Highly visible light active Ag@TiO2 nanocomposites synthesized using an electrochemically active biofilm: a novel biogenic approach

Abstract

Titanium dioxide (TiO₂) nanoparticles were decorated with different amounts of silver nanoparticles (AgNPs) using an electrochemically active biofilm (EAB), which is a biogenic approach that leads to the formation of Ag@TiO₂ nanocomposites. UV-vis spectroscopy, photoluminescence, X-ray diffraction and electron microscopy showed AgNPs, 2–5 nm in size, well-dispersed and anchored to the TiO₂ surface and overall synthesis of Ag@TiO₂ nanocomposites. The photocatalytic performance of the as-synthesized Ag@TiO₂ nanocomposites was evaluated in terms of their efficiency for the photodecomposition of methylene blue (MB) in an aqueous solution under visible light irradiation. The nanocomposites showed exceptionally high photodecomposition efficiency (>7 times) compared to commercial TiO₂ (Sigma). The enhanced photocatalytic activity was attributed to the synergistic contribution of both a delayed charge recombination rate caused by the high electronic mobility of the AgNPs and the increased surface area originating from the nanometer sized AgNPs on TiO₂. The nanocomposites also showed exceptionally high stability and reusability under similar experimental conditions.