Enhanced solar light photocatalytic and antimicrobial activity of green noble metal/TiO2 nanorods

Abstract

Au/TiO2 and Pt/TiO2 nanocomposites have been processed using a green method. Au and Pt colloidal nanoparticles have been primarily synthesized by mixing their corresponding metal ions with an aqueous solution of corn husk extract, followed by anchoring on the as-synthesized TiO2 nanorods. The structural and morphological properties of green-prepared nanomaterials were systematically investigated by various techniques. The UV–VIS absorption measurements confirmed the formation of colloidal Au and Pt with λmax at 550 and 345 nm, respectively. TEM results show anchoring of spherical Au particles (40 nm) on TiO2 nanorods while smaller Pt particles have been observed on Pt/TiO2 composite. It has been shown that the highest visible light harvesting capability was earned for Au/TiO2 composite due to the surface plasmon resonance (SPR) of Au nanoparticles. The photocatalytic and antimicrobial activity of the nanomaterials was investigated for disinfection of Escherichia coli under solar light irradiation. The green synthesized nanocomposites showed enhanced solar light photocatalytic and antimicrobial activity. The best photocatalytic and antimicrobial activity was obtained for Au/TiO2. This evidences the enhanced SPR of Au nanoparticles and hence an enhancement in the solar light accessible by TiO2 so that a higher amount of reactive oxygen species can be generated, which enhances photocatalytic and antibacterial activity.