Facile fabrication of a multifunctional aramid nanofiber-based composite paper

Nowadays, aramid nanofibers (ANFs), split from macroscopic Kevlar yarns in dimethyl sulfoxide (DMSO) and potassium hydroxide (KOH), can be used as versatile building blocks for macroscopic materials. Herein, novel Ag nanoparticles (NPs)/ANFs composite papers were facilely fabricated with a simple solution-blending and vacuum-filtration assembly. By adeptly exploiting the in situ reduction of dimethyl sulfoxide (DMSO), the Ag NPs with mean size of ∼10.2 nm can be well dispersed onto the surfaces of ANFs with electrostatic attraction between Ag+ ions and amide anions. The as-prepared Ag/ANFs composite papers exhibited flexibility and good mechanical and conductive properties. Moreover, the Ag/ANFs composite papers can act as high-performance catalysts and excellent surface enhanced Raman spectroscopy (SERS) substrates. When the feed weight ratios of ANFs and AgNO3 achieved 1 : 10, the Ag/ANFs-1 : 10 composite papers showed outstanding catalytic performance for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4 with a high first-order rate constant of 0.33 min−1. In addition, the Ag/ANFs-1 : 5 composite paper exhibited highly active and sensitive SERS enhancement for Rhodamine 6G (R6G) molecules at a detection limit of 10−12 M.