Green and reusable Ag/AgCl-TiO2 nanocomposites for visible light-triggered dye degradation

Abstract

• Ag/AgCl-TiO 2 nanocomposites are synthesized in a green, single-step process. • Satureja khuzistanica extract acts as a reducing agent and nanocomposite stabilizer. • More than 99% methyl orange is degraded under visible light irradiation. • High-efficiency TiO 2 -based photocatalysts developed for engineering and environmental applications. Ag/AgCl-TiO 2 plasmonic nanocomposites (NCs) are endowed with excellent visible-light photocatalytic activity. However, only a few studies investigated environmentally friendly approaches to their synthesis. In this work, Ag/AgCl-TiO 2 NCs at five different compositions were prepared in a single-step process by a green and cost-effective route, using Satureja khuzistanica Jamzad aqueous extract. The role of the aqueous plant extract as a reducing and stabilizing agent, and the formation of the NCs were evidenced by several techniques, including FT-IR, EDS, SEM, HRTEM, elemental mapping, and XRD. The morphological analysis demonstrated that the NCs formed nanoaggregates with an average size of 30 nm. The synthesized Ag/AgCl-TiO 2 NCs displayed a remarkable photoactivity in the visible light region, as confirmed by the significantly higher degradation rates of methyl orange (MO) compared to TiO 2 . In particular, the 15% Ag/TiO 2 molar ratio sample revealed a MO degradation efficiency higher than 99% under visible light, and retained high photocatalytic activity even after several degradations runs. Overall, the green, cost-effective, and scalable synthesis of Ag/AgCl-TiO 2 NCs herein reported provides a novel, more sustainable strategy for the high-efficiency modification of TiO 2 photocatalyst in engineering and other environmental applications.