Tailoring the surface reactivity of plasmonic Au@TiO2 photocatalyst bio-based chitosan fiber towards cleaner of harmful water pollutants under visible-light irradiation

A plasmonic fiber was rationally designed as an efficient visible-light photocatalyst for the breakdown of organic and inorganic pollutants. The nanostructured Au@TiO2 with tuneable size was fabricated via a photodeposition method and then soaked in chitosan fiber to produce the photoactive plasmonic fiber. Based on the X-ray photoelectron spectroscopy results, some of Ti4+ was reduced in situ to Ti3+ when Au was added, which enhanced the stability and degradation performance. Different water pollutants, including methylene blue, carbofuran, and metronidazole, were completely attacked and degraded by the plasmonic fiber but not the Au@TiO2 photocatalyst. Moreover, the active plasmonic fiber could convert toxic chromium, Cr(VI), to biocompatible Cr(III) (similar to 98.9%) in the presence of citric acid within 21 min. In some cases, the catalytic performance remained almost unchanged, even after being recycled 8 times, with little loss (similar to 4.1%). The plasmonic fiber exhibited enhanced degradation activity, consistent kinetic behavior, catalytic reduction, and stability. This fabric photocatalyst should contribute to possible energy saving and environmental applications. (C) 2019 Elsevier Ltd. All rights reserved.