TiO2@Au@CoMn2O4 core–shell nanorods for photo‒electrochemical and photocatalytic activity for decomposition of toxic organic compounds and photo reduction of Cr6+ ion

Abstract

TiO2@Au@CoMn2O4 core‒shell nanorods (NRs) were prepared using a novel and facile hydrothermal process. The UV–Visible absorption and emission spectra, Transmission electron microscopy (TEM) image, X-ray photoelectron spectroscopy (XPS) spectra and X-ray powder diffraction (XRD) pattern confirmed the formation of core-shell nanocomposite. The TiO2@Au@CoMn2O4 core-shell nanocomposites show superior photocatalytic degradation efficiency for degradation of toxic organic dyes such as rhodamine b, methylene blue and methylene orange. Taping experiments, using scavengers, were studied to explore the role of charge carriers and radicals in the photocatalytic degradation process. The catalytic activity of TiO2@Au@CoMn2O4 core–shell nanocomposite was further reconnoitred and compared for the photocatalytic reduction of Cr+6 ion. The superiority in the photocatalytic activity of TiO2@Au@CoMn2O4 core–shell nanocomposite is attributed to efficient harvesting of solar light, charge carrier separation at the interface and SPR generated hot electrons from Au nanoparticle. The photo‒electrochemical photocurrent generated under illumination by solar light established effective charge carrier generation and separation. The TiO2@Au@CoMn2O4 core-shell NRs thin film shows about 17.5 times higher photocurrent generation than the TiO2 NRs.