along with excellent thermal stability, recording a char output of 69.6 wt%. Notably, these CH POPs contain dynamic hydroxyl groups that can effectively attract Ag⁺ ions from silver nitrate solutions and facilitate their reduction into silver nanoparticles, resulting in the formation of Ag@Py-CH and Ag@TPA-CH POP nanocomposites. These nanocomposites serve as efficient nano-catalysts for the reduction of hazardous p-nitrophenol (p-NP) to the safer p-aminophenol (p-AP) at ambient temperature. Importantly, the Ag@Py-CH and Ag@TPA-CH POP nanocomposites demonstrate comparable normalized reduction rates of p-NP, reaching up to 65.3 mg s⁻¹. The quaternary amine sites in the Ag@TPA-CH POP nanocomposites play a crucial role in this catalytic reaction, enhancing interactions with the phenolic hydroxyl groups of p-NP and thereby accelerating the reduction process compared to Ag@Py-CH POP. This strategy presents a dynamic approach for the reduction of p-NP, leading to the clean production of p-AP.