Natural cellulose fiber derived hollow-tubular-oriented polydopamine: In-situ formation of Ag nanoparticles for reduction of 4-nitrophenol.

A facile method was reported to achieve hollow-tubular-oriented polydopamine (HTO-PDA) layer using natural kapok fiber (KF) as the bio-template without any pretreatments by altering hydrophobic fiber into hydrophilic one. Subsequently, the HTO-PDA can be utilized for direct in-situ deposition of Ag nanoparticles (NPs). The structures of pristine fiber and HTO-PDA, as well as the resulting Ag NPs attached HTO-PDA (Ag@HTO-PDA) were well characterized by means of scanning electron microscopy (SEM) coupled energy dispersion spectrum (EDS), x-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. Due to the presence of relatively uniform Ag NPs attached onto PDA layer, Ag@KF-HTO-PDA shows stable catalytic ability towards the reduction of 4-nitrophenol into its amino derivative. Further, this method was used for facile fabrication of Calotropis gigantea fiber derived, surface-functionalized material. The experimental data demonstrated also its excellent catalytic efficiency towards 4-nitrophenol reduction.