Interfacial Redox Polymerization of High Internal Phase Emulsion into Porous Monoliths for Continuous Flow Reduction of Nitroarenes

Nitroaromatic compounds are persistent environmental pollutants whose large-scale, efficient remediation remains challenging. Herein, we fabricate high-performance porous monoliths (PMs) via kinetics-regulated interfacial redox polymerization of polydivinylbenzene (PDVB) in high internal phase emulsions (HIPEs) for the continuous-flow reduction of nitroarenes. By strategically selecting oxidant/reductant pairs (e.g., benzoyl peroxide/vitamin C) to initiate polymerization at the oil-water interface, hierarchically porous structures were achieved with specific surface areas (SSA) reaching up to 467 m²·g⁻¹. Rapid interfacial initiation kinetics proved critical for generating abundant micro- and mesopores. Subsequent sulfonation introduced anchoring sites for the in situ deposition of silver nanoparticles (Ag NPs), yielding highly active PMs. The optimized monolithic catalyst exhibited exceptional activity and stability, maintaining over 90% conversion in the continuous-flow reduction of 4-nitrophenol for more than 24 h. This work demonstrates the efficacy of polymerization kinetics in tailoring porous architectures and underscores the promise of emulsion-templated monoliths in sustainable flow chemistry.