Polydopamine-Mediated Gold Nanostructure-Decorated Electrospun Polycaprolactone Fibers for Photocatalytic Dye Degradation

Abstract

Metallic nanoparticle (NP)-decorated electrospun micro/nanofibers as an ideal photocatalytic system for the degradation of organic dyes may provide unique advantages in terms of 3D morphology with high surface area, well-controlled porosity, low cost, good interconnectivity, and excellent flexibility. However, novel, flexible, low-cost, and efficient fabrication methods are still demanded to obtain photocatalytic activity. In this report, for the first time, we propose gold NP (AuNP)-decorated electrospun poly(Ɛ-caprolactone) (PCL) membrane fibers through a conformal thin layer of polydopamine (PDA). Herein, PDA could reduce the Au³⁺ ions and enable the adsorption of AuNPs without using any reducing agent or seed material. The proposed system could degrade methylene blue after a 6-h of daylight exposure with a rate constant of 4.83 × 10⁻³ and 4.64 × 10⁻³ min⁻¹ for citrate-stabilized AuNPs and reduction of Au ions cases, respectively. Even after fifth cycle of usage, AuNP-decorated electrospun fibers showed reasonable catalytic activity without any significant change in their morphology and chemical content. For the case of rhodamine 6G, the same systems provided 55.2% and 64.1% of dye degradation within a 5-h exposure. The proposed system presents unique advantages regarding control, flexibility, low cost, and efficiency in various catalytic applications.