Photocatalytic activity of Ag@TiO2 modified Co-Al Layered double hydroxide for the degradation of dye under visible/sunlight

Abstract

Eliminating the dyes from industrial wastewater is crucial for protecting aquatic ecosystems and reducing carcinogenic risks to human life. Herein, the work outlines an efficient ternary photocatalyst [Ag10TiO2-LDH] that was synthesized by the deposition of Ag plasmonic NPs and TiO2-P25 over the surface of LDH. The ternary composite is characterized by XRD, FTIR, DRS, DLS, PL, FESEM, EDS, and HRTEM. The major impact of incorporating Ag (silver) and LDH (layered double hydroxides) in the modification of TiO2 (titanium dioxide) photocatalysts is the reduction of the band gap that allows the photocatalyst to utilize the solar spectrum. The photoactivity is estimated by the degradation of Reactive Orange 16 dye under sunlight and visible light radiation. The optimized Ag110TiO2-LDH nanocomposite shows superior photoactivity by degrading RO-16 (92.3%, 87.2%) within 120 minutes under sunlight and visible light irradiation with rate constant value (k = 2.113 × 10-2 min-1, 1.712 × 10-2 min-1). Whereas the degradation observed was (54.05%, 49.94%) for bare LDH, and (71.29%, 67.97%) for binary composite under sunlight and visible light respectively. This increased photocatalytic efficiency is ascribed to the greater surface area, quick charge movement that enables the TiO2-LDH charge transfer process, and LSPR of plasmonic Ag nanoparticles. The TOC test result states that after being exposed to light for 120 minutes, the percent mineralization of RO-16 was decreased by 50% and 66.4% under visible light and sunlight, respectively. An effective charge transfer and photodegradation mechanism were directed by photoluminescence analysis (PL), band gap energy, DLS, and Zeta potential.