Synergistic Engineering of Nanoporous Structure and Surface Chemistry via Ultrasound-Assisted Oxidative Reactivation for Enhanced NO Adsorption

A “ultrasound-assisted oxidative reactivation” strategy was developed to precisely tune nanoscale porosity and interfacial chemistry of viscose-based activated carbon fibers (VACFs). Upon moderate H ₂ O ₂ oxidation, micropores in the 0.5-1.0 nm range were significantly enriched, accompanied by the generation of limited mesopores. Concurrently, surface functionalities evolved from C–O toward C = O and –OH groups, enhancing wall polarity and enabling synergistic physisorption–chemisorption of NO. Structure-activity relationship analysis revealed that efficient capture occurs when the kinetic diameter of NO (0.317 nm) matches pore sizes within the confinement window of 0.54–0.95 nm, whereas excessive alkaline activation collapsed micropores and deteriorated adsorption. Oxygenated groups further facilitated dipole and hydrogen-bond interactions, and under oxygen-containing atmospheres, catalyzed NO oxidation to NO ₂ with subsequent capture, amplifying removal capacity. The optimized condition (10 wt% H ₂ O ₂ , 80°C, 5 h) maximized micropore fraction and tailored surface chemistry without compromising the microcrystalline framework, resulting in superior NO adsorption. This work demonstrates an effective route for structural and interfacial engineering of VACFs, offering a broadly applicable basis for dual matching in molecular size and polarity toward multi-pollutant control.